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Sample records for herd size interactions

  1. Why herd size matters - mitigating the effects of livestock crashes.

    Marius Warg Næss

    Full Text Available Analysing the effect of pastoral risk management strategies provides insights into a system of subsistence that have persevered in marginal areas for hundreds to thousands of years and may shed light into the future of around 200 million households in the face of climate change. This study investigated the efficiency of herd accumulation as a buffer strategy by analysing changes in livestock holdings during an environmental crisis in the Saami reindeer husbandry in Norway. We found a positive relationship between: (1 pre- and post-collapse herd size; and (2 pre-collapse herd size and the number of animals lost during the collapse, indicating that herd accumulation is an effective but costly strategy. Policies that fail to incorporate the risk-beneficial aspect of herd accumulation will have a limited effect and may indeed fail entirely. In the context of climate change, official policies that incorporate pastoral risk management strategies may be the only solution for ensuring their continued existence.

  2. Impact if hyperprolific line of litter size in multiplication herd

    Zdeněk Tvrdoň

    2009-01-01

    Full Text Available The hyperprolific line is considered to be maximally effective in pursuit of progress in sow’s reproduction. Hyperprolific line efficiency is commonly evaluated in regard of breeding herd progress. We decided to study how effective it is with respect to increasing of litter size in multiplication herd. Our study is specific by using the data from practice, concretely it is based on the information about the ancestor of sows in multiplication herd. The ancestors could be the member either hyperprolific line or normal line. The information about performances of sows breed in multiplication herd was known. The mixed linear models in SAS for Windows 9.1.2. were conducted to statistical analysis. Our results indicated that no significant effect on litter size was achieved by selection criteria used in the hyperprolific line creation. In studied population no differences between TNB, NBA or NW were found on the 1st as well as on the 1st–5th litters. As we have mentioned above, the study is specific by using the data from practice. Therefore the studied population size is limited. It is necessary to take into consideration when the results are applied. Nevertheless, the results shown that other studies with larger population should be done to reevaluate the selection criteria.

  3. Microbial Herd Protection Mediated by Antagonistic Interaction in Polymicrobial Communities

    Wong, Megan J. Q.; Liang, Xiaoye; Smart, Matt; Tang, Le; Moore, Richard; Ingalls, Brian

    2016-01-01

    ABSTRACT In host and natural environments, microbes often exist in complex multispecies communities. The molecular mechanisms through which such communities develop and persist, despite significant antagonistic interactions between species, are not well understood. The type VI secretion system (T6SS) is a lethal weapon commonly employed by Gram-negative bacteria to inhibit neighboring species through the delivery of toxic effectors. It is well established that intraspecies protection is conferred by immunity proteins that neutralize effector toxicities. In contrast, the mechanisms for interspecies protection are not clear. Here we use two T6SS-active antagonistic bacterial species, Aeromonas hydrophila and Vibrio cholerae, to demonstrate that interspecies protection is dependent on effectors. A. hydrophila and V. cholerae do not share conserved immunity genes but could coexist equally in a mixture. However, mutants lacking the T6SS or effectors were effectively eliminated by the competing wild-type strain. Time-lapse microscopic analyses showed that mutually lethal interactions drive the segregation of mixed species into distinct single-species clusters by eliminating interspersed single cells. Cluster formation provides herd protection by abolishing lethal interactions inside each cluster and restricting the interactions to the boundary. Using an agent-based modeling approach, we simulated the antagonistic interactions of two hypothetical species. The resulting simulations recapitulated our experimental observations. These results provide mechanistic insights regarding the general role of microbial weapons in determining the structures of complex multispecies communities. IMPORTANCE Investigating the warfare of microbes allows us to better understand the ecological relationships in complex microbial communities such as the human microbiota. Here we use the T6SS, a deadly bacterial weapon, as a model to demonstrate the importance of lethal interactions in

  4. Microbial herd protection mediated by antagonistic interaction in polymicrobial communities.

    Wong, Megan; Liang, Xiaoye; Smart, Matt; Tang, Le; Moore, Richard; Ingalls, Brian; Dong, Tao G

    2016-09-16

    In the host and natural environments, microbes often exist in complex multispecies communities. The molecular mechanisms through which such communities develop and persist - despite significant antagonistic interactions between species - are not well understood. The type VI secretion system (T6SS) is a lethal weapon commonly employed by Gram-negative bacteria to inhibit neighboring species through delivery of toxic effectors. It is well established that intra-species protection is conferred by immunity proteins that neutralize effector toxicities. By contrast, the mechanisms for interspecies protection are not clear. Here we use two T6SS active antagonistic bacteria, Aeromonas hydrophila (AH) and Vibrio cholerae (VC), to demonstrate that interspecies protection is dependent on effectors. AH and VC do not share conserved immunity genes but could equally co-exist in a mixture. However, mutants lacking the T6SS or effectors were effectively eliminated by the other competing wild type. Time-lapse microscopy analyses show that mutually lethal interactions drive the segregation of mixed species into distinct single-species clusters by eliminating interspersed single cells. Cluster formation provides herd protection by abolishing lethal interaction inside each cluster and restricting it to the boundary. Using an agent-based modeling approach, we simulated the antagonistic interactions of two hypothetical species. The resulting simulations recapitulate our experimental observation. These results provide mechanistic insights for the general role of microbial weapons in determining the structures of complex multispecies communities. Investigating the warfare of microbes allows us to better understand the ecological relationships in complex microbial communities such as the human microbiota. Here we use the T6SS, a deadly bacterial weapon, as a model to demonstrate the importance of lethal interactions in determining community structures and exchange of genetic materials

  5. The porcupine caribou herd

    Griffith, Brad; Douglas, David C.; Walsh, Noreen E.; Young, Donald D.; McCabe, Thomas R.; Russell, Donald E.; White, Robert G.; Cameron, Raymond D.; Whitten, Kenneth R.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Documentation of the natural range of variation in ecological, life history, and physiological characteristics of caribou (Rangifer tarandus) of the Porcupine caribou herd is a necessary base for detecting or predicting any potential effects of industrial development on the performance (e.g., distribution, demography, weight-gain of individuals) of the herd. To demonstrate an effect of development, post-development performance must differ from pre-development performance while accounting for any natural environmental trends.We had 2 working hypotheses for our investigations: 1) performance of the Porcupine caribou herd was associated with environmental patterns and habitat quality, and 2) access to important habitats was a key influence on demography.We sought to document the range of natural variation in habitat conditions, herd size, demography (defined here as survival and reproduction), sources and magnitude of mortality, distribution, habitat use, and weight gain and loss, and to develop an understanding of the interactions among these characteristics of the herd.In addition, we investigated ways that we could use this background information, combined with auxiliary information from the adjacent Central Arctic caribou herd, to predict the direction and magnitude of any potential effects of industrial oil development in the 1002 Area of the Arctic National Wildlife Refuge on Porcupine caribou herd calf survival on the herd's calving grounds during June.

  6. Estimating age ratios and size of pacific walrus herds on coastal haulouts using video imaging.

    Daniel H Monson

    Full Text Available During Arctic summers, sea ice provides resting habitat for Pacific walruses as it drifts over foraging areas in the eastern Chukchi Sea. Climate-driven reductions in sea ice have recently created ice-free conditions in the Chukchi Sea by late summer causing walruses to rest at coastal haulouts along the Chukotka and Alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. Walrus age can be determined from the ratio of tusk length to snout dimensions. We evaluated use of images obtained from a gyro-stabilized video system mounted on a helicopter flying at high altitudes (to avoid disturbance to classify the sex and age of walruses hauled out on Alaska beaches in 2010-2011. We were able to classify 95% of randomly selected individuals to either an 8- or 3-category age class, and we found measurement-based age classifications were more repeatable than visual classifications when using images presenting the correct head profile. Herd density at coastal haulouts averaged 0.88 walruses/m(2 (std. err. = 0.02, herd size ranged from 8,300 to 19,400 (CV 0.03-0.06 and we documented ∼30,000 animals along ∼1 km of beach in 2011. Within the herds, dependent walruses (0-2 yr-olds tended to be located closer to water, and this tendency became more pronounced as the herd spent more time on the beach. Therefore, unbiased estimation of herd age-ratios will require a sampling design that allows for spatial and temporal structuring. In addition, randomly sampling walruses available at the edge of the herd for other purposes (e.g., tagging, biopsying will not sample walruses with an age structure representative of the herd. Sea ice losses are projected to continue, and population age structure data collected with aerial videography at coastal haulouts may provide demographic information vital to ongoing efforts to understand effects of climate change on this species.

  7. Dairy farmers with larger herd sizes adopt more precision dairy technologies.

    Gargiulo, J I; Eastwood, C R; Garcia, S C; Lyons, N A

    2018-06-01

    An increase in the average herd size on Australian dairy farms has also increased the labor and animal management pressure on farmers, thus potentially encouraging the adoption of precision technologies for enhanced management control. A survey was undertaken in 2015 in Australia to identify the relationship between herd size, current precision technology adoption, and perception of the future of precision technologies. Additionally, differences between farmers and service providers in relation to perception of future precision technology adoption were also investigated. Responses from 199 dairy farmers, and 102 service providers, were collected between May and August 2015 via an anonymous Internet-based questionnaire. Of the 199 dairy farmer responses, 10.4% corresponded to farms that had fewer than 150 cows, 37.7% had 151 to 300 cows, 35.5% had 301 to 500 cows; 6.0% had 501 to 700 cows, and 10.4% had more than 701 cows. The results showed that farmers with more than 500 cows adopted between 2 and 5 times more specific precision technologies, such as automatic cup removers, automatic milk plant wash systems, electronic cow identification systems and herd management software, when compared with smaller farms. Only minor differences were detected in perception of the future of precision technologies between either herd size or farmers and service providers. In particular, service providers expected a higher adoption of automatic milking and walk over weighing systems than farmers. Currently, the adoption of precision technology has mostly been of the type that reduces labor needs; however, respondents indicated that by 2025 adoption of data capturing technology for monitoring farm system parameters would be increased. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  8. The inclusion of herd-year-season by sire interaction in the ...

    The inclusion of herd-year-season by sire interaction in the estimation of genetic parameters in Bonsmara cattle. FWC Neser, KV Konstantinov, GJ Erasmus. Abstract. No abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  9. Associations between strain, herd size, age at first calving, culling reason and lifetime performance characteristics in Holstein-Friesian cows.

    Adamczyk, K; Makulska, J; Jagusiak, W; Węglarz, A

    2017-02-01

    Cow longevity and lifetime performance traits are good indicators of breeding effectiveness and animal welfare. They are also interrelated with the economics of dairy herd. Unfortunately, a high milk yield is often associated with deteriorated cow health and fertility and, consequently, with an increased culling rate. This situation, observed also in the Polish population of Holstein-Friesian cattle, inspired us to undertake a study on the associations between some factors and lifetime performance characteristics. The data set consisted of the records on 135 496 cows, including 131 526 of the Black and White strain (BW), and 3970 of the Red and White strain (RW) covered by performance recording and culled in 2012. It was found that cows of the BW strain and those from the largest herds (>100 cows) reached higher lifetime and mean daily energy-corrected milk (ECM) yields than cows of the RW strain and those from smaller herds culled at a similar age. Cows youngest at first calving (reasons for cow culling. Cow longevity and lifetime productivity were considerably affected by the interactions between the studied factors.

  10. Dynamical Models of Interactions between Herds Forage and Water Resources in Sahelian Region

    Jean Jules Tewa

    2014-01-01

    Full Text Available Optimal foraging is one of the capital topics nowadays in Sahelian region. The vast majority of feed consumed by ruminants in Sahelian region is still formed by natural pastures. Pastoral constraints are the high variability of available forage and drinking water in space and especially in time (highly seasonal, interannual variability and the scarcity of water resources. The mobility is the main functional and opportunistic adaptation to these constraints. Our goal in this paper is to formalize two dynamical models for interactions between a herd of domesticate animals, forage resources, and water resources inside a given Sahelian area, in order to confirm, explain, and predict by mathematical models some observations about pastoralism in Sahelian region. These models in some contexts can be similar to predator-prey models as forage and water resources can be considered as preys and herd’s animals as predators. These models exhibit very rich dynamics, since it predicts abrupt changes in consumer behaviour and disponibility of forage or water resources. The dynamics exhibits a possible coexistence between herd, resources, and water with alternative peaks in their trajectories.

  11. Dairy Herd Management Types Assessed from Indicators of Health, Reproduction, Replacement Milk Production

    Enevoldsen, Carsten; Hindhede, Jens; Kristensen, T.

    1996-01-01

    Variables related to health, reproduction, replacement milk production in 111 Danish dairy herds were studied with factor analysis. The objectives were to identify management types and to assess the relevance of those types for herd milk production. Median herd size and total milk production were...... 59 cows and 7100 kg of energy-corrected milk, respectively. Based on cow data, 22 herd variables were defined. A factor analysis identified 10 first-order factors and 5 second-order factors. The latter factors were valid indicators of replacement intensity, variability of milk production, potential...... for peak milk production, disease a complex pattern related to herd size and age, cow size live cattle sales. The potential for peak milk production, replacement intensity variability of milk production were strong predictors of herd milk production. Interactions with herd size were important. The derived...

  12. Population decline in the Delta caribou herd with reference to other Alaskan herds

    Patrick Valkenburg et al.

    1996-01-01

    Full Text Available After growing continuously for nearly 15 years, the Delta caribou herd began to decline in 1989. Most other Interior Alaskan herds also began declining. In the Delta herd, and in other herds, the declines were caused primarily by high summer mortality of calves and increased natural mortality of adult females. Other minor causes included increased winter mortality of calves, and reduced parturition rates of 3-year-old and older females. The decline in the Delta herd also coincided with increased wolf (Canis lupus numbers, winters with deeper than normal snow, and warm summers. Mean body weight of annual samples of 10-month-old female calves was consistently low during the decline. Except in some of the smallest Interior Alaskan herds, we conclude that evidence for population regulation in Alaskan caribou is weak, and that herds are likely to fluctuate within a wide range of densities due to complex interactions of predation and weather. Unless wolf numbers are influenced by man, the size of a caribou herd in a given year is likely to be largely a function of its size during the previous population low and the number of years of favorable weather in the interim.

  13. Field Investigation on the Prevalence of Trypanosomiasis in Camels in Relation to Sex, Age, Breed and Herd Size

    B. Bhutto, J. A. Gadahi, G. Shah1, P. Dewani2 and A.G. Arijo

    2010-07-01

    Full Text Available Blood samples were collected from 240 camels (183 male and 57 female of four breeds from six districts of Sindh. An overall infection was determined as 11.25%. Species of Trypanosoma was identified as Trypanosoma evansi. District wise infection was found to be 2.5, 7.5, 12.5, 15.00, 22.5 and 7.5% in Hyderabad, Mirpur Khas, Umerkot, Badin, Thatta and Larkana, respectively. A higher infection was found in females (15.79% as compared to males (9.84%. Highest (14.96% infection was noted in age group >7 years, followed by 8.57 and 4.65% in 3 to 7 years and less than to 3 years old camels, respectively. Four breeds of camels were surveyed and the highest infection rate was found in Sakrai breed (21.82%, followed by 16.67, 6.15 and 5.95% in Kharai, Sindhi and Dhati breeds respectively. When herd size was considered, infection rate was 1.67, 6.67, 15.00 and 21.67% in herds possessing 1 to 5, 6 to 10, 11 to 20 and more than 20 animals, respectively.

  14. Consultancy to dairy farmers relating to animal health and herd health management on small- and medium-sized farms.

    Pothmann, H; Nechanitzky, K; Sturmlechner, F; Drillich, M

    2014-02-01

    The objectives of this study were to obtain information about animal health challenges for dairy farmers of small- and medium-sized herds and about the fields in which consultancy services should be improved. The hyperlink to an internet-based survey was sent to 9,021 farmers in Austria. The survey included questions about the participants and their farms, about who is consulting with the farmers with regard to animal health, feeding, sire selection, construction of barns and animal husbandry, about animal health issues farmers find most challenging, and about their demands for improved consultancy services. The questionnaire was completed anonymously. Analyses were stratified by milk yield (categorized) and whether farmers worked full-time or part-time. The overall response rate was 11.3% (n=1,018). The majority of farms kept less than 20 cows (54.0%) or 20 to 50 cows (40.1%). With regard to animal health, the veterinarian was the most important consultant for the majority of farmers (84.6%). On issues related to feeding, sire selection, and stable construction, the veterinarian was seen as a less important consultant than specialists in these fields (20.4, 11.6, and 7.9% suggested the veterinarian as an important consultant in these areas). The survey indicated that reproductive disorders, udder disease, poor conception rate, lameness, and calf diarrhea represent the most important challenges to farmers. Of these, concerns about calf diarrhea were affected by milk yield of the herds and management. More high- than low-yielding farms (11.7 vs. 6.4%) and more full-time than part-time managed herds (9.6 vs.4.3%) regarded calf diarrhea as an important problem. Farmers would welcome improved consultancy with regard to fertility, feeding, and sire selection. The results indicated which animal health issues farmers find particularly challenging and displayed which areas farmers require improved consultancy services. Veterinarians and organizations offering consultancy

  15. Interactions between optimal replacement policies and feeding strategies in dairy herds

    Vargas, B.; Herrero, M.; Arendonk, van J.A.M.

    2001-01-01

    A dynamic performance model was integrated with a model that optimised culling and insemination policies in dairy herds using dynamic programming. The performance model estimated daily feed intake, milk yield and body weight change of dairy cows on the basis of availability and quality of feed and

  16. Conception Rate and Litter Size in Multiparous Sows after Intrauterine Insemination Using Frozen-Thawed Boar Semen in a Commercial Swine Herd in Thailand

    CHANAPIWAT, Panida; OLANRATMANEE, Em-On; KAEOKET, Kampon; TUMMARUK, Padet

    2014-01-01

    ABSTRACT The aim of the present study was to determine the conception rate and litter size in sows after fixed time intra-uterine insemination using frozen-thawed boar semen in a commercial swine herd in Thailand. Sixty-nine Landrace multiparous sows were randomly allocated into two groups, including control (n=36) and treatment (n=33). The control sows were inseminated with extended fresh semen (3 × 109 motile sperm/dose, 100 ml) at 24, 36 and 48 hr after the onset of estrus. The treatment s...

  17. Culling from the herd's perspective-Exploring herd-level management factors and culling rates in Québec dairy herds.

    Haine, Denis; Delgado, Hector; Cue, Roger; Sewalem, Asheber; Wade, Kevin; Lacroix, René; Lefebvre, Daniel; Arsenault, Julie; Bouchard, Émile; Dubuc, Jocelyn

    2017-11-01

    The relationship between cows' health, reproductive performance or disorders and their longevity is well demonstrated in the literature. However these associations at the cow level might not hold true at the herd level, and herd-level variables can modify cow-level outcomes independently of the cows' characteristics. The interaction between cow-level and herd-level variables is a relevant issue for understanding the culling of dairy cows. However it requires the appropriate group-level variables to assess any contextual effect. Based on 10 years of health and production data, the objectives of this paper are:(a) to quantify the culling rates of dairy herds in Québec; (b) to determine the profiles of the herds based on herd-level factors, such as demographics, reproduction, production and health indicators, and whether these profiles can be related to herd culling rates for use as potential contextual variables in multilevel modelling of culling risk. A retrospective longitudinal study was conducted on data from dairy herds in Québec, Canada, by extracting health information events from the dairy herd health management software used by most Québec producers and their veterinarians. Data were extracted for all lactations taking place between January 1st, 2001 and December 31st, 2010. A total of 432,733 lactations from 156,409 cows out of 763 herds were available for analysis. Thirty cow-level variables were aggregated for each herd and years of follow-up, and their relationship was investigated by Multiple Factor Analysis (MFA). The overall annual culling rate was 32%, with a 95% confidence interval (CI) of [31.6%,32.5%]. The dairy sale rate by 60 days in milk (DIM) was 3.2% [2.8%,3.6%]. The annual culling rate within 60 DIM was 8.2% [7.9%,8.4%]. The explained variance for each axis from the MFA was very low: 14.8% for the first axis and 13.1% for the second. From the MFA results, we conclude there is no relationship between the groups of herd-level indicators

  18. Communication in production animal medicine: modelling a complex interaction with the example of dairy herd health medicine

    Kleen Joachim L

    2011-07-01

    Full Text Available Abstract Background The importance of communication skills in veterinary medicine is increasingly recognised. Appropriate communication skills towards the client are of utmost importance in both companion animal practice and production animal field and consultancy work. The need for building a relationship with the client, alongside developing a structure for the consultation is widely recognised and applies to both types of veterinary practice. Results Veterinary advisory practice in production animal medicine is, however, characterised by a more complex communication on different levels. While the person-orientated communication is a permanent process between veterinarian and client with a rather personal perspective and defines the roles of interaction, the problem-orientated communication deals with emerging difficulties; the objective is to solve an acute health problem. The solution - orientated communication is a form of communication in which both veterinarian and client address longstanding situations or problems with the objective to improve herd health and subsequently productivity performance. All three forms of communication overlap. Conclusions Based on this model, it appears useful for a veterinary practice to offer both a curative and an advisory service, but to keep these two separated when deemed appropriate. In veterinary education, the strategies and techniques necessary for solution orientated communication should be included in the teaching of communication skills.

  19. Communication in production animal medicine: modelling a complex interaction with the example of dairy herd health medicine.

    Kleen, Joachim L; Atkinson, Owen; Noordhuizen, Jos Ptm

    2011-07-20

    The importance of communication skills in veterinary medicine is increasingly recognised. Appropriate communication skills towards the client are of utmost importance in both companion animal practice and production animal field and consultancy work. The need for building a relationship with the client, alongside developing a structure for the consultation is widely recognised and applies to both types of veterinary practice. Veterinary advisory practice in production animal medicine is, however, characterised by a more complex communication on different levels. While the person-orientated communication is a permanent process between veterinarian and client with a rather personal perspective and defines the roles of interaction, the problem-orientated communication deals with emerging difficulties; the objective is to solve an acute health problem. The solution - orientated communication is a form of communication in which both veterinarian and client address longstanding situations or problems with the objective to improve herd health and subsequently productivity performance. All three forms of communication overlap. Based on this model, it appears useful for a veterinary practice to offer both a curative and an advisory service, but to keep these two separated when deemed appropriate. In veterinary education, the strategies and techniques necessary for solution orientated communication should be included in the teaching of communication skills.

  20. Pension funds' herding

    Broeders, D.; Chen, D.; Minderhoud, P.; Schudel, W.

    2016-01-01

    This paper uses unique and detailed transaction data to analyse herding behavior among pension funds. We distinguish between weak, semi strong and strong herding behaviour. Weak herding occurs if pension funds have similar rebalancing strategies. Semi strong herding arises when pension funds react

  1. On the surveillance for animal diseases in small herds

    Greiner, Matthias; Dekker, Aldo

    2005-01-01

    Small herds may present a problem in surveillance for infectious animal diseases because typical levels of a within-herd design prevalence are not directly applicable. We suggest a definition of small herds as those smaller than 2/(within-herd design prevalence) on the basis that such herds would...... be expected to have less than two (i.e. only one) infected animals. Consequently, the probability of detecting small herds cannot be improved by choosing a larger sample size within the herd. We derive necessary sample sizes of herds and the probability ("confidence") of detecting disease within a stratum...... conservative (lower) estimates of the confidence for a given sample size and should therefore be preferred....

  2. Forecasting metal prices: Do forecasters herd?

    Pierdzioch, C.; Rulke, J. C.; Stadtmann, G.

    2013-01-01

    We analyze more than 20,000 forecasts of nine metal prices at four different forecast horizons. We document that forecasts are heterogeneous and report that anti-herding appears to be a source of this heterogeneity. Forecaster anti-herding reflects strategic interactions among forecasters...

  3. E-herding : patterns of online mass-behavior

    Langley, D.J.; Hoeve, M.; Ortt, J.R.; Pals, N.

    2012-01-01

    Herding is convergent social behavior driven by inter-personal interaction, without centralized coordination. Herding in the online setting, which we call e-herding, is important for marketing scholars and practitioners because of its potential impact on product adoption and brand image and because

  4. A Financial Market Model Incorporating Herd Behaviour.

    Wray, Christopher M; Bishop, Steven R

    2016-01-01

    Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents' accumulating information over a bounded state-space), and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents' accumulating information over an unbounded state-space), numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock returns and the market

  5. A Financial Market Model Incorporating Herd Behaviour.

    Christopher M Wray

    Full Text Available Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents' accumulating information over a bounded state-space, and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents' accumulating information over an unbounded state-space, numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock

  6. A Financial Market Model Incorporating Herd Behaviour

    2016-01-01

    Herd behaviour in financial markets is a recurring phenomenon that exacerbates asset price volatility, and is considered a possible contributor to market fragility. While numerous studies investigate herd behaviour in financial markets, it is often considered without reference to the pricing of financial instruments or other market dynamics. Here, a trader interaction model based upon informational cascades in the presence of information thresholds is used to construct a new model of asset price returns that allows for both quiescent and herd-like regimes. Agent interaction is modelled using a stochastic pulse-coupled network, parametrised by information thresholds and a network coupling probability. Agents may possess either one or two information thresholds that, in each case, determine the number of distinct states an agent may occupy before trading takes place. In the case where agents possess two thresholds (labelled as the finite state-space model, corresponding to agents’ accumulating information over a bounded state-space), and where coupling strength is maximal, an asymptotic expression for the cascade-size probability is derived and shown to follow a power law when a critical value of network coupling probability is attained. For a range of model parameters, a mixture of negative binomial distributions is used to approximate the cascade-size distribution. This approximation is subsequently used to express the volatility of model price returns in terms of the model parameter which controls the network coupling probability. In the case where agents possess a single pulse-coupling threshold (labelled as the semi-infinite state-space model corresponding to agents’ accumulating information over an unbounded state-space), numerical evidence is presented that demonstrates volatility clustering and long-memory patterns in the volatility of asset returns. Finally, output from the model is compared to both the distribution of historical stock returns and the

  7. INFORMATION ASYMMETRY AND HERDING BEHAVIOR

    Puput Tri Komalasari

    2016-06-01

    Full Text Available Conceptually, the stock market is strong form efficient in the long term. However, in practice, there are various forms of market anomalies that undermine the accuracy of the efficient market hypothesis. One factor suspected as the cause of market inefficiency is herding behavior. Investors herd when they imitate the actions of other investors. This behavior occurs when there is a continuous interaction among rational investors that prevents them from seeking information about market fundamentals. This study provides new insights by including information asymmetry as a moderating variable. This research examines the phenomenon of herding behavior in the Indonesia Stock Exchange as well as examines directly the effect of information asymmetry on herding behavior. The period of study is 2008 using time series of daily stocks data that actively traded in the capital market. Results of this study find that investor tends to follow market consensus when price changes at the low level, but when there is large price swing market participant acts independently from other investors. Interestingly, this study finds that information asymmetry is a necessary condition for the existence of herding behavior.

  8. Conception rate and litter size in multiparous sows after intrauterine insemination using frozen-thawed boar semen in a commercial swine herd in Thailand.

    Chanapiwat, Panida; Olanratmanee, Em-On; Kaeoket, Kampon; Tummaruk, Padet

    2014-10-01

    The aim of the present study was to determine the conception rate and litter size in sows after fixed time intra-uterine insemination using frozen-thawed boar semen in a commercial swine herd in Thailand. Sixty-nine Landrace multiparous sows were randomly allocated into two groups, including control (n=36) and treatment (n=33). The control sows were inseminated with extended fresh semen (3 × 10(9) motile sperm/dose, 100 ml) at 24, 36 and 48 hr after the onset of estrus. The treatment sows were inseminated with frozen-thawed semen (2 × 10(9) motile sperm/dose, 20 ml) at 24 and 36 hr after induction of ovulation by human chorionic gonadotropin. All inseminations were carried out by using an intra-uterine insemination technique. The time of ovulation was determined by using transrectal real-time B-mode ultrasonography. The conception rate, farrowing rate, total number of piglets born/litter (TB) and number of piglets born alive/litter (BA) were evaluated. The sows inseminated with extended fresh semen yield a higher TB (10.8 versus 9.0 piglets/l, P=0.015) and tended to have a higher conception rate (88.9% versus 75.8%, P=0.150) than sows inseminated with frozen-thawed semen. In conclusion, insemination using frozen-thawed boar semen can be practiced with convinced fertility under field conditions by fixed-time intrauterine insemination with 2 × 10(9) sperm/ dose of 20 ml at 24 and 36 hr after the onset of estrus.

  9. Conception Rate and Litter Size in Multiparous Sows after Intrauterine Insemination Using Frozen-Thawed Boar Semen in a Commercial Swine Herd in Thailand

    CHANAPIWAT, Panida; OLANRATMANEE, Em-On; KAEOKET, Kampon; TUMMARUK, Padet

    2014-01-01

    ABSTRACT The aim of the present study was to determine the conception rate and litter size in sows after fixed time intra-uterine insemination using frozen-thawed boar semen in a commercial swine herd in Thailand. Sixty-nine Landrace multiparous sows were randomly allocated into two groups, including control (n=36) and treatment (n=33). The control sows were inseminated with extended fresh semen (3 × 109 motile sperm/dose, 100 ml) at 24, 36 and 48 hr after the onset of estrus. The treatment sows were inseminated with frozen-thawed semen (2 × 109 motile sperm/dose, 20 ml) at 24 and 36 hr after induction of ovulation by human chorionic gonadotropin. All inseminations were carried out by using an intra-uterine insemination technique. The time of ovulation was determined by using transrectal real-time B-mode ultrasonography. The conception rate, farrowing rate, total number of piglets born/litter (TB) and number of piglets born alive/litter (BA) were evaluated. The sows inseminated with extended fresh semen yield a higher TB (10.8 versus 9.0 piglets/l, P=0.015) and tended to have a higher conception rate (88.9% versus 75.8%, P=0.150) than sows inseminated with frozen-thawed semen. In conclusion, insemination using frozen-thawed boar semen can be practiced with convinced fertility under field conditions by fixed-time intrauterine insemination with 2 × 109 sperm/ dose of 20 ml at 24 and 36 hr after the onset of estrus. PMID:24954517

  10. Family Size, Interaction, Affect and Stress

    Nye, F. Ivan; And Others

    1970-01-01

    Synthesizes previous research on relationship of family size to attitudes. Reduces findings to four propositions and submits these propositions to additional tests utilizing secondary data from two large surveys. Substantively, families of three or four children rank lower in all of the analyses than do families with one or two children. Presented…

  11. The influence of herd size, conspecific risk, and predation risk on the vigilance of elk (Cervus elaphus) in Yellowstone National Park, and, Interest, learning, and a thematic biology course

    Lung, Mark A.

    This dissertation is a composite of biological and educational research. The biological research concerns Rocky Mountain elk (Cervus elaphus ) behavior. The educational research presents ideas and findings on the influence of a thematic general biology course on student interest and perception of learning. The dissertation begins with a Preface that attempts to bring the ideas presented in later chapters together. Chapter One is a review of the literature concerning sociality, social behaviors, and elk biology. It summarizes current research literature as a means of introduction to Chapter Two. Chapter Two presents findings concerning the effects of herd size, predation risk, and the risk of being near conspecifics on two behaviors commonly associated with social animals---vigilance and aggression. Vigilance and aggression were measured in elk in Yellowstone National Park in two regions that varied in their presence of elk predators (wolves---Canis lupus, and grizzly bears---Ursus arctos) and in two seasons (spring and fall) that varied in the risks of being near conspecifics. Overall, male and female elk responded very differently. Male elk adjust their vigilance and aggression in response to changes in conspecific risk, but not to changes in predation risk. Female elk adjust their vigilance in response to changes in predation risk, but not to changes in conspecific risk. Males show no response in vigilance to changes in herd size. Non-reproductive females, however, adjust their levels of vigilance with changes in herd size in high risk regions. Interestingly, in the spring, vigilance decreases with increasing herd size, but in the fall, vigilance increases with increasing herd size. Chapter Three presents findings concerning the influence of a thematic course design on student perceptions of interest and teaming in a non-major's biology course (Bins 100: Concepts of Biology). I compared responses on student evaluations from two sections of Bios 100 taught in a

  12. Temporal trends in reproductive performance in Irish dairy herds and associated risk factors

    Mee John F

    2004-03-01

    Full Text Available Irish dairy herd fertility has been declining since the 1980s. The extent, nature and causes of this decline in fertility and the current status of Irish dairy herd fertility were described. An increase in calving interval of approximately one day per year has been recorded. The principal components of this trend have been an increased incidence of postpartum endocrinopathies, reduced expression of oestrus and a fall in conception rate. Both submission rate and calving-to-service interval have increased slightly over time. Significant risk factors associated with these trends have been strain substitution within the Holstein-Friesian breed and single trait selection for milk production. Critically, these changes have been reflected in loss of body condition. Contributory factors included increased herd size and possibly increased use of DIYAI. The most recent Irish study showed that 48% of cows conceived to first service and 14% of cows were not pregnant at the end of the industry-average 15-week spring breeding season. However, the top quartile of herds achieved a first-service conception rate of 59%, illustrating the wide variation between herds. These phenotypic trends were attributed to both genetic and environmental factors and their interactions. Recent Irish dairy herd fertility performance falls short of the targets set for seasonal compact calving.

  13. Seroprevalence of border disease in Danish sheep and goat herds

    Tegtmeier, C.; Stryhn, H.; Uttenthal, Åse

    2000-01-01

    A study was conducted in 1994-96 with the aim of assessing the serological prevalence of Border Disease (BD) among sheep and goats in Denmark and to investigate possible relations to herd factors. From each of 1000 herds, 2 blood samples were obtained from animals older than 1 year. The examination.......50. There was no difference between the prevalence in sheep and goat herds. Records for well over half of the herds could be combined with data from the Danish Central Husbandry Register. No association between occurrence of ED and herd size was found. Cattle were registered as contemporarily present on 135 out of 521 herds...... which was shown to be strongly associated to ED. The estimated herd prevalences of ED among farms with and without contemporary cattle were 0.24 and 0.042, respectively....

  14. Interaction between carbon fibers and polymer sizing: Influence of fiber surface chemistry and sizing reactivity

    Moosburger-Will, Judith; Bauer, Matthias; Laukmanis, Eva; Horny, Robert; Wetjen, Denise; Manske, Tamara; Schmidt-Stein, Felix; Töpker, Jochen; Horn, Siegfried

    2018-05-01

    Different aspects of the interaction of carbon fibers and epoxy-based polymer sizings are investigated, e.g. the wetting behavior, the strength of adhesion between fiber and sizing, and the thermal stability of the sizing layer. The influence of carbon fiber surface chemistry and sizing reactivity is investigated using fibers of different degree of anodic oxidation and sizings with different number of reactive epoxy groups per molecule. Wetting of the carbon fibers by the sizing dispersion is found to be specified by both, the degree of fiber activation and the sizing reactivity. In contrast, adhesion strength between fibers and sizing is dominated by the surface chemistry of the carbon fibers. Here, the number of surface oxygen groups seems to be the limiting factor. We also find that the sizing and the additional functionalities induced by anodic oxidation are removed by thermal treatment at 600 °C, leaving the carbon fiber in its original state after carbonization.

  15. Interaction between numbers and size during visual search

    Krause, F.; Bekkering, H.; Pratt, J.; Lindemann, O.

    2017-01-01

    The current study investigates an interaction between numbers and physical size (i.e. size congruity) in visual search. In three experiments, participants had to detect a physically large (or small) target item among physically small (or large) distractors in a search task comprising single-digit

  16. Interaction between numbers and size during visual search

    Krause, Florian; Bekkering, Harold; Pratt, Jay; Lindemann, Oliver

    2016-01-01

    The current study investigates an interaction between numbers and physical size (i.e. size congruity) in visual search. In three experiments, participants had to detect a physically large (or small) target item among physically small (or large) distractors in a search task comprising single-digit numbers. The relative numerical size of the digits was varied, such that the target item was either among the numerically large or small numbers in the search display and the relation between numeric...

  17. Population dynamics of caribou herds in southwestern Alaska

    Patrick Valkenburg

    2003-04-01

    Full Text Available The five naturally occurring and one transplanted caribou (Rangifer tarandus granti herd in southwestern Alaska composed about 20% of Alaska's caribou population in 2001. All five of the naturally occurring herds fluctuated considerably in size between the late 1800s and 2001 and for some herds the data provide an indication of long-term periodic (40-50 year fluctuations. At the present time, the Unimak (UCH and Southern Alaska Peninsula (SAP are recovering from population declines, the Northern Alaska Peninsula Herd (NAP appears to be nearing the end of a protracted decline, and the Mulchatna Herd (MCH appears to now be declining after 20 years of rapid growth. The remaining naturally occurring herd (Kilbuck has virtually disappeared. Nutrition had a significant effect on the size of 4-month-old and 10-month-old calves in the NAP and the Nushagak Peninsula Herd (NPCH and probably also on population growth in at least 4 (SAP, NAP, NPCH, and MCH of the six caribou herds in southwestern Alaska. Predation does not appear to be sufficient to keep caribou herds in southwestern Alaska from expanding, probably because rabies is endemic in red foxes (Vulpes vulpes and is periodically transferred to wolves (Canis lupus and other canids. However, we found evidence that pneumonia and hoof rot may result in significant mortality of caribou in southwestern Alaska, whereas there is no evidence that disease is important in the dynamics of Interior herds. Cooperative conservation programs, such as the Kilbuck Caribou Management Plan, can be successful in restraining traditional harvest and promoting growth in caribou herds. In southwestern Alaska we also found evidence that small caribou herds can be swamped and assimilated by large herds, and fidelity to traditional calving areas can be lost.

  18. Benchmarking dairy herd health status using routinely recorded herd summary data.

    Parker Gaddis, K L; Cole, J B; Clay, J S; Maltecca, C

    2016-02-01

    Genetic improvement of dairy cattle health through the use of producer-recorded data has been determined to be feasible. Low estimated heritabilities indicate that genetic progress will be slow. Variation observed in lowly heritable traits can largely be attributed to nongenetic factors, such as the environment. More rapid improvement of dairy cattle health may be attainable if herd health programs incorporate environmental and managerial aspects. More than 1,100 herd characteristics are regularly recorded on farm test-days. We combined these data with producer-recorded health event data, and parametric and nonparametric models were used to benchmark herd and cow health status. Health events were grouped into 3 categories for analyses: mastitis, reproductive, and metabolic. Both herd incidence and individual incidence were used as dependent variables. Models implemented included stepwise logistic regression, support vector machines, and random forests. At both the herd and individual levels, random forest models attained the highest accuracy for predicting health status in all health event categories when evaluated with 10-fold cross-validation. Accuracy (SD) ranged from 0.61 (0.04) to 0.63 (0.04) when using random forest models at the herd level. Accuracy of prediction (SD) at the individual cow level ranged from 0.87 (0.06) to 0.93 (0.001) with random forest models. Highly significant variables and key words from logistic regression and random forest models were also investigated. All models identified several of the same key factors for each health event category, including movement out of the herd, size of the herd, and weather-related variables. We concluded that benchmarking health status using routinely collected herd data is feasible. Nonparametric models were better suited to handle this complex data with numerous variables. These data mining techniques were able to perform prediction of health status and could add evidence to personal experience in herd

  19. Abortion studies in Iranian dairy herds

    Keshavarzi, Hamideh; Sadeghi-Sefidmazgi, Ali; Kristensen, Anders Ringgaard

    2017-01-01

    Abortions, especially those occurring during late pregnancy, lead to considerable economic losses. To estimate the financial losses related to pregnancy loss, at first the influencing factors on abortion need to be identified. Thus, the objective of this study was to determine and quantify the risk...... factors and their interactions for abortion in Iranian dairy herds. Based on data from 6 commercial herds, logistic regression was used to identify the risk factors for abortion. The basic time unit used in the study was a 3-week period corresponding to an estrus cycle. Thus, stage of lactation...... factors were herd effect, pregnancy stage, previous abortion, calving month, cumulative fat corrected milk (FCM) yield level, mastitis in current 3-weeks in milk, accumulated number of mastitis and all 2-way interactions. Pregnancy tests were performed between 35 and 50 days after insemination. Abortion...

  20. The scaling of human interactions with city size.

    Schläpfer, Markus; Bettencourt, Luís M A; Grauwin, Sébastian; Raschke, Mathias; Claxton, Rob; Smoreda, Zbigniew; West, Geoffrey B; Ratti, Carlo

    2014-09-06

    The size of cities is known to play a fundamental role in social and economic life. Yet, its relation to the structure of the underlying network of human interactions has not been investigated empirically in detail. In this paper, we map society-wide communication networks to the urban areas of two European countries. We show that both the total number of contacts and the total communication activity grow superlinearly with city population size, according to well-defined scaling relations and resulting from a multiplicative increase that affects most citizens. Perhaps surprisingly, however, the probability that an individual's contacts are also connected with each other remains largely unaffected. These empirical results predict a systematic and scale-invariant acceleration of interaction-based spreading phenomena as cities get bigger, which is numerically confirmed by applying epidemiological models to the studied networks. Our findings should provide a microscopic basis towards understanding the superlinear increase of different socioeconomic quantities with city size, that applies to almost all urban systems and includes, for instance, the creation of new inventions or the prevalence of certain contagious diseases. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  1. Prevalence, risk factors and spatial analysis of liver fluke infections in Danish cattle herds

    Olsen, Abbey; Frankena, Klaas; Bødker, Rene

    2015-01-01

    fitted the observed spatial pattern. Results: During the investigated period (2011-2013), an increase in annual herd prevalence was noted (2011-25.6%; 2012-28.4%; 2013-29.3%). The spatial analysis suggested significant clustering of positive and negative herds. Presence of streams, wetlands and pastures...... on farms showed a significant association with the presence of infection in cattle herds. Buying animals from positive herds was a risk factor on conventional farms. Additionally, risk of being infected with Fasciola hepatica was higher in non-dairy herds of medium size (>= 30 and ... to dairy and large (>= 100) cattle herds. The observed spatial pattern could be reproduced by predictions of the risk factor model. Conclusions: This study showed an increase in annual herd level prevalence (2011 to 2013) indicating that an increasing proportion of herds are infected with Fasciola hepatica...

  2. Interaction of equal-size bubbles in shear flow.

    Prakash, Jai; Lavrenteva, Olga M; Byk, Leonid; Nir, Avinoam

    2013-04-01

    The inertia-induced forces on two identical spherical bubbles in a simple shear flow at small but finite Reynolds number, for the case when the bubbles are within each other's inner viscous region, are calculated making use of the reciprocal theorem. This interaction force is further employed to model the dynamics of air bubbles injected to a viscous fluid sheared in a Couette device at the first shear flow instability where the bubbles are trapped inside the stable Taylor vortex. It was shown that, during a long time scale, the inertial interaction between the bubbles in the primary shear flow drives them away from each other and, as a result, equal-size bubbles eventually assume an ordered string with equal separation distances between all neighbors. We report on experiments showing the dynamic evolution of various numbers of bubbles. The results of the theory are in good agreement with the experimental observations.

  3. Online Anti-Brand Herds

    Langley, David J.; Tan, Chee-Wee; Worm, Daniël

    The online environment offers a fertile breeding ground for anti-brand herds of disgruntled consumers. Firms are often caught off guard by the unpredictability of such herds and, as a consequence, are forced into a reactive, defensive stance. We conduct a social media analysis that aims to shed...... light on the formation, growth, and dissolution of online anti-brand herds. First we expand on the concept of environmental turbulence to advance core properties unique to online herd behavior. Next, based on evidence gathered from 40 online anti-brand herd episodes targeting two prominent firms from...... the Netherlands, we develop an analytical model to investigate drivers of herd formation, growth, and dissolution. Finally, combining environmental turbulence literature with our empirical findings, we derive a novel typology of online anti-brand herd behaviors, and put forward six propositions to guide theory...

  4. Cubicle Refusal in Norwegian Dairy Herds

    Myren HJ

    2001-03-01

    Full Text Available In order to survey the behaviour of choosing the alley area instead of a cubicle as a lying place (cubicle refusal, a questionnaire was sent to the 273 dairy farms in Norway known to keep cows in cubicle housing systems. Sixty-six percent of the farmers contacted were included in the study. The median herd size was 18 cows (range 7–118. More than 85% of the herds had sheds providing one or more cubicles per cow. The mean herd occurrence of cubicle refusal was 6%, but showed great variation (range 0–55%. Regression analysis showed a significant association between rearing heifers in slatted floor pens and an increased cubicle refusal occurrence (p = 0.02, R2 = 0.05, while herd size, use of litter, or cubicle-to-animal ratio were not found to be associated with cubicle refusal. The practice of rearing heifers in slatted floor pens accounted for about one half of the observed cubicle refusal (etiologic fraction = 0.51.

  5. Quantifying the role of Trojan dams in the between-herd spread of bovine viral diarrhoea virus (BVDv) in Ireland.

    Reardon, Fiona; Graham, David A; Clegg, Tracy A; Tratalos, Jamie A; O'Sullivan, Padraig; More, Simon J

    2018-04-01

    A compulsory national programme to eradicate bovine viral diarrhoea virus (BVDv) began in Ireland on 1 January, 2013. The objective of the current study was to quantify the role of Trojan dams (animal(s) not persistently infected (PI) with BVDv but carrying PI foetus(es) and introduced to the herd while pregnant with the PI foetus(es)) in the farm-to-farm spread of BVDv in Ireland, and to identify herd-level risk factors for producing or introducing a Trojan dam. The study population included all BVD+ calves born in Ireland between 1 January, 2013 and 31 December, 2015, along with their dams. BVD+ calves included all calves on the national programme database with an initial positive or inconclusive virus test, without a confirmatory re-test (status BVDPOS) and those with an initial positive or inconclusive test and a positive confirmatory test (status BVDPI). The Trojan status of dams was determined after considering their history of movement and of potential BVDV exposure, relative to a defined window of susceptibility (WOS; days 30-120 of gestation). During 2013-15, there were 29,422 BVD+ birth events to dams that were not themselves BVD+, including 2526 (8.6%) most-likely attributable to Trojan dams. The percentage of these birth events attributable to Trojan dams was significantly different (P Trojan dam. In 2014 and 2015, the percentages were 11.8% and 13.3%, respectively. In 2013, in 7.8% of herds with one or more BVD+ birth to non-BVD+ dams, all of these births were attributable to Trojan dams. In 2014 and 2015, the percentages were 9.2% and 10.7%, respectively. A logistic GEE regression identified dam parity, herd size and an interaction between herd type and season as significant predictors for the birth of a BVD+ calf to a Trojan dam. Significant predictors for the sale of a Trojan dam from BVD+ herds included those selling more than one pregnant female and those with more than 2 BVD+ animals in the herd. Introduction of pregnant adult females is a

  6. High female mortality resulting in herd collapse in free-ranging domesticated reindeer (Rangifer tarandus tarandus in Sweden.

    Birgitta Åhman

    Full Text Available Reindeer herding in Sweden is a form of pastoralism practised by the indigenous Sámi population. The economy is mainly based on meat production. Herd size is generally regulated by harvest in order not to overuse grazing ranges and keep a productive herd. Nonetheless, herd growth and room for harvest is currently small in many areas. Negative herd growth and low harvest rate were observed in one of two herds in a reindeer herding community in Central Sweden. The herds (A and B used the same ranges from April until the autumn gathering in October-December, but were separated on different ranges over winter. Analyses of capture-recapture for 723 adult female reindeer over five years (2007-2012 revealed high annual losses (7.1% and 18.4%, for herd A and B respectively. A continuing decline in the total reindeer number in herd B demonstrated an inability to maintain the herd size in spite of a very small harvest. An estimated breakpoint for when herd size cannot be kept stable confirmed that the observed female mortality rate in herd B represented a state of herd collapse. Lower calving success in herd B compared to A indicated differences in winter foraging conditions. However, we found only minor differences in animal body condition between the herds in autumn. We found no evidence that a lower autumn body mass generally increased the risk for a female of dying from one autumn to the next. We conclude that the prime driver of the on-going collapse of herd B is not high animal density or poor body condition. Accidents or disease seem unlikely as major causes of mortality. Predation, primarily by lynx and wolverine, appears to be the most plausible reason for the high female mortality and state of collapse in the studied reindeer herding community.

  7. A global optimization algorithm inspired in the behavior of selfish herds.

    Fausto, Fernando; Cuevas, Erik; Valdivia, Arturo; González, Adrián

    2017-10-01

    In this paper, a novel swarm optimization algorithm called the Selfish Herd Optimizer (SHO) is proposed for solving global optimization problems. SHO is based on the simulation of the widely observed selfish herd behavior manifested by individuals within a herd of animals subjected to some form of predation risk. In SHO, individuals emulate the predatory interactions between groups of prey and predators by two types of search agents: the members of a selfish herd (the prey) and a pack of hungry predators. Depending on their classification as either a prey or a predator, each individual is conducted by a set of unique evolutionary operators inspired by such prey-predator relationship. These unique traits allow SHO to improve the balance between exploration and exploitation without altering the population size. To illustrate the proficiency and robustness of the proposed method, it is compared to other well-known evolutionary optimization approaches such as Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC), Firefly Algorithm (FA), Differential Evolution (DE), Genetic Algorithms (GA), Crow Search Algorithm (CSA), Dragonfly Algorithm (DA), Moth-flame Optimization Algorithm (MOA) and Sine Cosine Algorithm (SCA). The comparison examines several standard benchmark functions, commonly considered within the literature of evolutionary algorithms. The experimental results show the remarkable performance of our proposed approach against those of the other compared methods, and as such SHO is proven to be an excellent alternative to solve global optimization problems. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. The effect of grazing on cow mortality in Danish dairy herds

    Burow, Elke; Thomsen, Peter Thorup; Sørensen, Jan Tind

    2011-01-01

    The effect of summer grazing in large Danish dairy herds and certain management characteristics of grazing were studied for their impact on dairy cow mortality. Mortality data (from the Danish Cattle Database) from 391 Danish dairy herds (>100 cows) were combined with information from...... a questionnaire survey of grazing procedures on these herds in 2008. In all, 131 of the herds were identified as summer grazing and 260 as zero-grazing herds. The mortality was affected by an interaction of summer grazing and milking system. The risk of a cow dying was reduced to 46% in a grazing compared...... and pasture was associated with increased cow mortality....

  9. Survey of facility and management characteristics of large, Upper Midwest dairy herds clustered by Dairy Herd Improvement records.

    Brotzman, R L; Döpfer, D; Foy, M R; Hess, J P; Nordlund, K V; Bennett, T B; Cook, N B

    2015-11-01

    A survey of management practices was conducted to investigate potential associations with groupings of herds formed by cluster analysis (CA) of Dairy Herd Improvement (DHI) data of 557 Upper Midwest herds of 200 cows or greater. Differences in herd management practices were identified between the groups, despite underlying similarities; for example, freestall housing and milking in a parlor. Group 6 comprised larger herds with a high proportion of primiparous cows and most frequently utilized practices promoting increased production [e.g., 84.4% used recombinant bovine somatotropin (rbST)], decreased lameness (e.g., 96.9% used routine hoof trimming for cows), and improved efficiency in reproduction [e.g., 93.8% synchronized the first breeding in cows (SYNCH)] and labor (e.g., mean ± SD, 67 ± 19 cows per 50-h per week full-time equivalent worker). Group 1 had the best mean DHI performances and followed most closely group 6 for the rate of adoption of intensive management practices while tending to outperform group 6 despite a generally smaller mean herd size (e.g., 42.3 ± 3.6 kg vs. 39.9 ± 3.6 kg of energy-corrected milk production; 608 ± 352 cows vs. 1,716 ± 1,405 cows). Group 2 were smaller herds with relatively high levels of performance that used less intensive management (e.g., 100% milked twice daily) and less technology (33.3 vs. 73.0% of group 1 used rbST). Group 4 were smaller but poorer-performing herds with low turnover and least frequently used intensive management practices (e.g., 39.1% SYNCH; 30.4% allowed mature, high-producing cows access to pasture). Group 5 used modern technologies and practices associated with improved production, yet had the least desirable mean DHI performance of all 6 groups. This group had the lowest proportion of deep loose-bedded stalls (only 52.2% used sand bedding) and the highest proportion (34.8%) of herds not using routine hoof trimming. The survey of group 3 herds did not reveal strong trends in management. The

  10. A simulation model to quantify the value of implementing whole-herd Bovine viral diarrhea virus testing strategies in beef cow-calf herds.

    Nickell, Jason S; White, Brad J; Larson, Robert L; Renter, David G; Sanderson, Mike W

    2011-03-01

    Although numerous diagnostic tests are available to identify cattle persistently infected (PI) with Bovine viral diarrhea virus (BVDV) in cow-calf herds, data are sparse when evaluating the economic viability of individual tests or diagnostic strategies. Multiple factors influence BVDV testing in determining if testing should be performed and which strategy to use. A stochastic model was constructed to estimate the value of implementing various whole-herd BVDV cow-calf testing protocols. Three common BVDV tests (immunohistochemistry, antigen-capture enzyme-linked immunosorbent assay, and polymerase chain reaction) performed on skin tissue were evaluated as single- or two-test strategies. The estimated testing value was calculated for each strategy at 3 herd sizes that reflect typical farm sizes in the United States (50, 100, and 500 cows) and 3 probabilities of BVDV-positive herd status (0.077, 0.19, 0.47) based upon the literature. The economic value of testing was the difference in estimated gross revenue between simulated cow-calf herds that either did or did not apply the specific testing strategy. Beneficial economic outcomes were more frequently observed when the probability of a herd being BVDV positive was 0.47. Although the relative value ranking of many testing strategies varied by each scenario, the two-test strategy composed of immunohistochemistry had the highest estimated value in all but one herd size-herd prevalence permutation. These data indicate that the estimated value of applying BVDV whole-herd testing strategies is influenced by the selected strategy, herd size, and the probability of herd BVDV-positive status; therefore, these factors should be considered when designing optimum testing strategies for cow-calf herds.

  11. Vaccination, herd behavior, and herd immunity.

    Cohen, Matan J; Brezis, Mayer; Block, Colin; Diederich, Adele; Chinitz, David

    2013-11-01

    During the 2009 outbreak of novel influenza AH1N1, insufficient data were available to adequately inform decision makers about benefits and risks of vaccination and disease. We hypothesized that individuals would opt to mimic their peers, having no better decision anchor. We used Game Theory, decision analysis, and transmission models to simulate the impact of subjective risks and preference estimates on vaccination behavior. We asked 95 students to provide estimates of risk and health state valuations with regard to AH1N1 infection, complications, and expectations of vaccine benefits and risks. These estimates were included in a sequential chain of models: a dynamic epidemic model, a decision tree, and a population-level model. Additionally, participants' intentions to vaccinate or not at varying vaccination rates were documented. The model showed that at low vaccination rates, vaccination dominated. When vaccination rates increased above 78%, nonvaccination was the dominant strategy. We found that vaccination intentions did not correspond to the shift in strategy dominance and segregated to 3 types of intentions: regardless of what others do 29/95 (31%) intended to vaccinate while 27/95 (28%) did not; among 39 of 95 (41%) intention was positively associated with putative vaccination rates. Some people conform to the majority's choice, either shifting epidemic dynamics toward herd immunity or, conversely, limiting societal goals. Policy leaders should use models carefully, noting their limitations and theoretical assumptions. Behavior drivers were not explicitly explored in this study, and the discrepant results beg further investigation. Models including real subjective perceptions with empiric or subjective probabilities can provide insight into deviations from expected rational behavior and suggest interventions in order to provide better population outcomes.

  12. Reproductive performance in a select sample of dairy herds.

    Ferguson, James D; Skidmore, Andrew

    2013-02-01

    Sixteen herds were selected from a pool of 64 herds nominated by consultants for participation in a national survey to demonstrate excellence in reproductive performance. For inclusion in the survey, herds had to have comprehensive records in a farm computer database or participate in a Dairy Herd Improvement Association record system and have superior reproductive performance as judged by the herd advisor. Herd managers were asked to fill out a questionnaire to describe their reproductive management practices and provide herd records for data analysis. Reproductive analysis was based on individual cow records for active and cull dairy cows that calved during the calendar year 2010. Breeding records by cow were used to calculate indices for insemination rate (IR), conception rate (CR), pregnancy rate (PR), and culling. Herds ranged in size from 262 to 6,126 lactating and dry cows, with a mean of 1,654 [standard deviation (SD) 1,494] cows. Mean days to first insemination (DFS) was 71.2d (SD 4.7d), and IR for first insemination was 86.9%. Mean days between inseminations were 33.4d (SD 3.1d), and 15.4% of insemination intervals were greater than 48 d (range: 7.2 to 21.5%). First-service conception rate was 44.4% (SD 4.8%) across all herds and ranged from 37.5 to 51.8%. Mean PR was 32.0% (SD 3.9%) with a range of 26.5 to 39.4%. Lactation cull rate was 32.2% (SD 12.4%) with a range from 13.6 to 58.1%. Compared with mean data and SD for herds in the Raleigh Dairy Herd Improvement Association system, mean indices for these herds ranked them in the 99 th percentile for IR (using heat detection rate as comparison), 99 th percentile for PR, the bottom 18.6 percentile for DFS, and around the 50th percentile for CR. This suggests that excellent herd reproductive performance was associated with reproductive management that resulted in high insemination rates combined with average CR. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights

  13. Ecological role of hunting in population dynamics and its implications for co-management of the Porcupine caribou herd

    Thomas A. Hanley

    2000-04-01

    Full Text Available At a present population size of 160 000 animals, the Porcupine caribou herd has been subjected to an annual harvest rate of 2% for the past couple of decades. We modeled potential sensitivity of herd population dynamics to hunting and used that relation as a basis for a herd monitoring system. Maximum number of adult cows that could be harvested without causing a subsequent decline in herd size was calculated as a function of total number of adult cows in the herd and recruitment of calves to yearling age-class. Maximum cow harvest, therefore, is a threshold above which hunting has destabilizing effects on herd dynamics. Actual harvest in relation to theoretical maximum harvest provides a basis for prediction of herd sensitivity to hunting. Maximum harvest is a linear function of recruitment. Herd dynamics are especially sensitive to low recruitment, however, when combined with low herd size. The two relations involving recruitment and herd size provide the basis for predicting herd dynamics and sensitivity to hunting. Herd size is best estimated by aerial census, while an index of recruitment can be predicted by monitoring autumn body condition of adult females. Body condition can be estimated on the basis of a few simple metrics measured by hunters in the field. The hunters' data on body composition, combined with aerial census data on herd size, provide a useful tool for managers and co-management boards to devise policies and regulations to manage the herd. The population model and monitoring system can operate on the Internet and be accessible to all users in villages within the range of the Porcupine caribou herd.

  14. Herding Complex Networks

    Ruf, Sebastian F.

    2018-04-12

    The problem of controlling complex networks is of interest to disciplines ranging from biology to swarm robotics. However, controllability can be too strict a condition, failing to capture a range of desirable behaviors. Herdability, which describes the ability to drive a system to a specific set in the state space, was recently introduced as an alternative network control notion. This paper considers the application of herdability to the study of complex networks. The herdability of a class of networked systems is investigated and two problems related to ensuring system herdability are explored. The first is the input addition problem, which investigates which nodes in a network should receive inputs to ensure that the system is herdable. The second is a related problem of selecting the best single node from which to herd the network, in the case that a single node is guaranteed to make the system is herdable. In order to select the best herding node, a novel control energy based herdability centrality measure is introduced.

  15. Improving the time efficiency of identifying dairy herds with poorer welfare in a population.

    de Vries, M; Bokkers, E A M; van Schaik, G; Engel, B; Dijkstra, T; de Boer, I J M

    2016-10-01

    Animal-based welfare assessment is time consuming and expensive. A promising strategy for improving the efficiency of identifying dairy herds with poorer welfare is to first estimate levels of welfare in herds based on data that are more easily obtained. Our aims were to evaluate the potential of herd housing and management data for estimating the level of welfare in dairy herds, and to estimate the associated reduction in the number of farm visits required for identification of herds with poorer welfare in a population. Seven trained observers collected data on 6 animal-based welfare indicators in a selected sample of 181 loose-housed Dutch dairy herds (herd size: 22 to 211 cows). Severely lame cows, cows with lesions or swellings, cows with a dirty hindquarter, and very lean cows were counted, and avoidance distance was assessed for a sample of cows. Occurrence of displacements (social behavior) was recorded in the whole barn during 120 min of observation. For the same herds, data regarding cattle housing and management were collected on farms, and data relating to demography, management, milk production and composition, and fertility were extracted from national databases. A herd was classified as having poorer welfare when it belonged to the 25% worst-scoring herds. We used variables of herd housing and management data as potential predictors for individual animal-based welfare indicators in logistic regressions at the herd level. Prediction was less accurate for the avoidance distance index [area under the curve (AUC)=0.69], and moderately accurate for prevalence of severely lame cows (AUC=0.83), prevalence of cows with lesions or swellings (AUC=0.81), prevalence of cows with a dirty hindquarter (AUC=0.74), prevalence of very lean cows (AUC=0.83), and frequency of displacements (AUC=0.72). We compared the number of farm visits required for identifying herds with poorer welfare in a population for a risk-based screening with predictions based on herd housing

  16. Ecological role of hunting in population dynamics and its implications for co-management of the Porcupine caribou herd

    Hanley, Thomas A.; Russell, Donald E.

    2000-01-01

    At a present population size of 160 000 animals, the Porcupine caribou herd has been subjected to an annual harvest rate of 2% for the past couple of decades. We modeled potential sensitivity of herd population dynamics to hunting and used that relation as a basis for a herd monitoring system. Maximum number of adult cows that could be harvested without causing a subsequent decline in herd size was calculated as a function of total number of adult cows in the herd and recruitment of calves to...

  17. Trends in slaughter pig production and antimicrobial consumption in Danish slaughter pig herds, 2002-2008

    Vieira, Antonio; Pires, Sara Monteiro; Houe, H.

    2011-01-01

    Overuse of antimicrobials in food-animal production is thought to be a major risk factor for the development of resistant bacterial populations. Data on non-human antimicrobial usage is essential for planning of intervention strategies to lower resistance levels at the country, region or herd...... levels. In this study we evaluated Danish national antimicrobial usage data for five antimicrobial classes used in slaughter pigs in different herd sizes and data on the number of slaughter pigs produced per herd, between 2002 and 2008, in Denmark. The objective was to ascertain...... if there is an association between herd size and amount of antimicrobials consumed. During this period, the overall number of herds with slaughter pigs decreased by 43%, with larger herds becoming more prevalent. The tetracycline treatment incidence (TI) rate increased from 0·28 to 0·70 animal-defined daily dose (ADD)/100...

  18. Mastitis and related management factors in certified organic dairy herds in Sweden

    Hansson Ingrid

    2006-07-01

    Full Text Available Abstract Background Mastitis is one of the major threats to animal health, in organic farming as well as conventional. Preliminary studies of organic dairy herds have indicated better udder health in such herds, as compared to conventional herds. The aim of this paper was to further study mastitis and management related factors in certified organic dairy herds. Methods An observational study of 26 certified organic dairy herds in mid-eastern Sweden was conducted during one year. A large-animal practitioner visited the herds three times and clinically examined and sampled cows, and collected information about general health and management routines. Data on milk production and disorders treated by a veterinarian in the 26 herds, as well as in 1102 conventional herds, were retrieved from official records. Multivariable logistic regression was used to assess associations between herd type (organic vs. conventional and incidence of disorders. Results The organic herds that took part in the study ranged in size from 12 to 64 cows, in milk production from 3772 to 10334 kg per cow and year, and in bulk milk somatic cell counts from 83000 to 280000 cells/ml. The organic herds were found to have a lower incidence of clinical mastitis, teat injuries, and a lower proportion of cows with a high somatic cell count (as indicated by the UDS, Udder Disease Score compared to conventional herds. The spectrum of udder pathogenic bacteria was similar to that found in other Swedish studies. Treatment of mastitis was found to be similar to what is practised in conventional herds. Homeopathic remedies were not widely used in the treatment of clinical mastitis. The calves in most of these organic herds suckled their dams for only a few days, which were not considered to substantially affect the udder health. The main management factor that was different from conventional herds was the feeding strategy, where organic herds used a larger share of forage. Conclusion Udder

  19. Cow- and herd-level risk factors for on-farm mortality in Midwest US dairy herds.

    Shahid, M Q; Reneau, J K; Chester-Jones, H; Chebel, R C; Endres, M I

    2015-07-01

    The objectives of this study were to describe on-farm mortality and to investigate cow- and herd-level risk factors associated with on-farm mortality in Midwest US dairy herds using lactation survival analysis. We analyzed a total of approximately 5.9 million DHIA lactation records from 10 Midwest US states from January 2006 to December 2010. The cow-level independent variables used in the models were first test-day milk yield, milk fat percent, milk protein percent, fat-to-protein ratio, milk urea nitrogen, somatic cell score, previous dry period, previous calving interval, stillbirth, calf sex, twinning, calving difficulty, season of calving, parity, and breed. The herd-level variables included herd size, calving interval, somatic cell score, 305-d mature-equivalent milk yield, and herd stillbirth percentage. Descriptive analysis showed that overall cow-level mortality rate was 6.4 per 100 cow-years and it increased from 5.9 in 2006 to 6.8 in 2010. Mortality was the primary reason of leaving the herd (19.4% of total culls) followed by reproduction (14.6%), injuries and other (14.0%), low production (12.3%), and mastitis (10.5%). Risk factor analysis showed that increased hazard for mortality was associated with higher fat-to-protein ratio (>1.6 vs. 1 to 1.6), higher milk fat percent, lower milk protein percent, cows with male calves, cows carrying multiple calves, higher milk urea nitrogen, increasing parity, longer previous calving interval, higher first test-day somatic cell score, increased calving difficulty score, and breed (Holstein vs. others). Decreased hazard for mortality was associated with higher first test-day milk yield, higher milk protein, and shorter dry period. For herd-level factors, increased hazard for mortality was associated with increased herd size, increased percentage of stillbirths, higher somatic cell score, and increased herd calving interval. Cows in herds with higher milk yield had lower mortality hazard. Results of the study

  20. Estimating the Local Size and Coverage of Interaction Network Regions

    Eagle, Michael; Barnes, Tiffany

    2015-01-01

    Interactive problem solving environments, such as intelligent tutoring systems and educational video games, produce large amounts of transactional data which make it a challenge for both researchers and educators to understand how students work within the environment. Researchers have modeled the student-tutor interactions using complex network…

  1. Age-structured dynamic, stochastic and mechanistic simulation model of Salmonella Dublin infection within dairy herds

    Nielsen, Liza Rosenbaum; Kudahl, Anne Braad; Østergaard, Søren

    2012-01-01

    for the individual animals in each of the six age groups in the herd. The hygiene level was highly influential on the probability that the infection spread within the herd, duration of infection and epidemic size. The herd susceptibility level was also influential, but not likely to provide sufficient prevention...... of the six age-groups; 2) S. Dublin incidence and number of animals in each infection state; and 3) S. Dublin related morbidity and mortality in the acutely infected animals. The effects of introducing one infectious heifer on the risk of spread of S. Dublin within the herd and on the duration of infection...... and control of infection on its own. Herd size did not affect the probability of infection spread upon exposure, but the larger the herd the more important were management and housing practices that improve hygiene and reduce susceptibility to shorten durations of infection in the herd and to increase...

  2. Effect of grazing on the cow welfare of dairy herds evaluated by a multidimensional welfare index

    Burow, E.; Rousing, T.; Thomsen, P. T.

    2013-01-01

    Structural development in the prime sector has led to increasing herd sizes and new barn systems, followed by less summer grazing for dairy cows in Denmark. Effects of grazing on single welfare measures in dairy cows - for example, the presence of integument alterations or mortality - have been......) inspired multidimensional dairy cow welfare assessment protocol, the within-herd effect of summer grazing compared with winter barn housing in Danish dairy herds with cubicle free-stall systems for the lactating cows. Our hypothesis was that cow welfare in dairy herds was better during summer grazing than...... out to be more beneficial than few daily grazing hours (range average above 9 to 21 h) for the welfare of the dairy herds. In conclusion, this study reports a positive within-herd effect of summer grazing on dairy cow welfare, where many daily grazing hours were more beneficial than few daily grazing...

  3. Risk factors for displaced abomasum or ketosis in Swedish dairy herds.

    Stengärde, L; Hultgren, J; Tråvén, M; Holtenius, K; Emanuelson, U

    2012-03-01

    Risk factors associated with high or low long-term incidence of displaced abomasum (DA) or clinical ketosis were studied in 60 Swedish dairy herds, using multivariable logistic regression modelling. Forty high-incidence herds were included as cases and 20 low-incidence herds as controls. Incidence rates were calculated based on veterinary records of clinical diagnoses. During the 3-year period preceding the herd classification, herds with a high incidence had a disease incidence of DA or clinical ketosis above the 3rd quartile in a national database for disease recordings. Control herds had no cows with DA or clinical ketosis. All herds were visited during the housing period and herdsmen were interviewed about management routines, housing, feeding, milk yield, and herd health. Target groups were heifers in late gestation, dry cows, and cows in early lactation. Univariable logistic regression was used to screen for factors associated with being a high-incidence herd. A multivariable logistic regression model was built using stepwise regression. A higher maximum daily milk yield in multiparous cows and a large herd size (p=0.054 and p=0.066, respectively) tended to be associated with being a high-incidence herd. Not cleaning the heifer feeding platform daily increased the odds of having a high-incidence herd twelvefold (pketosis in Swedish dairy herds. These results confirm the importance of housing, management and feeding in the prevention of metabolic disorders in dairy cows around parturition and in early lactation. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Effects of Class Size and Attendance Policy on University Classroom Interaction in Taiwan

    Bai, Yin; Chang, Te-Sheng

    2016-01-01

    Classroom interaction experience is one of the main parts of students' learning lives. However, surprisingly little research has investigated students' perceptions of classroom interaction with different attendance policies across different class sizes in the higher education system. To elucidate the effects of class size and attendance policy on…

  5. The use of a cluster analysis in across herd genetic evaluation for ...

    To investigate the possibility of a genotype x environment interaction in Bonsmara cattle, a cluster analysis was performed on weaning weight records of 72 811 Bonsmara calves, the progeny of 1 434 sires and 24 186 dams in 35 herds. The following environmental factors were used to classify herds into clusters: solution ...

  6. Size matters: influence of the size of nanoparticles on their interactions with ligands immobilized on the solid surface.

    Piletska, Elena V; Piletsky, Sergey A

    2010-03-16

    The correlation between the size of biotinylated nanoparticles and their affinity in relation to interactions with the solid surface was investigated. The silica particles with a diameter of 50-200 nm containing amino groups on the surface were labeled with different quantities of biotin. The affinity properties of biotinylated nanoparticles were studied using a Biacore 3000 instrument equipped with a streptavidin-coated sensor chip (SA chip). It was shown that the increase in the particle size from 50 to 200 nm reduced the affinity (K(D)) of biotin-streptavidin interactions from 1.2 x 10(-12) to 1.2 x 10(-10) M. It was found that the particles with higher concentrations of immobilized biotin on particle surfaces demonstrated stronger binding with streptavidin.

  7. Courtship herding in the fiddler crab Uca elegans.

    How, Martin J; Hemmi, Jan M

    2008-12-01

    Male and female animals are not always complicit during reproduction, giving rise to coercion. One example of a system that is assumed to involve sexual coercion is the mate herding behaviour of fiddler crabs: males push females towards the home burrow with the goal of forcing copulation at the burrow entrance. We recorded and analysed in detail the courtship behaviour of a North Australian species of fiddler crab Uca elegans. Courtship was composed of four main phases: broadcast waving, outward run, herding and at burrow display. During interactions males produced claw-waving displays which were directed posteriorly towards the female and which varied in timing and structure depending on the courtship phase. We suggest that courtship herding in U. elegans is driven primarily by mate choice for the following reasons, (1) females can evade herding, (2) no other reproductive strategies were observed, (3) males broadcast their presence and accompany courtship with conspicuous claw waves, and (4) the behaviour ends with the female leading the male into the home burrow. As an alternative function for herding in U. elegans we suggest that the behaviour represents a form of courtship guiding, in which males direct complicit females to the correct home burrow.

  8. Investor mood, herding and the Ramadan effect

    Gavriilidis, Konstantinos; Kallinterakis, Vasileios; Tsalavoutas, Ioannis

    2016-01-01

    In view of evidence linking herding and social mood, we examine whether the positive mood documented during Ramadan translates into higher herding compared to non-Ramadan days. Drawing on a sample of seven majority Muslim countries, we report significant herding during Ramadan in most of our sample markets. Additionally, we show that herding appears significantly stronger within rather than outside Ramadan for most tests whereby its significance is manifested on both Ramadan- and non-Ramadan-...

  9. Ecology of the Porcupine caribou herd

    Kenneth R. Whitten

    1996-01-01

    Researchers have described general patterns of population regulation that fit most caribou (Rangifer tarandus) herds. Nevertheless, specific factors operating on particular populations vary greatly, and efforts to categorize herds according to the general patterns often lead to confusion. It is difficult for biologists to attempt to describe population dynamics in terms of density relationships for wide-ranging arctic caribou such as the Porcupine Herd. In these herds density varies as a func...

  10. Impacts of dairy diagnostic teams on herd performance.

    Weinand, D; Conlin, B J

    2003-05-01

    This study evaluated impacts of educational diagnostic teams of consultants used to transfer technology to dairy farms. Herd management performance changes were measured by comparing Dairy Herd Improvement data from 38 project farms to data from herds that were geographical contemporaries. The value of focused goals for effecting change was also assessed. Interviews provided producers' perception of project outcomes and insight on organization and conduct of dairy diagnostic teams. Changes observed in project herds were small compared with controls with tendencies for increased herd size and improved milk production per cow. Focused goals had greater impacts on increasing herd size, milk per cow, first lactation peak milk, reducing age at first calving, and percentages of cows with subclinical mastitis. Time, money, facility limitations, labor, and alternative priorities were the most cited constraints to implementing changes. Satisfaction scores of producers were significantly related to the degree that team recommendations were followed. Improved attitudes, quality of life, and financial well-being were benefits listed by a majority of producers from participation in the project. If similar projects were to be offered, 83% said they would participate again, and 69% indicated they would pay at least some of the costs. Project farms served as demonstration farms for 1930 other producers in their respective locales, resulting in a multiplier effect of original advice given by consultant teams. Suggestions by farmer participants for improvements in dairy diagnostic teams included needs for at least some unbiased team members, more frequent meetings, more follow-up on recommendations, and consistency of recommendations with family goals.

  11. Impact of US Brown Swiss genetics on milk quality from low-input herds in Switzerland: Interactions with grazing intake and pasture type

    Stergiadis, S.; Bieber, A.; Franeschin, E.; Isensee, A.; Eyre, M.D.; Maurer, V.; Chatzidimitriou, E.; Cozzi, G.; Bapst, B.; Stewart, G.; Gordon, A.; Butler, G.

    2015-01-01

    This study investigated the effect of, and interactions between, contrasting crossbreed genetics (US Brown Swiss [BS] x Improved Braunvieh [BV] x Original Braunvieh [OB]) and feeding regimes (especially grazing intake and pasture type) on milk fatty acid (FA) profiles. Concentrations of total polyunsaturated FAs, total omega-3 FAs and trans palmitoleic, vaccenic, a-linolenic, eicosapentaenoic and docosapentaenoic acids were higher in cows with a low proportion of BS genetics. Highest concentr...

  12. Effect of interaction between seed size and sowing depth of cashew ...

    Effect of interaction between seed size and sowing depth of cashew Anacardium occidentale (L) on seedlings emergence and height under treatment with organic and inorganic fertilizer in Gidan-Waya, Southern Guinea Savanna, Nigeria.

  13. Herding agent field application system development

    Buist, Ian; Belore, Randy [SL Ross Environmental Research (Canada)], email: ian@slross.com

    2011-07-01

    Chemical herding agents can be applied to deal with an oil slick. This study investigates the key system components of application systems for herding agents and shows how application systems can also be developed for operational herder usage in drift ice. These two application systems are respectively required for small boat and a helicopter operations. The factors, including the selection of flow rates, pressures and atomizing nozzle types, which give the appropriate herder droplet size distributions for small boat and aerial application systems were investigated in the initial stage of the study. In a later stage, on commercializing herders for in situ burning, further research is expected to deal with the many problems not tackled in the initial stage, such as the mounting of the nozzles, pumps and reservoirs on various aerial platforms and the provision of heating and insulation for cold-weather use. The paper presented the experiments and simulations that have been conducted as well as the basic design parameters for field application systems.

  14. Impact of US Brown Swiss genetics on milk quality from low-input herds in Switzerland: interactions with grazing intake and pasture type.

    Stergiadis, S; Bieber, A; Franceschin, E; Isensee, A; Eyre, M D; Maurer, V; Chatzidimitriou, E; Cozzi, G; Bapst, B; Stewart, G; Gordon, A; Butler, G

    2015-05-15

    This study investigated the effect of, and interactions between, contrasting crossbreed genetics (US Brown Swiss [BS] × Improved Braunvieh [BV] × Original Braunvieh [OB]) and feeding regimes (especially grazing intake and pasture type) on milk fatty acid (FA) profiles. Concentrations of total polyunsaturated FAs, total omega-3 FAs and trans palmitoleic, vaccenic, α-linolenic, eicosapentaenoic and docosapentaenoic acids were higher in cows with a low proportion of BS genetics. Highest concentrations of the nutritionally desirable FAs, trans palmitoleic, vaccenic and eicosapentaenoic acids were found for cows with a low proportion of BS genetics (0-24% and/or 25-49%) on high grazing intake (75-100% of dry matter intake) diets. Multivariate analysis indicated that the proportion of OB genetics is a positive driver for nutritionally desirable monounsaturated and polyunsaturated FAs while BS genetics proportion was positive driver for total and undesirable individual saturated FAs. Significant genetics × feeding regime interactions were also detected for a range of FAs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Parasites and parasite management practices of organic and conventional dairy herds in Minnesota.

    Sorge, U S; Moon, R D; Stromberg, B E; Schroth, S L; Michels, L; Wolff, L J; Kelton, D F; Heins, B J

    2015-05-01

    The objective of this study was to describe the prevalence and practices used to manage internal helminth parasites and external arthropod parasites on organic and conventional dairy herds in Minnesota. All organic (ORG) dairy herds in Minnesota (n=114) and a convenience sample of conventional herds were invited to participate in the study. Thirty-five ORG herds and 28 conventional herds were visited once in summer and fall of 2012. Conventional dairy herds were split into small conventional (SC,conventional herds (MC, ≥200 cows) so that SC herds were comparable in size to the ORG herds. Dairy managers were surveyed to assess their farm management practices and perceptions about parasites, hygiene scores were recorded for adult stock, and fecal samples were collected from a nominal 20 breeding-age heifers to characterize abundance of internal parasites. Nonparametric tests were used to compare fecal egg counts per gram (FEC) among farms grouped by management systems and practices. Organic farms had more designated pasture and were more likely to use rotational grazing compared with conventional farms, but the stocking densities of animals on pasture were similar among farm types. The overall FEC were very low, and only a few individual ORG heifers had FEC >500 eggs/gram. Samples from heifers on ORG farms had significantly more strongyle-type eggs than those on SC and MC farms (ORG: 6.6±2.1; SC: 0.5±0.3; MC: 0.8±0.7), but egg counts of other types of gastrointestinal parasites did not differ significantly among the 3 herd groups. Fly control measures were applied mainly to milking cows and preweaned calves and were used on 88.6% of ORG herds, 60.0% of SC herds, and 91.7% of MC herds. Approximately half of the producers reported having seen skin conditions suggestive of lice or tail mange in their cattle during the previous winter (ORG: 48.6%, SC: 57.1%, MC: 53.9%). Although most conventional producers reported treating these skin conditions, most organic

  16. The Fortymile caribou herd: novel proposed management and relevant biology, 1992-1997

    Rodney D. Boertje

    2000-04-01

    Full Text Available A diverse, international Fortymile Planning Team wrote a novel Fortymile caribou herd {Rangifer tarandus granti Management Plan in 1995 (Boertje & Gardner, 1996: 56-77. The primary goal of this plan is to begin restoring the Fortymile herd to its former range; >70% of the herd's former range was abandoned as herd size declined. Specific objectives call for increasing the Fortymile herd by at least 5-10% annually from 1998-2002. We describe demographics of the herd, factors limiting the herd, and condition of the herd and range during 1992-1997. These data were useful in proposing management actions for the herd and should be instrumental in future evaluations of the plan's actions. The following points summarize herd biology relevant to management proposed by the Fortymile Planning Team: 1. Herd numbers remained relatively stable during 1990-1995 (about 22 000-23 000 caribou. On 21 June 1996 we counted about 900 additional caribou in the herd, probably a result of increased pregnancy rates in 1996. On 26 June 1997 we counted about 2500 additional caribou in the herd, probably a result of recruitment of the abundant 1996 calves and excellent early survival of the 1997 calves. The Team deemed that implementing management actions during a period of natural growth would be opportune. 2. Wolf (Canis lupus and grizzly bear (Ursus arctos predation were the most important sources of mortality, despite over a decade of the most liberal regulations in the state for harvesting of wolves and grizzly bears. Wolves were the most important predator. Wolves killed between 2000 and 3000 caribou calves annually during this study and between 1000 and 2300 older caribou; 1200-1900 calves were killed from May through September. No significant differences in annual wolf predation rates on calves or adults were observed between 1994 and early winter 1997. Reducing wolf predation was judged by the Team to be the most manageable way to help hasten or stimulate

  17. Risk factors for infection of sow herds with porcine reproductive and respiratory syndrome (PRRS) virus

    Mortensen, Sten; Stryhn, Henrik; Søgaard, Rikke

    2002-01-01

    In 1992, the porcine reproductive and respiratory syndrome virus (PRRSV) of European type (PRRSV-EU) was introduced in Denmark. By 1996, the virus had spread to approximately 25% of the Danish herds. In January 1996, a modified-live vaccine based on the American type of the virus (PRRSV-US) was u......In 1992, the porcine reproductive and respiratory syndrome virus (PRRSV) of European type (PRRSV-EU) was introduced in Denmark. By 1996, the virus had spread to approximately 25% of the Danish herds. In January 1996, a modified-live vaccine based on the American type of the virus (PRRSV......-US) was used in replacement boars for Danish artificial insemination (AI) centres and from July 1996, the vaccine was used in PRRSV-EU infected herds for prevention of disease. Soon after vaccine introduction, PRRSV non-infected herds experienced outbreaks of disease due to infection with PRRSV...... in the case herds). The data were analysed using a Cox-regression model. The hazard of infection increased significantly with exposure from PRRSV-US-infected neighbouring herds, purchase of animals from herds incubating PRRSV-US infection, increasing herd size and purchase of semen from boars at PRRSV...

  18. Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure.

    Binzer, Amrei; Guill, Christian; Rall, Björn C; Brose, Ulrich

    2016-01-01

    Warming and eutrophication are two of the most important global change stressors for natural ecosystems, but their interaction is poorly understood. We used a dynamic model of complex, size-structured food webs to assess interactive effects on diversity and network structure. We found antagonistic impacts: Warming increases diversity in eutrophic systems and decreases it in oligotrophic systems. These effects interact with the community size structure: Communities of similarly sized species such as parasitoid-host systems are stabilized by warming and destabilized by eutrophication, whereas the diversity of size-structured predator-prey networks decreases strongly with warming, but decreases only weakly with eutrophication. Nonrandom extinction risks for generalists and specialists lead to higher connectance in networks without size structure and lower connectance in size-structured communities. Overall, our results unravel interactive impacts of warming and eutrophication and suggest that size structure may serve as an important proxy for predicting the community sensitivity to these global change stressors. © 2015 John Wiley & Sons Ltd.

  19. Impact of vaccine herd-protection effects in cost-effectiveness analyses of childhood vaccinations. A quantitative comparative analysis.

    Holubar, Marisa; Stavroulakis, Maria Christina; Maldonado, Yvonne; Ioannidis, John P A; Contopoulos-Ioannidis, Despina

    2017-01-01

    Inclusion of vaccine herd-protection effects in cost-effectiveness analyses (CEAs) can impact the CEAs-conclusions. However, empirical epidemiologic data on the size of herd-protection effects from original studies are limited. We performed a quantitative comparative analysis of the impact of herd-protection effects in CEAs for four childhood vaccinations (pneumococcal, meningococcal, rotavirus and influenza). We considered CEAs reporting incremental-cost-effectiveness-ratios (ICERs) (per quality-adjusted-life-years [QALY] gained; per life-years [LY] gained or per disability-adjusted-life-years [DALY] avoided), both with and without herd protection, while keeping all other model parameters stable. We calculated the size of the ICER-differences without vs with-herd-protection and estimated how often inclusion of herd-protection led to crossing of the cost-effectiveness threshold (of an assumed societal-willingness-to-pay) of $50,000 for more-developed countries or X3GDP/capita (WHO-threshold) for less-developed countries. We identified 35 CEA studies (20 pneumococcal, 4 meningococcal, 8 rotavirus and 3 influenza vaccines) with 99 ICER-analyses (55 per-QALY, 27 per-LY and 17 per-DALY). The median ICER-absolute differences per QALY, LY and DALY (without minus with herd-protection) were $15,620 (IQR: $877 to $48,376); $54,871 (IQR: $787 to $115,026) and $49 (IQR: $15 to $1,636) respectively. When the target-vaccination strategy was not cost-saving without herd-protection, inclusion of herd-protection always resulted in more favorable results. In CEAs that had ICERs above the cost-effectiveness threshold without herd-protection, inclusion of herd-protection led to crossing of that threshold in 45% of the cases. This impacted only CEAs for more developed countries, as all but one CEAs for less developed countries had ICERs below the WHO-cost-effectiveness threshold even without herd-protection. In several analyses, recommendation for the adoption of the target

  20. The new classification system for slaughter-pig herds in the Danish Salmonella surveillance-and-control program

    Alban, L.; Stege, Helle; Dahl, J.

    2002-01-01

    the Danish Salmonella Database including all herds in 2000. The classification scheme has been adjusted on the following points. (1) The sampling has been simplified into 60, 75, or 100 samples per herd per year depending on herd size. This means more-precise estimates for the seroprevalence among smaller......The Danish surveillance-and-control program for Salmonella in slaughter pigs was introduced in 1995. The key element of the program is a quick and correct identification of herds with high seroprevalence. After 5 years, the classification scheme was evaluated-and a revision was made. Data from two...

  1. Gross margin losses due to Salmonella Dublin infection in Danish dairy cattle herds estimated by simulation modelling

    Nielsen, Torben Dahl; Kudahl, Anne Braad; Østergaard, S.

    2013-01-01

    and dynamic simulation model. The model incorporated six age groups (neonatal, pre-weaned calves, weaned calves, growing heifers, breeding heifers and cows) and five infection stages (susceptible, acutely infected, carrier, super shedder and resistant). The effects of introducing one S. Dublin infectious......Salmonella Dublin affects production and animal health in cattle herds. The objective of this study was to quantify the gross margin (GM) losses following introduction and spread of S. Dublin within dairy herds. The GM losses were estimated using an age-structured stochastic, mechanistic...... with poorer management and herd size, e.g. average annual GM losses were estimated to 49 euros per stall for the first year after infection, and to 8 euros per stall annually averaged over the 10 years after herd infection for a 200 cow stall herd with very good management. In contrast, a 200 cow stall herd...

  2. Effects of herd management practices on somatic cell counts in an arid climate

    Ali Sadeghi-Sefidmazgi

    2014-09-01

    Full Text Available The objective of this study was to evaluate associations between average lactation somatic cell counts (SCC and herd management practices in an arid climate. A total of 38,530 average lactation SCC records for 10,216 Holstein cows gathered on 25 dairy farms from January 2009 to October 2012 in Isfahan (Iran were analyzed. Average lactation SCC (cells × 1,000 was 250.79 ranging from 90.31 to 483.23 cells/mL across investigated farms. Herd-level management factors associated with average lactation SCC were determined separately using mixed linear models in the MIXED procedure with average lactation somatic cell score (SCS included as the dependent variable. Some of the management practices associated with low average lactation SCS included sawdust combined with sand bedding, using automatic cup removers, disinfection of the teats by dipping into disinfectant, using washable towels for teat cleaning, free-stall barns, wet disposable tissue for udder washing, wearing gloves during milking and the use of humidifiers and shade. Lower-production herds and larger-size herds had lower average lactation somatic cell counts. Most herd management practices associated with average lactation SCC in dairy herds in the arid region of Isfahan are in agreement with most previous studies. However, different results are found for use of humidifier, bedding materials and herd size.

  3. Nonlinear dynamics of contact interaction of a size-dependent plate supported by a size-dependent beam

    Awrejcewicz, J.; Krysko, V. A.; Yakovleva, T. V.; Pavlov, S. P.; Krysko, V. A.

    2018-05-01

    A mathematical model of complex vibrations exhibited by contact dynamics of size-dependent beam-plate constructions was derived by taking the account of constraints between these structural members. The governing equations were yielded by variational principles based on the moment theory of elasticity. The centre of the investigated plate was supported by a beam. The plate and the beam satisfied the Kirchhoff/Euler-Bernoulli hypotheses. The derived partial differential equations (PDEs) were reduced to the Cauchy problems by the Faedo-Galerkin method in higher approximations, whereas the Cauchy problem was solved using a few Runge-Kutta methods. Reliability of results was validated by comparing the solutions obtained by qualitatively different methods. Complex vibrations were investigated with the help of methods of nonlinear dynamics such as vibration signals, phase portraits, Fourier power spectra, wavelet analysis, and estimation of the largest Lyapunov exponents based on the Rosenstein, Kantz, and Wolf methods. The effect of size-dependent parameters of the beam and plate on their contact interaction was investigated. It was detected and illustrated that the first contact between the size-dependent structural members implies chaotic vibrations. In addition, problems of chaotic synchronization between a nanoplate and a nanobeam were addressed.

  4. Size-density scaling in protists and the links between consumer-resource interaction parameters.

    DeLong, John P; Vasseur, David A

    2012-11-01

    Recent work indicates that the interaction between body-size-dependent demographic processes can generate macroecological patterns such as the scaling of population density with body size. In this study, we evaluate this possibility for grazing protists and also test whether demographic parameters in these models are correlated after controlling for body size. We compiled data on the body-size dependence of consumer-resource interactions and population density for heterotrophic protists grazing algae in laboratory studies. We then used nested dynamic models to predict both the height and slope of the scaling relationship between population density and body size for these protists. We also controlled for consumer size and assessed links between model parameters. Finally, we used the models and the parameter estimates to assess the individual- and population-level dependence of resource use on body-size and prey-size selection. The predicted size-density scaling for all models matched closely to the observed scaling, and the simplest model was sufficient to predict the pattern. Variation around the mean size-density scaling relationship may be generated by variation in prey productivity and area of capture, but residuals are relatively insensitive to variation in prey size selection. After controlling for body size, many consumer-resource interaction parameters were correlated, and a positive correlation between residual prey size selection and conversion efficiency neutralizes the apparent fitness advantage of taking large prey. Our results indicate that widespread community-level patterns can be explained with simple population models that apply consistently across a range of sizes. They also indicate that the parameter space governing the dynamics and the steady states in these systems is structured such that some parts of the parameter space are unlikely to represent real systems. Finally, predator-prey size ratios represent a kind of conundrum, because they are

  5. Risk factors for Coxiella burnetii antibodies in bulk tank milk from Danish dairy herds

    Agger, Jens Frederik; Paul, Suman; Christoffersen, Anna-Bodil

    2013-01-01

    .2), artificial insemination by other people than artificial insemination technicians (OR = 7.7), routine herd health contract with the veterinarian (OR = 4.3) and hygiene precautions taken by veterinarians (OR = 5). In addition, herd size, hired labour, trading of cattle between farms, quarantine and use...

  6. The essential role of vibronic interactions in electron pairing in the micro- and macroscopic sized materials

    Kato, Takashi

    2010-01-01

    Graphical abstract: The electron-phonon interactions destroy the electron pairs formed by Coulomb interactions, and at the same time, form the energy gap by which the electron pairs become stable. - Abstract: In order to discuss how the nondissipative delocalized diamagnetic currents in the microscopic sized materials are closely related to the conventional superconductivity in the macroscopic sized materials, the unified theory, by which various sized superconductivity can be explained, is suggested. It has been believed for a long time that the electron-phonon interactions play an essential role in the attractive electron-electron interactions, as described in the Bardeen-Cooper-Schrieffer (BCS) theory in the conventional superconductivity. However, it is suggested in this paper that the electron-phonon interactions do not play an essential role in the attractive electron-electron interactions but play an essential role in the forming of energy gap by which the electron pairs formed by the attractive Coulomb interactions in the conventional superconducting states become more stable than those in the normal metallic states at low temperatures.

  7. Predation rate by wolves on the Porcupine caribou herd

    Robert D. Hayes

    2000-04-01

    Full Text Available Large migratory catibou {Rangifer tarandus herds in the Arctic tend to be cyclic, and population trends are mainly driven by changes in forage or weather events, not by predation. We estimated daily kill rate by wolves on adult caribou in winter, then constructed a time and space dependent model to estimate annual wolf (Canis lupus predation rate (P annual on adult Porcupine caribou. Our model adjusts predation seasonally depending on caribou distribution: Pannual = SIGMAdaily* W *Ap(2*Dp. In our model we assumed that wolves killed adult caribou at a constant rate (Kdaily, 0.08 caribou wolf1 day1 based on our studies and elsewhere; that wolf density (W doubled to 6 wolves 1000 km2-1 on all seasonal ranges; and that the average area occupied by the Porcupine caribou herd (PCH in eight seasonal life cycle periods (Dp was two times gteater than the area described by the outer boundaries of telemetry data (Ap /1000 km2. Results from our model projected that wolves kill about 7600 adult caribou each year, regardless of herd size. The model estimated that wolves removed 5.8 to 7.4% of adult caribou as the herd declined in the 1990s. Our predation rate model supports the hypothesis of Bergerud that spacing away by caribou is an effective anti-predatory strategy that greatly reduces wolf predation on adult caribou in the spring and summer.

  8. Herd-level risk factors for Campylobacter fetus infection, Brucella seropositivity and within-herd seroprevalence of brucellosis in cattle in northern Nigeria.

    Mai, H M; Irons, P C; Kabir, J; Thompson, P N

    2013-09-01

    Brucellosis and campylobacteriosis are economically important diseases affecting bovine reproductive efficiency in Nigeria. A questionnaire-based survey was conducted in 271 cattle herds in Adamawa, Kaduna and Kano states of northern Nigeria using multistage cluster sampling. Serum from 4745 mature animals was tested for Brucella antibodies using the Rose-Bengal plate test and positives were confirmed in series-testing protocol using competitive enzyme-linked immunosorbent assay. Preputial scrapings from 602 bulls were tested using culture and identification for Campylobacter fetus. For each disease, a herd was classified as positive if one or more animals tested positive. For each herd, information on potential managemental and environmental risk factors was collected through a questionnaire administered during an interview with the manager, owner or herdsman. Multiple logistic regression models were used to model the odds of herd infection for each disease. A zero-inflated Poisson model was used to model the count of Brucella-positive animals within herds, with the number tested as an exposure variable. The presence of small ruminants (sheep and/or goats) on the same farm, and buying-in of >3 new animals in the previous year or failure to practice quarantine were associated with increased odds of herd-level campylobacteriosis and brucellosis, as well as increased within-herd counts of Brucella-positive animals. In addition, high rainfall, initial acquisition of animals from markets, practice of gynaecological examination and failure to practice herd prophylactic measures were positively associated with the odds of C. fetus infection in the herd. Herd size of >15, pastoral management system and presence of handling facility on the farm were associated with increased odds, and gynaecological examination with reduced odds of herd-level Brucella seropositivity. Furthermore, the zero-inflated Poisson model showed that borrowing or sharing of bulls was associated with

  9. Size-dependent Fano Interaction in the Laser-etched Silicon Nanostructures

    Kumar Rajesh

    2008-01-01

    Full Text Available AbstractPhoto-excitation and size-dependent Raman scattering studies on the silicon (Si nanostructures (NSs prepared by laser-induced etching are presented here. Asymmetric and red-shifted Raman line-shapes are observed due to photo-excited Fano interaction in the quantum confined nanoparticles. The Fano interaction is observed between photo-excited electronic transitions and discrete phonons in Si NSs. Photo-excited Fano studies on different Si NSs show that the Fano interaction is high for smaller size of Si NSs. Higher Fano interaction for smaller Si NSs is attributed to the enhanced interference between photo-excited electronic Raman scattering and phonon Raman scattering.

  10. Dynamics of moving interacting atoms in a laser radiation field and optical size resonances

    Gadomskii, O.N.; Glukhov, A.G.

    2005-01-01

    The forces acting on interacting moving atoms exposed to resonant laser radiation are calculated. It is shown that the forces acting on the atoms include the radiation pressure forces as well as the external and internal bias forces. The dependences of the forces on the atomic spacing, polarization, and laser radiation frequency are given. It is found that the internal bias force associated with the interaction of atomic dipoles via the reemitted field may play an important role in the dynamics of dense atomic ensembles in a light field. It is shown that optical size resonances appear in the system of interacting atoms at frequencies differing substantially from transition frequencies in the spectrum of atoms. It is noted that optical size resonances as well as the Doppler frequency shift in the spectrum of interacting atoms play a significant role in the processes of laser-radiation-controlled motion of the atoms

  11. Diagnostic herd sensitivity using environmental samples

    Vigre, Håkan; Josefsen, Mathilde Hartmann; Seyfarth, Anne Mette

    either at farm or slaughter. Three sample matrices were collected; dust samples (5 environmental swabs), nasal swabs (10 pools with 5 animals per pool) and air samples (1 filter). Based on the assumption that MRSA occurred in all 48 herds the overall herd sensitivity was 58% for nasal swabs, 33% for dust....... In our example, the prevalence of infected pigs in each herd was estimated from the pooled samples of nasal swabs. Logistic regression was used to estimate the effect of animal prevalence on the probability to detect MRSA in the dust and air samples at herd level. The results show a significant increase...

  12. Factors associated with frequency of abortions recorded through Dairy Herd Improvement test plans.

    Norman, H D; Miller, R H; Wright, J R; Hutchison, J L; Olson, K M

    2012-07-01

    Frequency of abortions recorded through Dairy Herd Improvement (DHI) testing was summarized for cows with lactations completed from 2001 through 2009. For 8.5 million DHI lactations of cows that had recorded breeding dates and were >151 d pregnant at lactation termination, the frequency of recorded abortions was 1.31%. Effects of year, herd-year, month, and pregnancy stage at lactation termination; parity; breed; milk yield; herd size; geographic region; and state within region associated with DHI-recorded abortion were examined. Abortions recorded through DHI (minimum gestation of 152 d required) were more frequent during early gestation; least squares means (LSM) were 4.38, 3.27, 1.19, and 0.59% for 152 to 175, 176 to 200, 201 to 225, and 226 to 250 d pregnant, respectively. Frequency of DHI-recorded abortions was 1.40% for parity 1 and 1.01% for parity ≥ 8. Abortion frequency was highest from May through August (1.42 to 1.53%) and lowest from October through February (1.09 to 1.21%). Frequency of DHI-recorded abortions was higher for Holsteins (1.32%) than for Jerseys (1.10%) and other breeds (1.27%). Little relationship was found between DHI-recorded abortions and herd size. Abortion frequencies for effects should be considered to be underestimated because many abortions, especially those caused by genetic recessives, go undetected. Therefore, various nonreturn rates (NRR; 60, 80, …, 200 d) were calculated to document pregnancy loss confirmed by the absence of homozygotes in the population. Breeding records for April 2011 US Department of Agriculture sire conception rate evaluations were analyzed with the model used for official evaluations with the addition of an interaction between carrier status of the service sire (embryo's sire) and cow sire (embryo's maternal grandsire). Over 13 million matings were examined using various NRR for Holstein lethal recessive traits (brachyspina and complex vertebral malformation) and undesirable recessive haplotypes (HH1

  13. Short communication: Microbiological quality of raw cow milk and its association with herd management practices in Northern China.

    Lan, X Y; Zhao, S G; Zheng, N; Li, S L; Zhang, Y D; Liu, H M; McKillip, J; Wang, J Q

    2017-06-01

    Contamination of raw milk with bacterial pathogens is potentially hazardous to human health. The aim of this study was to evaluate the total bacteria count (TBC) and presence of pathogens in raw milk in Northern China along with the associated herd management practices. A total of 160 raw milk samples were collected from 80 dairy herds in Northern China. All raw milk samples were analyzed for TBC and pathogens by culturing. The results showed that the number of raw milk samples with TBC milk samples were Staphylococcus aureus positive, 72 (45.00%) were Escherichia coli positive, 2 (1.25%) were Salmonella positive, 2 (1.25%) were Listeria monocytogenes positive, and 3 (1.88%) were Campylobacter positive. The prevalence of S. aureus was influenced by season, herd size, milking frequency, disinfection frequency, and use of a Dairy Herd Improvement program. The TBC was influenced by season and milk frequency. The correlation between TBC and prevalence of S. aureus or E. coli is significant. The effect size statistical analysis showed that season and herd (but not Dairy Herd Improvement, herd size, milking frequency, disinfection frequency, and area) were the most important factors affecting TBC in raw milk. In conclusion, the presence of bacteria in raw milk was associated with season and herd management practices, and further comprehensive study will be powerful for effectively characterizing various factors affecting milk microbial quality in bulk tanks in China. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. Initial insights on the performances and management of dairy cattle herds combining two breeds with contrasting features.

    Magne, M A; Thénard, V; Mihout, S

    2016-05-01

    Finding ways of increasing animal production with low external inputs and without compromising reproductive performances is a key issue of livestock systems sustainability. One way is to take advantage of the diversity and interactions among components within livestock systems. Among studies that investigate the influence of differences in animals' individual abilities in a herd, few focus on combinations of cow breeds with contrasting features in dairy cattle herds. This study aimed to analyse the performances and management of such multi-breed dairy cattle herds. These herds were composed of two types of dairy breeds: 'specialist' (Holstein) and 'generalist' (e.g. Montbeliarde, Simmental, etc.). Based on recorded milk data in southern French region, we performed (i) to compare the performances of dairy herds according to breed-type composition: multi-breed, single specialist breed or single generalist breed and (ii) to test the difference of milk performances of specialist and generalist breed cows (n = 10 682) per multi-breed dairy herd within a sample of 22 farms. The sampled farmers were also interviewed to characterise herd management through multivariate analysis. Multi-breed dairy herds had a better trade-off among milk yield, milk fat and protein contents, herd reproduction and concentrate-conversion efficiency than single-breed herds. Conversely, they did not offer advantages in terms of milk prices and udder health. Compared to specialist dairy herds, they produce less milk with the same concentrate-conversion efficiency but have better reproductive performances. Compared to generalist dairy herds, they produce more milk with better concentrate-conversion efficiency but have worse reproductive performances. Within herds, specialist and generalist breed cows significantly differed in milk performances, showing their complementarity. The former produced more milk for a longer lactation length while the latter produced milk with higher protein and fat

  15. Comparison of caribou physical characteristics from Yukon and neighboring caribou herds

    David A. Gauthier

    1986-06-01

    Full Text Available Data on seven external body measurements of caribou from six woodland and two barren-ground caribou herds from Yukon, Alaska, Alberta and British Columbia were compared. Comparisons between females in the fall and winter and mature males in the fall revealed that (1 barren-ground Porcupine caribou were consistently smaller than caribou from other herds, (2 British Columbia and Alberta caribou tended to be larger than Yukon caribou, or the Alaskan caribou studied, (3 central Yukon caribou were intermediate in body size, (4 no difference was found between Yukon «mountain» and «woodland» type caribou in body size, and (5 the barren-ground Fortymile caribou were more similar in physical characteristics to Yukon woodland or mountain caribou than to those of the barren-ground Porcupine herd. These data support Banfield's (1961 view of a gradient of decreasing physical size from the northern British Columbia — Alberta herds through the Yukon mountain or woodland herds to the northern barren-ground herds.

  16. Dynamic dipole-dipole interactions between excitons in quantum dots of different sizes

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng

    2004-01-01

    A model of the resonance dynamic dipole-dipole interaction between excitons confined in quantum dots (QDs) of different sizes at close enough distance is given in terms of parity inheritance and exchange of virtual photons. Microphotoluminescence spectra of GaAs-AlGaAs coupled QDs are proposed to...

  17. A study of interaction effect theoretical with combination size grain on magnetics in of permanent magnet

    Tarihoran, Doansi; Manaf, Azwar

    2002-01-01

    Stoner-Wohlfarth theory, SW shows a deviation around 30-40% to the measurement result of a permanent magnetic material with nanometer-sized grains. This is caused by this theory neglecting the interacting grain factor. This research modifies SW theory by calculating the grain interacting effect. The modification is made by assuming the interacting energy of a mono-domain grain has ellipsoidal shaped focused at the edge of the grain. SW grain in this calculation model is a box-shaped in a grain with edges of the box placed in the skin's grain. The result shows that interacting effect make remanent polarization increasing drastically and coercive field value decreasing when grain's size reaches 20% of size of the first mono-domain grain. For material with ND 2 Fe 14 B phase, the optimum coercive field value and remanent polarization that producing maximum product energy, (BH) m ax obtained in a material with 5 nanometer-size grains. Qualitatively there is as appropriate result between the calculation and measurement

  18. Dynamic Dipole-Dipole Interactions between Excitons in Quantum Dots of Different Sizes

    Matsueda, Hideaki; Leosson, Kristjan; Xu, Zhangcheng

    2005-01-01

    Micro-photoluminescence spectra of GaAs/AlGaAs coupled quantum dots (QDs) are given, and proposed to be analyzed by our resonance dynamic dipole-dipole interaction (RDDDI) model, based on parity inheritance and exchange of virtual photons among QDs of different sizes....

  19. Size-dependent interaction of silica nanoparticles with lysozyme and bovine serum albumin proteins

    Yadav, Indresh; Aswal, Vinod K.; Kohlbrecher, Joachim

    2016-05-01

    The interaction of three different sized (diameter 10, 18, and 28 nm) anionic silica nanoparticles with two model proteins—cationic lysozyme [molecular weight (MW) 14.7 kDa)] and anionic bovine serum albumin (BSA) (MW 66.4 kDa) has been studied by UV-vis spectroscopy, dynamic light scattering (DLS), and small-angle neutron scattering (SANS). The adsorption behavior of proteins on the nanoparticles, measured by UV-vis spectroscopy, is found to be very different for lysozyme and BSA. Lysozyme adsorbs strongly on the nanoparticles and shows exponential behavior as a function of lysozyme concentration irrespective of the nanoparticle size. The total amount of adsorbed lysozyme, as governed by the surface-to-volume ratio, increases on lowering the size of the nanoparticles for a fixed volume fraction of the nanoparticles. On the other hand, BSA does not show any adsorption for all the different sizes of the nanoparticles. Despite having different interactions, both proteins induce similar phase behavior where the nanoparticle-protein system transforms from one phase (clear) to two phase (turbid) as a function of protein concentration. The phase behavior is modified towards the lower concentrations for both proteins with increasing the nanoparticle size. DLS suggests that the phase behavior arises as a result of the nanoparticles' aggregation on the addition of proteins. The size-dependent modifications in the interaction potential, responsible for the phase behavior, have been determined by SANS data as modeled using the two-Yukawa potential accounting for the repulsive and attractive interactions in the systems. The protein-induced interaction between the nanoparticles is found to be short-range attraction for lysozyme and long-range attraction for BSA. The magnitude of attractive interaction irrespective of protein type is enhanced with increase in the size of the nanoparticles. The total (attractive+repulsive) potential leading to two-phase formation is found to be

  20. Application of microsatellite markers for breeding and genetic conservation of herds of Pantaneiro sheep

    Bruno do Amaral Crispim

    2014-11-01

    Conclusions: The results of the statistical parameters indicated that populations of Pantaneiro sheep require special attention on herd management, and it's further necessary to implement breeder exchange programs in order to preserve the genetic variability of these populations. Furthermore, the maintenance of those populations in their typical habitats is rather required to allow different responses from the herds to the interactions between genotype and environment.

  1. Modelling Pasture-based Automatic Milking System Herds: The Impact of Large Herd on Milk Yield and Economics

    M. R. Islam

    2015-07-01

    Full Text Available The aim of this modelling study was to investigate the effect of large herd size (and land areas on walking distances and milking interval (MI, and their impact on milk yield and economic penalties when 50% of the total diets were provided from home grown feed either as pasture or grazeable complementary forage rotation (CFR in an automatic milking system (AMS. Twelve scenarios consisting of 3 AMS herds (400, 600, 800 cows, 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as ‘moderate’; optimum pasture utilisation of 19.7 t DM/ha, termed as ‘high’ and 2 rates of incorporation of grazeable complementary forage system (CFS: 0, 30%; CFS = 65% farm is CFR and 35% of farm is pasture were investigated. Walking distances, energy loss due to walking, MI, reduction in milk yield and income loss were calculated for each treatment based on information available in the literature. With moderate pasture utilisation and 0% CFR, increasing the herd size from 400 to 800 cows resulted in an increase in total walking distances between the parlour and the paddock from 3.5 to 6.3 km. Consequently, MI increased from 15.2 to 16.4 h with increased herd size from 400 to 800 cows. High pasture utilisation (allowing for an increased stocking density reduced the total walking distances up to 1 km, thus reduced the MI by up to 0.5 h compared to the moderate pasture, 800 cow herd combination. The high pasture utilisation combined with 30% of the farm in CFR in the farm reduced the total walking distances by up to 1.7 km and MI by up to 0.8 h compared to the moderate pasture and 800 cow herd combination. For moderate pasture utilisation, increasing the herd size from 400 to 800 cows resulted in more dramatic milk yield penalty as yield increasing from c.f. 2.6 and 5.1 kg/cow/d respectively, which incurred a loss of up to $AU 1.9/cow/d. Milk yield losses of 0.61 kg and 0.25 kg for every km increase in total walking distance

  2. Modelling Pasture-based Automatic Milking System Herds: The Impact of Large Herd on Milk Yield and Economics.

    Islam, M R; Clark, C E F; Garcia, S C; Kerrisk, K L

    2015-07-01

    The aim of this modelling study was to investigate the effect of large herd size (and land areas) on walking distances and milking interval (MI), and their impact on milk yield and economic penalties when 50% of the total diets were provided from home grown feed either as pasture or grazeable complementary forage rotation (CFR) in an automatic milking system (AMS). Twelve scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as 'moderate'; optimum pasture utilisation of 19.7 t DM/ha, termed as 'high') and 2 rates of incorporation of grazeable complementary forage system (CFS: 0, 30%; CFS = 65% farm is CFR and 35% of farm is pasture) were investigated. Walking distances, energy loss due to walking, MI, reduction in milk yield and income loss were calculated for each treatment based on information available in the literature. With moderate pasture utilisation and 0% CFR, increasing the herd size from 400 to 800 cows resulted in an increase in total walking distances between the parlour and the paddock from 3.5 to 6.3 km. Consequently, MI increased from 15.2 to 16.4 h with increased herd size from 400 to 800 cows. High pasture utilisation (allowing for an increased stocking density) reduced the total walking distances up to 1 km, thus reduced the MI by up to 0.5 h compared to the moderate pasture, 800 cow herd combination. The high pasture utilisation combined with 30% of the farm in CFR in the farm reduced the total walking distances by up to 1.7 km and MI by up to 0.8 h compared to the moderate pasture and 800 cow herd combination. For moderate pasture utilisation, increasing the herd size from 400 to 800 cows resulted in more dramatic milk yield penalty as yield increasing from c.f. 2.6 and 5.1 kg/cow/d respectively, which incurred a loss of up to $AU 1.9/cow/d. Milk yield losses of 0.61 kg and 0.25 kg for every km increase in total walking distance (voluntary return

  3. Penis size interacts with body shape and height to influence male attractiveness.

    Mautz, Brian S; Wong, Bob B M; Peters, Richard A; Jennions, Michael D

    2013-04-23

    Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male's relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits.

  4. Particle interaction of lubricated or unlubricated binary mixtures according to their particle size and densification mechanism.

    Di Martino, Piera; Joiris, Etienne; Martelli, Sante

    2004-09-01

    The aim of this study is to assess an experimental approach for technological development of a direct compression formulation. A simple formula was considered composed by an active ingredient, a diluent and a lubricant. The active ingredient and diluent were selected as an example according to their typical densification mechanism: the nitrofurantoine, a fragmenting material, and the cellulose microcrystalline (Vivapur), which is a typical visco-elastic material, equally displaying good bind and disintegrant properties. For each ingredient, samples of different particle size distribution were selected. Initially, tabletability of pure materials was studied by a rotary press without magnesium stearate. Vivapur tabletability decreases with increase in particle size. The addition of magnesium stearate as lubricant decreases tabletability of Vivapur of greater particle size, while it kept unmodified that of Vivapur of lower particle size. Differences in tabletability can be related to differences in particle-particle interactions; for Vivapur of higher particle size (Vivapur 200, 102 and 101), the lower surface area develops lower surface available for bonds, while for Vivapur of lower particle size (99 and 105) the greater surface area allows high particle proximity favouring particle cohesivity. Nitrofurantoine shows great differences in compression behaviour according to its particle size distribution. Large crystals show poorer tabletability than fine crystals, further decreased by lubricant addition. The large crystals poor tabletability is due to their poor compactibility, in spite of high compressibility and plastic intrinsic deformability; in fact, in spite of the high densification tendency, the nature of the involved bonds is very weak. Nitrofurantoine samples were then mixed with Vivapurs in different proportions. Compression behaviour of binary mixes (tabletability and compressibility) was then evaluated according to diluents proportion in the mixes. The

  5. Effect of the size of charged spherical macroparticles on their electrostatic interaction in an equilibrium plasma

    Filippov, A. V., E-mail: fav@triniti.ru; Derbenev, I. N. [State Research Center of the Russian Federation, Troitsk Institute for Innovation and Fusion Research (Russian Federation)

    2016-12-15

    The effect of the size of two charged spherical macroparticles on their electrostatic interaction in an equilibrium plasma is analyzed within the linearized Poisson–Botzmann model. It is established that, under the interaction of two charged dielectric macroparticles in an equilibrium plasma, the forces acting on each particle turn out to be generally unequal. The forces become equal only in the case of conducting macroparticles or in the case of dielectric macroparticles of the same size and charge. They also turn out to be equal when the surface potentials of the macroparticles remain constant under the variation of interparticle distances. Formulas are proposed that allow one to calculate the interaction force with a high degree of accuracy under the condition that the radii of macroparticles are much less than the screening length, which is usually satisfied in experiments with dusty plasmas.

  6. Herd-level risk factors for subclinical Salmonella infection in European finishing-pig herds

    Wong, Danilo Lo Fo; Dahl, J.; Stege, H.

    2004-01-01

    Our objective was to find herd factors associated with pigs testing seropositive for Salmonella. Data were collected from 359 finishing-pig herds in Germany, Denmark, Greece, The Netherlands and Sweden, between 1996 and 1998. Pigs fed non-pelleted feed (dry or wet) had 2- and 2.5-times lower odds...... recruiting from more than three supplier herds had three-times higher odds to test seropositive than pigs in herds which breed their own replacement stock or recruit from a maximum of three supplier herds....

  7. Biosecurity in 121 Danish sow herds

    Boklund, Anette; Mortensen, Sten; Houe, H.

    2003-01-01

    Herds are under constant risk of introducing new pathogens from different sources. In this article we describe biosecurity practices in Danish sow herds. Between December 1, 1999 and February 29, 2000, 121 sow units were interviewed regarding biosecurity on the site. The questionnaire contained 6...

  8. Demographic dynamics and off-take of cattle herds in southern Mali.

    Ba, Alassane; Lesnoff, Matthieu; Poccard-Chapuis, Rene; Moulin, Charles-Henri

    2011-08-01

    The herds of 95 families were monitored for 1 year in eight villages in the cotton-growing region of southern Mali. In 2006-2007, reproduction performances were average, with 0.54 calvings/year per cow, and mortality was low. Herd numerical productivity is not very high, less than 0.13/year, because of the high proportion of males kept for animal draught. Depending on the herd size, the behaviour of the families differs, in terms of off-take and in-take of animals. Families that only have one or two draught animals seek to increase their animal draught capacity, with a negative net off-take (-0.13/year). Families with two to three cows have a very low net off-take (0.02/year), with culling of adult animals compensated by purchase. They therefore capitalised this year, with an annual herd growth of 8%. Families with a very large herd (20 to 50 cows) take off more of their stock, with a net off-take of 0.08/year (very few animal purchases) and make a stock growth of 5%. And finally, families with an average-sized herd (6 to 19 cows) take off the whole of the year's production, with a net off-take of 0.11/year and a nil stock growth rate. The use of a demographic model made it possible to measure the sensitivity of the productivity rate to the different demographic parameters.

  9. Influência da interação touro x rebanho na estimação da correlação entre efeitos genéticos direto e materno em bovinos da raça Nelore Influence of sire x herd interaction on the estimation of correlation between direct and maternal genetic effects in Nellore cattle

    Joanir Pereira Eler

    2000-12-01

    Full Text Available A interação touro x rebanho foi avaliada em uma população com 30.789 registros de animais da raça Nelore nascidos entre 1984 e 1994 em doze fazendas localizadas em três Estados do Sudeste e Centro-Oeste brasileiro, com um total de 48.495 animais no pedigree. As características consideradas foram os pesos ao nascer (PESNAS e à desmama (PESDES e o ganho de peso da desmama ao sobreano (GP345. O efeito da interação touro x rebanho foi considerado aleatório em modelos animais uni e bicaraterística, usando MTDFREML. Esse efeito foi importante para PESNAS (6% da variância fenotípica e influenciou os componentes de variância e covariância e, conseqüentemente, os parâmetros genéticos. O efeito foi menor (cerca de 1% da variância fenotípica para PESDES, mas alterou as estimativas dos componentes de variância e covariância. Para GP345, o efeito foi pequeno, embora significativo pelos verossimilhança. As correlações genéticas entre efeitos direto e materno são próximas de zero, ou até mesmo positivas, se a interação touro x rebanho for incluída no modelo, e sempre negativas se ela for omitida.Sire x herd interactions were studied in 30,789 records of birth (BW and weaning weight (WW and weight gain from weaning to 18 months of age (G345 of Nellore cattle born from 1984 to 1994 in twelve farms located in three states of central and southeastern Brazil, with a total of 48.495 animals in pedigree. Sire x herd interaction was considered as a random effect in single trait and two traits animal models using MTDFREML. This effect was important for BW (6% of the phenotypic variance and it both affected variance and covariance components and, consequently, genetic parameters. The effect was smaller for WW (around 1% of the phenotypic variance, but influenced the estimates of (co variance components. For G345, Sire x Herd effect was small. Likelihood tests showed that this effect was significant for all traits. This study showed that

  10. A four year longitudinal sero-epidemiological study of bovine herpesvirus type-1 (BHV-1 in adult cattle in 107 unvaccinated herds in south west England

    Ramirez-Villaescusa Ana M

    2009-01-01

    Full Text Available Abstract Background Bovine herpesvirus type-1 (BHV-1 is an important pathogen of cattle that presents with a variety of clinical signs, including the upper respiratory tract infection infectious bovine rhinotracheitis (IBR. A seroepidemiological study of BHV-1 antibodies was conducted in England from 2002 – 2004: 29,782 blood samples were taken from 15,736 cattle from 114 herds which were visited on up to three occasions. Antibody concentration was measured using a commercial ELISA. Farm management information was collected using an interview questionnaire, and herd size and cattle movements were obtained from the cattle tuberculosis testing database and the British Cattle Movement Service. Hierarchical statistical models were used to investigate associations between cattle and herd variables and the continuous outcome percentage positive (PP values from the ELISA test in unvaccinated herds. Results There were 7 vaccinated herds, all with at least one seropositive bovine. In unvaccinated herds 83.2% had at least one BHV-1 seropositive bovine, and the mean cattle and herd BHV-1 seroprevalence were 42.5% and 43.1% respectively. There were positive associations between PP value, age, herd size, presence of dairy cattle. Adult cattle in herds with grower cattle had lower PP values than those in herds without grower cattle. Purchased cattle had significantly lower PP values than homebred cattle, whereas cattle in herds that were totally restocked after the foot-and-mouth epidemic in 2001 had significantly higher PP values than those in continuously stocked herds. Samples taken in spring and summer had significantly lower PP values than those taken in winter, whereas those taken in autumn had significantly higher PP values than those taken in winter. The risks estimated from a logistic regression model with a binary outcome (seropositive yes/no were similar. Conclusion The prevalence of BHV-1 seropositivity in cattle and herds has increased since

  11. Use of swivel desks and aisle space to promote interaction in mid-sized college classrooms.

    Robert G. Henshaw

    2011-12-01

    Full Text Available Traditional designs for most mid-sized college classrooms discourage 1 face-to-face interaction among students, 2 instructor movement in the classroom, and 3 efficient transitions between different kinds of learning activities. An experimental classroom piloted during Spring Semester 2011 at the University of North Carolina at Chapel Hill uses clusters of stationary desks that swivel 360-degrees and aisle space to address these challenges. The findings from a study involving ten courses taught in the room suggest that there is a need for designs that not only promote quality interactions but also facilitate movement between small group work, class discussion, and lecture.

  12. Fluorosis in a dairy herd

    Jones, W G

    1972-04-29

    Investigation of a high incidence of hip arthritis in a herd of Ayrshires resulted in the discovery of abnormal levels of fluorine in samples of bone. Suspicion of fluorosis was not aroused earlier as the area is not contaminated by industrial fall-out. In addition, many affected animals had no lesions in their teeth; this was because their dentition was complete before ingesting fluorine from a mineral supplement. Only cows receiving toxic levels of fluorine during their first lactation showed lesions, and these were confined to the fourth pair of incisors. Two metabolic profile tests were caried out to establish that the input-output balance in the main metabolites was normal. Analysis of various constituents of the diet revealed significant levels of fluorine in the mineral supplement only. Arthritis was the most prominent feature. This led to debility, with loss of milk and carcase value. Confirmation of fluorosis was obtained by analysis of bone and urine.

  13. Role of the anisotropy in the interactions between nano- and micro-sized particles

    Rovigatti, Lorenzo

    2012-01-01

    The present Thesis focuses on the thermodynamic and dynamic behaviour of anisotropically interacting colloids by means of theoretical and numerical techniques. Colloidal suspensions, i.e. micro-- and nano--sized particles dispersed in a continuous phase, are a topic of great interest in several fields, including material science, soft matter and biophysics. Common in everyday life in the form of soap, milk, cream, etc., colloids have been used for decades as models for atomic and molecula...

  14. Limitations of interaction-point spot-size tuning at the SLC

    Emma, P.; Hendrickson, L.J.; Zimmermann, F.; Raimondi, P.

    1997-05-01

    At the Stanford Linear Collider (SLC), the interaction-point spot size is minimized by repeatedly correcting, for both beams, various low-order optical aberrations, such as dispersion, waist position or coupling. These corrections are performed about every 8 hours, by minimizing the IP spot size while exciting different orthogonal combinations of final-focus magnets. The spot size itself is determined by measuring the beam deflection angle as a function of the beam-beam separation. Additional information is derived from the energy loss due to beamstrahlung and from luminosity-related signals. In the 1996 SLC run, the typical corrections were so large as to imply a 20-40% average luminosity loss due to residual uncompensated or fluctuating tunable aberrations. In this paper, the authors explore the origin of these large tuning corrections and study possible mitigations for the next SLC run

  15. Interaction of lysozyme protein with different sized silica nanoparticles and their resultant structures

    Yadav, Indresh, E-mail: iykumarindresh288@gmail.com; Aswal, V. K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kohlbrecher, J. [Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 PSI Villigen (Switzerland)

    2016-05-23

    The interaction of model protein-lysozyme with three different sized anionic silica nanoparticles has been studied by UV-vis spectroscopy, dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The surface area and curvature of the nanoparticles change with size, which significantly influence their interaction with protein. The lysozyme adsorbs on the surface of the nanoparticles due to electrostatic attraction and leads to the phase transformation from one phase (clear) to two-phase (turbid) of the nanoparticle-protein system. The dominance of lysozyme induced short-range attraction over long-range electrostatic repulsion between nanoparticles is responsible for phase transformation and modeled by the two-Yukawa potential. The magnitude of the attractive interaction increases with the size of the nanoparticles as a result the phase transformation commences relatively at lower concentration of lysozyme. The structure of the nanoparticle-protein system in two-phase is characterized by the diffusion limited aggregate type of mass fractal morphology.

  16. Effects of Litter Size on Maternal – Offspring Interactions in Sheep

    Dinu Gavojdian

    2013-05-01

    Full Text Available The aim of the current research was to evaluate the effects that litter size (single vs. twin born lambs has on maternal – offspring interactions in Turcana mountain sheep breed during the first 4 weeks after lambing. Behavioural patterns such as dam – lamb(s contact, suckling (duration and periods and vocalization frequency were studied. During first 24 hours after lambing, ewes spend on average 40.9±3.15 minutes in close contact with their lambs, while the following weeks they have spent significantly (p≤0.05 less time in contact with the lambs i.e. 20.6±3.17 in day 7, 16.8±2.15 in day 14 and 14.5±1.26 minutes in day 21. Litter size had no significant effect (p≥0.05 on the frequency of vocalizations or the time spent in contact with their lamb(s in Turcana ewes. Results of the current research shown that litter size in multiparous Turcana mountain sheep breed had limited effects on the ewe-lamb interactions. The experienced ewes, based on the excellent mothering ability and strong maternal instincts, can rear with minimal stress twin litters when winter lambing occurs indoors and under proper management. Further comparative studies are planned in order to study the effects of triplet births and parity on maternal-offspring interactions in Turcana ewes.

  17. Ecology of the Porcupine caribou herd

    Kenneth R. Whitten

    1996-01-01

    Full Text Available Researchers have described general patterns of population regulation that fit most caribou (Rangifer tarandus herds. Nevertheless, specific factors operating on particular populations vary greatly, and efforts to categorize herds according to the general patterns often lead to confusion. It is difficult for biologists to attempt to describe population dynamics in terms of density relationships for wide-ranging arctic caribou such as the Porcupine Herd. In these herds density varies as a function of dispersal and erratic movement patterns and is not simply the number of caribou divided by a fixed range area. Density is also a poor surrogate for resource availability per individual caribou because climatic factors affect forage and/or access to forage independendy of caribou numbers. Thus classic signs of nutritional stress such as delayed puberty, reduced productivity, and winter starvation can occur when a population is small as well as large and do not necessarily denote food competition brought on by high density, per se. Nutritional stress and exacerbated predation due to adverse weather conditions occasionally cause the Porcupine Herd to decline, and limiting factors such as poor nutrition, predation, harvest, accidents, and disease act in combination to keep herd growth rates low during periods of good weather. Adverse weather setbacks occur frequently, and the herd remains within a fairly restricted range of densities over long time periods. There is no true density dependent regulation and no equilibrium in this system.

  18. An epidemiological investigation of the early phase of the porcine epidemic diarrhea (PED) outbreak in Canadian swine herds in 2014: A case-control study.

    Perri, Amanda M; Poljak, Zvonimir; Dewey, Cate; Harding, John C S; O'Sullivan, Terri L

    2018-02-01

    The first case of porcine epidemic diarrhea (PED) in Canada was diagnosed in January 2014 in Ontario, approximately 9 months after PED emerged in the United States. An early investigation of the Canadian outbreak suspected that the probable source of the virus was contaminated feed. The objective of this study was to evaluate the role of feed and other possible factors in the early phase of the PED outbreak in Canadian swine herds. The study period of interest for this case-control study was January 22nd to March 1st, 2014. A case herd was defined as a swine herd with a confirmed positive laboratory diagnostic test (RT-PCR) results for PED virus, along with pigs exhibiting typical clinical signs at the herd level during the study period. A questionnaire was administered to participating producers from the 22 Canadian swine herds enrolled (n = 9 case and n = 13 control herds). Case herd producers were asked to provide information from the initial day of onset of clinical signs and 30 days prior to that day. Control herds were matched to a case herd on the basis of province, herd type and approximate size. The period of interest for a control herd was matched to the initial day of clinical signs of PED for the case herd, along with the 30 days prior to this day. The questionnaire questions focused on herd demographics, biosecurity protocols, live animal movements onto and off sites, deadstock movements, feed and people movements for both the case and control herds. The questionnaire for control herds were based on their matched case's period of interest, and together with case herds formed a matched stratum. Multivariable exact conditional logistic regression and mixed multivariable logistic regression models, with the matched stratum as a random effect, were used to assess the association between various risk factors and the odds of PED introduction into a herd. After adjusting for biosecurity practices, the odds of a PED occurrence was 38.1 (95% CI: 2

  19. Evaluation of milk yield losses associated with Salmonella antibodies in bulk tank milk in bovine dairy herds.

    Nielsen, T D; Green, L E; Kudahl, A B; Østergaard, S; Nielsen, L R

    2012-09-01

    The effect of Salmonella on milk production is not well established in cattle. The objective of this study was to investigate whether introduction of Salmonella into dairy cattle herds was associated with reduced milk yield and determine the duration of any such effect. Longitudinal data from 2005 through 2009 were used, with data from 12 mo before until 18 mo after the estimated date of infection. Twenty-eight case herds were selected based on an increase in the level of Salmonella-specific antibodies in bulk-tank milk from levels consistently energy-corrected milk (ECM)/cow were used to investigate daily milk yield before and after the estimated herd infection date for cows in parities 1, 2, and 3+. Control herds were used to evaluate whether the effects in the case herds could be reproduced in herds without Salmonella infection. Herd size, days in milk, somatic cell count, season, and year were included in the models. Yield in first-parity cows was reduced by a mean of 1.4 kg (95% confidence interval: 0.5 to 2.3) of ECM/cow per day from 7 to 15 mo after the estimated herd infection date, compared with that of first-parity cows in the same herds in the 12 mo before the estimated herd infection date. Yield for parity 3+ cows was reduced by a mean of 3.0 kg (95% confidence interval: 1.3 to 4.8) of ECM/cow per day from 7 to 15 mo after herd infection compared with that of parity 3+ cows in the 12 mo before the estimated herd infection. We observed minor differences in yield in second-parity cows before and after herd infection and observed no difference between cows in control herds before and after the simulated infection date. Milk yield decreased significantly in affected herds and the reduction was detectable several months after the increase in bulk tank milk Salmonella antibodies. It took more than 1 yr for milk yield to return to preinfection levels. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Time budgets of lactating dairy cattle in commercial freestall herds.

    Gomez, A; Cook, N B

    2010-12-01

    The aim of this study was to examine the time budgets of 205 lactating dairy cows housed in 16 freestall barns in Wisconsin and to determine the relationships between components of the time budget and herd- and cow-level fixed effects using mixed models. Using continuous video surveillance, time lying in the stall, time standing in the stall, time standing in the alleys (including drinking), time feeding, and time milking (time out of the pen for milking and transit) during a 24-h period were measured for each cow. In addition, the number of lying bouts and the mean duration of each lying bout per 24-h period were determined. Time milking varied between cows from 0.5 to 6.0 h/d, with a mean ± standard deviation of 2.7 ± 1.1h/d. Time milking was influenced significantly by pen stocking density, and time milking negatively affected time feeding, time lying, and time in the alley, but not time standing in the stall. Locomotion score, either directly or through an interaction with stall base type (a rubber crumb-filled mattress, MAT, or sand bedding, SAND), influenced pen activity. Lame cows spent less time feeding, less time in the alleys, and more time standing in the stalls in MAT herds, but not in SAND herds. The effect of lameness on lying time is complex and dependent on the time available for rest and differences in resting behavior observed between cows in MAT and SAND herds. In MAT herds, rest was characterized by a larger number of lying bouts of shorter duration than in SAND herds (mean = 14.4; confidence interval, CI: 12.4 to 16.5 vs. mean = 10.2; CI: 8.2 to 12.2 bouts per d, and mean = 1.0; CI: 0.9 to 1.1 vs. mean = 1.3, CI: 1.2 to 1.4h bout duration for MAT and SAND herds, respectively). Lameness was associated with an increase in time standing in the stall and a reduction in the mean (CI) number of lying bouts per day from 13.2 (CI: 12.3 to 14.1) bouts/d for nonlame cows to 10.9 (CI: 9.30 to 12.8) bouts/d for moderately lame cows, and an overall

  1. Interactive effects of body-size structure and adaptive foraging on food-web stability.

    Heckmann, Lotta; Drossel, Barbara; Brose, Ulrich; Guill, Christian

    2012-03-01

    Body-size structure of food webs and adaptive foraging of consumers are two of the dominant concepts of our understanding how natural ecosystems maintain their stability and diversity. The interplay of these two processes, however, is a critically important yet unresolved issue. To fill this gap in our knowledge of ecosystem stability, we investigate dynamic random and niche model food webs to evaluate the proportion of persistent species. We show that stronger body-size structures and faster adaptation stabilise these food webs. Body-size structures yield stabilising configurations of interaction strength distributions across food webs, and adaptive foraging emphasises links to resources closer to the base. Moreover, both mechanisms combined have a cumulative effect. Most importantly, unstructured random webs evolve via adaptive foraging into stable size-structured food webs. This offers a mechanistic explanation of how size structure adaptively emerges in complex food webs, thus building a novel bridge between these two important stabilising mechanisms. © 2012 Blackwell Publishing Ltd/CNRS.

  2. Gastrointestinal nematodes and anthelmintic resistance in Danish goat herds

    Holm, Signe A.; Sørensen, Camilla; Thamsborg, Stig M.

    2014-01-01

    The prevalence of gastrointestinal parasites in Danish goats and the presence of anthelmintic resistance (AR) in 10 selected herds were investigated during April-September 2012. All Danish herds (n = 137) with 10 or more adult goats were invited to participate, and of these 27 herds met......, resistance to the most commonly used anthelmintics is widespread in larger goat herds throughout Denmark....

  3. Developing an interactive portion size assessment system (IPSAS) for use with children.

    Foster, E; Hawkins, A; Simpson, E; Adamson, A J

    2014-01-01

    Novel methods of assessing dietary intake are required to reduce the participant burden in dietary surveys, improve participation rates and thereby improve the representativeness of the sample and minimise the impact of measuring dietary intake on a subject's food intake during the recording period. One method of reducing the burden placed on participants in recording dietary intake is to replace weighing of foods with estimation of portion size using tools such as food photographs. The interactive portion size assessment system (IPSAS) is an interactive portion size assessment system for use in assessing portion sizes of foods consumed by children aged 18 months to 16 years. The system is computer-based and is designed to be administered during an interview for a food diary or 24-h recall. The portion sizes depicted are age-specific and based on the weights of foods served to children during the UK National Diet and Nutrition Surveys. The system displays digital images of food used to estimate the amount of each food served to the child and the amount of any food left over. Foods are categorised within the system using a three-tier structure. Twenty-seven food group icons are used with two further drop-down menus to select first the food group, then the food category and, finally, the actual food product. Each food is linked to UK food composition codes and all photographs are linked to the weight of the food depicted. Nutritional output is via a companion database. The present study describes the development of the IPSAS and the structure of the system. © 2013 The Authors Journal of Human Nutrition and Dietetics © 2013 The British Dietetic Association Ltd.

  4. Towards a theory of cortical columns: From spiking neurons to interacting neural populations of finite size

    Gerstner, Wulfram

    2017-01-01

    Neural population equations such as neural mass or field models are widely used to study brain activity on a large scale. However, the relation of these models to the properties of single neurons is unclear. Here we derive an equation for several interacting populations at the mesoscopic scale starting from a microscopic model of randomly connected generalized integrate-and-fire neuron models. Each population consists of 50–2000 neurons of the same type but different populations account for different neuron types. The stochastic population equations that we find reveal how spike-history effects in single-neuron dynamics such as refractoriness and adaptation interact with finite-size fluctuations on the population level. Efficient integration of the stochastic mesoscopic equations reproduces the statistical behavior of the population activities obtained from microscopic simulations of a full spiking neural network model. The theory describes nonlinear emergent dynamics such as finite-size-induced stochastic transitions in multistable networks and synchronization in balanced networks of excitatory and inhibitory neurons. The mesoscopic equations are employed to rapidly integrate a model of a cortical microcircuit consisting of eight neuron types, which allows us to predict spontaneous population activities as well as evoked responses to thalamic input. Our theory establishes a general framework for modeling finite-size neural population dynamics based on single cell and synapse parameters and offers an efficient approach to analyzing cortical circuits and computations. PMID:28422957

  5. Towards a theory of cortical columns: From spiking neurons to interacting neural populations of finite size.

    Schwalger, Tilo; Deger, Moritz; Gerstner, Wulfram

    2017-04-01

    Neural population equations such as neural mass or field models are widely used to study brain activity on a large scale. However, the relation of these models to the properties of single neurons is unclear. Here we derive an equation for several interacting populations at the mesoscopic scale starting from a microscopic model of randomly connected generalized integrate-and-fire neuron models. Each population consists of 50-2000 neurons of the same type but different populations account for different neuron types. The stochastic population equations that we find reveal how spike-history effects in single-neuron dynamics such as refractoriness and adaptation interact with finite-size fluctuations on the population level. Efficient integration of the stochastic mesoscopic equations reproduces the statistical behavior of the population activities obtained from microscopic simulations of a full spiking neural network model. The theory describes nonlinear emergent dynamics such as finite-size-induced stochastic transitions in multistable networks and synchronization in balanced networks of excitatory and inhibitory neurons. The mesoscopic equations are employed to rapidly integrate a model of a cortical microcircuit consisting of eight neuron types, which allows us to predict spontaneous population activities as well as evoked responses to thalamic input. Our theory establishes a general framework for modeling finite-size neural population dynamics based on single cell and synapse parameters and offers an efficient approach to analyzing cortical circuits and computations.

  6. Within-herd prevalence of Salmonella Dublin in endemically infected dairy herds

    Nielsen, Liza Rosenbaum

    2013-01-01

    SUMMARY In this study within-herd prevalence of Salmonella Dublin was investigated in three age groups (calves, young stock, adult cows) during five herd visits at 3-month intervals of 14 endemically infected dairy herds. A total of 10162 paired faecal cultures and antibody measurements were used...... stock and adult cows than in calves. Hierarchical mixed-model results showed that seroprevalence was associated with the bacteriological status in calves and cows, but not in young stock. These results can be used to develop and validate theoretical infection dynamics models and to design effective...... control programmes for Salmonella Dublin in dairy herds....

  7. THE HERD BEHAVIOR AND THE FINANCIAL INSTABILITY

    CRISTIAN IONESCU

    2012-01-01

    Full Text Available Given the international financial situation of the last 50 years, and considering the complexity and severity of the financial crises, it is important to study the episodes of financial instability, and especially to understand both operating mechanisms and propagation mechanisms. One endogenous mechanism of financial instability is the herd behavior, which may increase the volatility and the amplitude of any sub-part of the financial system. This paper aims to analyze this phenomenon, considering the behavior of the financial market participants, the role of information in the making decisions process, banking responsibility regarding the herd behavior. The paper also illustrates two examples of herd behavior (run bank and the "too many to fail" problem, and presents three herding measures, in an attempt to achieve a quantitative analysis of the phenomenon, besides the qualitative analysis exposed above.

  8. Applying a synthetic approach to the resilience of Finnish reindeer herding as a changing livelihood

    Simo Sarkki

    2016-12-01

    Full Text Available Reindeer herding is an emblematic livelihood for Northern Finland, culturally important for local people and valuable in tourism marketing. We examine the livelihood resilience of Finnish reindeer herding by narrowing the focus of general resilience on social-ecological systems (SESs to a specific livelihood while also acknowledging wider contexts in which reindeer herding is embedded. The questions for specified resilience can be combined with the applied DPSIR approach (Drivers; Pressures: resilience to what; State: resilience of what; Impacts: resilience for whom; Responses: resilience by whom and how. This paper is based on a synthesis of the authors' extensive anthropological fieldwork on reindeer herding and other land uses in Northern Finland. Our objective is to synthesize various opportunities and challenges that underpin the resilience of reindeer herding as a viable livelihood. The DPSIR approach, applied here as a three step procedure, helps focus the analysis on different components of SES and their dynamic interactions. First, various land use-related DPSIR factors and their relations (synergies and trade-offs to reindeer herding are mapped. Second, detailed DPSIR factors underpinning the resilience of reindeer herding are identified. Third, examples of interrelations between DPSIR factors are explored, revealing the key dynamics between Pressures, State, Impacts, and Responses related to the livelihood resilience of reindeer herding. In the Discussion section, we recommend that future applications of the DPSIR approach in examining livelihood resilience should (1 address cumulative pressures, (2 consider the state dimension as more tuned toward the social side of SES, (3 assess both the negative and positive impacts of environmental change on the examined livelihood by a combination of science led top-down and participatory bottom-up approaches, and (4 examine and propose governance solutions as well as local adaptations by

  9. Quantifying the risk of spread of bovine viral diarrhoea virus (BVDV) between contiguous herds in Ireland.

    Graham, D A; Clegg, T A; Thulke, H-H; O'Sullivan, P; McGrath, G; More, S J

    2016-04-01

    The control of bovine viral diarrhoea virus (BVDV) mainly focuses on the identification and restriction of persistently infected (PI) animals. However, other transmission pathways can also result in new breakdowns, including the movement of animals pregnant with PI calves (Trojan animals) and the spread of infection between contiguous farms. Contiguous spread is likely an important problem in the BVD eradication programme in Ireland, given the spatial distribution of residual infection, and the highly fragmented nature of land holdings on many Irish farms. In this study, we seek to quantify the risk of BVD spread between contiguous herds in Ireland. Multivariable logistic models were used to estimate the risk of a herd having BVD positive calves in January to June 2014 (the study period) when contiguous to a herd that had at least one BVD positive calf born in 2013. The models included risk factors relating to the study herd and to neighbouring herds. Separate multivariable models were built for each of four "PI-neighbour" factors relating to the presence of BVD+ animals and/or the presence of offspring of PI breeding animals. In total, 58,483 study herds were enrolled. The final model contained the province, the log of the number of calf births born during the study period, the number of cattle purchased between January 2013 and January 2014, and with a two-way interaction between the number of animals of unknown BVD status in the study herd and the PI-neighbour risk factor. When the number of PI-neighbour herds was used as the PI-neighbour risk factor, the odds ratio (OR) associated with the number of PI-neighbour herds ranged from 1.07 to 3.02, depending on the number of unknown animals present. To further explore the risk associated with PI-neighbour factors, the models were repeated using a subset of the study herds (n=7440) that contained no animals of unknown status. The best fitting model including "any PI-neighbour" as the PI-neighbour factor and also

  10. Size-effects at a crack-tip interacting with a number of voids

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2008-01-01

    A strain gradient plasticity theory is used to analyse the growth of discretely represented voids in front of a blunting crack tip, in order to study the influence of size effects on two competing mechanisms of crack growth. For a very small void volume fraction the crack tip tends to interact...... of the characteristic material length relative to the initial void radius. For a case showing the multiple void mechanism, it is found that the effect of the material length can change the behaviour towards the void by void mechanism. A material model with three characteristic length scales is compared with a one...

  11. The effect of diet and opponent size on aggressive interactions involving caribbean crazy ants (Nylanderia fulva.

    Katherine C Horn

    Full Text Available Biotic interactions are often important in the establishment and spread of invasive species. In particular, competition between introduced and native species can strongly influence the distribution and spread of exotic species and in some cases competition among introduced species can be important. The Caribbean crazy ant, Nylanderia fulva, was recently introduced to the Gulf Coast of Texas, and appears to be spreading inland. It has been hypothesized that competition with the red imported fire ant, Solenopsis invicta, may be an important factor in the spread of crazy ants. We investigated the potential of interspecific competition among these two introduced ants by measuring interspecific aggression between Caribbean crazy ant workers and workers of Solenopsis invicta. Specifically, we examined the effect of body size and diet on individual-level aggressive interactions among crazy ant workers and fire ants. We found that differences in diet did not alter interactions between crazy ant workers from different nests, but carbohydrate level did play an important role in antagonistic interactions with fire ants: crazy ants on low sugar diets were more aggressive and less likely to be killed in aggressive encounters with fire ants. We found that large fire ants engaged in fewer fights with crazy ants than small fire ants, but fire ant size affected neither fire ant nor crazy ant mortality. Overall, crazy ants experienced higher mortality than fire ants after aggressive encounters. Our findings suggest that fire ant workers might outcompete crazy ant workers on an individual level, providing some biotic resistance to crazy ant range expansion. However, this resistance may be overcome by crazy ants that have a restricted sugar intake, which may occur when crazy ants are excluded from resources by fire ants.

  12. Migratory divides and their consequences for dispersal, population size and parasite-host interactions.

    Møller, A P; Garamszegi, L Z; Peralta-Sánchez, J M; Soler, J J

    2011-08-01

    Populations of migratory birds differ in their direction of migration with neighbouring populations often migrating in divergent directions separated by migratory divides. A total of 26% of 103 passerine bird species in Europe had migratory divides that were located disproportionately often along a longitudinal gradient in Central Europe, consistent with the assumption of a Quaternary glacial origin of such divides in the Iberian and Balkan peninsulas followed by recolonization. Given that studies have shown significant genetic differentiation and reduced gene flow across migratory divides, we hypothesized that an absence of migratory divides would result in elevated rates of gene flow and hence a reduced level of local adaptation. In a comparative study, species with migratory divides had larger population sizes and population densities and longer dispersal distances than species without migratory divides. Species with migratory divides tended to be habitat generalists. Bird species with migratory divides had higher richness of blood parasites and higher growth rates of Staphylococcus on their eggs during the incubation period. There was weaker cell-mediated immunity in adults and stronger cell lysis in species with migratory divides. These findings may suggest that migratory divides constitute barriers to dispersal with consequences for ecology and evolution of distributions, population sizes, habitats and parasite-host interactions. They also suggest that migratory divides may play a role in local adaptation in host-parasite interactions. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  13. Effect of Growing Size of Interaction Neighbors on the Evolution of Cooperation in Spatial Snowdrift Game

    Zhang Juanjuan; Sun Shiwen; Wang Li; Xia Chengyi; Wang Juan; Wang Zhen

    2012-01-01

    In this paper, we study the influence of the size of interaction neighbors (k) on the evolution of cooperation in the spatial snowdrift game. At first, we consider the effects of noise K and cost-to-benefit ratio r, the simulation results indicate that the evolution of cooperation depends on the combined action of noise and cost-to-benefit ratio. For a lower r, the cooperators are multitudinous and the cooperation frequency ultimately increases to 1 as the increase of noise. However, for a higher r, the defectors account for the majority of the game and dominate the game if the noise is large enough. Then we mainly investigate how k influences the evolution of cooperation by varying the noise in detail. We find that the frequency of cooperators is closely related to the size of neighborhood and cost-to-benefit ratio r. In the case of lower r, the augmentation of k plays no positive role in promoting the cooperation as compared with that of k = 4, while for higher r the cooperation is improved for a growing size of neighborhood. At last, based on the above discussions, we explore the cluster-forming mechanism among the cooperators. The current results are beneficial to further understand the evolution of cooperation in many natural, social and biological systems. (general)

  14. Interactions between fluvial forces and vegetation size, density and morphology influence plant mortality during experimental floods

    Stella, J. C.; Kui, L.; Manners, R.; Wilcox, A. C.; Lightbody, A.; Sklar, L. S.

    2015-12-01

    Introduction and methods Fluvial disturbance is a key driver of riparian vegetation dynamics in river corridors. Despite an increasing understanding of ecohydraulic interactions between plants and fluvial forces, the interactive influences of plant morphology and sediment supply on plant mortality, a key demographic factor, are largely unknown. To better understand these processes, we designed and conducted a series of flume experiments to: (1) quantify effects of plant traits that interact with flow and sediment transport on plant loss to scour during floods; and (2) predict plant dislodgement for different species across a range of plant sizes, patch densities, and sediment condition (equilibrium transport versus sediment deficit). We ran ten experimental floods in a 28 m long × 0.6 m wide × 0.71 m tall flume, using live, 1-3 year-old tamarisk and cottonwood seedlings with contrasting morphologies with varied combinations of size and density. Results and discussion Both sediment supply and plant traits (morphology and composition) have significant impacts on plant vulnerability during floods. Sediment deficit resulted in bed degradation and a 35% greater risk of plant loss compared to equilibrium sediment conditions. The probability of plant dislodgement in sparse patches was 4.5 times greater than in dense patches. Tamarisk plants and patches had greater frontal area, basal diameter and longer roots compared to cottonwood across all seedling heights. These traits, as well as its lower crown position reduced tamarisk's vulnerability to scour by 75%. Compared with cottonwood, tamarisk exhibits better resistance to floods, due to its greater root biomass and longer roots that stabilize soil, and its greater frontal area and lower crown that effectively trap sediment. These traits likely contribute to riverscape-scale changes in channel morphology that are evident where tamarisk has invaded native riparian communities, and explain the persistence of tamarisk

  15. Escaping Electrons from Intense Laser-Solid Interactions as a Function of Laser Spot Size

    Rusby Dean

    2018-01-01

    Full Text Available The interaction of a high-intensity laser with a solid target produces an energetic distribution of electrons that pass into the target. These electrons reach the rear surface of the target creating strong electric potentials that act to restrict the further escape of additional electrons. The measurement of the angle, flux and spectra of the electrons that do escape gives insights to the initial interaction. Here, the escaping electrons have been measured using a differentially filtered image plate stack, from interactions with intensities from mid 1020-1017 W/cm2, where the intensity has been reduced by defocussing to increase the size of the focal spot. An increase in electron flux is initially observed as the intensity is reduced from 4x1020 to 6x1018 W/cm2. The temperature of the electron distribution is also measured and found to be relatively constant. 2D particle-in-cell modelling is used to demonstrate the importance of pre-plasma conditions in understanding these observations.

  16. Prevalence of intestinal pathogens in Danish finishing pig herds

    Stege, H.; Jensen, Tim Kåre; Møller, Kristian

    2000-01-01

    Our aim was to determine the prevalence of the intestinal bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Serpulina intermedia, Brachyspira innocens, Brachyspira pilosicoli, pathogenic Escherichia coli (serogroups 0138, 0139, 0141 and 0149) and Salmonella enterica in Danish...... were collected and examined by polymerase chain reaction (PCR) or culture. L. intracellularis was found in 74 herds (93.7%), B. hyodysenteriae in two herds (2.5%), S. intermedia in 10 herds (12.7%), B. innocens in 27 herds (34.2%), B. pilosicoli in 15 herds (19.0%), pathogenic E. call in 19 herds (24...

  17. Mitigating Herding in Hierarchical Crowdsourcing Networks.

    Yu, Han; Miao, Chunyan; Leung, Cyril; Chen, Yiqiang; Fauvel, Simon; Lesser, Victor R; Yang, Qiang

    2016-12-05

    Hierarchical crowdsourcing networks (HCNs) provide a useful mechanism for social mobilization. However, spontaneous evolution of the complex resource allocation dynamics can lead to undesirable herding behaviours in which a small group of reputable workers are overloaded while leaving other workers idle. Existing herding control mechanisms designed for typical crowdsourcing systems are not effective in HCNs. In order to bridge this gap, we investigate the herding dynamics in HCNs and propose a Lyapunov optimization based decision support approach - the Reputation-aware Task Sub-delegation approach with dynamic worker effort Pricing (RTS-P) - with objective functions aiming to achieve superlinear time-averaged collective productivity in an HCN. By considering the workers' current reputation, workload, eagerness to work, and trust relationships, RTS-P provides a systematic approach to mitigate herding by helping workers make joint decisions on task sub-delegation, task acceptance, and effort pricing in a distributed manner. It is an individual-level decision support approach which results in the emergence of productive and robust collective patterns in HCNs. High resolution simulations demonstrate that RTS-P mitigates herding more effectively than state-of-the-art approaches.

  18. Seasonal resource value and male size influence male aggressive interactions in the leaf footed cactus bug, Narnia femorata.

    Nolen, Zachary J; Allen, Pablo E; Miller, Christine W

    2017-05-01

    In animal contests, resource value (the quality of a given resource) and resource holding potential (a male's absolute fighting ability) are two important factors determining the level of engagement and outcome of contests. Few studies have tested these factors simultaneously. Here, we investigated whether natural, seasonal differences in cactus phenology (fruit quality) influence interactions between males in the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae). We also considered whether males were more likely to interact when they were similar in size, as predicted by theory. Finally, we examined if male size relative to the size of an opponent predicted competitive success. We found that males have more interactions on cactus with high value ripe fruit, as we predicted. Further, we found that males that were closer in size were more likely to interact, and larger males were more likely to become dominant. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Neospora caninum in beef herds in New South Wales, Australia. 2: analysis of risk factors.

    Moloney, B J; Heuer, C; Kirkland, P D

    2017-04-01

    To determine the influence of farm-level and animal-level factors on the seroprevalence of antibodies to Neospora caninum and associations between seropositivity and reproductive outcomes. A questionnaire for a cross-sectional survey was posted to the 63 properties with a herd size ≥50 beef breeding cows that had participated in a previous seroprevalence study. Correspondence analysis, which does not appear to have been used previously in any Australian studies of livestock diseases, was used in conjunction with logistic regression to analyse the data. Geographic factors that increased the risk of seropositivity included higher rainfall North Coast location. Herd management factors that increased the risk of seropositivity included the use of Bos indicus genetics, cross-breeding and running several breeds in the one herd. Using fox control measures was found to be protective against infection with N. caninum. The risk of abortion was 12-fold greater in individual animals that were seropositive for N. caninum. Within a herd, the calving rate was 10.4% lower in herds with one or more N. caninum-positive animals (P = 0.03), but the difference in abortion rate was not significant between seropositive and seronegative herds (0.3% higher, P > 0.3). This study confirmed previous observations of increased risks for N. caninum seropositivity with being located in the coastal subtropics, some styles of herd management and canid exposure. In addition, it suggested that cross-breeding and proximity to an urban area may increase the risk, and that having pet dogs may reduce the risk of seropositivity. © 2017 State of New South Wales.

  20. The particle size distribution of fragmented melt debris from molten fuel coolant interactions

    Fletcher, D.F.

    1984-04-01

    Results are presented of a study of the types of statistical distributions which arise when examining debris from Molten Fuel Coolant Interactions. The lognormal probability distribution and the modifications of this distribution which result from the mixing of two distributions or the removal of some debris are described. Methods of fitting these distributions to real data are detailed. A two stage fragmentation model has been developed in an attempt to distinguish between the debris produced by coarse mixing and fine scale fragmentation. However, attempts to fit this model to real data have proved unsuccessful. It was found that the debris particle size distributions from experiments at Winfrith with thermite generated uranium dioxide/molybdenum melts were Upper Limit Lognormal. (U.K.)

  1. Size exclusion chromatography of lignin: The mechanistic aspects and elimination of undesired secondary interactions.

    Andrianova, Anastasia A; Yeudakimenka, Natallia A; Lilak, Samuel L; Kozliak, Evguenii I; Ugrinov, Angel; Sibi, Mukund P; Kubátová, Alena

    2018-01-26

    Characterization of lignin and its degradation products, more specifically determination of their molecular weight (MW) distribution, is essential for assessment and applications of these potentially renewable phenolics. Several representative gel filtration and gel permeation systems were evaluated in this work focusing on understanding of undesired secondary non-SEC interactions while utilizing four sets of commercially available polymeric standards as well as low-MW lignin model compounds including diarene standards synthesized in-house. The gel permeation column with a nonpolar highly cross-linked porous polystyrene/divinylbenzene-based stationary phase provided the most effective separation by MW for both low and high MW model compounds. Notably, the column with a higher pore and lower particle size provided a better resolution towards polymeric standards, even though the particle size effect was downplayed in the earlier SEC studies of lignin. For two other evaluated gel filtration and gel permeation columns, the separation was strongly affected by functionalities of the analytes and correlated with the compounds' pK a rather than MW. We showed that the separation on the stationary phases featuring polar hydroxyl groups led to specific column-analyte secondary interactions, perhaps based on their hydrogen bonding with lignin. Further, the SEC column evaluation yielded similar results with two sets of chemically different standards. This setup may be used as a general approach to selecting an applicable column for lignin SEC analysis. We confirmed the obtained results with a different independent method implementing a novel approach for lignin number-average MW (M n ) calculation based on laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS) data. The determined M n corroborated the SEC results. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Resonant atom-field interaction in large-size coupled-cavity arrays

    Ciccarello, Francesco

    2011-01-01

    We consider an array of coupled cavities with staggered intercavity couplings, where each cavity mode interacts with an atom. In contrast to large-size arrays with uniform hopping rates where the atomic dynamics is known to be frozen in the strong-hopping regime, we show that resonant atom-field dynamics with significant energy exchange can occur in the case of staggered hopping rates even in the thermodynamic limit. This effect arises from the joint emergence of an energy gap in the free photonic dispersion relation and a discrete frequency at the gap's center. The latter corresponds to a bound normal mode stemming solely from the finiteness of the array length. Depending on which cavity is excited, either the atomic dynamics is frozen or a Jaynes-Cummings-like energy exchange is triggered between the bound photonic mode and its atomic analog. As these phenomena are effective with any number of cavities, they are prone to be experimentally observed even in small-size arrays.

  3. Influence of grain size and exchange interaction on the LLB modeling procedure

    Vogler, Christoph; Abert, Claas; Bruckner, Florian; Suess, Dieter; Praetorius, Dirk

    2016-12-01

    Reliably predicting bit-error rates in realistic heat-assisted magnetic recording simulations is a challenging task. Integrating the Landau-Lifshitz-Bloch (LLB) equation, within a coarse graining approach, can reduce the computational effort to determine the magnetization dynamics in the vicinity of the Curie temperature, compared to solving the atomistic Landau-Lifshitz-Gilbert equation. If the aim is that the dynamics of both approaches coincide, temperature dependent material functions, such as the zero-field equilibrium magnetization as well as the parallel and normal susceptibilities, must be modeled carefully in order to use them as input in the LLB equation. We present an extensive study on how these functions depend on grain size and exchange interactions. We show that, if the size or the exchange constant of a reference grain is modified, the material functions can be scaled, according to the changed Curie temperature, yielding negligible errors. This is shown to be valid for volume changes of up to ±40% and variations of the exchange constant of up to ±10%. Besides the temperature dependent material curves, computed switching probabilities also agree well with probabilities separately determined for each system. Our study suggests that there is no need to recalculate the required LLB input functions for each particle. Within the presented limits, it is sufficient to scale them to the Curie temperature of the altered system.

  4. A variational constitutive model for the distribution and interactions of multi-sized voids

    Liu, Jinxing

    2013-07-29

    The evolution of defects or voids, generally recognized as the basic failure mechanism in most metals and alloys, has been intensively studied. Most investigations have been limited to spatially periodic cases with non-random distributions of the radii of the voids. In this study, we use a new form of the incompressibility of the matrix to propose the formula for the volumetric plastic energy of a void inside a porous medium. As a consequence, we are able to account for the weakening effect of the surrounding voids and to propose a general model for the distribution and interactions of multi-sized voids. We found that the single parameter in classical Gurson-type models, namely void volume fraction is not sufficient for the model. The relative growth rates of voids of different sizes, which can in principle be obtained through physical or numerical experiments, are required. To demonstrate the feasibility of the model, we analyze two cases. The first case represents exactly the same assumption hidden in the classical Gurson\\'s model, while the second embodies the competitive mechanism due to void size differences despite in a much simpler manner than the general case. Coalescence is implemented by allowing an accelerated void growth after an empirical critical porosity in a way that is the same as the Gurson-Tvergaard-Needleman model. The constitutive model presented here is validated through good agreements with experimental data. Its capacity for reproducing realistic failure patterns is shown by simulating a tensile test on a notched round bar. © 2013 The Author(s).

  5. Short versus long range interactions and the size of two-body weakly bound objects

    Lombard, R.J.; Volpe, C.

    2003-01-01

    Very weakly bound systems may manifest intriguing ''universal'' properties, independent of the specific interaction which keeps the system bound. An interesting example is given by relations between the size of the system and the separation energy, or scaling laws. So far, scaling laws have been investigated for short-range and long-range (repulsive) potentials. We report here on scaling laws for weakly bound two-body systems valid for a larger class of potentials, i.e. short-range potentials having a repulsive core and long-range attractive potentials. We emphasize analogies and differences between the short- and the long-range case. In particular, we show that the emergence of halos is a threshold phenomenon which can arise when the system is bound not only by short-range interactions but also by long-range ones, and this for any value of the orbital angular momentum l. These results enlarge the image of halo systems we are accustomed to. (orig.)

  6. Dairy Herd Mastitis Program in Argentina: Farm Clusters and Effects on Bulk Milk Somatic Cell Counts

    C Vissio1*, SA Dieser2, CG Raspanti2, JA Giraudo1, CI Bogni2, LM Odierno2 and AJ Larriestra1

    2013-01-01

    Full Text Available This research has been conducted to characterize dairy farm clusters according to mastitis control program practiced among small and medium dairy producer from Argentina, and also to evaluate the effect of such farm cluster patterns on bulk milk somatic cell count (BMSCC. Two samples of 51 (cross-sectional and 38 (longitudinal herds were selected to identify farm clusters and study the influence of management on monthly BMSCC, respectively. The cross-sectional sample involved the milking routine and facilities assessment of each herd visited. Hierarchical cluster analysis was used to find the most discriminating farm attributes in the cross sectional sample. Afterward, the herd cluster typologies were identified in the longitudinal sample. Herd monthly BMSCC average was evaluated during 12 months fitting a linear mixed model. Two clusters were identified, the farms in the Cluster I applied a comprehensive mastitis program in opposite to Cluster II. Post-dipping, dry cow therapy and milking machine test were routinely applied in Cluster I. In the longitudinal study, 14 out of 38 dairy herds were labeled as Cluster I and the rest were assigned to Cluster II. Significant difference in BMSCC was found between cluster I and II (60,000 cells/mL. The present study showed the relevance and potential impact of promoting mastitis control practices among small and medium sized dairy producers in Argentina.

  7. Visual monitoring of reproduction in dairy herds

    Thysen, Iver; Enevoldsen, Carsten

    1994-01-01

    Two complementary approaches to produce visual information from reproduction records are described and exemplified. The Event Display shows all reproductive events, over a year, for all cows in a herd, by symbols placed in an array with columns representing calendar weeks and rows representing...... individual cows. The Reproduction Monitor consists of graphs of insemination and pregnancy rates evaluated weekly with a Bayesian technique. These visual monitoring tools are well suited to explore temporal variation in reproductive performance, they provide a quick overview of herd performance...

  8. Non-conventional screening of the Coulomb interaction in low-dimensional and finite-size systems

    van den Brink, J.; Sawatzky, G.A.

    2000-01-01

    We study the screening of the Coulomb interaction in non-polar systems by polarizable atoms. We show that in low dimensions and small finite-size systems this screening deviates strongly from that conventionally assumed. In fact in one dimension the short-range interaction is strongly screened and

  9. Herd-level risk factors for bovine viral diarrhea infection in cattle of Tamil Nadu.

    Kumar, Subbiah Krishna; Palanivel, K M; Sukumar, K; Ronald, B Samuel Masilamoni; Selvaraju, G; Ponnudurai, G

    2018-04-01

    A cross-sectional study was carried out to identify risk factors for bovine viral diarrhea virus (BVDV) infection in 62 randomly selected dairy herds which were tested for BVD serum antibodies by using an indirect ELISA kit (IDEXX). Results from the chi-square test analysis were interpreted by analyzing by chi-square test. A sum of 500 sera samples were screened and 66 animals (13.20%) showed positive for BVDV antibody. Within herd, BVD seroprevalence was 12-65%. This study concluded that epidemiological risk factors like location, herd size, housing patterns like, tail to tail system, roofing pattern, distance between the manure pit and farm, and distance between farms were significantly associated with BVDV serological status (P < 0.05).

  10. An analysis of herding behavior in security analysts’ networks

    Zhao, Zheng; Zhang, YongJie; Feng, Xu; Zhang, Wei

    2014-11-01

    In this paper, we build undirected weighted networks to study herding behavior among analysts and to analyze the characteristics and the structure of these networks. We then construct a new indicator based on the average degree of nodes and the average weighted clustering coefficient to research the various types of herding behavior. Our findings suggest that every industry has, to a certain degree, herding behavior among analysts. While there is obvious uninformed herding behavior in real estate and certain other industries, industries such as mining and nonferrous metals have informed herding behavior caused by analysts’ similar reactions to public information. Furthermore, we relate the two types of herding behavior to stock price and find that uninformed herding behavior has a positive effect on market prices, whereas informed herding behavior has a negative effect.

  11. Herd Clustering: A synergistic data clustering approach using collective intelligence

    Wong, Kachun; Peng, Chengbin; Li, Yue; Chan, Takming

    2014-01-01

    , this principle is used to develop a new clustering algorithm. Inspired by herd behavior, the clustering method is a synergistic approach using collective intelligence called Herd Clustering (HC). The novel part is laid in its first stage where data instances

  12. Factors associated with the occurrence of MRSA CC398 in herds of fattening pigs in Germany

    Alt Katja

    2011-11-01

    Full Text Available Abstract Background The purpose of this study was to investigate the prevalence of MRSA in herds of fattening pigs in different regions of Germany, and to determine factors associated with the occurrence of this pathogen. For this purpose pooled dust samples were collected, and a questionnaire covered information regarding herd characteristics and management practices. Samples were pre-enriched in high-salt medium followed by selective enrichment containing cefoxitin/aztreonam, and culturing. Presumptive colonies were confirmed by multiplex-PCR targeting nuc-, mecA- and 16S rRNA-genes. Isolates were spa- and SCCmec-, and in selected cases, multilocus sequence-typed. Susceptibilities to 13 antimicrobials were determined by broth microdilution. Statistical analysis was carried out using backward stepwise logistic regression to calculate odds ratios with the MRSA test result as the outcome and herd characteristics as categorical covariates. Results Overall, 152 of 290 (52% fattening pig farms tested positive for MRSA. The prevalence in the east, north- and south-west of Germany ranged from 39 to 59%. t011 (66% and t034 (23% were the most commonly identified spa-types, and 85% of isolates carried SCCmec Type V. Identified spa-types were all associated with clonal complex CC398. Susceptibility testing revealed that all isolates were resistant to tetracycline. High resistance rates were also found for sulfamethoxazole/trimethoprim (40%, and quinupristin/dalfopristin (32%. In addition, 83% of strains displayed multidrug resistant (> 3 substance classes phenotypes. Logistic regression revealed herd size (large farms OR: 5.4; CI: 2.7-11.2; p Conclusions MRSA CC398 is widely distributed among herds of fattening pigs in Germany. Farm management plays a crucial role in the dissemination of MRSA with herd size, and production type representing potential major indicators.

  13. Factors associated with the occurrence of MRSA CC398 in herds of fattening pigs in Germany.

    Alt, Katja; Fetsch, Alexandra; Schroeter, Andreas; Guerra, Beatriz; Hammerl, Jens A; Hertwig, Stefan; Senkov, Natalja; Geinets, Anna; Mueller-Graf, Christine; Braeunig, Juliane; Kaesbohrer, Annemarie; Appel, Bernd; Hensel, Andreas; Tenhagen, Bernd-Alois

    2011-11-10

    The purpose of this study was to investigate the prevalence of MRSA in herds of fattening pigs in different regions of Germany, and to determine factors associated with the occurrence of this pathogen. For this purpose pooled dust samples were collected, and a questionnaire covered information regarding herd characteristics and management practices. Samples were pre-enriched in high-salt medium followed by selective enrichment containing cefoxitin/aztreonam, and culturing. Presumptive colonies were confirmed by multiplex-PCR targeting nuc-, mecA- and 16S rRNA-genes. Isolates were spa- and SCCmec-, and in selected cases, multilocus sequence-typed. Susceptibilities to 13 antimicrobials were determined by broth microdilution. Statistical analysis was carried out using backward stepwise logistic regression to calculate odds ratios with the MRSA test result as the outcome and herd characteristics as categorical covariates. Overall, 152 of 290 (52%) fattening pig farms tested positive for MRSA. The prevalence in the east, north- and south-west of Germany ranged from 39 to 59%.t011 (66%) and t034 (23%) were the most commonly identified spa-types, and 85% of isolates carried SCCmec Type V. Identified spa-types were all associated with clonal complex CC398. Susceptibility testing revealed that all isolates were resistant to tetracycline. High resistance rates were also found for sulfamethoxazole/trimethoprim (40%), and quinupristin/dalfopristin (32%). In addition, 83% of strains displayed multidrug resistant (> 3 substance classes) phenotypes.Logistic regression revealed herd size (large farms OR: 5.4; CI: 2.7-11.2; p pig operations. MRSA CC398 is widely distributed among herds of fattening pigs in Germany. Farm management plays a crucial role in the dissemination of MRSA with herd size, and production type representing potential major indicators.

  14. Assessing animal welfare in sow herds using data on meat inspection, medication and mortality.

    Knage-Rasmussen, K M; Rousing, T; Sørensen, J T; Houe, H

    2015-03-01

    This paper aims to contribute to the development of a cost-effective alternative to expensive on-farm animal-based welfare assessment systems. The objective of the study was to design an animal welfare index based on central database information (DBWI), and to validate it against an animal welfare index based on-farm animal-based measurements (AWI). Data on 63 Danish sow herds with herd-sizes of 80 to 2500 sows and an average herd size of 501 were collected from three central databases containing: Meat inspection data collected at animal level in the abattoir, mortality data at herd level from the rendering plants of DAKA, and medicine records at both herd and animal group level (sow with piglets, weaners or finishers) from the central database Vetstat. Selected measurements taken from these central databases were used to construct the DBWI. The relative welfare impacts of both individual database measurements and the databases overall were assigned in consultation with a panel consisting of 12 experts. The experts were drawn from production advisory activities, animal science and in one case an animal welfare organization. The expert panel weighted each measurement on a scale from 1 (not-important) to 5 (very important). The experts also gave opinions on the relative weightings of measurements for each of the three databases by stating a relative weight of each database in the DBWI. On the basis of this, the aggregated DBWI was normalized. The aggregation of AWI was based on weighted summary of herd prevalence's of 20 clinical and behavioural measurements originating from a 1 day data collection. AWI did not show linear dependency of DBWI. This suggests that DBWI is not suited to replace an animal welfare index using on-farm animal-based measurements.

  15. A Cow- and Herd-specific Bio-Economic Model of Intramammary Infections in Dairy Cows

    Kirkeby, Carsten Thure; Gussmann, Maya Katrin; Græsbøll, Kaare

    Introduction. Mastitis, or intramammary infection (IMI), is one of the most significant diseases in dairy herds worldwide. It is caused by environmental and contagious bacteria. Simulation models have proven useful for evaluating the effect of different control strategies. However, previous...... published models are not cow-specific and therefore not so detailed in the simulation of host-pathogen interactions. If a simulation model is to be used by dairy farmers as a decision-making tool, it needs to be cow-specific because daily management decisions are made on cow level. Furthermore, as IMI......, contagious or mixed), the model should be able to reflect this diversity. Our objective was thus to create a pathogen-, cow- and herd-specific bio-economic simulation model that could simulate multiple pathogens and strains at the same time within a dairy herd. This model should be able to simulate realistic...

  16. Influence of social mixing and group size on skin lesions and mounting in organic entire male pigs

    Thomsen, Rikke; Edwards, Sandra A; Rousing, Tine

    2016-01-01

    in management procedures and production system might be needed. Elements from the organic pig production system might be beneficial in this aspect. The aim of this article is to investigate the effect of grouping strategy including social mixing and group size on levels of mounting behaviour and skin lesions...... at weaning. A second mixing occurred at insertion to fattening pens for pigs being regrouped. Counting of skin lesions (1348 or 1124 pigs) and registration of mounting behaviour (1434 or 1258 pigs) were done on two occasions during the experimental period. No interactive effects were found between social...... mixing and group size on either skin lesions or mounting frequency. Herd differences were found for both mounting frequency and number of skin lesions. No association between skin lesions and mounting were revealed. Social mixing and group size were shown as interacting effects with herds on mounting...

  17. Forecasting Housing Approvals in Australia: Do Forecasters Herd?

    Stadtmann, Georg; Pierdzioch; Rülke

    2012-01-01

    Price trends in housing markets may reflect herding of market participants. A natural question is whether such herding, to the extent that it occurred, reflects herding in forecasts of professional forecasters. Using more than 6,000 forecasts of housing approvals for Australia, we did not find...

  18. 9 CFR 77.36 - Interstate movement from qualified herds.

    2010-01-01

    ... date of movement. If a group of captive cervids from a qualified herd is being moved interstate... unclassified herd. (4) Captive cervids being moved interstate for the purpose of exhibition only may be moved... being moved directly from a classified herd, the captive cervid must be isolated from all other animals...

  19. Aspects of bovine herpesvirus-1 infection in dairy and beef herds in the Republic of Ireland

    Doherty Michael L

    2011-06-01

    Full Text Available Abstract Background Infection with bovine herpesvirus-1 (BHV-1 causes a wide range of disease manifestations, including respiratory disease and abortion, with world-wide distribution. The primary objective of the present study was to describe aspects of BHV-1 infection and control on Irish farms, including herd-level seroprevalence (based on pooled sera and vaccine usage. Methods The characteristics of a diagnostic indirect BHV-1 antibody ELISA test when used on serum pools were evaluated using laboratory replicates for use in the seroprevalence study. The output from this indirect ELISA was expressed as a percentage positivity (PP value. A proposed cut off (PCO PP was applied in a cross-sectional study of a stratified random sample of 1,175 Irish dairy and beef cattle herds in 2009, using serum pools, to estimate herd seroprevalence. The study was observational, based primarily on the analysis of existing samples, and only aggregated results were reported. For these reasons, ethical approval was not required. Bulk milk samples from a subset of 111 dairy herds were analysed using the same ELISA. Information regarding vaccine usage was determined in a telephone survey. Results A PCO PP of 7.88% was determined to give 97.1% sensitivity and 100% specificity relative to the use of the ELISA on individual sera giving maximization of the prevalence independent Youden's index, on receiver operating characteristics analysis of replicate results. The herd-level BHV-1 seroprevalence was 74.9% (95% CI - 69.9%-79.8%, with no significant difference between dairy and beef herds. 95.5% agreement in herd classification was found between bulk milk and serum pools. Only 1.8 percent of farmers used BHV-1 marker vaccine, 80% of which was live while 75% of vaccinated herds were dairy. A significant association was found between herd size (quartiles and seroprevalence (quartiles. Conclusions The results from this study indicate BHV-1 infection is endemic, although

  20. Herd- and sow-related risk factors for lameness in organic and conventional sow herds

    Knage-Rasmussen, Kristian Møllegaard; Houe, Hans; Rousing, Tine

    2014-01-01

    included in the study were clinical parameters and factors related to the production system. Sows were examined visually by one of four trained observers. The organic sows were assigned scores for lameness, body condition, hoof length, bursitis, abscesses and leg wounds, while the conventional sows were...... assigned scores for lameness, body condition and bursitis. A multivariable analysis was carried out by logistic regression with the herd and observer as random effects. The average herd lameness prevalence in gestation and lactation sows in organic herds was 11% in summer/autumn and 4.6% in winter....../spring. ‘Wounds, bursitis and abscess’ on legs (OR=4.7, P3 (OR=1.79, P=0.008) were associated with increased risk of lameness in Danish organic sow herds. Season (winter/spring v. summer/autumn) lowered the risk of lameness (OR=0.37, P

  1. Some herding, record keeping and treatment methods used in Alaskan reindeer herds

    Robert A. Dieterich

    1986-06-01

    Full Text Available Approximately 20000 reindeer (Rangifer tarandus in Alaska are gathered once or twice yearly to facilitate identification, serologic sampling, treatment and antler removal. Various air and land craft are used to bring the animals into a corral system from which they can be herded into a padded, pneumatically operated, squeeze apparatus. Ear tags are applied or read if already in place and ears are notched. A portable, computerized rapid data retrieval system is used to record reproductive success, vaccination and treatment status and other miscellaneous information. Ivermectin is being administered in the early winter months to treat reindeer in many herds for warbles, nasal bots and internal parasites. A killed, homologous Brucella suis type 4 vaccine is being used in two large (3500 herds. Efforts are being made to incorporate other innovative methods to improve herding and corralling methods.

  2. Size-scaling behaviour of the electronic polarizability of one-dimensional interacting systems

    Chiappe, G.; Louis, E.; Vergés, J. A.

    2018-05-01

    Electronic polarizability of finite chains is accurately calculated from the total energy variation of the system produced by small but finite static electric fields applied along the chain direction. Normalized polarizability, that is, polarizability divided by chain length, diverges as the second power of length for metallic systems but approaches a constant value for insulating systems. This behaviour provides a very convenient way to characterize the wave-function malleability of finite systems as it avoids the need of attaching infinite contacts to the chain ends. Hubbard model calculations at half filling show that the method works for a small U  =  1 interaction value that corresponds to a really small spectral gap of 0.005 (hopping t  =  ‑1 is assumed). Once successfully checked, the method has been applied to the long-range hopping model of Gebhard and Ruckenstein showing 1/r hopping decay (Gebhard and Ruckenstein 1992 Phys. Rev. Lett. 68 244; Gebhard et al 1994 Phys. Rev. B 49 10926). Metallicity for U values below the reported metal-insulator transition is obtained but the surprise comes for U values larger than the critical one (when a gap appears in the spectral density of states) because a steady increase of the normalized polarizability with size is obtained. This critical size-scaling behaviour can be understood as corresponding to a molecule which polarizability is unbounded. We have checked that a real transfer of charge from one chain end to the opposite occurs as a response to very small electric fields in spite of the existence of a large gap of the order of U for one-particle excitations. Finally, ab initio quantum chemistry calculations of realistic poly-acetylene chains prove that the occurrence of such critical behaviour in real systems is unlikely.

  3. Interactive contribution of grain size and grain orientation to coercivity of melt spun ribbons

    Wang, N.; Li, G.; Yao, W.J.; Wen, X.X.

    2010-01-01

    During melt spinning process, the improvement of certain grain orientation and the refinement of grain size with surface velocity have interactive and contradictory effects on the magnetic properties. The contributions of these effects have seldom been taken into account and they were discussed in this paper via Fe-2, 4, 6.5 wt% Si alloys. Heat treatment at 1173 K for 1 h was performed to show the annealing impact. The X-ray diffraction patterns show that the high surface velocity and heat treatment increase the intensity ratio of line (2 0 0) to (1 1 0) of A2 phase. The (2 0 0) line corresponds to (2 0 0) plane in direction, easy magnetization direction of α-Fe phase in Fe-Si alloy. The improvement of this grain orientation with the surface velocity decreases the coercivity, which should increase due to the grain refinement. It is revealed that the texture promoted by the anisotropic heat release during melt spinning process is one factor to improve the magnetic properties and should be considered when preparing soft magnetic materials.

  4. House Price Forecasts, Forecaster Herding, and the Recent Crisis

    Christian Pierdzioch

    2012-11-01

    Full Text Available We used the Wall Street Journal survey data for the period 2006–2012 to analyze whether forecasts of house prices and housing starts provide evidence of (anti-herding of forecasters. Forecasts are consistent with herding (anti-herding of forecasters if forecasts are biased towards (away from the consensus forecast. We found that anti-herding is prevalent among forecasters of house prices. We also report that, following the recent crisis, the prevalence of forecaster anti-herding seems to have changed over time.

  5. House Price Forecasts, Forecaster Herding, and the Recent Crisis

    Stadtmann, Georg; Pierdzioch; Ruelke

    2013-01-01

    We used the Wall Street Journal survey data for the period 2006–2012 to analyze whether forecasts of house prices and housing starts provide evidence of (anti-)herding of forecasters. Forecasts are consistent with herding (anti-herding) of forecasters if forecasts are biased towards (away from) t......) the consensus forecast. We found that anti-herding is prevalent among forecasters of house prices. We also report that, following the recent crisis, the prevalence of forecaster anti-herding seems to have changed over time....

  6. Clinical mastitis in Macedonian dairy herds

    Trajčev M.

    2013-01-01

    Full Text Available The purpose of this study is the determination of the occurrence and prevalence of clinical mastitis and lactation incidence risk on three dairy farms. A one year study on a total of 1031 black-white breed cows with a total of 1267 lactations was performed. Each dairy farm implemented a different technology of rearing and was of different herd size (farm A - tie-stalls, 162 cows; farm B - loose-housing system with open shed and deep bedding, 357 dairy cows; and farm C - loosehousing system with enclosed shed, 512 cows. Clinical mastitis in cows was detected by clinical examination of the udder and determination of abnormalities in the milk. To distinguish two consecutive cases of clinical mastitis within the same lactation a time period of nine days was used. Annual prevalence rate of clinical mastitis for the entire population of cows was 34.13% on cow level, and 30.07% on lactation level. There was a high prevalence rate of clinical mastitis in primiparous cows, 21.43%, 40.77% and 12.55%, on farms A, B and C, respectively. Lactation incident risk for cows on farm A was 25.00%, farm B 95.58% and farm C 21.49%. The prevalence of clinical mastitis and lactation incidence risk tended to increase with increasing parity. The annual lactation risk for the entire population of cows was 45.86%. All indicators for the determination of the occurrence of clinical mastitis in dairy farms, which were observed during the research, showed the greatest values on farm B. Most of the cows manifested one (68.24% or two (18.63% cases of clinical mastitis during lactation. There was a long period in lactation until the appearance of the first case of clinical mastitis (112.21 ± 92.04 days. Generally, clinical mastitis was registered during the whole period of the survey, with some fluctuations between different seasons. The method of GLM (General Linear Model, univariate procedure, was used to analyze associations between the incidence of clinical mastitis and

  7. Bipartite networks improve understanding of effects of waterbody size and angling method on angler–fish interactions

    Chizinski, Christopher J.; Martin, Dustin R.; Shizuka, Daizaburo; Pope, Kevin L.

    2018-01-01

    Networks used to study interactions could provide insights to fisheries. We compiled data from 27 297 interviews of anglers across waterbodies that ranged in size from 1 to 12 113 ha. Catch rates of fish species among anglers grouped by species targeted generally differed between angling methods (bank or boat). We constructed angler–catch bipartite networks (angling method specific) between anglers and fish and measured several network metrics. There was considerable variation in networks among waterbodies, with multiple metrics influenced by waterbody size. Number of species-targeting angler groups and number of fish species caught increased with increasing waterbody size. Mean number of links for species-targeting angler groups and fish species caught also increased with waterbody size. Connectance (realized proportion of possible links) of angler–catch interaction networks decreased slower for boat anglers than for bank anglers with increasing waterbody size. Network specialization (deviation of number of interactions from expected) was not significantly related to waterbody size or angling methods. Application of bipartite networks in fishery science requires careful interpretation of outputs, especially considering the numerous confounding factors prevalent in recreational fisheries.

  8. Finite-size, chemical-potential and magnetic effects on the phase transition in a four-fermion interacting model

    Correa, E.B.S. [Universidade Federal do Sul e Sudeste do Para, Instituto de Ciencias Exatas, Maraba (Brazil); Centro Brasileiro de Pesquisas Fisicas-CBPF/MCTI, Rio de Janeiro (Brazil); Linhares, C.A. [Universidade do Estado do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro (Brazil); Malbouisson, A.P.C. [Centro Brasileiro de Pesquisas Fisicas-CBPF/MCTI, Rio de Janeiro (Brazil); Malbouisson, J.M.C. [Universidade Federal da Bahia, Instituto de Fisica, Salvador (Brazil); Santana, A.E. [Universidade de Brasilia, Instituto de Fisica, Brasilia, DF (Brazil)

    2017-04-15

    We study effects coming from finite size, chemical potential and from a magnetic background on a massive version of a four-fermion interacting model. This is performed in four dimensions as an application of recent developments for dealing with field theories defined on toroidal spaces. We study effects of the magnetic field and chemical potential on the size-dependent phase structure of the model, in particular, how the applied magnetic field affects the size-dependent critical temperature. A connection with some aspects of the hadronic phase transition is established. (orig.)

  9. Organometallic approach to polymer-protected antibacterial silver nanoparticles: optimal nanoparticle size-selection for bacteria interaction

    Crespo, Julian; Garcia-Barrasa, Jorge; Lopez-de-Luzuriaga, Jose M.; Monge, Miguel, E-mail: miguel.monge@unirioja.es; Olmos, M. Elena [Universidad de La Rioja, Centro de Investigacion en Sintesis Quimica (CISQ), Departamento de Quimica (Spain); Saenz, Yolanda; Torres, Carmen [Centro de Investigacion Biomedica de La Rioja, Area de Microbiologia Molecular (Spain)

    2012-12-15

    The optimal size-specific affinity of silver nanoparticles (Ag NPs) towards E. coli bacteria has been studied. For this purpose, Ag NPs coated with polyvinylpyrrolidone (PVP) and cellulose acetate (CA) have been prepared using an organometallic approach. The complex NBu{sub 4}[Ag(C{sub 6}F{sub 5}){sub 2}] has been treated with AgClO{sub 4} in a 1:1 molar ratio giving rise to the nanoparticle precursor [Ag(C{sub 6}F{sub 5})] in solution. Addition of an excess of PVP (1) or CA (2) and 5 h of reflux in tetrahydrofuran (THF) at 66 Degree-Sign C leads to Ag NPs of small size (4.8 {+-} 3.0 nm for PVP-Ag NPs and 3.0 {+-} 1.2 nm for CA-Ag NPs) that coexist in both cases with larger nanoparticles between 7 and 25 nm. Both nanomaterials display a high antibacterial effectiveness against E. coli. The TEM analysis of the nanoparticle-bacterial cell membrane interaction shows an optimal size-specific affinity for PVP-Ag NPs of 5.4 {+-} 0.7 nm in the presence of larger size silver nanoparticles.Graphical AbstractAn organometallic approach permits the synthesis of small size silver nanoparticles (ca 5 nm) as a main population in the presence of larger size nanoparticles. Optimal silver nanoparticle size-selection (5.4 nm) for the interaction with the bacterial membrane is achieved.

  10. Agent-based model with multi-level herding for complex financial systems

    Chen, Jun-Jie; Tan, Lei; Zheng, Bo

    2015-02-01

    In complex financial systems, the sector structure and volatility clustering are respectively important features of the spatial and temporal correlations. However, the microscopic generation mechanism of the sector structure is not yet understood. Especially, how to produce these two features in one model remains challenging. We introduce a novel interaction mechanism, i.e., the multi-level herding, in constructing an agent-based model to investigate the sector structure combined with volatility clustering. According to the previous market performance, agents trade in groups, and their herding behavior comprises the herding at stock, sector and market levels. Further, we propose methods to determine the key model parameters from historical market data, rather than from statistical fitting of the results. From the simulation, we obtain the sector structure and volatility clustering, as well as the eigenvalue distribution of the cross-correlation matrix, for the New York and Hong Kong stock exchanges. These properties are in agreement with the empirical ones. Our results quantitatively reveal that the multi-level herding is the microscopic generation mechanism of the sector structure, and provide new insight into the spatio-temporal interactions in financial systems at the microscopic level.

  11. Serological patterns of Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, Pasteurella multocida and Streptococcus suis in pig herds affected by pleuritis.

    Wallgren, Per; Nörregård, Erik; Molander, Benedicta; Persson, Maria; Ehlorsson, Carl-Johan

    2016-10-04

    Respiratory illness is traditionally regarded as the disease of the growing pig, and has historically mainly been associated to bacterial infections with focus on Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. These bacteria still are of great importance, but continuously increasing herd sizes have complicated the scenario and the influence of secondary invaders may have been increased. The aim of this study was to evaluate the presence of A. pleuropneumoniae and M. hyopneumoniae, as well as that of the secondary invaders Pasteurella multocida and Streptococcus suis by serology in four pig herds (A-D) using age segregated rearing systems with high incidences of pleuritic lesions at slaughter. Pleuritic lesions registered at slaughter ranged from 20.5 to 33.1 % in the four herds. In herd A, the levels of serum antibodies to A. pleuropneumoniae exceeded A 450  > 1.5, but not to any other microbe searched for. The seroconversion took place early during the fattening period. Similar levels of serum antibodies to A. pleuropneumoniae were also recorded in herd B, with a subsequent increase in levels of antibodies to P. multocida. Pigs seroconverted to both agents during the early phase of the fattening period. In herd C, pigs seroconverted to P. multocida during the early phase of the fattening period and thereafter to A. pleuropneumoniae. In herd D, the levels of antibodies to P. multocida exceeded A 450  > 1.0 in absence (A 450  hyopneumoniae and to S. suis remained below A 450  hyopneumoniae late during the rearing period (herd B-D), or not at all (herd A). Different serological patterns were found in the four herds with high levels of serum antibodies to A. pleuropneumoniae and P. multocida, either alone or in combination with each other. Seroconversion to M. hyopneumoniae late during the rearing period or not at all, confirmed the positive effect of age segregated rearing in preventing or delaying infections with M

  12. Runne-Beana: Dog Herds Ethnographer

    Myrdene Anderson

    2016-12-01

    Full Text Available Saami society in Lapland (now often called Saapmi, particularly the seasonally-nomadic reindeer-breeding sector, is predicated upon mobility and autonomy of its actors. Runne-Beana, a talented reindeer-herding dog, exhibited both mobility and autonomy when allocating to himself a peripatetic ethnographer, on the first day of five years of doctoral dissertation fieldwork in arctic Norway in 1972. That family’s and the wider community’s reactions to Runne-Beana’s behavior, and mine, highlight the tensions when mobility and autonomy compound with ideologies of ownership and control. At the same time, his companionship profoundly shaped all field relationships, engendering an understanding of dog culture as it is manifest in the herder/herding dog/reindeer triad and in the interpenetration of assumptions concerning child/dog enculturation.

  13. Dynamic production monitoring in pig herds II

    Bono, Claudia; Cornou, Cecile; Lundbye-Christensen, Søren

    2013-01-01

    an expectation-maximization (EM) algorithm applied on a dataset containing data from 15 herds, each of them including insemination and farrowing observations over a period ranging from 150 to 800 weeks. The model included a set of parameters describing the parity-specific farrowing rate and the re......-insemination effect. It also provided reliable forecasting on weekly basis. Statistical control tools were used to give warnings in case of impaired farrowing rate. For each herd, farrowing rate profile, analysis of model components over time and detection of alarms were computed. The model provided a good overview...... of the development of the parity specific farrowing rate over time and the control charts were able to detect impaired results. Suggestions for future improvements include addition of parity-specific control charts, calibration of the charts for use in practice and inclusion of a sow effect in the farrowing model....

  14. Epidemiological situation of Herpesvirus infections in buffalo herds: Bubaline Herpesvirus1 or Bovine Herpesvirus1?

    G.L. Autorino

    2010-02-01

    Full Text Available Information on the distribution and related epidemiological characteristics of herpesvirus infections, and in particular referring to Bovine Herpesvirus 1 (BoHV1 and Bubaline Herpesvirus 1 (BuHV1 in buffaloes, have to date not been reported. Different studies based on serological surveys and viral isolation describe the circulation of both infections in this species. The specific etiological attribution of the infections in sero-surveys can be uncertain because of antigenic cross-reactivity of these ruminant α-herpesvirus and therefore depends on the diagnostic techniques employed. For this , we proceeded in verifying the diffusion of the two infections in a buffalo population of Central Italy. The sample size for the number of herds to test was defined considering an expected prevalence > 20% and the number of heads to be tested within each herd was established using an expected prevalence of > 25% (absolute precision of 5%, with 95% confidence level. The 155 herds to test were those with no IBR vaccination history. A maximum of 15 random blood samples were collected within the >3 year age category. The same sampling criteria was adopted when cows were present on buffalo farms to study the possible role of this species. Through the combined use of gB-gE Elisa tests, we assigned a specific infection status, for the BuHV1 infection status (gB-pos/gE-neg, as confirmed by an experimental infection conducted by us inoculating buffaloes with the BuHV1 “strain Metzler”, and for the BoHV1 status (gBpos/ gE-pos as that observed for the infection in bovines. Prevalence of infection, based on the Elisa status of each animal, were estimated for the whole sample and within each herd. Furthermore, the selected farms were investigated for their numeric consistency, presence of bovines, occurrence of typical clinical herpesvirus disorders occurring during the year prior to sampling. The association of these factors with the infection status was verified

  15. Herd-level risk factors for bovine tuberculosis in French cattle herds.

    Marsot, Maud; Béral, Marina; Scoizec, Axelle; Mathevon, Yoann; Durand, Benoit; Courcoul, Aurélie

    2016-09-01

    Although officially free of bovine tuberculosis (bTB), France has been experiencing a slight increase in the incidence and geographical spread of the infection. Eradication of bTB requires determining the infection risk factors. Although several studies identifying bTB risk factors have been conducted in the United Kingdom and Spain, no information is currently available regarding bTB risk factors in French cattle. The objective of this work was thus to study the factors associated with the risk of bTB in cattle herds in three French administrative divisions (départements of Ardennes, Côte d'Or and Dordogne). A case-control study was conducted to compare herds having experienced a bTB outbreak between 2012 and early 2014 with randomly selected control herds of the three study départements. A questionnaire of farming practices, inter-herd contacts (e.g. at pasture or via vehicles or materials), and the presence of other domestic species was carried out in the selected herds. Data on other variables of interest included animal movements between farms and potential contacts between cattle and wildlife (e.g. badger and wild boar abundances) were also collected. Multivariable logistic regression and multimodel inference methods were used to assess risk factors related to bTB. A total of 216 herds (72 cases and 144 controls) were analyzed. The two main risk factors were the presence of a recent neighboring outbreak, being defined as a neighboring herd at pasture reported as infected in the past two years (odds ratio (OR)=3.6; population attributable fraction (PAF)=30.7%) and the presence of a farm building for cattle housing or for feed storage located at more than 300-m from inhabited areas (OR=2.3; PAF=27.6%). Another risk factor was related to sharing water points at pasture with a recent neighboring outbreak. Results illustrated the multifactorial nature of bTB dynamics. The risk factors related to recently infected neighboring herds could be attributable to

  16. Understanding the Effect of Response Rate and Class Size Interaction on Students Evaluation of Teaching in a Higher Education

    Al Kuwaiti, Ahmed; AlQuraan, Mahmoud; Subbarayalu, Arun Vijay

    2016-01-01

    Objective: This study aims to investigate the interaction between response rate and class size and its effects on students' evaluation of instructors and the courses offered at a higher education Institution in Saudi Arabia. Study Design: A retrospective study design was chosen. Methods: One thousand four hundred and forty four different courses…

  17. Quantum-size effects in the energy loss of charged particles interacting with a confined two-dimensional electron gas

    Borisov, A. G.; Juaristi, J. I.; Muino, R. Diez; Sanchez-Portal, D.; Echenique, P. M.

    2006-01-01

    Time-dependent density-functional theory is used to calculate quantum-size effects in the energy loss of antiprotons interacting with a confined two-dimensional electron gas. The antiprotons follow a trajectory normal to jellium circular clusters of variable size, crossing every cluster at its geometrical center. Analysis of the characteristic time scales that define the process is made. For high-enough velocities, the interaction time between the projectile and the target electrons is shorter than the time needed for the density excitation to travel along the cluster. The finite-size object then behaves as an infinite system, and no quantum-size effects appear in the energy loss. For small velocities, the discretization of levels in the cluster plays a role and the energy loss does depend on the system size. A comparison to results obtained using linear theory of screening is made, and the relative contributions of electron-hole pair and plasmon excitations to the total energy loss are analyzed. This comparison also allows us to show the importance of a nonlinear treatment of the screening in the interaction process

  18. Influence of age, sex and herd characteristics on the occurrence of verocytotoxin-producing Escherichia coli O157 in Danish dairy farms

    Nielsen, E.M.; Tegtmeier, Conny; Andersen, Hans Jørgen

    2002-01-01

    animals were sampled, and 3.6% of these excreted VTEC O157. These animals were located on 10 farms (17%). On average, 21% of the sampled animals in the positive herds excreted VTEC O157. Register data, including age, sex, breed, housing conditions and herd composition, were extracted from a database....... No influence of herd size or housing conditions was found. A strong effect of age was seen with 2-6-month-old calves as the high-risk age group (8.6% positive) in contrast to calves...

  19. Epidemiology and impact of Fasciola hepatica exposure in high-yielding dairy herds.

    Howell, Alison; Baylis, Matthew; Smith, Rob; Pinchbeck, Gina; Williams, Diana

    2015-09-01

    The liver fluke Fasciola hepatica is a trematode parasite with a worldwide distribution and is the cause of important production losses in the dairy industry. The aim of this observational study was to assess the prevalence of exposure to F. hepatica in a group of high yielding dairy herds, to determine the risk factors and investigate their associations with production and fertility parameters. Bulk milk tank samples from 606 herds that supply a single retailer with liquid milk were tested with an antibody ELISA for F. hepatica. Multivariable linear regression was used to investigate the effect of farm management and environmental risk factors on F. hepatica exposure. Higher rainfall, grazing boggy pasture, presence of beef cattle on farm, access to a stream or pond and smaller herd size were associated with an increased risk of exposure. Univariable regression was used to look for associations between fluke exposure and production-related variables including milk yield, composition, somatic cell count and calving index. Although causation cannot be assumed, a significant (phepatica exposure and estimated milk yield at the herd level, representing a 15% decrease in yield for an increase in F. hepatica exposure from the 25th to the 75th percentile. This remained significant when fertility, farm management and environmental factors were controlled for. No associations were found between F. hepatica exposure and any of the other production, disease or fertility variables. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Modeling the lowest-cost splitting of a herd of cows by optimizing a cost function

    Gajamannage, Kelum; Bollt, Erik M.; Porter, Mason A.; Dawkins, Marian S.

    2017-06-01

    Animals live in groups to defend against predation and to obtain food. However, for some animals—especially ones that spend long periods of time feeding—there are costs if a group chooses to move on before their nutritional needs are satisfied. If the conflict between feeding and keeping up with a group becomes too large, it may be advantageous for some groups of animals to split into subgroups with similar nutritional needs. We model the costs and benefits of splitting in a herd of cows using a cost function that quantifies individual variation in hunger, desire to lie down, and predation risk. We model the costs associated with hunger and lying desire as the standard deviations of individuals within a group, and we model predation risk as an inverse exponential function of the group size. We minimize the cost function over all plausible groups that can arise from a given herd and study the dynamics of group splitting. We examine how the cow dynamics and cost function depend on the parameters in the model and consider two biologically-motivated examples: (1) group switching and group fission in a herd of relatively homogeneous cows, and (2) a herd with an equal number of adult males (larger animals) and adult females (smaller animals).

  1. Contextual herd factors associated with cow culling risk in Québec dairy herds: A multilevel analysis.

    Haine, Denis; Delgado, Hector; Cue, Roger; Sewalem, Asheber; Wade, Kevin; Lacroix, René; Lefebvre, Daniel; Arsenault, Julie; Bouchard, Émile; Dubuc, Jocelyn

    2017-09-01

    Several health disorders, such as milk fever, displaced abomasum, and mastitis, as well as impaired reproductive performance, are known risk factors for the removal of affected cows from a dairy herd. While cow-level risk factors are well documented in the literature, herd-level associations have been less frequently investigated. The objective of this study was to investigate the effect of cow- and herd-level determinants on variations in culling risk in Québec dairy herds: whether herd influences a cow's culling risk. For this, we assessed the influence of herd membership on cow culling risk according to displaced abomasum, milk fever, and retained placenta. A retrospective longitudinal study was conducted on data from dairy herds in the Province of Québec, Canada, by extracting health information events from the dairy herd health management software used by most Québec dairy producers and their veterinarians. Data were extracted for all lactations starting between January 1st and December 31st, 2010. Using multilevel logistic regression, we analysed a total of 10,529 cows from 201 herds that met the inclusion criteria. Milk fever and displaced abomasum were demonstrated to increase the cow culling risk. A minor general herd effect was found for the culling risk (i.e. an intra-class correlation of 1.0% and median odds ratio [MOR] of 1.20). The proportion of first lactation cows was responsible for this significant, but weak herd effect on individual cow culling risk, after taking into account the cow-level factors. On the other hand, the herd's average milk production was a protective factor. The planning and management of forthcoming replacement animals has to be taken into consideration when assessing cow culling risks and herd culling rates. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Multifractality and herding behavior in the Japanese stock market

    Cajueiro, Daniel O.; Tabak, Benjamin M.

    2009-01-01

    In this paper we present evidence of multifractality and herding behavior for a large set of Japanese stocks traded in the Tokyo Stock Exchange. We find evidence that herding behavior occurs in periods of extreme market movements. Therefore, based on the intuition behind the tests to detect herding phenomenon developed, for instance, in Christie and Huang [Christie W, Huang R. Following the pied pier: do individual returns herd around the market? Financ Analysts J 1995;51:31-7] and Chang et al. [Chang EC, Cheng JW, Khorana A. Examination of herd behavior in equity markets: an international perspective. J Bank Finance 2000;24:1651-99], we suggest that herding behavior may be one of the causes of multifractality.

  3. Effect of laser spot size on fusion neutron yield in laser–deuterium cluster interactions

    Chen Guanglong; Lu Haiyang; Wang Cheng; Liu Jiansheng; Li Ruxin; Ni Guoquan; Xu Zhizhan

    2008-01-01

    The effect of the laser spot size on the neutron yield of table-top nuclear fusion from explosions of a femtosecond intense laser pulse heated deuterium clusters is investigated by using a simplified model, in which the cluster size distribution and the energy attenuation of the laser as it propagates through the cluster jet are taken into account. It has been found that there exists a proper laser spot size for the maximum fusion neutron yield for a given laser pulse and a specific deuterium gas cluster jet. The proper spot size, which is dependent on the laser parameters and the cluster jet parameters, has been calculated and compared with the available experimental data. A reasonable agreement between the calculated results and the published experimental results is found

  4. Mechanism of Interaction between Entrepreneurial Spirit and Growth of Small and Medium Sized Private Enterprises

    Peng XIE

    2016-01-01

    In the context of government appeal of " mass entrepreneurship and innovation",all areas launched the movement of " mass entrepreneurship" and " grassroots entrepreneurship". As parts of vitality of China’s market economy,small and medium sized private enterprises become grassroots of market competition in talents,funds,and technologies. This paper combined three levels of entrepreneurial spirit and small and medium sized private enterprises,studied acting mechanism of entrepreneurial spirit,discussed competitive power of small and medium sized private enterprises,and recommended that small and medium sized private enterprises should cultivate core competitive power,adapt to external environment,and create external environment support,to realize sound development.

  5. Influence of austenite grain size on recrystallisation-precipitation interaction in a V-microalloyed steel

    Quispe, A.; Medina, S.F.; Gomez, M.; Chaves, J.I.

    2007-01-01

    By means of torsion tests using small specimens, the influence of austenite grain size on strain induced precipitation kinetics has been determined in a vanadium microalloyed steel. Determination of recrystallisation-precipitation-time-temperature (RPTT) diagrams for two austenite grain sizes allows values of the aforementioned magnitudes to be determined. An ample discussion is made of the quantitative influence found and its relation with nucleation and growth mechanisms of precipitates. The results are compared with the quantitative influence exerted by the other variables, reaching the conclusion that the austenite grain size has a notable influence on strain induced precipitation kinetics which should not be underestimated. Finally, the influence of austenite grain size is included in a strain induced precipitation model constructed by the authors of this work and which also takes into account the other aforementioned variables

  6. Post-weaning multisystemic wasting syndrome (PMWS) in Danish pig herds: productivity, clinical symptoms, and pathology

    Nielsen, E. Okholm; Enøe, Claes; Jorsal, Sven Erik Lind

    2008-01-01

    were 36 g and 52 g less in the case herds than in the control herds. By examining three weaner pigs from each herd the PMWS diagnosis was confirmed by histopathology and immunohistochemistry in 78 per cent of the case herds, but at least one PMWS-positive weaner pig was found in 19 of the control herds...

  7. Postweaning multisystematic wasting syndrome in Danish pig herds: productivity, clinical signs and pathology

    Okholm Nielsen, Elisabeth; Enøe, Claes; Jorsal, Sven Erik Lind

    2008-01-01

    were 36 g and 52 g less in the case herds than in the control herds. By examining three weaner pigs from each herd the PMWS diagnosis was confirmed by histopathology and immunohistochemistry in 78 per cent of the case herds, but at least one PMWS-positive weaner pig was found in 19 of the control herds...

  8. Assessment of Structural Traits and Management Related to Dairy Herds in the Peri-urban Area of Bobo Dioulasso (South West of Burkina Faso

    M. Mattoni

    2007-04-01

    Full Text Available To define mean herd size, structural traits, animal sourcing and use, management and aspects related to the milk production, 118 dairy herds, involved in a FAO dairy development project were studied. The mean herd size after allocation to clusters: Small (≤38 heads, Medium (>38, ≤61 heads and Large (>61 heads was 52.8±25.8, ranging from 7 to 134 heads of cattle. The following genotypes: Cross bred (CR 58.8%, Zebu (ZB 23.2% and Taurine cattle (TA 18.0% which were not uniformly distributed neither across nor within herds were identified. Sex ratio was two thirds of females (70.6%, one third of males (28.1% and a low proportion (1.3% of castrated males. No mature TA males compared to 53.3% of the male ZB and 31.4% of the male CR, were indicated as potential sires. Investments in purchase of animals were higher in Small than in Medium and Large herds; of all purchased sires 53.8% were found in Small herds vs. 28.2% and 18.0% in Medium and Large. Herd property was equally distributed between single (56.8% and multi property (43.2%. There was more manpower available per 100 cows in Small, being almost double and triple than in Medium and Large herds. Although milk extracted, was similar in all clusters averaging 2.4±0.5 litres/day/cow, milk off take rate, due to higher proportion of lactating cows, appeared higher in Small herds.

  9. The relationship between antibody status to bovine corona virus and bovine respiratory syncytial virus and disease incidence, reproduction and herd characteristics in dairy herds

    Tråvén Madeleine

    2010-06-01

    Full Text Available Abstract Background Bovine respiratory syncytial virus (BRSV and bovine corona virus (BCV affects cattle worldwide. Our objective was to evaluate the effects of these infections on general health and reproduction parameters measurable on herd level and to explore the association between antibody status and some herd characteristics. Methods We collected a pooled milk sample from five primiparous cows from 79 Swedish dairy herds in September 2006. The samples were analysed for immunoglobulin G antibodies to BCV and BRSV with indirect enzyme-linked immunosorbent assays. Herd level data from 1 September 2005 to 30 August 2006 were accessed retrospectively. The location of the herds was mapped using a geographical information system. Results Ten herds were antibody negative to both viruses and were compared with 69 herds positive to BCV or BRSV or both. Positive herds had a higher (P = 0.001 bulk tank milk somatic cell count (BMSCC compared with negative herds. The medians for all other analyzed health and reproductive parameters were consistently in favour of the herds negative to both viruses although the differences were not statistically significant. A higher proportion (P = 0.01 of herds used professional technicians for artificial insemination, rather than farm personnel, amongst the 33 herds negative to BCV compared with the 46 positive herds. Conclusions Our result shows that herds that were antibody positive to BCV and/or BRSV had a higher BMSCC compared with herds negative to BCV and BRSV. There was also tendency that negative herds had a better general herd health compared with positive. A higher proportion amongst the BCV negative herds used external technicians for AI instead of farm personnel, indicating that it is possible to avoid infection although having regular visits. Negative herds were located in close proximity to positive herds, indicating that local spread and airborne transmission between herds might not be of great

  10. Herd Protection from Drinking Water, Sanitation, and Hygiene Interventions.

    Fuller, James A; Eisenberg, Joseph N S

    2016-11-02

    Herd immunity arises when a communicable disease is less able to propagate because a substantial portion of the population is immune. Nonimmunizing interventions, such as insecticide-treated bednets and deworming drugs, have shown similar herd-protective effects. Less is known about the herd protection from drinking water, sanitation, and hand hygiene (WASH) interventions. We first constructed a transmission model to illustrate mechanisms through which different WASH interventions may provide herd protection. We then conducted an extensive review of the literature to assess the validity of the model results and identify current gaps in research. The model suggests that herd protection accounts for a substantial portion of the total protection provided by WASH interventions. However, both the literature and the model suggest that sanitation interventions in particular are the most likely to provide herd protection, since they reduce environmental contamination. Many studies fail to account for these indirect effects and thus underestimate the total impact an intervention may have. Although cluster-randomized trials of WASH interventions have reported the total or overall efficacy of WASH interventions, they have not quantified the role of herd protection. Just as it does in immunization policy, understanding the role of herd protection from WASH interventions can help inform coverage targets and strategies that indirectly protect those that are unable to be reached by WASH campaigns. Toward this end, studies are needed to confirm the differential role that herd protection plays across the WASH interventions suggested by our transmission model. © The American Society of Tropical Medicine and Hygiene.

  11. Herd-level association between antimicrobial use and antimicrobial resistance in bovine mastitis Staphylococcus aureus isolates on Canadian dairy farms.

    Saini, V; McClure, J T; Scholl, D T; DeVries, T J; Barkema, H W

    2012-04-01

    Surveillance of antimicrobial use and resistance is needed to manage antimicrobial resistance in bacteria. In this study, data were collected on antimicrobial use and resistance in Staphylococcus aureus (n=562), isolated from intramammary infections and (sub)clinical mastitis cases on 89 dairy farms in 4 regions of Canada [Alberta, Ontario, Québec, and the Maritime Provinces (Prince Edward Island, Nova Scotia, and New Brunswick)]. Dairy producers were asked to deposit empty drug containers into specially provided receptacles, and antimicrobial drug use rate was calculated to quantify antimicrobial use. Minimum inhibitory concentrations were determined using the Sensititer bovine mastitis plate system (TREK Diagnostic Systems Inc., Cleveland, OH), containing antimicrobials commonly used for mastitis treatment and control. Multivariable logistic regression models were built to determine herd-level risk factors of penicillin, ampicillin, pirlimycin, penicillin-novobiocin combination, tetracycline and sulfadimethoxine resistance in Staph. aureus isolates. Intramammary administration of the penicillin-novobiocin combination for dry cow therapy was associated with penicillin and ampicillin resistance [odds ratio (OR): 2.17 and 3.10, respectively]. Systemic administration of penicillin was associated with penicillin resistance (OR: 1.63). Intramammary administration of pirlimycin for lactating cow mastitis treatment was associated with pirlimycin resistance as well (OR: 2.07). Average herd parity was associated with ampicillin and tetracycline resistance (OR: 3.88 and 0.02, respectively). Average herd size was also associated with tetracycline resistance (OR: 1.02). Dairy herds in the Maritime region had higher odds of penicillin and lower odds of ampicillin resistance than dairy herds in Québec (OR: 2.18 and 0.19, respectively). Alberta dairy herds had lower odds of ampicillin and sulfadimethoxine resistance than dairy herds in Québec (OR: 0.04 and 0.08, respectively

  12. Evaluating perspectives for PRRS virus elimination from pig dense areas with a risk factor based herd index.

    Fahrion, A S; Beilage, E grosse; Nathues, H; Dürr, S; Doherr, M G

    2014-06-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) is wide-spread in pig populations globally. In many regions of Europe with intensive pig production and high herd densities, the virus is endemic and can cause disease and production losses. This fuels discussion about the feasibility and sustainability of virus elimination from larger geographic regions. The implementation of a program aiming at virus elimination for areas with high pig density is unprecedented and its potential success is unknown. The objective of this work was to approach pig population data with a simple method that could support assessing the feasibility of a sustainable regional PRRSV elimination. Based on known risk factors such as pig herd structure and neighborhood conditions, an index characterizing individual herds' potential for endemic virus circulation and reinfection was designed. This index was subsequently used to compare data of all pig herds in two regions with different pig- and herd-densities in Lower Saxony (North-West Germany) where PRRSV is endemic. Distribution of the indexed herds was displayed using GIS. Clusters of high herd index densities forming potential risk hot spots were identified which could represent key target areas for surveillance and biosecurity measures under a control program aimed at virus elimination. In an additional step, for the study region with the higher pig density (2463 pigs/km(2) farmland), the potential distribution of PRRSV-free and non-free herds during the implementation of a national control program aiming at national virus elimination was modeled. Complex herd and trade network structures suggest that PRRSV elimination in regions with intensive pig farming like that of middle Europe would have to involve legal regulation and be accompanied by important trade and animal movement restrictions. The proposed methodology of risk index mapping could be adapted to areas varying in size, herd structure and density. Interpreted in the

  13. Escaping Electrons from Intense Laser-Solid Interactions as a Function of Laser Spot Size

    Rusby, Dean; Gray, Ross; Butler, Nick; Dance, Rachel; Scott, Graeme; Bagnoud, Vincent; Zielbauer, Bernhard; McKenna, Paul; Neely, David

    2018-01-01

    The interaction of a high-intensity laser with a solid target produces an energetic distribution of electrons that pass into the target. These electrons reach the rear surface of the target creating strong electric potentials that act to restrict the further escape of additional electrons. The measurement of the angle, flux and spectra of the electrons that do escape gives insights to the initial interaction. Here, the escaping electrons have been measured using a differentially filtered imag...

  14. Herd prevalence of bovine brucellosis and analysis of risk factors in cattle in urban and peri-urban areas of the Kampala economic zone, Uganda

    Eisler Mark C

    2011-10-01

    Full Text Available Abstract Background Human brucellosis has been found to be prevalent in the urban areas of Kampala, the capital city of Uganda. A cross-sectional study was designed to generate precise information on the prevalence of brucellosis in cattle and risk factors for the disease in its urban and peri-urban dairy farming systems. Results The adjusted herd prevalence of brucellosis was 6.5% (11/177, 95% CI: 3.6%-10.0% and the adjusted individual animal prevalence was 5.0% (21/423, 95% CI: 2.7% - 9.3% based on diagnosis using commercial kits of the competitive enzyme-linked immunosorbent assay (CELISA for Brucella abortus antibodies. Mean within-herd prevalence was found to be 25.9% (95% CI: 9.7% - 53.1% and brucellosis prevalence in an infected herd ranged from 9.1% to 50%. A risk factor could not be identified at the animal level but two risk factors were identified at the herd level: large herd size and history of abortion. The mean number of milking cows in a free-grazing herd (5.0 was significantly larger than a herd with a movement restricted (1.7, p Conclusions Vaccination should be targeted at commercial large-scale farms with free-grazing farming to control brucellosis in cattle in and around Kampala city.

  15. Using a Herd Profile to Determine Age-Specific Prevalence of Bovine Leukemia Virus in Michigan Dairy Herds

    Ronald J. Erskine

    2012-01-01

    Full Text Available Enzootic bovine leukosis is a contagious disease of cattle caused by the retrovirus, bovine leukemia virus (BLV and is the most common cause of malignant neoplasm in cattle. In order to facilitate surveillance of this disease in dairy herds, we developed a method to combine ELISA of milk collected during routine production testing with a prescribed sampling of cows that is independent of the proportion of cows within each lactation. In 113 Michigan dairy herds, milk samples from ten cows in each of the 1st, 2nd, 3rd, and ≥4th lactations were analyzed for anti-Bovine Leukemia Virus (BLV antibodies by milk ELISA. For each herd, a BLV herd profile (BHP was calculated as the simple average of the percent of BLV-positive cows within each of the four lactation groups. The mean BHP for all herds was 32.8%, with means of 18.5, 28.8, 39.2, and 44.8% of 1st, 2nd, 3rd, and ≥4th lactation animals infected, respectively. In eight herds, we determined the correlation between the BHP, and true herd prevalence by testing the entire lactating herd (r=0.988,  P<0.0001. The BHP allows discrimination of lactation-specific BLV prevalence within a dairy herd, to help identify risk factors and management plans that may be important in transmission of BLV.

  16. Effects of abortion and other risk factors on conception rate in Iranian dairy herds

    Keshavarzi, Hamideh; Sadeghi-Sefidmazgi, Ali; Stygar, Anna Helena

    2017-01-01

    factor because of a significant interaction with IDIM and milk yield level. In conclusion, this study revealed that difference in CR between as well as within studied herds was remarkable. Moreover, calving season (due to for example heat stress in the warmer season) is a more important factor...... days after calving (2nd – 14th estrus cycle (3-WIM period)). After eliminating outliers and periods with missing records, the dataset included 200,580 insemination records of 31,830 cows observed between 2004 and 2014. A logistic regression model was developed to evaluate the effects of herd, parity......, calving season, cumulative fat corrected milk yield level (CFCML), mastitis in current 3-weeks in milk period (MAS), experience of mastitis in previous 3-WIM periods (EMAS), days in milk for insemination (IDIM) and all significant 2-way interactions on CR. Overall, the CR (total cows pregnant/total number...

  17. Strong CH/O interactions between polycyclic aromatic hydrocarbons and water: Influence of aromatic system size.

    Veljković, Dušan Ž

    2018-03-01

    Energies of CH/O interactions between water molecule and polycyclic aromatic hydrocarbons with a different number of aromatic rings were calculated using ab initio calculations at MP2/cc-PVTZ level. Results show that an additional aromatic ring in structure of polycyclic aromatic hydrocarbons significantly strengthens CH/O interactions. Calculated interaction energies in optimized structures of the most stable tetracene/water complex is -2.27 kcal/mol, anthracene/water is -2.13 kcal/mol and naphthalene/water is -1.97 kcal/mol. These interactions are stronger than CH/O contacts in benzene/water complex (-1.44 kcal/mol) while CH/O contacts in tetracene/water complex are even stronger than CH/O contacts in pyridine/water complexes (-2.21 kcal/mol). Electrostatic potential maps for different polycyclic aromatic hydrocarbons were calculated and used to explain trends in the energies of interactions. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Pitch-verticality and pitch-size cross-modal interactions

    Bonetti, Leonardo; Costa, Marco

    2017-01-01

    Two studies were conducted on cross-modal matching between pitch and sound source localization on the vertical axis, and pitch and size. In the first study 100 Hz, 200 Hz, 600 Hz, and 800 Hz tones were emitted by a loudspeaker positioned 60 cm above or below to the participant’s ear level. Using...

  19. Genotype by environment interaction for litter size in pigs as quantified by reaction norms analysis

    Knap, P W; Su, G

    2008-01-01

    A Bayesian procedure was used to estimate linear reaction norms (i.e. individual G × E plots) on 297 518 litter size records of 121 104 sows, daughters of 2040 sires, recorded on 144 farms in North and Latin America, Europe, Asia and Australia. The method allowed for simultaneous estimation of al...

  20. The niche construction of cultural complexity: interactions between innovations, population size and the environment.

    Fogarty, Laurel; Creanza, Nicole

    2017-12-05

    Niche construction is a process through which organisms alter their environments and, in doing so, influence or change the selective pressures to which they are subject. 'Cultural niche construction' refers specifically to the effect of cultural traits on the selective environments of other biological or cultural traits and may be especially important in human evolution. In addition, the relationship between population size and cultural accumulation has been the subject of extensive debate, in part because anthropological studies have demonstrated a significant association between population size and toolkit complexity in only a subset of studied cultures. Here, we review the role of cultural innovation in constructing human evolutionary niches and introduce a new model to describe the accumulation of human cultural traits that incorporates the effects of cultural niche construction. We consider the results of this model in light of available data on human toolkit sizes across populations to help elucidate the important differences between food-gathering societies and food-producing societies, in which niche construction may be a more potent force. These results support the idea that a population's relationship with its environment, represented here by cultural niche construction, should be considered alongside population size in studies of cultural complexity.This article is part of the themed issue 'Process and pattern in innovations from cells to societies'. © 2017 The Author(s).

  1. Flow rate through microfilters: Influence of the pore size distribution, hydrodynamic interactions, wall slip, and inertia

    Jensen, Kaare Hartvig; Valente, Andre X. C. N.; Stone, Howard A.

    2014-01-01

    We examine the fluid mechanics of viscous flow through filters consisting of perforated thin plates. We classify the effects that contribute to the hydraulic resistance of the filter. Classical analyses assume a single pore size and account only for filter thickness. We extend these results to ob...

  2. Effects of different dry period lengths on production and economy in the dairy herd estimated by stochastic simulation

    Sørensen, J.T.; Enevoldsen, Carsten; Kristensen, T.

    1993-01-01

    exhibited two different rates of voluntary culling for reproductive failure and milk production, and the feeding regimes consisted of grass silage ad lib. and either 8 or 12 kg of concentrates/day in the first 24 weeks of lactation. The economic result was studied under a herd size and a milk quota...

  3. Collective motion of groups of self-propelled particles following interacting leaders

    Ferdinandy, B.; Ozogány, K.; Vicsek, T.

    2017-08-01

    In order to keep their cohesiveness during locomotion gregarious animals must make collective decisions. Many species boast complex societies with multiple levels of communities. A common case is when two dominant levels exist, one corresponding to leaders and the other consisting of followers. In this paper we study the collective motion of such two-level assemblies of self-propelled particles. We present a model adapted from one originally proposed to describe the movement of cells resulting in a smoothly varying coherent motion. We shall use the terminology corresponding to large groups of some mammals where leaders and followers form a group called a harem. We study the emergence (self-organization) of sub-groups within a herd during locomotion by computer simulations. The resulting processes are compared with our prior observations of a Przewalski horse herd (Hortobágy, Hungary) which we use as results from a published case study. We find that the model reproduces key features of a herd composed of harems moving on open ground, including fights for followers between leaders and bachelor groups (group of leaders without followers). One of our findings, however, does not agree with the observations. While in our model the emerging group size distribution is normal, the group size distribution of the observed herd based on historical data have been found to follow lognormal distribution. We argue that this indicates that the formation (and the size) of the harems must involve a more complex social topology than simple spatial-distance based interactions.

  4. Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality.

    Xu, Renfeng; Wang, Huachun; Thibos, Larry N; Bradley, Arthur

    2017-04-01

    Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1  cd/m2, and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5  cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving defocused image

  5. Controlling herding in minority game systems

    Zhang, Ji-Qiang; Huang, Zi-Gang; Wu, Zhi-Xi; Su, Riqi; Lai, Ying-Cheng

    2016-02-01

    Resource allocation takes place in various types of real-world complex systems such as urban traffic, social services institutions, economical and ecosystems. Mathematically, the dynamical process of resource allocation can be modeled as minority games. Spontaneous evolution of the resource allocation dynamics, however, often leads to a harmful herding behavior accompanied by strong fluctuations in which a large majority of agents crowd temporarily for a few resources, leaving many others unused. Developing effective control methods to suppress and eliminate herding is an important but open problem. Here we develop a pinning control method, that the fluctuations of the system consist of intrinsic and systematic components allows us to design a control scheme with separated control variables. A striking finding is the universal existence of an optimal pinning fraction to minimize the variance of the system, regardless of the pinning patterns and the network topology. We carry out a generally applicable theory to explain the emergence of optimal pinning and to predict the dependence of the optimal pinning fraction on the network topology. Our work represents a general framework to deal with the broader problem of controlling collective dynamics in complex systems with potential applications in social, economical and political systems.

  6. Herd health and management of dairy cow

    Ćaǧlayan, Alper; Yüca, Songül

    2016-04-01

    Herd management requires multidisciplinary practices including animal feeding, gynecology, artificial insemination, immunology, and similar topics. Animal feeding is the most delicate subject as the fodder expense is 70% of the farm cost and as nearly all of the metabolic diseases arising out as health problem are because of misfeeding. However, a business organization's being able to maintain making profit will be possible by taking a healthy calf from breeding herd every year. For this reason, precision registrations of birth and artificial insemination, following-up pregnant state of animals, and making the other animals pregnant as soon as possible should be primary aim. It should not be forgotten that diarrhea and pneumonia in calves are among the most frequently witnessed infection related health problems. Mastitis, metritis and foot diseases take an important place in mature cows. These diseases can be minimized by vaccinations that are done properly and in suitable time, in-service training of staffs, making shelters suitable for animals welfare, and improving the hygienic conditions.

  7. Relationships between functional herd life and conformation traits in ...

    The genetic relationship between conformation traits and functional herd life of the South African Jersey population was investigated. Data on conformation traits (n = 46 238) and functional herd life (n = 90 530) on registered South African Jersey cows calving between 1989 and 2008 were obtained from the Integrated ...

  8. Maximum herd efficiency in meat production I. Optima for slaughter ...

    Profit rate for a meat production enterprise can be decomposedinto the unit price for meat and herd ... supply and demand, whereas breeding improvement is gen- ... Herd efficiency is total live mass for slaughter divided by costs .... tenance and above-maintenance components by Dickerson, and ..... Growth and productivity.

  9. Breakeven costs for embryo transfer in a commercial dairy herd.

    Ferris, T A; Troyer, B W

    1987-11-01

    Differences in Estimated Breeding Values expressed in dollars were compared by simulation of two, 100-cow, closed herds. One herd practiced normal intensity of female selection. The other herd generated various herd replacements by embryo transfer by varying 1) selection rate of embryo transfer dams and 2) numbers of daughters per dam from which embryos were transferred, while varying the merit of mates of embryo transfer dams. Estimated Breeding Value dollars were compounded each generation and regressed to remove age adjustments and added feed and health costs. Beginning values in both herds included a standard deviation of 55 Cow Index dollars, herd average of -23 Cow Index dollars, and a 120 Predicted Difference dollars for mates of dams not embryo transferred. Average merit of all sires used increased $12 per year. Herd calving rate (.70), proportion females (.5), calf loss (.15), and heifer survival rate (.83) were used. Breakeven cost per embryo transfer cow entering the milking herd was computed by Net Present Value analysis using a 10% discount rate over 10 and 20 yr. Breakeven cost or the maximum expense that would allow a 10% return on the expenditure ranged from $135 to $510 per surviving cow, $24 to $125 per transfer, $47 to $178 per pregnancy, and $81 to $357 per female calf born. As the number of replacements resulting from embryo transfer increased, breakeven cost per embryo transfer cow decreased due to diminishing return.

  10. 9 CFR 77.35 - Interstate movement from accredited herds.

    2010-01-01

    ... accredited herd. If a group of captive cervids from an accredited herd is being moved interstate together to... cervids is being moved together, the entire group must be isolated from all other livestock during the... from isolation; or (3) If the captive cervid to be added is not being moved directly from a classified...

  11. Stochastic models to simulate paratuberculosis in dairy herds

    Nielsen, S.S.; Weber, M.F.; Kudahl, Anne Margrethe Braad

    2011-01-01

    in the design of certification, surveillance, and control strategies for paratuberculosis in cattle herds. A detailed comparison is made between the Dutch JohneSSim and the Danish PTB-Simherd, using the same context of a set of control strategies in a typical Dutch/Danish herd. The conclusion is that while...

  12. Financial aspects of veterinary herd health management programmes

    Ifende, V.I.; Derks, M.; Hooijer, G.A.; Hogeveen, H.

    2014-01-01

    Veterinary herd health management (VHHM) programmes are meant to support herd health and farmers’ income (Brand and Guard 1996). They were introduced in the Netherlands in the 1970s (Sol and Renkema 1984) and at present many veterinarians provide them to farmers. VHHM comprises a basic structure of

  13. Patterns of herding and their occurrence in an online setting

    Langley, D.J.; Hoeve, M.C.; Ortt, J.R.; Pals, N.; Vecht, B. van der

    2014-01-01

    When groups of consumers share information or express their opinions about products and services, their attitudes or behavior sometime align without centralized coordination, a phenomenon known as herding. Building on pattern-based explanations of herding from the cognitive science literature, we

  14. Genetic value of herd life adjusted for milk production.

    Allaire, F R; Gibson, J P

    1992-05-01

    Cow herd life adjusted for lactational milk production was investigated as a genetic trait in the breeding objective. Under a simple model, the relative economic weight of milk to adjusted herd life on a per genetic standard deviation basis was equal to CVY/dCVL where CVY and CVL are the genetic coefficients of variation of milk production and adjusted herd life, respectively, and d is the depreciation per year per cow divided by the total fixed costs per year per cow. The relative economic value of milk to adjusted herd life at the prices and parameters for North America was about 3.2. An increase of 100-kg milk was equivalent to 2.2 mo of adjusted herd life. Three to 7% lower economic gain is expected when only improved milk production is sought compared with a breeding objective that included both production and adjusted herd life for relative value changed +/- 20%. A favorable economic gain to cost ratio probably exists for herd life used as a genetic trait to supplement milk in the breeding objective. Cow survival records are inexpensive, and herd life evaluations from such records may not extend the generation interval when such an evaluation is used in bull sire selection.

  15. Control of Yersinia enterocolitica in pigs at herd level

    Skjerve, Eystein; Lium, Bjørn; Nielsen, Bent

    1998-01-01

    of slaughter pigs (OR = 0.44) also lowered the herd prevalence. The most expressed risk factor was using an own farm vehicle for transport of slaughter pigs to abattoirs (OR = 12.92). Separation between clean and unclean section in herds (OR = 2.67), daily observations of a cat with kittens on the farm (OR = 2...

  16. Patterns of Herding and their Occurrence in an Online Setting

    Langley, David J.; Hoeve, Maarten C.; Ortt, J. Roland; Pals, Nico; van der Vecht, Bob

    When groups of consumers share information or express their opinions about products and services, their attitudes or behavior sometime align without centralized coordination, a phenomenon known as herding. Building on pattern-based explanations of herding from the cognitive science literature, we

  17. Size effects of solvent molecules on the phase behavior and effective interaction of colloidal systems with the bridging attraction

    Chen, Jie; Wang, Xuewu; Kline, Steven R; Liu, Yun

    2016-01-01

    There has been much recent research interest towards understanding the phase behavior of colloidal systems interacting with a bridging attraction, where the small solvent particles and large solute colloidal particles can be reversibly associated with each other. These systems show interesting phase behavior compared to the more widely studied depletion attraction systems. Here, we use Baxter’s two-component sticky hard sphere model with a Percus–Yevick closure to solve the Ornstein–Zernike equation and study the size effect on colloidal systems with bridging attractions. The spinodal decomposition regions, percolation transition boundaries and binodal regions are systematically investigated as a function of the relative size of the small solvent and large solute particles as well as the attraction strength between the small and large particles. In the phase space determined by the concentrations of small and large particles, the spinodal and binodal regions form isolated islands. The locations and shapes of the spinodal and binodal regions sensitively depend on the relative size of the small and large particles and the attraction strength between them. The percolation region shrinks by decreasing the size ratio, while the binodal region slightly expands with the decrease of the size ratio. Our results are very important in understanding the phase behavior for a bridging attraction colloidal system, a model system that provides insight into oppositely charged colloidal systems, protein phase behavior, and colloidal gelation mechanisms. (paper)

  18. Size effects of solvent molecules on the phase behavior and effective interaction of colloidal systems with the bridging attraction.

    Chen, Jie; Wang, Xuewu; Kline, Steven R; Liu, Yun

    2016-11-16

    There has been much recent research interest towards understanding the phase behavior of colloidal systems interacting with a bridging attraction, where the small solvent particles and large solute colloidal particles can be reversibly associated with each other. These systems show interesting phase behavior compared to the more widely studied depletion attraction systems. Here, we use Baxter's two-component sticky hard sphere model with a Percus-Yevick closure to solve the Ornstein-Zernike equation and study the size effect on colloidal systems with bridging attractions. The spinodal decomposition regions, percolation transition boundaries and binodal regions are systematically investigated as a function of the relative size of the small solvent and large solute particles as well as the attraction strength between the small and large particles. In the phase space determined by the concentrations of small and large particles, the spinodal and binodal regions form isolated islands. The locations and shapes of the spinodal and binodal regions sensitively depend on the relative size of the small and large particles and the attraction strength between them. The percolation region shrinks by decreasing the size ratio, while the binodal region slightly expands with the decrease of the size ratio. Our results are very important in understanding the phase behavior for a bridging attraction colloidal system, a model system that provides insight into oppositely charged colloidal systems, protein phase behavior, and colloidal gelation mechanisms.

  19. A Note regarding Problems with Interaction and Varying Block Sizes in a Comparison of Endotracheal Tubes

    Richard L. Einsporn

    2014-01-01

    Full Text Available A randomized clinical experiment to compare two types of endotracheal tubes utilized a block design where each of the six participating anesthesiologists performed tube insertions for an equal number of patients for each type of tube. Five anesthesiologists intubated at least three patients with each tube type, but one anesthesiologist intubated only one patient per tube type. Overall, one type of tube outperformed the other on all three effectiveness measures. However, analysis of the data using an interaction model gave conflicting and misleading results, making the tube with the better performance appear to perform worse. This surprising result was caused by the undue influence of the data for the anesthesiologist who intubated only two patients. We therefore urge caution in interpreting results from interaction models with designs containing small blocks.

  20. Dairy operation management practices and herd milk production.

    Losinger, W C; Heinrichs, A J

    1996-03-01

    A national US survey collected data on herd milk production and management of Holstein herds. Step-wise selection identified management practices that were related to herd milk production using only operations that calculated herd milk production as well as using data from all operations. Results were similar. Milk production was highest in the West. Operations with 25% registered cattle had higher production than operations with no registered cattle. Dairy operations that reported a mean BW > 545 kg at first calving had higher mean milk production than operations with a mean BW or = 27 mo at first calving. In addition, use of the following management practices was associated with higher rolling herd average milk production: calves born in individual areas in buildings, calves hand-fed first colostrum, starter grain fed to preweaned calves, ionophores fed to heifers from birth to first calving, DHIA record-keeping system used, computerized records, and no new cattle introduced in the previous 12 mo.

  1. Modeling salmonella Dublin into the dairy herd simulation model Simherd

    Kudahl, Anne Braad

    2010-01-01

    Infection with Salmonella Dublin in the dairy herd and effects of the infection and relevant control measures are currently being modeled into the dairy herd simulation model called Simherd. The aim is to compare the effects of different control strategies against Salmonella Dublin on both within...... of the simulations will therefore be used for decision support in the national surveillance and eradication program against Salmonella Dublin. Basic structures of the model are programmed and will be presented at the workshop. The model is in a phase of face-validation by a group of Salmonella......-herd- prevalence and economy by simulations. The project Dublin on both within-herd- prevalence and economy by simulations. The project is a part of a larger national project "Salmonella 2007 - 2011" with the main objective to reduce the prevalence of Salmonella Dublin in Danish Dairy herds. Results...

  2. Diagnostic studies of abortion in Danish dairy herds

    Agerholm, J.S.; Willadsen, C. M.; Nielsen, Thomas Krogh

    1997-01-01

    Diagnostic findings in 218 aborted bovine foetuses are reported. The materials were examined in a matched case-control study of 69 Danish dairy herds with a sudden increase in the number of abortions and a corresponding 69 control herds. Foetuses aborted during the subsequent 6-month period were...... examined to identify the cause of abortion if possible. A total of 186 specimens were submitted from case herds and 32 from control herds. A likely cause of abortion was diagnosed in 73 foetuses. The most common cause was bovine viral diarrhoea virus (BVDV: 13%) followed by Neospora caninum infection (10......%), mycosis (5%) and Bacillus licheniformis infection (4%). Foetal and/or placental lesions were found in a further 27 cases. Only BVDV infection and neosporosis were diagnosed in more than one foetus per herd and only protozoal associated abortions occurred significantly more frequently in the case, rather...

  3. A questionnaire study of associations between potential risk factors and salmonella status in Swedish dairy herds.

    Ågren, Estelle C C; Frössling, Jenny; Wahlström, Helene; Emanuelson, Ulf; Sternberg Lewerin, Susanna

    2017-08-01

    In this study associations between potential risk factors and salmonella status in Swedish dairy herds were investigated. A case-control study design was used, including existing as well as new cases. Herds were assigned a salmonella status on the basis of antibody analysis of bulk milk samples. Information on potential risk factors was collected from registry data and from farmers via a questionnaire. Univariable and multivariable logistic regression analyses were used to investigate associations between salmonella status and potential risk factors. In addition, multivariate analysis with Additive Bayesian Network (ABN) modelling was performed to improve understanding of the complex relationship between all the variables. Because of the difficulty in identifying associations between potential risk factors and infections with low prevalence and a large regional variation, exposure of potential risk factors in the high-prevalence region (Öland) were compared to exposure in other regions in Sweden. In total 483 of 996 (48%) farmers responded to the questionnaire, 69 herds had test-positive bulk milk samples. The strongest association with salmonella status was 'presence of salmonella test-positive herds pastures and providing protective clothing for visitors. The latter is probably a reflection of increased disease awareness in Öland. The ABN model showed associations between herd size and housing as well as several management procedures. This provides an explanation why herd size frequently has been identified as a risk factor for salmonella by other studies. The study confirms the importance of local transmission routes for salmonella, but does not identify specific components in this local spread. Therefore, it supports the use of a broad biosecurity approach in the prevention of salmonella. In Öland, some potential risk factors are more common than in other parts of Sweden. Theoretically these could contribute to the spread of salmonella, but this was not

  4. Scaling of laser-plasma interactions with laser wavelength and plasma size

    Max, C.E.; Campbell, E.M.; Mead, W.C.; Kruer, W.L.; Phillion, D.W.; Turner, R.E.; Lasinski, B.F.; Estabrook, K.G.

    1983-01-01

    Plasma size is an important parameter in wavelength-scaling experiments because it determines both the threshold and potential gain for a variety of laser-plasma instabilities. Most experiments to date have of necessity produced relatively small plasmas, due to laser energy and pulse-length limitations. We have discussed in detail three recent Livermore experiments which had large enough plasmas that some instability thresholds were exceeded or approached. Our evidence for Raman scatter, filamentation, and the two-plasmon decay instability needs to be confirmed in experiments which measure several instability signatures simultaneously, and which produce more quantitative information about the local density and temperature profiles than we have today

  5. Scaling of laser-plasma interactions with laser wavelength and plasma size

    Max, C.E.; Campbell, E.M.; Mead, W.C.; Kruer, W.L.; Phillion, D.W.; Turner, R.E.; Lasinski, B.F.; Estabrook, K.G.

    1983-01-25

    Plasma size is an important parameter in wavelength-scaling experiments because it determines both the threshold and potential gain for a variety of laser-plasma instabilities. Most experiments to date have of necessity produced relatively small plasmas, due to laser energy and pulse-length limitations. We have discussed in detail three recent Livermore experiments which had large enough plasmas that some instability thresholds were exceeded or approached. Our evidence for Raman scatter, filamentation, and the two-plasmon decay instability needs to be confirmed in experiments which measure several instability signatures simultaneously, and which produce more quantitative information about the local density and temperature profiles than we have today.

  6. Behavioural processes in social context: female abductions, male herding and female grooming in hamadryas baboons.

    Polo, Pablo; Colmenares, Fernando

    2012-06-01

    The formation of bonds between strangers is an event that occurs routinely in many social animals, including humans, and, as social bonds in general, they affect the individuals' welfare and biological fitness. The present study was motivated by an interest in the behavioural processes that drive bond formation in a social context of hostility, in which the incumbent partners vary greatly in physical power and reproductive interests, a situation in which individuals of many group-living species find themselves often throughout their lives. We focused on the quantitative analysis of female abductions via male aggressive herding in a nonhuman primate, the hamadryas baboon, in which intersexual bonds are known to be strong. We tested three hypotheses informed by sexual conflict/sexual coercion theory (male herding-as-conditioning and female grooming-as-appeasement) and by socioecological theory (unit size and female competition). The results supported the predictions: males resorted to coercive tactics (aggressive herding) with abducted females, and abducted females elevated the amount of grooming directed at their new unit males; in fact, they escaped from the otherwise negative effect of unit size on female-to-male grooming. These findings reveal that conflicts of interest are natural ingredients underpinning social bonds and that resorting to coercive aggression may be an option especially when partners differ greatly in their physical power. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Economic impact of clinical mastitis in a dairy herd assessed by stochastic simulation using different methods to model yield losses

    Hagnestam-Nielsen, Christel; Østergaard, Søren

    2009-01-01

    The main aim of the present study was to examine the economic consequences of a reduction in the incidence of clinical mastitis (CM) at herd level under current Swedish farming conditions. A second objective was to ask whether the estimated cost of CM alters depending upon whether the model...... with 150 cows (9000 kg of energy-corrected milk per cow-year). Four herd types, defined by production level and reproductive performance, were modelled to investigate possible interactions between herd type and response to a reduction in the risk of CM. Technical and economic results, given the initial...... incidence of CM (25.6 per 100 cow-years), were studied together with the consequences of reducing the initial risk of CM by 50% and 90% throughout lactation and the consequences of reducing the initial risk by 50% and 90% before peak yield. A conventional way of modelling yield losses - i.e. one employing...

  8. The influence of selected litter and herd factors on treatments for lameness in suckling piglets from 35 Danish herds

    Christensen, J.

    1996-01-01

    was: high-risk litters are (1) large litters, (2) litters with previous diseases or deaths, (3) litters where the nursing sow had been treated, or (4) litters from high-parity sows. Litters from large conventional herds or from herds with a high stocking density were expected to have a high risk...

  9. Interactive effects of size, contrast, intensity and configuration of background objects in evoking disruptive camouflage in cuttlefish.

    Chiao, Chuan-Chin; Chubb, Charles; Hanlon, Roger T

    2007-07-01

    Disruptive body coloration is a primary camouflage tactic of cuttlefish. Because rapid changeable coloration of cephalopods is guided visually, we can present different visual backgrounds (e.g., computer-generated, two-dimensional prints) and video record the animal's response by describing and grading its body pattern. We showed previously that strength of cuttlefish disruptive patterning depends on the size, contrast, and density of discrete light elements on a homogeneous dark background. Here we report five experiments on the interactions of these and other features. Results show that Weber contrast of light background elements is--in combination with element size--a powerful determinant of disruptive response strength. Furthermore, the strength of disruptive patterning decreases with increasing mean substrate intensity (with other factors held constant). Interestingly, when element size, Weber contrast and mean substrate intensity are kept constant, strength of disruptive patterning depends on the configuration of clusters of small light elements. This study highlights the interactions of multiple features of natural microhabitats that directly influence which camouflage pattern a cuttlefish will choose.

  10. Breeding for reproduction traits in context of multiplication herds efficiency in swine

    Petr Humpolíček

    2013-01-01

    Full Text Available Presented study is a follow-up to the studies focused on effect of different selection pressure applied on two subpopulations of purebred Czech Large White sows on performance in multiplication herds. Higher selection pressure particularly on litter size and number of function nipples, while lower pressure on growth performance was applied in one population. About 1214 farrows of 393 F1 Czech Large White sows were included into statistical evaluation. The mixed linear models using the procedure REML in SAS for Windows 9.1.2. was used. The hypothesis that progeny of sows from hyper-prolific subpopulation breed in multiplier herds have different performance was not confirmed which is in contrast to previous studies. This non-homogeneity can be related to non-additive genetic effects which are caused by crossbreeding while selection methods are based on additive models.

  11. The Isolation of DNA by Polycharged Magnetic Particles: An Analysis of the Interaction by Zeta Potential and Particle Size.

    Haddad, Yazan; Xhaxhiu, Kledi; Kopel, Pavel; Hynek, David; Zitka, Ondrej; Adam, Vojtech

    2016-04-20

    Magnetic isolation of biological targets is in major demand in the biotechnology industry today. This study considers the interaction of four surface-modified magnetic micro- and nanoparticles with selected DNA fragments. Different surface modifications of nanomaghemite precursors were investigated: MAN37 (silica-coated), MAN127 (polyvinylpyrrolidone-coated), MAN158 (phosphate-coated), and MAN164 (tripolyphosphate-coated). All particles were positive polycharged agglomerated monodispersed systems. Mean particle sizes were 0.48, 2.97, 2.93, and 3.67 μm for MAN37, MAN127, MAN164, and MAN158, respectively. DNA fragments exhibited negative zeta potential of -0.22 mV under binding conditions (high ionic strength, low pH, and dehydration). A decrease in zeta potential of particles upon exposure to DNA was observed with exception of MAN158 particles. The measured particle size of MAN164 particles increased by nearly twofold upon exposure to DNA. Quantitative PCR isolation of DNA with a high retrieval rate was observed by magnetic particles MAN127 and MAN164. Interaction between polycharged magnetic particles and DNA is mediated by various binding mechanisms such as hydrophobic and electrostatic interactions. Future development of DNA isolation technology requires an understanding of the physical and biochemical conditions of this process.

  12. Association between stall surface and some animal welfare measurements in freestall dairy herds using recycled manure solids for bedding.

    Husfeldt, A W; Endres, M I

    2012-10-01

    The objective of this cross-sectional study was to investigate the association between stall surface and some animal welfare measurements in upper Midwest US dairy operations using recycled manure solids as bedding material. The study included 34 dairy operations with herd sizes ranging from 130 to 3,700 lactating cows. Forty-five percent of the herds had mattresses and 55% had deep-bedded stalls. Farms were visited once between July and October 2009. At the time of visit, at least 50% of the cows in each lactating pen were scored for locomotion, hygiene, and hock lesions. On-farm herd records were collected for the entire year and used to investigate mortality, culling, milk production, and mastitis incidence. Stall surface was associated with lameness and hock lesion prevalence. Lameness prevalence (locomotion score ≥ 3 on a 1 to 5 scale) was lower in deep-bedded freestalls (14.4%) than freestalls with mattresses (19.8%). Severe lameness prevalence (locomotion score ≥ 4) was also lower for cows housed in deep-bedded freestalls (3.6%) than for cows housed in freestalls with mattresses (5.9%). In addition, the prevalence of hock lesions (hock lesion scores ≥ 2 on a 1 to 3 scale, with 1=no lesion, 2=hair loss or mild lesion, and 3=swelling or severe lesion) and severe hock lesions (hock lesion score=3) was lower in herds with deep-bedded freestalls (49.4%; 6.4%) than in herds with mattresses (67.3%; 13.2%). Herd turnover rates were not associated with stall surface; however, the percentage of removals due to voluntary (low milk production, disposition, and dairy) and involuntary (death, illness, injury, and reproductive) reasons was different between deep-bedded and mattress-based freestalls. Voluntary removals averaged 16% of all herd removals in deep-bedded herds, whereas in mattress herds, these removals were 8%. Other welfare measurements such as cow hygiene, mortality rate, mastitis incidence, and milk production were not associated with stall surface

  13. Effects of hydrodynamic interaction on random adhesive loose packings of micron-sized particles

    Liu Wenwei

    2017-01-01

    Full Text Available Random loose packings of monodisperse spherical micron-sized particles under a uniform flow field are investigated via an adhesive discrete-element method with the two-way coupling between the particles and the fluid. Characterized by a dimensionless adhesion parameter, the packing fraction follows the similar law to that without fluid, but results in larger values due to the hydrodynamic compression. The total pressure drop through the packed bed shows a critical behaviour at the packing fraction of ϕ ≈ 0.22 in the present study. The normalized permeability of the packed bed for different parameters increases with the increase of porosities and is also in consistent with the Kozeny-Carman equation.

  14. Conflicts between reindeer herding and an expanding caribou herd in Alaska

    Greg L. Finstad

    2002-04-01

    Full Text Available The reindeer industry has existed in Alaska since 1892. This industry has largely been concentrated on the Seward Peninsula, Alaska because suitable habitat has been available and caribou have been absent here for over 100 years. Until recently, reindeer meat and velvet antler production consistently generated millions of dollars in revenue critical to the economies of rural Alaskan communities. From 1976 to 1996 the Western Arctic Caribou Herd (WACH increased from about 75 000 to 463 000 animals. Concurrently, seasonal range use of the WACH shifted westward onto traditional reindeer ranges of the Seward Peninsula. Reindeer herders lost 75-100% of their herds through commingling and out¬migration with wild caribou. This loss of over 12 000 reindeer represents a potential economic value of 13 million dollars. Sustainable meat and velvet antler production and the economies of western Alaskan are likely to be affected by these changes.

  15. Measuring and modeling the interaction among reward size, delay to reward, and satiation level on motivation in monkeys.

    Minamimoto, Takafumi; La Camera, Giancarlo; Richmond, Barry J

    2009-01-01

    Motivation is usually inferred from the likelihood or the intensity with which behavior is carried out. It is sensitive to external factors (e.g., the identity, amount, and timing of a rewarding outcome) and internal factors (e.g., hunger or thirst). We trained macaque monkeys to perform a nonchoice instrumental task (a sequential red-green color discrimination) while manipulating two external factors: reward size and delay-to-reward. We also inferred the state of one internal factor, level of satiation, by monitoring the accumulated reward. A visual cue indicated the forthcoming reward size and delay-to-reward in each trial. The fraction of trials completed correctly by the monkeys increased linearly with reward size and was hyperbolically discounted by delay-to-reward duration, relations that are similar to those found in free operant and choice tasks. The fraction of correct trials also decreased progressively as a function of the satiation level. Similar (albeit noiser) relations were obtained for reaction times. The combined effect of reward size, delay-to-reward, and satiation level on the proportion of correct trials is well described as a multiplication of the effects of the single factors when each factor is examined alone. These results provide a quantitative account of the interaction of external and internal factors on instrumental behavior, and allow us to extend the concept of subjective value of a rewarding outcome, usually confined to external factors, to account also for slow changes in the internal drive of the subject.

  16. Effects of interactions between powder particle size and binder viscosity on agglomerate growth mechanisms in a high shear mixer.

    Johansen, A; Schaefer, T

    2001-01-01

    A study was performed in order to elucidate the effects of the interactions between powder particle size and binder viscosity on the mechanisms involved in agglomerate formation and growth. Calcium carbonates having mean particle sizes in the range of 5-214 microm and polyethylene glycols having viscosities in the range of approximately 50-100000 mPas were melt agglomerated in a high shear mixer. Agglomerate growth by nucleation and coalescence was found to dominate when agglomerating small powder particles and binders with a low viscosity. Increasing the binder viscosity increased the formation of agglomerates by immersion of powder particles in the surface of the binder droplets. With a larger powder particle size, an increasing binder viscosity was necessary in order to obtain an agglomerate strength being sufficient to avoid breakage. Due to a low agglomerate strength, a satisfying agglomeration of very large particles (214 microm) could not be obtained, even with very viscous binders. The study demonstrated that the optimum agglomerate growth occurred when the agglomerates were of an intermediate strength causing an intermediate deformability of the agglomerates. In order to produce spherical agglomerates (pellets), a low viscosity binder has to be chosen when agglomerating a powder with a small particle size, and a high viscosity binder must be applied in agglomeration of powders with large particles.

  17. INTERACTIONS BETWEEN ORGANIZATIONAL SIZE AND SOME IT FACTORS IN THE CONTEXT OF ERP SUCCESS ASSESSMENT: AN EXPLORATORY INVESTIGATION

    EDUARD EDELHAUSER

    2011-01-01

    Full Text Available The study set sights on Romanian organizations which implemented a SIVECO ERP and BI software. The methodology used is both quantitative and qualitative. The research results were obtained with the use of a questionnaire, and our purpose was to demonstrate some hypothesis concerning the size of the organisation, the management method and the IT&C based decision. The questionnaire was operated with SPSS 17, through a linear regression analysis. The research has revealed how the organizational size and the IT factors interaction in the 2010 Romanian organizations. The research has a high level of originality, such a study has been never conducted before for computer based advanced management methods implementation.

  18. REPLACEMENT IN RABBIT HERDS: A REVIEW

    Ibrahim F.M. Marai

    2010-08-01

    Full Text Available Doe rabbit's replacement constitutes the annual renewal rate of new breeders that must be incorporated into the production stock. Criterion for culling non-productive animals differs significantly among fryer production colonies, foundation stocks and a colony with continuous enzootic disease or continuous malnourishment. In commercial rabbit production, good management improves the health and productivity of the entire herd, by reducing the all-time high replacement rates and improving economic viability. In the present article, a comprehensive review of numerous experiences in the rabbit production field of different countries, was presented. Basic recommendations for professional breeders were highlighted, covering critical issues such as the need for continuously upgrading the health status of the colony, the positive effect of   genetic selection and the nutritional conditioning and special treatment of young does being groomed as future replacements.

  19. Continuous limit of a crowd motion and herding model: Analysis and numerical simulations

    Pietschmann, Jan-Frederik

    2011-11-01

    In this paper we study the continuum limit of a cellular automaton model used for simulating human crowds with herding behaviour. We derive a system of non-linear partial differential equations resembling the Keller-Segel model for chemotaxis, however with a non-monotone interaction. The latter has interesting consequences on the behaviour of the model\\'s solutions, which we highlight in its analysis. In particular we study the possibility of stationary states, the formation of clusters and explore their connection to congestion. We also introduce an efficient numerical simulation approach based on an appropriate hybrid discontinuous Galerkin method, which in particular allows flexible treatment of complicated geometries. Extensive numerical studies also provide a better understanding of the strengths and shortcomings of the herding model, in particular we examine trapping effects of crowds behind nonconvex obstacles. © American Institute of Mathematical Sciences.

  20. Continuous limit of a crowd motion and herding model: Analysis and numerical simulations

    Pietschmann, Jan-Frederik; Markowich, Peter Alexander; Burger, Martin

    2011-01-01

    In this paper we study the continuum limit of a cellular automaton model used for simulating human crowds with herding behaviour. We derive a system of non-linear partial differential equations resembling the Keller-Segel model for chemotaxis, however with a non-monotone interaction. The latter has interesting consequences on the behaviour of the model's solutions, which we highlight in its analysis. In particular we study the possibility of stationary states, the formation of clusters and explore their connection to congestion. We also introduce an efficient numerical simulation approach based on an appropriate hybrid discontinuous Galerkin method, which in particular allows flexible treatment of complicated geometries. Extensive numerical studies also provide a better understanding of the strengths and shortcomings of the herding model, in particular we examine trapping effects of crowds behind nonconvex obstacles. © American Institute of Mathematical Sciences.

  1. Relationship between stepping and kicking behavior and milking management in dairy cattle herds

    L. Cerqueira, Joaquim; Araújo, José P P; Blanco-Penedo, Isabel

    2017-01-01

    We studied the relationship between behavior during milking with milking parlor management, measuring the occurrence of steps and kicks, and cow-related factors. We also investigated the link between stepping and kicking during milking and udder health. A total of 2,903 direct observations...... of milking behavior were collected in 44 dairy herds in the north of Portugal. The results showed great variability in the occurrence of stepping and kicking among herds during milking. Mixed linear and logistic regression models for factors associated with stepping and kicking were developed. Cows in tandem...... of the visit also showed a trend toward higher kicking frequency. The results suggest that animal welfare measures, like kicking and stepping, are suitable for epidemiologic studies. Significant interactions were observed when animals were affected by challenging health and welfare situations....

  2. New target for high-intensity laser-matter interaction: Gravitational flow of micrometer-sized powders

    Servol, M.; Quere, F.; Bougeard, M.; Monot, P.; Martin, Ph.; Faenov, A.Ya; Pikuz, T.A.; Audebert, P.; Francucci, M.; Petrocelli, G.

    2005-01-01

    The design of efficient targets for high-intensity laser-matter interaction is essential to fully exploit the advantages of laser-induced photons or particles sources. We present an advantageous kind of target, consisting in a free gravitational flow of micrometer-sized powder, and describe its main technical characteristics. We demonstrate a laser-induced keV x-ray source using this target, and show that the photon flux obtained for the Kα line of Si by irradiating different silica powders is comparable to the one obtained with a bulk silica target

  3. Herd-level prevalence and associated risk factors for Toxoplasma gondii, Neospora caninum, Chlamydia abortus and bovine viral diarrhoea virus in commercial dairy and beef cattle in eastern, northern and northeastern China.

    Sun, Wu-Wen; Meng, Qing-Feng; Cong, Wei; Shan, Xiao-Feng; Wang, Chun-Feng; Qian, Ai-Dong

    2015-11-01

    Although the seroprevalence of Toxoplasma gondii, Neospora caninum, Chlamydia abortus and bovine viral diarrhea virus infection in cattle have been reported in some areas in China, most of them were conducted with small number of cattle samples and very limited districts and neglected the assessment of herd management factors associated with herd-level prevalence of these pathogen infections. Thus, from September 2013 to December 2014, a large-scale seroprevalence study was conducted to determine the animal-level and herd-level seroprevalence and identify herd-level risk factors associated with these pathogen infections in 4487 cattle from 134 herds in five provinces (Heilongjiang, Jilin, Liaoning, Shandong, Hebei) and Inner Mongolia Autonomous Region of China. At animal level, the true prevalence of antibodies against T. gondii, N. caninum, C. abortus and bovine viral diarrhoea virus (BVDV) was 10.48, 17.14, 11.92 and 50.10%, respectively. At herd level, the true prevalence of antibodies against T. gondii, N. caninum, C. abortus and BVDV was 27.16, 29.10, 37.31 and 40.30%, respectively. Multivariate analysis of these characteristics showed that source of water and presence of felids were significantly associated with T. gondii infection in the studied cattle herds. Source of water was significantly associated with N. caninum infection in the studied cattle herds. While herd size and management system were significantly associated with BVDV infection in the studied cattle herds, this is the first report of herd-level prevalence and associated risk factors of T. gondii, N. caninum, C. abortus and BVDV infection in cattle in China.

  4. Simulations of two sedimenting-interacting spheres with different sizes and initial configurations using immersed boundary method

    Liao, Chuan-Chieh; Hsiao, Wen-Wei; Lin, Ting-Yu; Lin, Chao-An

    2015-06-01

    Numerical investigations are carried out for the drafting, kissing and tumbling (DKT) phenomenon of two freely falling spheres within a long container by using an immersed-boundary method. The method is first validated with flows induced by a sphere settling under gravity in a small container for which experimental data are available. The hydrodynamic interactions of two spheres are then studied with different sizes and initial configurations. When a regular sphere is placed below the larger one, the duration of kissing decreases in pace with the increase in diameter ratio. On the other hand, the time duration of the kissing stage increases in tandem with the increase in diameter ratio as the large sphere is placed below the regular one, and there is no DKT interactions beyond threshold diameter ratio. Also, the gap between homogeneous spheres remains constant at the terminal velocity, whereas the gaps between the inhomogeneous spheres increase due to the differential terminal velocity.

  5. Bead-bead interaction parameters in dissipative particle dynamics: Relation to bead-size, solubility parameter, and surface tension

    Maiti, Amitesh; McGrother, Simon

    2004-01-01

    Dissipative particle dynamics (DPD) is a mesoscale modeling method for simulating equilibrium and dynamical properties of polymers in solution. The basic idea has been around for several decades in the form of bead-spring models. A few years ago, Groot and Warren [J. Chem. Phys. 107, 4423 (1997)] established an important link between DPD and the Flory-Huggins χ-parameter theory for polymer solutions. We revisit the Groot-Warren theory and investigate the DPD interaction parameters as a function of bead size. In particular, we show a consistent scheme of computing the interfacial tension in a segregated binary mixture. Results for three systems chosen for illustration are in excellent agreement with experimental results. This opens the door for determining DPD interactions using interfacial tension as a fitting parameter.

  6. Defining the Pen Islands Caribou Herd of southern Hudson Bay

    Kenneth F. Abraham

    1998-03-01

    Full Text Available In this paper, we describe the Pen Islands Herd of caribou, the largest aggregation of caribou in Ontario (it also occupies a portion of northeastern Manitoba. Photographic counts showed the herd had a minimum population of 2300 in 1979, 4660 in 1986, 7424 in 1987 and 10 798 in 1994. Throughout the 1980s, the Pen Islands caribou exhibited population behaviour similar to migratory barren-ground caribou herds, although morphology suggests they are woodland caribou or possibly a mixture of subspecies. The herd had well-defined traditional tundra calving grounds, formed nursery groups and large mobile post-calving aggregations, and migrated over 400 km between tundra summer habitats and boreal forest winter habitats. Its migration took it into three Canadian jurisdictions (Ontario, Manitoba, Northwest Territories and it was important to residents of both Manitoba and Ontario. It is clear that the herd should be managed as a migratory herd and the critical importance of both the coastal and variable large winter ranges should be noted in ensuring the herd's habitat needs are secure.

  7. Challenging the myth of the irrational dairy farmer; understanding decision-making related to herd health.

    Kristensen, E; Jakobsen, E B

    2011-01-01

    Veterinarians working with dairy cows are suggested to refocus their efforts from being task-oriented providers of single-cow therapy and develop themselves into advice-oriented herd health management advisors. The practising cattle veterinarian's ability to translate knowledge into on-farm application requires a profound understanding of the dairy farm as an integrated system. Consequently, educating and motivating farmers are key issues. To achieve such insight the veterinarian needs to work with several scientific disciplines, especially epidemiology and (behavioural) economics. This trans-disciplinary approach offers new methodological possibilities and challenges to students of dairy herd health management. Advisors working with dairy herd health management may sometimes experience that farmers do not follow their advice. Potentially, this could lead to the interpretation that such farmers are behaving irrationally. However, farmers who are confronted with advice suggesting a change of behaviour are placed in a state of cognitive dissonance. To solve such dissonance they may either comply with the advice or reduce the dissonance by convincing themselves that the suggested change in management is impossible to implement. Consequently, herd health management advisors must understand the fundamental and instrumental relationships between individual farmers' values, behaviour and perception of risk, to stimulate and qualify the farmer's decision-making in a way that will increase the farmer's satisfaction and subjective well-being. Traditionally, studies on herd health economics have focussed on financial methods to measure the value of technical outcomes from suggested changes in management, following the basic assumption that farmers strive to maximise profit. Farmers, however, may be motivated by very different activities, e.g. animal health and welfare or other farmers' recognition, making it impossible to provide 'one-size-fts-all' consultancy because the

  8. Benthic algal production across lake size gradients: interactions among morphometry, nutrients, and light.

    Vadeboncoeur, Yvonne; Peterson, Garry; Vander Zanden, M Jake; Kalff, Jacob

    2008-09-01

    Attached algae play a minor role in conceptual and empirical models of lake ecosystem function but paradoxically form the energetic base of food webs that support a wide variety of fishes. To explore the apparent mismatch between perceived limits on contributions of periphyton to whole-lake primary production and its importance to consumers, we modeled the contribution of periphyton to whole-ecosystem primary production across lake size, shape, and nutrient gradients. The distribution of available benthic habitat for periphyton is influenced by the ratio of mean depth to maximum depth (DR = z/ z(max)). We modeled total phytoplankton production from water-column nutrient availability, z, and light. Periphyton production was a function of light-saturated photosynthesis (BPmax) and light availability at depth. The model demonstrated that depth ratio (DR) and light attenuation strongly determined the maximum possible contribution of benthic algae to lake production, and the benthic proportion of whole-lake primary production (BPf) declined with increasing nutrients. Shallow lakes (z benthic or pelagic primary productivity depending on trophic status. Moderately deep oligotrophic lakes had substantial contributions by benthic primary productivity at low depth ratios and when maximum benthic photosynthesis was moderate or high. Extremely large, deep lakes always had low fractional contributions of benthic primary production. An analysis of the world's largest lakes showed that the shapes of natural lakes shift increasingly toward lower depth ratios with increasing depth, maximizing the potential importance of littoral primary production in large-lake food webs. The repeatedly demonstrated importance of periphyton to lake food webs may reflect the combination of low depth ratios and high light penetration characteristic of large, oligotrophic lakes that in turn lead to substantial contributions of periphyton to autochthonous production.

  9. Calf management practices and associations with herd-level morbidity and mortality on beef cow-calf operations.

    Murray, C F; Fick, L J; Pajor, E A; Barkema, H W; Jelinski, M D; Windeyer, M C

    2016-03-01

    The objective of this study was to investigate calf management practices on beef cow-calf operations and determine associations with herd-level morbidity and mortality of pre-weaned calves. A 40-question survey about management practices, morbidity and mortality was administered to cow-calf producers by distributing paper surveys and by circulating an online link through various media. A total of 267 producers completed the survey. Data were analyzed with descriptive statistics and multivariable linear regression models. Average herd-level treatment risk for pre-weaning calf diarrhea (PCD) and bovine respiratory disease (BRD) were 4.9% and 3.0%, respectively. Average herd-level mortality within the first 24 h of life (stillbirth), from 1 to 7 days and 7 days to weaning were 2.3%, 1.1%, and 1.4%, respectively. Operations that never intervened at parturition had 4.7% higher PCD than those that occasionally did. On operations using small elastrator bands for castration, PCD was 1.9% higher than those using other methods. For every increase of 100 cows in herd size, BRD decreased by 1.1%. The association between BRD and PCD varied by when calving season began. Operations that used off-farm, frozen colostrum had a 1.1% increase in stillbirths. Operations that verified a calf had suckled had 0.7% lower mortality from 1 to 7 days of age. Those that intervened when colostrum was abnormal or that used small elastrator bands for castration had 1.9% and 1.4% higher mortality during the 1st week of life, respectively, compared with other operations. Mortality from 7 days to weaning was lower by 0.7% when calving season started in April compared with January or February and was higher by 1.0% for each additional week of calving season. Operations that intervened with colostrum consumption for assisted calvings had lower mortality from 7 days to weaning by 0.8% compared with those that did not. For every 1.0% increase in BRD, mortality from 7 days to weaning increased by 1

  10. Short communication: Factors affecting vitamin B12 concentration in milk of commercial dairy herds: An exploratory study.

    Duplessis, M; Pellerin, D; Cue, R I; Girard, C L

    2016-06-01

    Only bacteria can synthesize vitamin B12, and this requires adequate Co supply. The natural source of vitamin B12 in human diets comes from animal products, especially those from ruminants. This study aimed to describe variability regarding vitamin B12 concentration in milk among and within commercial dairy herds in early lactation. A secondary objective was to explore potential causes for this variability such as genetic variation and diet characteristics. In total, 399 dairy cows (135 primiparous and 264 multiparous; 386 Holstein and 13 Jersey cows) in 15 commercial herds were involved. Milk samples were taken at 27.4±4.1 and 55.4±4.1d in milk. Neither parity (primiparous vs. multiparous) nor sampling time affected milk concentrations of vitamin B12. Nevertheless, vitamin B12 concentration in milk was highly variable among and within dairy herds. The lowest vitamin B12 concentration in milk of cows was observed in the Jersey herd. Among herds, vitamin B12 concentration in milk ranged from 2,309 to 3,878 pg/mL; one glass (250mL) of milk from those herds would provide between 23 and 40% of the vitamin B12 recommended daily allowance. Among individual cows, however, this provision varied between 16 and 57% of the recommendation. In spite of the limited size of the studied population, the heritability value was 0.23, suggesting that genetic selection could modify milk vitamin B12 concentration. We observed a positive relationship between milk vitamin B12 concentration and dietary acid detergent fiber content and a negative relationship between milk concentration of vitamin B12 and dietary crude protein content. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. Prevalence and herd-level risk factors for bovine tuberculosis in the State of Paraná, Brazil

    Maria do Carmo Pessôa Silva

    2016-11-01

    Full Text Available Bovine tuberculosis is a zoonosis with worldwide distribution. Its control has a direct impact on public health and livestock production. This study estimated the prevalence of infected herds and adult bovines and evaluated risk factors associated with the presence of tuberculosis within herds in the state of Paraná. The state was divided in seven livestock regions and independent sampling was performed. A total of 1,419 farms were sampled and 16,045 animals were tested using the intradermal comparative cervical tuberculin diagnostic test. The apparent and estimated prevalence rates in farms and adult bovine animals were 2.15% (95% CI: 1.31-3.00 and 0.42% (95% CI: 0.04-0.81, respectively. It was not possible to state with 95% confidence that the disease prevalence in any region was significantly different from that in other regions. There were no positive animals in the western region, and the prevalence of positive herds and animals in the other regions ranged from 1.03% to 3.89% and 0.17% to 1.08%, respectively. The logistic regression model identified larger herd size (OR = 2.4 and mechanical cmilking (OR = 5.18 as risk factors associated with the presence of bovine tuberculosis. The combination of low prevalence with risk factors associated to larger herds and more intensive dairy farming, renders the state of Paraná a good candidate for the implementation of industry-based free-herd accreditation schemes and makes a case for planning risk-based surveillance targeted at major dairy basins.

  12. Factors associated with the growing-finishing performances of swine herds: an exploratory study on serological and herd level indicators.

    Fablet, C; Rose, N; Grasland, B; Robert, N; Lewandowski, E; Gosselin, M

    2018-01-01

    Growing and finishing performances of pigs strongly influence farm efficiency and profitability. The performances of the pigs rely on the herd health status and also on several non-infectious factors. Many recommendations for the improvement of the technical performances of a herd are based on the results of studies assessing the effect of one or a limited number of infections or environmental factors. Few studies investigated jointly the influence of both type of factors on swine herd performances. This work aimed at identifying infectious and non-infectious factors associated with the growing and finishing performances of 41 French swine herds. Two groups of herds were identified using a clustering analysis: a cluster of 24 herds with the highest technical performance values (mean average daily gain = 781.1 g/day +/- 26.3; mean feed conversion ratio = 2.5 kg/kg +/- 0.1; mean mortality rate = 4.1% +/- 0.9; and mean carcass slaughter weight = 121.2 kg +/- 5.2) and a cluster of 17 herds with the lowest performance values (mean average daily gain =715.8 g/day +/- 26.5; mean feed conversion ratio = 2.6 kg/kg +/- 0.1; mean mortality rate = 6.8% +/- 2.0; and mean carcass slaughter weight = 117.7 kg +/- 3.6). Multiple correspondence analysis was used to identify factors associated with the level of technical performance. Infection with the porcine reproductive and respiratory syndrome virus and the porcine circovirus type 2 were infectious factors associated with the cluster having the lowest performance values. This cluster also featured farrow-to-finish type herds, a short interval between successive batches of pigs (≤3 weeks) and mixing of pigs from different batches in the growing or/and finishing steps. Inconsistency between nursery and fattening building management was another factor associated with the low-performance cluster. The odds of a herd showing low growing-finishing performance was significantly

  13. Herd Behavior and Financial Crashes: An Interacting Particle System Approach

    Vincenzo Crescimanna

    2016-01-01

    Full Text Available We provide an approach based on a modification of the Ising model to describe the dynamics of stock markets. Our model incorporates three different factors: imitation, the impact of external news, and private information; moreover, it is characterized by coupling coefficients, static in time, but not identical for each agent. By analogy with physical models, we consider the temperature parameter of the system, assuming that it evolves with memory of the past, hence considering how former news influences realized market returns. We show that a standard Ising potential assumption is not sufficient to reproduce the stylized facts characterizing financial markets; this is because it assigns low probabilities to rare events. Hence, we study a variation of the previous setting providing, also by concrete computations, new insights and improvements.

  14. Population dynamics of the Kaminuriak caribou herd, 1968 - 1985

    Douglas C. Heard

    1986-06-01

    Full Text Available The Kaminuraik caribou herd apparently declined from about 120 000 animals in 1950 to 63 000 in 1968. Beginning in 1968 documentation of herd trend was based on the estimate of the number of breeding (pregnant and post-partum females on the calving ground during the birth peak. It appeared as if we understood the basic population processes responsible for the decline when we correctly predicted a drop from 14 800 breeding females in 1977 to 13 000 in 1980. However a three-fold increase, to 41 000 breeding females in 1982, and continued growth thereafter, was unanticipated. Most of that increase must have resulted from an immigration of cows to the herd's traditional calving ground around Kaminuriak Lake, although increased birth rates, and increased survival rates also contributed to herd growth. Immigrant cows probably came from the northeastern mainland of the NWT

  15. Bovine mastitis: prevalence, risk factors and isolation of Staphylococcus aureus in dairy herds at Hawassa milk shed, South Ethiopia.

    Abebe, Rahmeto; Hatiya, Hagere; Abera, Mesele; Megersa, Bekele; Asmare, Kassahun

    2016-12-03

    Mastitis is a disease of major economic importance in dairy industry worldwide. It is of particular concern in developing countries like Ethiopia, where milk and milk products are scarce. The objectives of the study were to estimate the prevalence of mastitis, identify the cow-and herd-level potential risk factors and isolate Staphylococcus aureus, one of etiological agents for contagious mastitis, from cows positive for mastitis. A total of 529 lactating cows selected randomly from 95 herds were screened by California mastitis test (CMT) for sub-clinical mastitis. Also 172 milk samples collected from CMT positive cows were cultured for isolation of S. aureus. Based on CMT result and clinical examination, the prevalence of mastitis at herd-level was 74.7% (95% CI: 64.5, 82.8). The corresponding cow-level prevalence was 62.6% (95% CI: 58.3, 66.7), of which 59.2 and 3.4% were sub-clinical and clinical mastitis cases, respectively. S. aureus was isolated from 51.2% of the milk samples cultured and 73.2% of the herds affected with mastitis. In the multivariable logistic regression model, the herd-level factors significantly associated (p mastitis were herd size, bedding material, and milking mastitic cows last, while at cow-level, breed, parity, stage of lactation, udder and leg hygiene, and teat end shape were noted to have a significant effect on mastitis occurrence. The very high prevalence of mastitis, more importantly the sub-clinical one, in the herds examined revealed the huge potential economic loss the sector suffers. Perhaps this was attributed to lack of implementation of the routine mastitis prevention and control practices by all of the herd owners. The findings of this study warrants the need for strategic approach including dairy extension that focus on enhancing dairy farmers' awareness and practice of hygienic milking, regular screening for sub-clinical mastitis, dry cow therapy and culling of chronically infected cows.

  16. The evalution of reproduction parametres in chosen herd of sheep

    BENEŠOVÁ, Kristýna

    2009-01-01

    It has been observed the breed herd of Texel sheep in the foothills area of Orlické mountains in the year 2005-2008. The base of herd was consisted of 374 ewes, 575 lambs and 6 rams in total. These parametres of reproduction - conception, fertility, rearing, empty ewes, abortions, lambing, stillborn, death after born, were monitored at ewes. For the parametres of reproduction at ewes were found significant effects of ewe´s age and ram´s line.

  17. Prolonging herd immunity to cholera via vaccination: Accounting for human mobility and waning vaccine effects.

    Corey M Peak

    2018-02-01

    Full Text Available Oral cholera vaccination is an approach to preventing outbreaks in at-risk settings and controlling cholera in endemic settings. However, vaccine-derived herd immunity may be short-lived due to interactions between human mobility and imperfect or waning vaccine efficacy. As the supply and utilization of oral cholera vaccines grows, critical questions related to herd immunity are emerging, including: who should be targeted; when should revaccination be performed; and why have cholera outbreaks occurred in recently vaccinated populations?We use mathematical models to simulate routine and mass oral cholera vaccination in populations with varying degrees of migration, transmission intensity, and vaccine coverage. We show that migration and waning vaccine efficacy strongly influence the duration of herd immunity while birth and death rates have relatively minimal impacts. As compared to either periodic mass vaccination or routine vaccination alone, a community could be protected longer by a blended "Mass and Maintain" strategy. We show that vaccination may be best targeted at populations with intermediate degrees of mobility as compared to communities with very high or very low population turnover. Using a case study of an internally displaced person camp in South Sudan which underwent high-coverage mass vaccination in 2014 and 2015, we show that waning vaccine direct effects and high population turnover rendered the camp over 80% susceptible at the time of the cholera outbreak beginning in October 2016.Oral cholera vaccines can be powerful tools for quickly protecting a population for a period of time that depends critically on vaccine coverage, vaccine efficacy over time, and the rate of population turnover through human mobility. Due to waning herd immunity, epidemics in vaccinated communities are possible but become less likely through complementary interventions or data-driven revaccination strategies.

  18. Population growth, movements, and status of the Nushagak Peninsula Caribou Herd following reintroduction, 1988 - 2000

    Gail H. Collins

    2003-04-01

    Full Text Available Barren ground caribou (Rangifer tarandus were reintroduced to the Nushagak Peninsula, Alaska in February of 1988 after an absence of more than 100 years. Since reintroduction, herd growth and population dynamics have been monitored closely. At this time, there has been no significant dispersal from the herds' core range. The Nushagak Peninsula Caribou Herd (NPCH grew rapidly from 146 reintroduced individuals to over 1000 in 13 years. Dramatic mean annual growth during the first 6 years (1988-1994 of 38% (r = 0.32 can be attributed to the high percentage of females in the initial reintroduction, high calf production and survival, exceptional range conditions, few predators, and no hunting. However, the populations' exceptional growth (peak counts of 1400 slowed and stabilized between 1996¬1998 and then decreased between 1998 and 2000. Size, body condition and weights of calves captured in 2000 were significantly lower than those captured in 1995 and 1997. Although calf production also decreased from close to 100% (1990-1995 to about 91% (1996-2000, overall calf survival continued to be high. Legal harvest began in 1995, and harvest reports have accounted for approximately 3% of population mortality annually. Although brown bears (Ursus arctos and wolves (Canis lupus are present, the extent of predation is unknown. Mean home range of the NPCH was 674 km2 and group sizes were greatest during post-calving aggregation in July (mean = 127. Caribou population density on the Nushagak Peninsula reached approximately 1.2 caribou/km2 in 1997 before declining to about 1.0 caribou/km2. A range survey in 1994 noted only trace utilization of lichens on the Nushagak Peninsula by caribou. A subsequent survey in 1999 found moderate to severe utilization in 46% of plots, suggesting the reintroduced herd was beginning to alter range condition. Between 1997 and 2000, both calf production and condition of 10-month-old calves declined. Calving has also been delayed

  19. Success and failure of reindeer herding in Greenland

    Christine Cuyler

    1999-04-01

    Full Text Available Animal husbandry is a recent innovation in Greenland, specifically reindeer husbandry is less than 50 years old. Reindeer husbandry was first established in mid-west Greenland and later in southern Greenland. The Greenland hunter tradition and culture is, however, still dominant in many communities. During the 1980s and 1990s, the incompatibility of these two traditions resulted in the failure of reindeer husbandry in mid-west Greenland. There were neither herding nor seasonal herd movements. Animals remained year round on the winter range, which was destroyed as lichens were trampled every summer. Without seasonal herd movements both sustainable range use and control of the herd were lost. Today, there are just two semi-domestic reindeer herds left, and both are in southern Greenland. One herd is commercially successful, and the other is under development. In mid-west Greenland, semi-domestic reindeer husbandry officially ended in 1998, and a hunt was initiated to remove the remaining population. Possibly, by the year 2000 any animals left in this region will be considered wild caribou.

  20. Markets, Herding and Response to External Information.

    Carro, Adrián; Toral, Raúl; San Miguel, Maxi

    2015-01-01

    We focus on the influence of external sources of information upon financial markets. In particular, we develop a stochastic agent-based market model characterized by a certain herding behavior as well as allowing traders to be influenced by an external dynamic signal of information. This signal can be interpreted as a time-varying advertising, public perception or rumor, in favor or against one of two possible trading behaviors, thus breaking the symmetry of the system and acting as a continuously varying exogenous shock. As an illustration, we use a well-known German Indicator of Economic Sentiment as information input and compare our results with Germany's leading stock market index, the DAX, in order to calibrate some of the model parameters. We study the conditions for the ensemble of agents to more accurately follow the information input signal. The response of the system to the external information is maximal for an intermediate range of values of a market parameter, suggesting the existence of three different market regimes: amplification, precise assimilation and undervaluation of incoming information.

  1. Markets, Herding and Response to External Information.

    Adrián Carro

    Full Text Available We focus on the influence of external sources of information upon financial markets. In particular, we develop a stochastic agent-based market model characterized by a certain herding behavior as well as allowing traders to be influenced by an external dynamic signal of information. This signal can be interpreted as a time-varying advertising, public perception or rumor, in favor or against one of two possible trading behaviors, thus breaking the symmetry of the system and acting as a continuously varying exogenous shock. As an illustration, we use a well-known German Indicator of Economic Sentiment as information input and compare our results with Germany's leading stock market index, the DAX, in order to calibrate some of the model parameters. We study the conditions for the ensemble of agents to more accurately follow the information input signal. The response of the system to the external information is maximal for an intermediate range of values of a market parameter, suggesting the existence of three different market regimes: amplification, precise assimilation and undervaluation of incoming information.

  2. Interactions between mammalian cells and nano- or micro-sized wear particles: physico-chemical views against biological approaches.

    Prokopovich, Polina

    2014-11-01

    Total joint arthroplasty (TJA) is a more and more frequent approach for the treatment of end-stage osteoarthritis in young and active adults; it successfully relieves joint pain and improves function significantly enhancing the health-related quality of life. Aseptic loosening and other wear-related complications are some of the most recurrent reasons for revision of TJA. This review focuses on current understanding of the biological reactions to prosthetic wear debris comparing in vivo and in vitro results. Mechanisms of interactions of various types of cells with metal, polymeric and ceramic wear particles are summarised. Alternative views based on multidisciplinary approaches are proposed to consider physico-chemical, surface parameters of wear particles (such as: particle size, geometry and charge) and material (particle chemical composition and its nature) with biological effects (cellular responses). Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Analyses on the Performance and Interaction Between the Impeller and Casing in a Small-Size Turbo-Compressor

    Kim, Youn-Jea; Kim, Dong-Won

    The effects of casing shapes on the performance and the interaction between an impeller and a casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the turbo-compressor with circular and single volute casings from the inlet to a discharge nozzle. The optimum design for each element is important to develop the small-size turbo-compressor using alternative refrigerant as a working fluid. Typically, the rotating speed of the compressor is in the range of 40000-45000rpm because of the small size of an impeller diameter. A blade of an impeller has backswept two-dimensional shape due to tip clearance and a vane diffuser has wedge type. In order to predict the flow pattern inside the entire impeller, the vaneless diffuser and the casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and time-averaged three-dimensional Navier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure recovery and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around the casing and pressure difference between the inlet and the outlet of the compressor are performed for the circular casing. The comparison of experimental and numerical results is conducted, and reasonable agreement is obtained.

  4. A strain-, cow-, and herd-specific bio-economic simulation model of intramammary infections in dairy cattle herds.

    Gussmann, Maya; Kirkeby, Carsten; Græsbøll, Kaare; Farre, Michael; Halasa, Tariq

    2018-07-14

    Intramammary infections (IMI) in dairy cattle lead to economic losses for farmers, both through reduced milk production and disease control measures. We present the first strain-, cow- and herd-specific bio-economic simulation model of intramammary infections in a dairy cattle herd. The model can be used to investigate the cost-effectiveness of different prevention and control strategies against IMI. The objective of this study was to describe a transmission framework, which simulates spread of IMI causing pathogens through different transmission modes. These include the traditional contagious and environmental spread and a new opportunistic transmission mode. In addition, the within-herd transmission dynamics of IMI causing pathogens were studied. Sensitivity analysis was conducted to investigate the influence of input parameters on model predictions. The results show that the model is able to represent various within-herd levels of IMI prevalence, depending on the simulated pathogens and their parameter settings. The parameters can be adjusted to include different combinations of IMI causing pathogens at different prevalence levels, representing herd-specific situations. The model is most sensitive to varying the transmission rate parameters and the strain-specific recovery rates from IMI. It can be used for investigating both short term operational and long term strategic decisions for the prevention and control of IMI in dairy cattle herds. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Efficient and robust pupil size and blink estimation from near-field video sequences for human-machine interaction.

    Chen, Siyuan; Epps, Julien

    2014-12-01

    Monitoring pupil and blink dynamics has applications in cognitive load measurement during human-machine interaction. However, accurate, efficient, and robust pupil size and blink estimation pose significant challenges to the efficacy of real-time applications due to the variability of eye images, hence to date, require manual intervention for fine tuning of parameters. In this paper, a novel self-tuning threshold method, which is applicable to any infrared-illuminated eye images without a tuning parameter, is proposed for segmenting the pupil from the background images recorded by a low cost webcam placed near the eye. A convex hull and a dual-ellipse fitting method are also proposed to select pupil boundary points and to detect the eyelid occlusion state. Experimental results on a realistic video dataset show that the measurement accuracy using the proposed methods is higher than that of widely used manually tuned parameter methods or fixed parameter methods. Importantly, it demonstrates convenience and robustness for an accurate and fast estimate of eye activity in the presence of variations due to different users, task types, load, and environments. Cognitive load measurement in human-machine interaction can benefit from this computationally efficient implementation without requiring a threshold calibration beforehand. Thus, one can envisage a mini IR camera embedded in a lightweight glasses frame, like Google Glass, for convenient applications of real-time adaptive aiding and task management in the future.

  6. Role of Carboxylate ligands in the Synthesis of AuNPs: Size Control, Molecular Interaction and Catalytic Activity

    Aljohani, Hind Abdullah

    2016-05-22

    low temperature. The structure of the citrate layer on the AuNP surface may be a key factor in gaining a more detailed understanding of nanoparticle formation and stabilization. This can be affecting the catalytic activity. These thoughts invited us to systematically examine the role of sodium citrate as a stabilizer of gold nanoparticles, which is the main theme of this thesis. This research is focused on three main objectives, controlling the size of the gold nanoparticles based on citrate (and other carboxylate ligands Trisodium citrate dihydrate, Isocitric Acid, Citric acid, Trimesic acid, Succinic Acid, Phthalic acid, Disodium glutarate, Tartaric Acid, Sodium acetate, Acetic Acid and Formic Acid by varying the concentration of Gold/sodium citrate, investigating the interaction of the citrate layer on the AuNP surface, and testing the activity of the Au/TiO2 catalysts for the oxidation of carbon monoxide. This thesis will be divided into five chapters. In Chapter 1, a general literature study on the various applications and methods of synthesis of Au nanoparticles is described. Then we present the main synthetic pathways of Au nanoparticles we selected. A part of the bibliographic study was given to the use of Au nanoparticles in catalysis. In Chapter 2, we give a brief description of the different experimental procedures and characterization techniques utilized over the course of the present work. The study of the size control and the interaction between gold nanoparticles and the stabilizer (carboxylate groups) was achieved by using various characterization techniques such as UV-visible spectroscopy, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Nuclear Magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FTIR). In Chapter 3, we discuss the synthesis and size control of Au nanoparticles by following the growth of these nanoparticles by UV-Visible spectroscopy and TEM. We

  7. Sow-level risk factors for stillbirth of piglets in organic sow herds

    Rangstrup-Christensen, Lena; Krogh, Mogens Agerbo; Pedersen, Lene Juul

    2017-01-01

    In Danish organic pig production, one-third of total born piglets die before weaning, and stillbirth has previously crudely been estimated to account for 27% of the total preweaning mortality. The objective of this study was to evaluate season, litter size, parity and body condition of the sow...... as risk factors for stillbirth in nine commercial Danish organic pig herds. The study was conducted over a 1-year period, and the data included registrations on 5170 farrowings with 82 906 total born piglets. The average number of total born piglets per litter was 16.0, and the number of stillborn piglets...

  8. Size versus polarizability in protein-ligand interactions: binding of noble gases within engineered cavities in phage T4 lysozyme.

    Quillin, M L; Breyer, W A; Griswold, I J; Matthews, B W

    2000-09-29

    To investigate the relative importance of size and polarizability in ligand binding within proteins, we have determined the crystal structures of pseudo wild-type and cavity-containing mutant phage T4 lysozymes in the presence of argon, krypton, and xenon. These proteins provide a representative sample of predominantly apolar cavities of varying size and shape. Even though the volumes of these cavities range up to the equivalent of five xenon atoms, the noble gases bind preferentially at highly localized sites that appear to be defined by constrictions in the walls of the cavities, coupled with the relatively large radii of the noble gases. The cavities within pseudo wild-type and L121A lysozymes each bind only a single atom of noble gas, while the cavities within mutants L133A and F153A have two independent binding sites, and the L99A cavity has three interacting sites. The binding of noble gases within two double mutants was studied to characterize the additivity of binding at such sites. In general, when a cavity in a protein is created by a "large-to-small" substitution, the surrounding residues relax somewhat to reduce the volume of the cavity. The binding of xenon and, to a lesser degree, krypton and argon, tend to expand the volume of the cavity and to return it closer to what it would have been had no relaxation occurred. In nearly all cases, the extent of binding of the noble gases follows the trend xenon>krypton>argon. Pressure titrations of the L99A mutant have confirmed that the crystallographic occupancies accurately reflect fractional saturation of the binding sites. The trend in noble gas affinity can be understood in terms of the effects of size and polarizability on the intermolecular potential. The plasticity of the protein matrix permits repulsion due to increased ligand size to be more than compensated for by attraction due to increased ligand polarizability. These results have implications for the mechanism of general anesthesia, the migration

  9. Estimating the herd immunity effect of rotavirus vaccine.

    Pollard, Suzanne L; Malpica-Llanos, Tanya; Friberg, Ingrid K; Fischer-Walker, Christa; Ashraf, Sania; Walker, Neff

    2015-07-31

    Diarrhea is one of the leading causes of death in children under 5, and an estimated 39% of these deaths are attributable to rotavirus. Currently two live, oral rotavirus vaccines have been introduced on the market; however, the herd immunity effect associated with rotavirus vaccine has not yet been quantified. The purpose of this meta-analysis was to estimate the herd immunity effects associated with rotavirus vaccines. We performed a systematic literature review of articles published between 2008 and 2014 that measured the impact of rotavirus vaccine on severe gastroenteritis (GE) morbidity or mortality. We assessed the quality of published studies using a standard protocol and conducted meta-analyses to estimate the herd immunity effect in children less than one year of age across all years presented in the studies. We conducted these analyses separately for studies reporting a rotavirus-specific GE outcome and those reporting an all-cause GE outcome. In studies reporting a rotavirus-specific GE outcome, four of five of which were conducted in the United States, the median herd effect across all study years was 22% [19-25%]. In studies reporting an all-cause GE outcome, all of which were conducted in Latin America, the median herd effect was 24.9% [11-30%]. There is evidence that rotavirus vaccination confers a herd immunity effect in children under one year of age in the United States and Latin American countries. Given the high variability in vaccine efficacy across regions, more studies are needed to better examine herd immunity effects in high mortality regions. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Generalized herd effects and vaccine evaluation: impact of live influenza vaccine on off-target bacterial colonisation.

    Mina, Michael J

    2017-06-01

    Interactions between pathogens and commensal microbes are major contributors to health and disease. Infectious diseases however are most often considered independent, viewed within a one-host one-pathogen paradigm and, by extension, the interventions used to treat and prevent them are measured and evaluated within this same paradigm. Vaccines, especially live vaccines, by stimulating immune responses or directly interacting with other microbes can alter the environment in which they act, with effects that span across pathogen species. Live attenuated infl uenza vaccines for example, while safe, increase upper respiratory tract bacterial carriage density of important human commensal pathogens like Streptococcus pneumoniae and Staphylococcus aureus. Further, by altering the ecological niche and dynamics of phylogenetically distinct microbes within the host, vaccines may unintentionally affect transmission of non-vaccine targeted pathogens. Thus, vaccine effects may span across species and across scales, from the individual to the population level. In keeping with traditional vaccine herd-effects that indirectly protect even unvaccinated individuals by reducing population prevalence of vaccine-targeted pathogens, we call these cross-species cross-scale effects "generalized herd-effects". As opposed to traditional herd-effects, "generalized" relaxes the assumption that the effect occurs at the level of the vaccine-target pathogen and "herd effect" implies, as usual, that the effects indirectly impact the population at large, including unvaccinated bystanders. Unlike traditional herd-effects that decrease population prevalence of the vaccine-target, generalized herd-effects may decrease or increase prevalence and disease by the off-target pathogen. LAIV, for example, by increasing pneumococcal density in the upper respiratory tract of vaccine recipients, especially children, may increase pneumococcal transmission and prevalence, leading to excess pneumococcal invasive

  11. Comparison of Brachyspira hyodysenteriae Isolates Recovered from Pigs in Apparently Healthy Multiplier Herds with Isolates from Herds with Swine Dysentery.

    Tom La

    Full Text Available Swine dysentery (SD is a mucohaemorrhagic colitis of grower/finisher pigs classically resulting from infection by the anaerobic intestinal spirochaete Brachyspira hyodysenteriae. This study aimed to determine whether B. hyodysenteriae isolates from pigs in three healthy German multiplier herds supplying gilts to other farms differed from isolates from nine German production herds with SD. Isolates were subjected to whole genomic sequencing, and in silico multilocus sequence typing showed that those from the three multiplier herds were of previously undescribed sequence types (ST132, ST133 and ST134, with all isolates from the same herd having the same ST. All isolates were examined for the presence of 332 genes encoding predicted virulence or virulence lifestyle associated factors, and these were well conserved. Isolates from one multiplier herd were atypical in being weakly haemolytic: they had 10 amino acid substitutions in the haemolysin III protein and five in the haemolysin activation protein compared to reference strain WA1, and had a disruption in the promoter site of the hlyA gene. These changes likely contribute to the weakly haemolytic phenotype and putative lack of virulence. These same isolates also had nine base pair insertions in the iron metabolism genes bitB and bitC and lacked five of six plasmid genes that previously have been associated with colonisation. Other overall differences between isolates from the different herds were in genes from three of five outer membrane proteins, which were not found in all the isolates, and in members of a block of six plasmid genes. Isolates from three herds with SD had all six plasmid genes, while isolates lacking some of these genes were found in the three healthy herds-but also in isolates from six herds with SD. Other differences in genes of unknown function or in gene expression may contribute to variation in virulence; alternatively, superior husbandry and better general health may have

  12. Diffusion of finite-sized hard-core interacting particles in a one-dimensional box: Tagged particle dynamics.

    Lizana, L; Ambjörnsson, T

    2009-11-01

    We solve a nonequilibrium statistical-mechanics problem exactly, namely, the single-file dynamics of N hard-core interacting particles (the particles cannot pass each other) of size Delta diffusing in a one-dimensional system of finite length L with reflecting boundaries at the ends. We obtain an exact expression for the conditional probability density function rhoT(yT,t|yT,0) that a tagged particle T (T=1,...,N) is at position yT at time t given that it at time t=0 was at position yT,0. Using a Bethe ansatz we obtain the N -particle probability density function and, by integrating out the coordinates (and averaging over initial positions) of all particles but particle T , we arrive at an exact expression for rhoT(yT,t|yT,0) in terms of Jacobi polynomials or hypergeometric functions. Going beyond previous studies, we consider the asymptotic limit of large N , maintaining L finite, using a nonstandard asymptotic technique. We derive an exact expression for rhoT(yT,t|yT,0) for a tagged particle located roughly in the middle of the system, from which we find that there are three time regimes of interest for finite-sized systems: (A) for times much smaller than the collision time tparticle concentration and D is the diffusion constant for each particle, the tagged particle undergoes a normal diffusion; (B) for times much larger than the collision time t >taucoll but times smaller than the equilibrium time ttaue , rhoT(yT,t|yT,0) approaches a polynomial-type equilibrium probability density function. Notably, only regimes (A) and (B) are found in the previously considered infinite systems.

  13. Herd-level interpretation of test results for epidemiologic studies of animal diseases

    Christensen, Jette; Gardner, Ian A.

    2000-01-01

    Correct classification of the true status of herds is an important component of epidemiologic studies and animal disease-control programs. We review theoretical aspects of herd-level testing through consideration of test performance (herd-level sensitivity, specificity and predictive values......), the factors affecting these estimates, and available software for calculations. We present new aspects and considerations concerning the effect of precision and bias in estimation of individual-test performance on herd-test performance and suggest methods (pooled testing, targeted sampling of subpopulations...... with higher prevalence, and use of combinations of tests) to improve herd-level sensitivity when the expected within-herd prevalence is low....

  14. Herd factors associated with dairy cow mortality.

    McConnel, C; Lombard, J; Wagner, B; Kopral, C; Garry, F

    2015-08-01

    Summary studies of dairy cow removal indicate increasing levels of mortality over the past several decades. This poses a serious problem for the US dairy industry. The objective of this project was to evaluate associations between facilities, herd management practices, disease occurrence and death rates on US dairy operations through an analysis of the National Animal Health Monitoring System's Dairy 2007 survey. The survey included farms in 17 states that represented 79.5% of US dairy operations and 82.5% of the US dairy cow population. During the first phase of the study operations were randomly selected from a sampling list maintained by the National Agricultural Statistics Service. Only farms that participated in phase I and had 30 or more dairy cows were eligible to participate in phase II. In total, 459 farms had complete data for all selected variables and were included in this analysis. Univariable associations between dairy cow mortality and 162 a priori identified operation-level management practices or characteristics were evaluated. Sixty of the 162 management factors explored in the univariate analysis met initial screening criteria and were further evaluated in a multivariable model exploring more complex relationships. The final weighted, negative binomial regression model included six variables. Based on the incidence rate ratio, this model predicted 32.0% less mortality for operations that vaccinated heifers for at least one of the following: bovine viral diarrhea, infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial virus, Haemophilus somnus, leptospirosis, Salmonella, Escherichia coli or clostridia. The final multivariable model also predicted a 27.0% increase in mortality for operations from which a bulk tank milk sample tested ELISA positive for bovine leukosis virus. Additionally, an 18.0% higher mortality was predicted for operations that used necropsies to determine the cause of death for some proportion of dead

  15. Body size affects the strength of social interactions and spatial organization of a schooling fish (Pseudomugil signifer)

    Romenskyy, Maksym; Herbert-Read, James E.; Ward, Ashley J. W.; Sumpter, David J. T.

    2017-04-01

    While a rich variety of self-propelled particle models propose to explain the collective motion of fish and other animals, rigorous statistical comparison between models and data remains a challenge. Plausible models should be flexible enough to capture changes in the collective behaviour of animal groups at their different developmental stages and group sizes. Here, we analyse the statistical properties of schooling fish (Pseudomugil signifer) through a combination of experiments and simulations. We make novel use of a Boltzmann inversion method, usually applied in molecular dynamics, to identify the effective potential of the mean force of fish interactions. Specifically, we show that larger fish have a larger repulsion zone, but stronger attraction, resulting in greater alignment in their collective motion. We model the collective dynamics of schools using a self-propelled particle model, modified to include varying particle speed and a local repulsion rule. We demonstrate that the statistical properties of the fish schools are reproduced by our model, thereby capturing a number of features of the behaviour and development of schooling fish.

  16. Herd-level risk factors for lameness in freestall farms in the northeastern United States and California.

    Chapinal, N; Barrientos, A K; von Keyserlingk, M A G; Galo, E; Weary, D M

    2013-01-01

    The objective was to investigate the association between herd-level management and facility design factors and the prevalence of lameness in high-producing dairy cows in freestall herds in the northeastern United States (NE; Vermont, New York, Pennsylvania) and California (CA). Housing and management measures such as pen space, stall design, bedding type, and milking routine were collected for the high-producing pen in 40 farms in NE and 39 farms in CA. All cows in the pen were gait scored using a 1-to-5 scale and classified as clinically lame (score ≥3) or severely lame (score ≥4). Measures associated with the (logit-transformed) proportion of clinically or severely lame cows at the univariable level were submitted to multivariable general linear models. In NE, lameness increased on farms that used sawdust bedding [odds ratio (OR)=1.71; 95% confidence interval (CI)=1.06-2.76] and decreased with herd size (OR=0.94; CI=0.90-0.97, for a 100-cow increase), use of deep bedding (OR=0.48; CI=0.29-0.79), and access to pasture (OR=0.52; CI=0.32-0.85). The multivariable model included herd size, access to pasture, and provision of deep bedding, and explained 50% of the variation in clinical lameness. Severe lameness increased with the percentage of stalls with fecal contamination (OR=1.15; CI=1.06-1.25, for a 10% increase) and with use of sawdust bedding (OR=2.13; CI=1.31-3.47), and decreased with use of deep bedding (OR=0.31; CI=0.19-0.50), sand bedding (OR=0.32; CI=0.19-0.53), herd size (OR=0.93; CI=-0.89-0.97, for a 100-cow increase), and rearing replacement heifers on site (OR=0.57; CI=0.32-0.99). The multivariable model included deep bedding and herd size, and explained 59% of the variation of severe lameness. In CA, clinical lameness increased with the percentage of stalls containing fecal contamination (OR=1.15; CI=1.05-1.26, for a 10% increase), and decreased with herd size (OR=0.96; CI=0.94-0.99, for a 100-cow increase), presence of rubber in the alley to the

  17. Technical indicators of financial performance in the dairy herd

    Kristensen, Erling Lundager; Østergaard, Søren; Krogh, Mogens Agerbo

    2008-01-01

    Monte Carlo simulation was used to predict the long-term financial performance related to the technical performance of dairy herds. The indicators addressed were derived from data collected routinely in the herd. They indicated technical performance that can be affected by the farmer...... or the consultant, and they were derived from expected cause-effect relations between technical performance and financial performance at the herd level. The study included the indicators shape of lactation curve, reproduction efficiency, heifer management, variation between cows in lactation curve persistency...... cow was analyzed as the measure of financial performance. The potential effects of the selected indicators on the gross margin were estimated by means of an ANOVA. The final model allowed estimation of the financial value of specific changes within the key performance indicators. This study indicated...

  18. Traditional ecological knowledge underlying herding decisions of pastoralists.

    Tamou, C; de Boer, I J M; Ripoll-Bosch, R; Oosting, S J

    2018-04-01

    Pastoralists have traditional ecological knowledge (TEK), which is important for their livelihoods and for policies and interventions. Pastoralism is under pressure, however, which may result in a decline of pastoral lifestyle and its related TEK. We, therefore, addressed the following objectives (i) to inventorise and assess how pastoralists characterise and value soils and forages in their environment, (ii) to analyse how soil, forage and livestock (i.e. cattle) characteristics relate to herding decisions and (iii) to determine whether TEK underlying herding decisions differs across generations. Data were collected through focus groups and individual interviews with 72 pastoralists, belonging to three generations and to three agro-ecological zones. Using a three-point scale (high, medium, low), four grasses and three tree forages were assessed in terms of nutritional quality for milk, meat, health and strength. Using their own visual criteria, pastoralists identified five different soils, which they selected for herding at different times of the year. Pastoralists stated that Pokuri was the best soil because of its low moisture content, whereas Karaal was the worst because forage hardly grows on it. They stated that perennials, such as Andropogon gayanus and Loxoderra ledermannii, were of high nutritional quality, whereas annuals such as Andropogon pseudapricus and Hyparrhenia involucrata were of low nutritional quality. Afzelia africana was perceived of high quality for milk production, whereas Khaya senegalensis had the highest quality for meat, health and strength. Pastoralists first used soil, then forage and finally livestock characteristics in their herding decisions. Pastoralists' TEK was not associated with their generations, but with their agro-ecological zones. This study suggests that pastoralists had common and detailed TEK about soils, forages and livestock characteristics, underlying their herding decisions. To conclude, pastoralists use a holistic

  19. An on-farm investigation of beef suckler herds using an animal welfare index (AWI).

    Mazurek, Mickael; Prendiville, Daniel J; Crowe, Mark A; Veissier, Isabelle; Earley, Bernadette

    2010-12-13

    Beef suckler farms (194 farms throughout 13 counties) were assessed once with housed cattle and once with cattle at grass using an animal welfare index (AWI). Twenty-three of the 194 farms were revisited a year later and re-evaluated using the AWI and the Tier-Gerechtheits-Index 35L/2000 (TGI35L/2000). Thirty-three indicators were collected in five categories: locomotion (5 indicators); social interactions (between animals) (7), flooring (5), environment (7) and Stockpersonship (9). Three indicators relating to the size of the farm were also collected.Improving animal welfare is an increasingly important aspect of livestock production systems predominantly due to increased consumer concern about the source of animal products. The objectives were (i) to evaluate animal welfare of Irish beef suckler herds using an animal welfare index (AWI), (ii) to examine correlations between parameters, how they influence the AWI and investigate the applicability of the parameters used, (iii) to investigate the impact of the activity of the farmer (full-time or part-time), the interest of the farmer and the number of animals on the AWI. The mean AWI was 65% and ranged from 54% to 83%. The grazing period represented 16.5% of the total points of the AWI. Seventy percent of the farms were rated as "Very Good" or "Excellent". There was no difference (P > 0.05) in AWI between full-time and part-time farmers. Part-time farmers had greater (P = 0.01) "social interactions": calving (P = 0.03) and weaning (P animals (P = 0.03) and their animals had less lameness (P = 0.01). The number of animals on-farm and the interest of the Stockperson were negatively and positively correlated (P = 0.001), respectively, with the AWI. A hierarchical classification was performed to examine how the indicators influenced the AWI. The AWI was easily applicable for an on-farm evaluation of welfare. The Stockpersonship was an important factor in determining the AWI (11% of the total variation) more

  20. Stochastic models to simulate paratuberculosis in dairy herds

    Nielsen, Søren Saxmose; Weber, M.F.; Kudahl, Anne Margrethe Braad

    2011-01-01

    Stochastic simulation models are widely accepted as a means of assessing the impact of changes in daily management and the control of different diseases, such as paratuberculosis, in dairy herds. This paper summarises and discusses the assumptions of four stochastic simulation models and their use...... the models are somewhat different in their underlying principles and do put slightly different values on the different strategies, their overall findings are similar. Therefore, simulation models may be useful in planning paratuberculosis strategies in dairy herds, although as with all models caution...

  1. Antimicrobial use in Danish pig herds with and without postweaning multisystemic wasting syndrome

    Jensen, Vibeke Frøkjær; Enøe, Claes; Wachmann, Henrik

    2010-01-01

    A retrospective cohort study was performed on 130 pig herds in Denmark, to assess the effect of PMWS on the use of antimicrobial drug. The study comprised 65 herds diagnosed with PMWS during 2003–2004, and matched by the veterinary practitioner with 65 herds free from PMWS. Information...... on antimicrobial use 1 year before and 1 year after the diagnosis was achieved from the National Prescription Medicine Monitoring Database, VetStat, and summarized on quarter within age group and herd. The multiple linear regression analysis comprised antimicrobial use as the outcome variable with (1) quarter...... relative to diagnosis of PMWS in the positive herd (same date for the negative match), (2) diagnosis of PMWS (same date used for matched PMWS(−) herd), (3) season and (4) temporal trend as fixed effects. Relative to the unaffected herds, the antimicrobial use in the sow units in the PMWS(+) herds...

  2. Sero prevalence and risk factors associated with bovine herpes virus type 1 (BHV1) infection in non-vaccinated cattle herds in Andalusia (South of Spain)

    Gonzalez-Garcia, M. A.; Arenas-Casas, A.; Carbonero-Martinez, A.; Borge-Rodriguez, C.; Garcia-Bocanegra, I.; Maldonado, J. L.; Gomez-Pacheco, J. M.; Perea-Remujo, J. A.

    2009-07-01

    An epidemiological and serological survey of bovine herpes virus 1 (BHV1) infection was conducted in Andalusia from January to April of 2000. A total of 4,035 blood samples were collected from 164 herds. A questionnaire, which included variables potentially associated with infection, was filled out for each herd. Serum samples were obtained to identify specific BHV1 antibodies and were tested using a blocking ELISA test. The observed crude odds ratio (OR) (estimate of the chance of a particular event occurring in an exposed group in relation to its rate of occurrence in a nonexposed group) for vaccination is 9.8 (95 % confidence interval: 8.3-11.7). The vaccinated group comprised large dairy farms. This study can only be considered as representative of unvaccinated, small to medium size dairy farms and beef farms in Andalusia. True sero prevalence of the BHV1 virus in non vaccinated bovine populations in Andalusia reached 45.7% of individuals and 70.4% of herds. Risk factors for BHV1 infection in bovine Andalusian non vaccinated herds are nonexistence of specific cattle infrastructure (OR: 3.07), beef crossbreeding (OR: 7.90), affiliation with Livestock Health Defence Associations (OR: 2.57), a history of reproductive disorders (OR: 8.39), external replacement (OR: 2.74), proximity to an urban area (OR: 6.11) and herd size (41.98). To control for confounding effects, a binomial logistic regression model was developed. From this regression, BHV1 infections are concentrated in large herds, with external replacement, located close to urban areas. This is the first published report on BHV1 prevalence in the South of Spain. (Author) 14 refs.

  3. The effect of source herd and abattoir factors on pig carcass Salmonella contamination evaluated by multilevel modelling

    Baptista, Filipa Matos; Dahl, Jan; Nielsen, Liza Rosenbaum

    2010-01-01

    In Denmark, a Surveillance-and-Control Programme for Salmonella in pigs has been in place for several years. This study investigated factors associated with Salmonella pig carcass contamination, namely estimated daily number of Salmonella seropositive pigs delivered to slaughter, average Salmonella...... seroprevalence of the source herds that delivered each of five pigs contributing to the pool, weekday, year, season and abattoir size. A total of 20128 pooled carcass swabs collected in 22 Danish abattoirs, from 2002 to 2008, were included in a multilevel logistic regression model. Study results indicate...... that the probability of Salmonella positive carcasses is mainly influenced by the Salmonella herd seroprevalence of the swabbed pigs, the number of seropositive pigs delivered to the abattoir on the same day and weekday. Further reduction in carcass pool Salmonella prevalence may require new or improved methods...

  4. A European longitudinal study in Salmonella seronegative and seropositive-classified finishing pig herds

    Wong, Danilo Lo Fo; Dahl, J.; Wingstrand, Anne

    2004-01-01

    and was performed between October 1996 and May 1999. The Salmonella status of finishing pig herds was determined by an initial blood sampling of approximately 50 finishing pigs close to market weight per herd. The development of the Salmonella status of the selected herds was assessed at seven subsequent sampling...

  5. Cattle transfers between herds under paratuberculosis surveillance in The Netherlands are not random

    Weber, M.F.; Roermund, van H.J.W.; Vernooij, J.C.M.; Kalis, C.H.J.; Stegeman, J.A.

    2006-01-01

    The rate and structure of cattle transfers between 206 Dutch cattle herds with a 'Mycobacterium avium subsp. paratuberculosis (Map)-free' status by November 2002, were analyzed over a 3-year period (November 1999-November 2002). Of the 206 'Map-free' herds, 184 were closed herds during the period

  6. Modelling the dynamics of the health-production complex in livestock herds

    Sørensen, J.T.; Enevoldsen, Carsten

    1992-01-01

    This paper reviews how the dynamics of the health-production complex in livestock herds is mimicked by livestock herd simulation models. Twelve models simulating the dynamics of dairy, beef, sheep and sow herds were examined. All models basically included options to alter input and output...

  7. Patterns of stillbirth and dystocia in Ontario cow-calf herds.

    McDermott, J J; Allen, O B; Martin, S W; Alves, D M

    1992-01-01

    The association between a number of individual animal and herd level factors and calving problems in beef cows and heifers were examined. Data were from the 1987 calving season for a subset of 123 herds which maintained individual-animal records, from a sample of 180 randomly selected Ontario cow-calf herds. The median herd dystocia rate was 5.8% and 24.4% of herds had no dystocias. The median herd stillbirth rate was 2.8%, and 33.3% of herds had no stillbirths. Dystocias and stillbirths were much more common in heifers than in cows. Separate statistical models of dystocia and stillbirth for cows and heifers were created. Dystocia in cows was associated with calf sex, previous calving assistance and large breed type and birth weight. Variations in 1987 cow herd dystocia rates were associated with calving season, location and density, and the herd dystocia rate in 1986. Dystocia in heifers was associated with large breed type and calf birth weight. Herd-level management practices associated with increased heifer dystocia rates included breeding heifers to calve earlier than cows and rearing heifers together with the cow herd. Stillbirths for both cows and heifers were associated with calving assistance, particularly hard assistance. Herd-level management and other factors were unassociated with stillbirths. PMID:1586893

  8. EVALUATION OF AN O-ANTIGEN ELISA FOR SCREENING CATTLE HERDS FOR SALMONELLA-TYPHIMURIUM

    Hoorfar, Jeffrey; Bitsch, V.

    1995-01-01

    A total of 2585 serum samples from 62 dairy herds located in four different regions of Denmark were tested in an O-antigen (0:1,4,5,12)-based ELISA for the detection of antibodies against Salmonella typhimurium. Ten closed herds from an island with no reported occurrence of salmonellosis for seve......A total of 2585 serum samples from 62 dairy herds located in four different regions of Denmark were tested in an O-antigen (0:1,4,5,12)-based ELISA for the detection of antibodies against Salmonella typhimurium. Ten closed herds from an island with no reported occurrence of salmonellosis...... for several years, and 12 herds from a salmonella enzootic area which had had clinical outbreaks of S typhimurium were used to define a herd ELISA cut-off value. When herds with at least 5 per cent of the serum samples having an optical density of >0.5 were considered ELISA-positive, all 10 herds from...... the salmonellosis-free island were ELISA-negative, and all but one of the 12 S typhimurium-infected herds were ELISA-positive, which resulted in a herd test sensitivity of 0.92 and herd test specificity of 1.0. Eleven of the 12 S typhimurium-infected herds were negative in a blocking ELISA based on a monoclonal...

  9. Optimizing productivity, herd structure, environmental performance, and profitability of dairy cattle herds.

    Liang, D; Cabrera, V E

    2015-04-01

    This study used the Integrated Farm System Model to simulate the whole farm performance of a representative Wisconsin dairy farm and predict its economic and environmental outputs based on 25 yr of daily local weather data (1986 to 2010). The studied farm, located in southern Wisconsin, had 100 milking cows and 100 ha of cropland with no replacement heifers kept on the farm. Sensitivity analyses were conducted to test the effect of management strategies on energy-corrected milk production (ECM; 4.0% fat and 3.5% protein), net return to management, and greenhouse gas (GHG; including biogenic CO2) emission. The management strategies included (1) target milk production, for which the model optimized available resources to attain, and (2) herd structure, represented by the percentage of first-lactation cows. Weather conditions affected the outputs by changing the farm quantity and the quality of produced feed resources. As expected, when target milk production increased, the ECM increased positively and linearly to a certain level, and then it increased nonlinearly at a decreasing rate, constrained by available feed nutrients. Thereafter, the ECM reached the maximum potential milk production and remained flat regardless of higher target milk production input. Greenhouse gas emissions decreased between 3.4 and 7.3% at different first-lactation cow percentages. As the first-lactation cow percent increased from 15 to 45% in 5% intervals, GHG increased between 9.4 and 11.3% at different levels of target milk production. A high percentage of first-lactation cows reduced the maximum potential milk production. Net return to management had a similar changing trend as ECM. As the target milk production increased from 9,979 to 11,793 kg, the net return to management increased between 31 and 46% at different first-lactation cow percentages. Results revealed a win-win situation when increasing milk production or improving herd structure, which concurrently increased farm net

  10. Regional Eradication of Mycoplasma hyopneumoniae From Pig Herds and Documentation of Freedom of the Disease

    Tuovinen V

    2001-09-01

    Full Text Available The objectives of this study were to 1 screen all sow herds in a region for M. hyopneumoniae, 2 to effectuate an eradication programme in all those herds which were shown to be infected with M. hyopneumoniae, and 3 to follow the success of the screening and the eradication programmes. The ultimate goal was to eradicate M. hyopneumoniae from all member herds of a cooperative slaughterhouse (153 farrowing herds + 85 farrowing-to-finishing herds + 150 specialised finishing herds before year 2000. During 1998 and 1999, a total of 5067 colostral whey and 755 serum samples (mean, 25 samples/herd were collected from sow herds and analysed for antibodies to M. hyopneumoniae by ELISA. Antibodies were detected in 208 (3.6% samples. Two farrowing herds (1.3% and 20 farrowing-to-finishing herds (23.5% were shown to be infected with M. hyopneumoniae. A programme to eradicate the infection from these herds was undertaken. During March 2000, a survey was made to prove the success of the screening and the eradication programmes. In total, 509 serum samples were collected randomly from slaughtered finishing pigs. Antibodies to M. hyopneumoniae were not detected in 506 of the samples, whereas 3 samples were considered suspicious or positive. Accordingly, 3 herds were shown to be infected. One of the herds was previously falsely classified as non-infected. Two of the herds were finishing herds practising continuous flow system (CF. Unlike finishing herds which practice all-in/all-out management routines on herd level, CF herds do not get rid of transmissible diseases spontaneously between batches, for which reason a screening was made in the rest of the CF herds (total n = 7. Consequently, 2 more infected herds were detected. In addition to the results of the survey, a decreasing prevalence of lung lesions at slaughter (from 5.2% to 0.1% and lack of clinical breakdowns indicated that all member herds were finally free from M. hyopneumoniae in the end of year 2000.

  11. Herding, Information Cascades and Volatility Spillovers in Futures Markets

    M.J. McAleer (Michael); K. Radalj (Kim)

    2013-01-01

    textabstractEconomists and financial analysts have begun to recognise the importance of the actions of other agents in the decision-making process. Herding is the deliberate mimicking of the decisions of other agents. Examples of mimicry range from the choice of restaurant, fashion and financial

  12. THE HERDING BEHAVIOR ON SMALL CAPITAL MARKETS: EVIDENCE FROM ROMANIA

    Andreea Pece

    2014-07-01

    Full Text Available The evolution of financial markets is influenced by the speculative bubbles and by the occurance of financial crisis. The speculative bubbles are formed on the markets when take place an unsustainable growth in the price of a financial asset, which leads to a high level of instability and to the rise of financial crashes. One of the cause of speculative bubbles is the herding behavior of investors characterized by trading in the same direction on the market, the same stocks, in the same period of time, or when they ignore the private information and trades similar with other investors, which may lead to incorrect trading decision. The aim of this paper is to test the existence of herding behavior on the Romanian stock market and the impact of the subprime financial crisis on the behavior of investors. We have analyzed the Romanian stock market on sector level by using firm level data. The statistical methodology used in this paper was proposed by Chang et al. (2000 and uses the cross sectional absolute deviation of returns (CSAD as a measure of return dispersion.The results indicate the existence of herding behavior of investors in various sectors, both for upper and lower markets. We also conclude that during the subprime crisis, is no evidence of herding, due to the fact that the impact of the crisis was transmitted globally.

  13. The management of bovine reproduction in elite herds.

    Sheldon, I Martin; Wathes, D Claire; Dobson, Hilary

    2006-01-01

    The management of bovine reproduction is the cornerstone of health provision in elite herds. Aims and objectives for reproductive performance should be herd specific and data to monitor progress should not only be frequently collected, but also analysed and reported. Strategic monitoring of animals should include a vaginal examination for evidence of uterine disease, as well as transrectal ultrasonography of the genital tract. There has been considerable advancement in our ability to intervene in the reproduction of cattle during the last 50 years. However, it is salutary to note that during this time fertility has consistently declined, despite increasing veterinary intervention. Most elite herds use artificial insemination and success depends on accurate detection of oestrus expression, but this appears to be less overt than 25 years ago. In addition, half the cattle have abnormal oestrous cycles after parturition and conception rates are decreasing by 1% per year. Risk factors for abnormal oestrous cycles include puerperal problems, negative energy balance, which can be evaluated by body condition scoring, and uterine disease. Bacterial contamination of the uterus is ubiquitous after parturition in cattle and disease disrupts ovarian follicle growth and function. Reproduction is also disrupted by stress associated with clinical disease, pain or a sub-optimal environment. The challenge for veterinarians providing reproduction control programmes to elite herds is to transfer our knowledge of the problems underlying subfertility to the farm, in order to provide effective solutions.

  14. Prevalence of Coxielle Burnetii anbitodies in Danish Dairy herds

    Agger, Jens F.; Christoffersen, Anna-Bodil; Rattenborg, Erik

    2010-01-01

    During recent years in Denmark higher rates of antibodies to Coxiella burnetii have been detected in animals and humans than previously reported. A study based on bulk tank milk samples from 100 randomly selected dairy herds was performed to estimate the prevalence and geographical distribution o...

  15. Detection of a Novel Porcine Parvovirus in Chinese Swine Herds

    To determine whether the recently reported novel porcine parvovirus type 4 (PPV4) is prevalent in China, a set of PPV4 specific primers were designed and used for the molecular survey of PPV4 among clinical samples. The results indicated a positive detection for PPV4 in Chinese swine herds of 1.84% ...

  16. Herd health and production management in dairy practice.

    Brand, A.; Noordhuizen, J.P.T.M.; Schukken, Y.H.

    1996-01-01

    This text aims to teach students, practitioners and farm advisors how to give management support to the dairy farmer in order to optimize the health, productivity and welfare of his herd. The book covers management practices and farm conditions which have both positive and negative influences on

  17. Maximum herd efficiency in meat production I. Optima for slaughter ...

    Optimal replacement involves either the minimum or maximumrate that can be achieved, and depends on the relative costs and output involved in the keeping of different age classes of reproduction animals. Finally, the relationship between replacement rate and herd age structure is explained. Die winsverhoudingby ...

  18. 9 CFR 77.37 - Interstate movement from monitored herds.

    2010-01-01

    ... being moved interstate together to the same destination, all captive cervids in the group may be moved... to the premises of the monitored herd; or (3) If the captive cervid to be added is not being moved... captive cervids is being moved together, the entire group must be isolated from all other animals during...

  19. Population characteristics of a central Appalachian white tailed deer herd

    Tyler A. Campbell; Benjamin R. Laseter; W. Mark Ford; Karl V. Miller; Karl V. Miller

    2005-01-01

    Reliable estimates of white-tailed deer (Odocoileus virginianus) population parameters are needed for effective population management. We used radiotelemetrv to compare survival and cause-specific mortality rates between male and female white-tailed deer and present reproductive data for a high-density deer herd in the central Appalachians of West Virginia during...

  20. Genetic diversity in selected stud and commercial herds of the ...

    The Afrikaner is one of three indigenous cattle breeds found in South Africa. Afrikaner cattle were originally extensively used for crossbreeding purposes and breed development. The objective of this study was to determine the genetic diversity of selected stud and commercial herds from the whole South African Afrikaner ...

  1. [Emissions from dairy industry and the influence of herd management].

    Dämmgen, Ulrich; Brade, Wilfried; Haenel, Hans-Dieter; Rösemann, Claus; Dämmgen, Jürgen; Meyer, Ulrich

    2017-08-11

    The purpose of this paper is to identify specific emission-reduction opportunities in dairy herds arising from aspects of useful herd management with the potential to reduce emissions, which are within the scope of veterinary activities. In future, it might be one of a veterinarian's advisory capacities to deal with the aspect of climate and environmental protection in animal husbandry. The models involved are similar to those of the national agricultural emission inventory. They allow quantifying the impacts of improved animal health, extended productive lifespan and grazing of an entire dairy herd (cows, calves, heifers and bulls) on emissions from the herd itself, in addition to those originating from the entire production chain, including provision of primary energy, water, feed production and processing. Ammonia emissions are the main focus. The reductions achieved here are not huge, though noticeable. They do not create extra costs. As can be shown, improved animal health and welfare are also environmentally beneficial. The reduction of greenhouse gas and air pollutant (eutrophying and acidifying gases and particles) emissions is an acknowledged political goal. If Germany wants to achieve the emission ceilings it has agreed to, agriculture will have to contribute. Planning will have to precede action if agriculture is itself to keep control of the processes.

  2. Assessment of inbreeding depression for functional herd life in the ...

    The objective of this study was to investigate the effect of inbreeding depression on functional herd life in the South African Jersey population based on individual level and rate of inbreeding. A pedigree file of the South African Jersey breed (n = 912 638) was obtained from the Integrated Registration and Genetic ...

  3. Anthelmintic resistance in a herd of alpacas (Vicugna pacos)

    Galvan, Noe; Middleton, John R.; Nagy, Dusty W.; Schultz, Loren G.; Schaeffer, Josh W.

    2012-01-01

    A herd of alpacas was examined because of a history of severe endoparasitism, anemia, hypoproteinemia, and weight loss. Resistance of gastrointestinal nematodes to albendazole, fenbendazole, and doramectin was documented. This report suggests that anthelmintic resistance may be an emerging problem in South American camelids in North America. PMID:23729829

  4. A self-adapting herding model: The agent judge-abilities influence the dynamic behaviors

    Dong, Linrong

    2008-10-01

    We propose a self-adapting herding model, in which the financial markets consist of agent clusters with different sizes and market desires. The ratio of successful exchange and merger depends on the volatility of the market and the market desires of the agent clusters. The desires are assigned in term of the wealth of the agent clusters when they merge. After an exchange, the beneficial cluster’s desire keeps on the same, the losing one’s desire is altered which is correlative with the agent judge-ability. A parameter R is given to all agents to denote the judge-ability. The numerical calculation shows that the dynamic behaviors of the market are influenced distinctly by R, which includes the exponential magnitudes of the probability distribution of sizes of the agent clusters and the volatility autocorrelation of the returns, the intensity and frequency of the volatility.

  5. Emergence of bovine ehrlichiosis in Belgian cattle herds.

    Guyot, Hugues; Ramery, Eve; O'Grady, Luke; Sandersen, Charlotte; Rollin, Frédéric

    2011-06-01

    Bovine ehrlichiosis is a tick-borne rickettsial disease caused by Anaplasma phagocytophilum. The disease can also be transmitted to humans. Outbreaks in cattle have been described in many European countries. In Belgium, infections caused by A. phagocytophilum have been reported in humans and dogs; however, this paper details the first report of ehrlichiosis in cattle herds in Belgium. The first case described was in a dairy herd located in eastern Belgium. Clinical signs included hyperthermia, polypnea, and swelling of the limbs. The other case was diagnosed in a second, mixed purpose herd in western Belgium. Within the second herd, all of the affected animals came from the same pasture. All animals in that pasture showed recurrent hyperthermia, and some also showed signs of mastitis and late-term abortions. Blood smears and serology revealed the presence of A. phagocytophilum in the majority of animals with pyrexia. Furthermore, the presence of leptospirosis, Neospora caninum, and Q fever antibodies was tested by serological analysis, but all results were negative. Paired serology for Adenovirus, BHV-4, BHV-1, BVD, PI3, and RSV-B did not show any significant seroconversion. Milk samples from cows affected by mastitis revealed minor pathogens. Fecal testing for the presence of Dictyocaulus viviparus in the first herd was negative. Recurrent pyrexia in pastured cattle is a non-specific sign, and can be related to several different pathogens. Bovine ehrlichiosis is transmitted by the tick species Ixodes ricinus which is known to be present throughout Belgium. Belgian practitioners should include ehrlichiosis in their differential diagnosis when confronted with pastured cattle suffering from recurrent pyrexia. Copyright © 2011 Elsevier GmbH. All rights reserved.

  6. Ecological implications of bovine tuberculosis in African Buffalo herds

    Caron, Alex; Cross, Paul C.; du Toit, Johan T.

    2003-01-01

    Following the recent invasion of bovine tuberculosis (BTB) into the Kruger National Park, South Africa, we conducted a study on the maintenance host, African buffalo, to investigate associations between BTB prevalence and calf:cow ratio, age structure, body condition, and endoparasite load. Statistical analyses compared herds of zero, medium (1–40%), and high (>40%) BTB prevalence. To control for ecological variation across the park we collected data in northern, central, and southern regions and restricted some analyses to particular regions of the park. Body condition declined over the course of the 2001 dry season, and buffaloes in the southern region of the park, with the highest BTB prevalence, were in worse condition than buffaloes in the northern region (which receives less annual rainfall but is still virtually BTB-free). Herd-level analyses of the entire park, the south and central regions, and just the southern region all indicated that herds of higher BTB prevalence were in worse condition and lost condition faster through the dry season than herds of lower BTB prevalence. Fecal endoparasite egg counts increased during the dry season and were associated with both decreased body condition and increased BTB prevalence. Although we did not detect any obvious effect of BTB on the age structure of the buffalo population, our findings indicate early symptoms of wider scale BTB-related ecological disturbances: buffalo herds with high BTB prevalence appear more vulnerable to drought (because of a decrease in body condition and an increase in endoparasite load), and because lions selectively kill weak buffaloes their prey base is accumulating a disproportionately high prevalence of BTB, to which lions are susceptible.Rea10.1890/02-5266d More: http://www.esajournals.org/doi/abs

  7. New evidence of anti-herding of oil-price forecasters

    Pierdzioch, Christian; Ruelke, Jan Christoph; Stadtmann, Georg

    2010-01-01

    We used the oil-price forecasts of the Survey of Professional Forecasters published by the European Central Bank to analyze whether oil-price forecasters herd or anti-herd. Oil-price forecasts are consistent with herding (anti-herding) of forecasters if forecasts are biased towards (away from) the consensus forecast. Based on a new empirical test developed by Bernhardt et al. (J. Financ. Econ. 80: 657-675, 2006), we found strong evidence of anti-herding among oil-price forecasters. (author)

  8. Is There Herd Effect on Stocks with High Liquidity of the Brazilian Market?

    Juliana Xavier Serapio da Silva

    2015-08-01

    Full Text Available Purpose: This work aims to verify the herd behavior in both liquid stocks of Brazilian stock exchange, i.e. Petrobras and Vale.Methodology: This work uses the methods of Christie and Huang (1995 and price pressure with high frequency data to detect the herd behavior between 2010 and 2014.Findings: The first method suggest that there are no signs of herd behavior using 30 minutes intervals data. However, there is evidence of price pressure for the sample with all intraday data.Originality: Herd behavior studies usually focus on mutual funds. This work analyses the herd behavior based on individual stock prices. 

  9. A strain-, cow-, and herd-speciÞc bio-economic simulation model of intramammary infections in dairy cattle herds

    Gussmann, Maya Katrin; Kirkeby, Carsten Thure; Græsbøll, Kaare

    2018-01-01

    Intramammary infections (IMI) in dairy cattle lead to economic losses for farmers, both through reduced milk production and disease control measures. We present the first strain-, cow- and herd-specific bio-economic simulation model of intramammary infections in a dairy cattle herd. The model can...... various within-herd levels of IMI prevalence, depending on the simulated pathogens and their parameter settings. The parameters can be adjusted to include different combinations of IMI causing pathogens at different prevalence levels, representing herd-specific situations. The model is most sensitive...

  10. A field study to determine the prevalence, dairy herd management systems, and fresh cow clinical conditions associated with ketosis in western European dairy herds.

    Berge, Anna C; Vertenten, Geert

    2014-01-01

    The aim of this study was to determine the prevalence, major management systems, and fresh cow clinical conditions associated with ketosis in western European dairy herds. A total of 131 dairies were enrolled in Germany, France, Italy, the Netherlands, and the United Kingdom during 2011 to 2012. A milk-based test for ketones (Keto-Test; Sanwa Kagaku Kenkyusho Co. Ltd., Nagoya, Japan; distributed by Elanco Animal Health, Antwerp, Belgium) was used for screening cows between d 7 and 21 after calving and ketosis was defined as a Keto-Test ≥100µmol/L. Study cows were observed for clinical disease up to 35d postcalving. Multivariate analysis (generalized estimating equation logistic regression) was performed to determine country, farm, management, feed, and cow factors associated with ketosis and to determine associations between ketosis and fresh cow diseases. Thirty-nine percent of the cows were classified as having ketosis. The herd average of ketosis was 43% in Germany, 53% in France, 31% in Italy, 46% in the Netherlands, and 31% in the United Kingdom. Of the 131 farms, 112 (85%) had 25% or more of their fresh cows resulting as positive for ketosis. Clinical ketosis was not reported in most farms and the highest level of clinical ketosis reported was 23%. The risks of ketosis were significantly lower in Italy and the United Kingdom compared with France, the Netherlands, and Germany. Larger herd size was associated with a decreased risk of ketosis. The farms that fed partially mixed rations had 1.5 times higher odds of ketosis than those that fed total mixed rations. Cows that calved in April to June had the highest odds of ketosis, with about twice as high odds compared with cows that calved in July to September. The cows that calved in January to March tended to have 1.5 times higher risk of ketosis compared with cows that calved in July to September. The odds of ketosis in parity 2 and parity 3 to 7 was significantly higher (1.5 and 2.8 times higher

  11. Theoretical value of pre-trade testing for Salmonella in Swedish cattle herds.

    Sternberg Lewerin, Susanna

    2018-05-01

    The Swedish Salmonella control programme includes mandatory action if Salmonella is detected in a herd. The aim of this study was to assess the relative value of different strategies for pre-movement testing of cattle. Three fictitious herds were included: dairy, beef and specialised calf-fattening. The yearly risks of introducing Salmonella with and without individual serological or bulk milk testing were assessed as well as the effects of sourcing animals from low-prevalence areas or reducing the number of source herds. The initial risk was highest for the calf-fattening herd and lowest for the beef herd. For the beef and dairy herds, the yearly risk of Salmonella introduction was reduced by about 75% with individual testing. Sourcing animals from low-prevalence areas reduced the risk by >99%. For the calf-fattening herd, the yearly risk was reduced by almost 50% by individual testing or sourcing animals from a maximum of five herds. The method was useful for illustrating effects of risk mitigation when introducing animals into a herd. Sourcing animals from low-risk areas (or herds) is more effective than single testing of individual animals or bulk milk. A comprehensive approach to reduce the risk of introducing Salmonella from source herds is justified. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. HERDING BEHAVIOR UNDER MARKETS CONDITION: EMPIRICAL EVIDENCE ON THE EUROPEAN FINANCIAL MARKETS

    Moatemri Ouarda

    2013-01-01

    Full Text Available This study presents four main contributions to the literature of behavior herding. Firstly, it extends the behavioral researches of herding of the investors on a developed market and mainly on a European market as a whole. Secondly, we are interested in examination of herding behavior at the level of sectors by using data at the levels of companies. Thirdly, this document estimates the implications of herding behavior in terms of returns, volatility and volume of transaction. Fourthly, the herding behavior is revealed as well during the period of the recent global financial crisis in 2007-2008 and of Asian crisis. Our results reveal a strong evidence of herding behavior sharply contributed to a bearish situation characterized by a strong volatility and a trading volume. The repercussion of herding during the period of the recent financial crisis is clearly revealed for the sectors of the finance and the technology.

  13. A case-control study of risk factors for bovine cysticercosis in Danish cattle herds

    Calvo Artavia, Francisco Fernando; Nielsen, Liza Rosenbaum; Dahl, J.

    2013-01-01

    than in countries with few lightly infected cases per year. The aim of the present case-control study was to quantify associations between potential herd-level risk factors and BC in Danish cattle herds. Risk factors can be used in the design of a risk-based meat inspection system targeted towards...... a questionnaire and register data from the Danish Cattle Database were grouped into meaningful variables and used to investigate the risk factors for BC using a multivariable logistic regression model. Case herds were almost three times more likely than control herds to let all or most animals out grazing. Case...... the animals with the highest risk of BC. Cases (n = 77) included herds that hosted at least one animal diagnosed with BC at meat inspection, from 2006 to 2010. Control herds (n = 231) consisted of randomly selected herds that had not hosted any animals diagnosed with BC between 2004 and 2010. The answers from...

  14. The effect of cephalosporin usage on the occurrence of ESCs producing E. coli in pig herds

    Dalhoff Andersen, Vibe; Jensen, Vibeke Frøkjær; Agersø, Yvonne

    in 19 pig herds which have had five to fourteen prescriptions of ceph. and 20 pig herds without prescribed ceph. in a previous 12 month period. The 39 herds were all integrated and represent typical Danish pig farms. The occurrence of ESCs producing E. coli in the herds were tested in a total of 9...... pooled samples per herd. A pig herd was considered positive if one or more of the nine samples contained ESCs producing E. coli. Initially, the association between usages of ceph. and occurrence of ESCs producing E. coli in the pig herds was analyzed using logistic regression, and the effect was adjusted...... of ESCs producing E. coli was estimated as risk ratio(RR). The results showed that consumption of ceph. increased the risk of occurrence of ESCs producing E. coli significantly with a RR of 5 (95% CI: 2-11). This demonstrates that ceph. usage significant affect the occurrence of ESCs resistance...

  15. Ribosomal protein NtRPL17 interacts with kinesin-12 family protein NtKRP and functions in the regulation of embryo/seed size and radicle growth.

    Tian, Shujuan; Wu, Jingjing; Liu, Yuan; Huang, Xiaorong; Li, Fen; Wang, Zhaodan; Sun, Meng-Xiang

    2017-11-28

    We previously reported that a novel motor protein belonging to the kinesin-12 family, NtKRP, displays critical roles in regulating embryo and seed size establishment. However, it remains unknown exactly how NtKRP contributes to this developmental process. Here, we report that a 60S ribosomal protein NtRPL17 directly interacts with NtKRP. The phenotypes of NtRPL17 RNAi lines show notable embryo and seed size reduction. Structural observations of the NtRPL17-silenced embryos/seeds reveal that the embryo size reduction is due to a decrease in cell number. In these embryos, cell division cycle progression is delayed at the G2/M transition. These phenotypes are similar to that in NtKRP-silenced embryos/seeds, indicating that NtKRP and NtRPL17 function as partners in the same regulatory pathway during seed development and specifically regulate cell cycle progression to control embryo/seed size. This work reveals that NtRPL17, as a widely distributed ribosomal protein, plays a critical role in seed development and provides a new clue in the regulation of seed size. Confirmation of the interaction between NtKRP and NtRPL17 and their co-function in the control of the cell cycle also suggests that the mechanism might be conserved in both plants and animals. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR SCREENING OF MILK SAMPLES FOR SALMONELLA-TYPHIMURIUM IN DAIRY HERDS

    Hoorfar, Jeffrey; Wedderkopp, A.

    1995-01-01

    We investigated the ability of an antibody-specific, O antigen-based ELISA to document Salmonella typhimurium herd infections by screening of milk samples. Three cattle populations, 20 herds with no history of salmonellosis, 8 herds with history of S typhimurium epsiodes within the previous 7...... months, and 220 herds of unknown disease status, were tested. A herd was considered ELISA positive if at least 5% of the cows had OD values > 0.3. Among the 20 herds without history of salmonellosis, only 2 herds were ELISA positive, whereas all 8 herds with a known history of salmonellosis were ELISA...... positive (herd specificity, 0.9 and herd sensitivity, 1.0). A sig nificant correlation (P history of salmonellosis. It was concluded that ELISA testing of individual milk sam ples can be used for surveillance...

  17. Surface-supported Ag islands stabilized by a quantum size effect: Their interaction with small molecules relevant to ethylene epoxidation

    Shao, Dahai [Iowa State Univ., Ames, IA (United States)

    2013-05-15

    This dissertation focuses on how QSE-stabilized, surface-supported Ag nanoclusters will interact with ethylene or oxygen. Experiments are performed to determine whether the QSE-mediated Ag islands react differently toward adsorption of ethylene or oxygen, or whether the adsorption of these small molecules will affect the QSE-mediated stability of Ag islands. Studies of the interaction of oxygen with Ag/Si(111)-7×7 were previously reported, but these studies were performed at a low Ag coverage where 3D Ag islands were not formed. So the study of such a system at a higher Ag coverage will be a subject of this work. The interaction of ethylene with Ag/Si(111)-7×7, as well as the interaction of oxygen with Ag/NiAl(110) are also important parts of this study.

  18. Crack growth prediction method considering interaction between multiple cracks. Growth of surface cracks of dissimilar size under cyclic tensile and bending load

    Kamaya, Masayuki; Miyokawa, Eiichi; Kikuchi, Masanori

    2011-01-01

    When multiple cracks approach one another, the stress intensity factor is likely to change due to the interaction of the stress field. This causes change in growth rate and shape of cracks. In particular, when cracks are in parallel position to the loading direction, the shape of cracks becomes non-planar. In this study, the complex growth of interacting cracks is evaluated by using the S-Version finite element method, in which local detailed finite element mesh (local mesh) is superposed on coarse finite element model (global mesh) representing the global structure. In order to investigate the effect of interaction on the growth behavior, two parallel surface cracks are subjected to cyclic tensile or bending load. It is shown that the smaller crack is shielded by larger crack due to the interaction and stops growing when the difference in size of two cracks is significant. Based on simulations of various conditions, a procedure and criteria for evaluating crack growth for fitness-for-service assessment is proposed. According to the procedure, the interaction is not necessary to be considered in the crack growth prediction when the difference in size of two cracks exceeds the criterion. (author)

  19. Herd Clustering: A synergistic data clustering approach using collective intelligence

    Wong, Kachun

    2014-10-01

    Traditional data mining methods emphasize on analytical abilities to decipher data, assuming that data are static during a mining process. We challenge this assumption, arguing that we can improve the analysis by vitalizing data. In this paper, this principle is used to develop a new clustering algorithm. Inspired by herd behavior, the clustering method is a synergistic approach using collective intelligence called Herd Clustering (HC). The novel part is laid in its first stage where data instances are represented by moving particles. Particles attract each other locally and form clusters by themselves as shown in the case studies reported. To demonstrate its effectiveness, the performance of HC is compared to other state-of-the art clustering methods on more than thirty datasets using four performance metrics. An application for DNA motif discovery is also conducted. The results support the effectiveness of HC and thus the underlying philosophy. © 2014 Elsevier B.V.

  20. Reproductive handle of the herd of cattle of double purpose

    Castro Hernandez, A.

    1988-01-01

    The influence of the environmental factors is analyzed, in the reproductive efficiency of herd cattle of double purpose. The reproductive behavior begins with the gestation of the heifers. Under the conditions of the Colombian tropic these they reach the weight required for the reproduction to an age but late that in the temperate areas. Once the first childbirth, the cow takes place it enters in exhaustion that makes that this animal is the but difficult to reproduce after the childbirth, that which demands special cares of handling and feeding. The interval among the childbirth to evaluate the reproductive efficiency. Environmental factors that influence significantly. The use of the practice simple of handling, health, selection and feeding produces significant increments in the fertility of the herd of cattle of double purpose. One practices of effective handling in the improvement of the reproductive behavior of the cows of double purpose it is the restricted nursing

  1. Pig herd monitoring and undesirable tripping and stepping prevention

    Gronskyte, Ruta; Clemmensen, Line Katrine Harder; Hviid, Marchen Sonja

    2015-01-01

    Humane handling and slaughter of livestock are of major concern in modern societies. Monitoring animal wellbeing in slaughterhouses is critical in preventing unnecessary stress and physical damage to livestock, which can also affect the meat quality. The goal of this study is to monitor pig herds...... at the slaughterhouse and identify undesirable events such as pigs tripping or stepping on each other. In this paper, we monitor pig behavior in color videos recorded during unloading from transportation trucks. We monitor the movement of a pig herd where the pigs enter and leave a surveyed area. The method is based...... on optical flow, which is not well explored for monitoring all types of animals, but is the method of choice for human crowd monitoring. We recommend using modified angular histograms to summarize the optical flow vectors. We show that the classification rate based on support vector machines is 93% of all...

  2. Dynamic Morphological Changes Induced By GM1 and Protein Interactions on the Surface of Cell-Sized Liposomes

    Masahiro Takagi

    2013-06-01

    Full Text Available It is important to understand the physicochemical mechanisms that are responsible for the morphological changes in the cell membrane in the presence of various stimuli such as osmotic pressure. Lipid rafts are believed to play a crucial role in various cellular processes. It is well established that Ctb (Cholera toxin B subunit recognizes and binds to GM1 (monosialotetrahexosylganglioside on the cell surface with high specificity and affinity. Taking advantage of Ctb-GM1 interaction, we examined how Ctb and GM1 molecules affect the dynamic movement of liposomes. GM1 a natural ligand for cholera toxin, was incorporated into liposome and the interaction between fluorescent Ctb and the liposome was analyzed. The interaction plays an important role in determining the various surface interaction phenomena. Incorporation of GM1 into membrane leads to an increase of the line tension leading to either rupture of liposome membrane or change in the morphology of the membrane. This change in morphology was found to be GM1 concentration specific. The interaction between Ctb-GM1 leads to fast and easy rupture or to morphological changes of the liposome. The interactions of Ctb and the glycosyl chain are believed to affect the surface and the curvature of the membrane. Thus, the results are highly beneficial in the study of signal transduction processes.

  3. Herd composition and slaughtering strategy in reindeer husbandry – revisited

    Øystein Holand

    2007-04-01

    Full Text Available I will review the drastic change seen in herd composition and slaughtering strategy the last decades inthe reindeer husbandry of Fennoscandia (i. e. Finland, Norway and Sweden. Herd composition was traditionally a function of the multipurpose herd, where reproduction of draught power played a major role. Hence, the slaughter scheme was based on adult males, in particular castrates. The herd represented the owner's capital and was viewed as the best insurance for staying in business. Indeed, a big and well composed herd announced social status as well as authority. Historically this has resulted in rises and falls in reindeer numbers. Control of the herd was being emphasized through age and sex composition and selection of behavioural traits and easily recognisable animals which favour handling. A high proportion of adults alleviated control of the herd as it eased the herding and reduced the mortality risk as they were able to withstand the highly stochastic environment. The introduction of the snowmobiles in the 1960s revolutionized the herding and transportation and hence reduced the importance of the male segment of the herd and amplified the ongoing transformation of the modern society into a market based economy. Now, the challenge was to efficiently convert the limited primary plant production into animal product, mainly meat. This is primarily achieved by balancing the animal numbers in accordance to the forage resources. However, also herd composition and slaughtering strategy are essential for maximizing the meat output per area unit. A highest possible proportion of reproductive females combined with a slaughtering scheme based on calves was tested and partly implemented in Soviet-Union already in the 1930s and introduced in the 1960s in Finland. Also in parts of Norway and Sweden this scheme was modified and tested. However, the formal work of refining and testing this new strategy based on modern population theory blended with

  4. Graph-based impact analysis as a framework for incorporating practitioner knowledge in dairy herd health management.

    Krieger, M; Schwabenbauer, E-M; Hoischen-Taubner, S; Emanuelson, U; Sundrum, A

    2018-03-01

    Production diseases in dairy cows are multifactorial, which means they emerge from complex interactions between many different farm variables. Variables with a large impact on production diseases can be identified for groups of farms using statistical models, but these methods cannot be used to identify highly influential variables in individual farms. This, however, is necessary for herd health planning, because farm conditions and associated health problems vary largely between farms. The aim of this study was to rank variables according to their anticipated effect on production diseases on the farm level by applying a graph-based impact analysis on 192 European organic dairy farms. Direct impacts between 13 pre-defined variables were estimated for each farm during a round-table discussion attended by practitioners, that is farmer, veterinarian and herd advisor. Indirect impacts were elaborated through graph analysis taking into account impact strengths. Across farms, factors supposedly exerting the most influence on production diseases were 'feeding', 'hygiene' and 'treatment' (direct impacts), as well as 'knowledge and skills' and 'herd health monitoring' (indirect impacts). Factors strongly influenced by production diseases were 'milk performance', 'financial resources' and 'labour capacity' (directly and indirectly). Ranking of variables on the farm level revealed considerable differences between farms in terms of their most influential and most influenced farm factors. Consequently, very different strategies may be required to reduce production diseases in these farms. The method is based on perceptions and estimations and thus prone to errors. From our point of view, however, this weakness is clearly outweighed by the ability to assess and to analyse farm-specific relationships and thus to complement general knowledge with contextual knowledge. Therefore, we conclude that graph-based impact analysis represents a promising decision support tool for herd

  5. Relation between antimicrobial use and resistance in Belgian pig herds

    Callens, Benedicte; Boyen, Filip; Maes, Dominiek; Haesebrouck, Freddy; Butaye, Patrick; Dewulf, Jeroen

    2011-01-01

    The aim of this study was to determine the link between the characteristics of antimicrobial therapy and occurrence of antimicrobial resistance in Escherichia coli of clinically healthy pigs exposed to antimicrobial treatments. A total of 918 Escherichia coli isolates were obtained from faecal samples, collected from 50 pig herds at the end of the fattening period and susceptibility was tested towards 15 different antimicrobial agents, using the disk diffusion method. The Antimicrobial Resist...

  6. herd levels and standard lactation curves for south african jersey

    Protein. 34.2. 370.7. 148.1. 37.6. 31.3. 482.8. 191.1. 53.8. According to the standard deviations in Table 1, much more variation exists for 305-day yields of. Holstein cows in comparison with Jersey cows, resulting in upper limits of herd levels ranging from 3487.7 kg to more than 11 219.2 kg for adjusted 305-day milk yield, ...

  7. Rotavirus vaccination and herd immunity: an evidence-based review

    Seybolt LM

    2012-06-01

    Full Text Available Lorna M Seybolt, Rodolfo E BéguéDepartment of Pediatrics, Division of Infectious Diseases, Louisiana State University Health Sciences Center, New Orleans, LA, USAAbstract: Until recently, rotavirus was the most common cause of diarrhea in infants and young children with over 100 million cases and 400,000 deaths every year worldwide. Yet, its epidemiology is changing rapidly with the introduction of two rotavirus vaccines in the mid 2000s. Both vaccines were shown to be highly efficacious in prelicensure studies to reduce severe rotavirus disease; the efficacy being more pronounced in high- and middle-income countries than in low-income countries. Herd immunity – the indirect protection of unimmunized individuals as a result of others being immunized – was not expected to be a benefit of rotavirus vaccination programs since the vaccines were thought to reduce severe disease but not to decrease virus transmission significantly. Postlicensure studies, however, have suggested that this assumption may need reassessment. Studies in a variety of settings have shown evidence of greater than expected declines in rotavirus disease. While these studies were not designed specifically to detect herd immunity – and few failed to detect this phenomenon – the consistency of the evidence is compelling. These studies are reviewed and described here. While further work is needed, clarifying the presence of herd immunity is not just an academic exercise but an important issue for rotavirus control, especially in lower income countries where the incidence of the disease is highest and the direct protection of the vaccines is lower.Keywords: rotavirus, vaccine, herd immunity, efficacy

  8. Predation rate by wolves on the Porcupine caribou herd

    Hayes, Robert D.; Russell, Donald E.

    2000-01-01

    Large migratory catibou {Rangifer tarandus) herds in the Arctic tend to be cyclic, and population trends are mainly driven by changes in forage or weather events, not by predation. We estimated daily kill rate by wolves on adult caribou in winter, then constructed a time and space dependent model to estimate annual wolf (Canis lupus) predation rate (P annual) on adult Porcupine caribou. Our model adjusts predation seasonally depending on caribou distribution: Pannual = SIGMAdaily* W *Ap(2)*Dp...

  9. Co-management of the Porcupine Caribou Herd

    Albert Peter; Doug Urquhart

    1996-01-01

    The success of a co-management organization rests with the user communities. Over the years members of the Porcupine Caribou Management Board have observed that it is the knowledge and concerns held by the people in the communities which are affected by caribou management policies, that provide the greatest inspiration to the Board. In return, the Board must never lose sight of its primary objective which is to manage and conserve the Porcupine Caribou Herd by incorporating native participati...

  10. Modelled female sale options demonstrate improved profitability in northern beef herds.

    Niethe, G E; Holmes, W E

    2008-12-01

    To examine the impact of improving the average value of cows sold, the risk of decreasing the number weaned, and total sales on the profitability of northern Australian cattle breeding properties. Gather, model and interpret breeder herd performances and production parameters on properties from six beef-producing regions in northern Australia. Production parameters, prices, costs and herd structure were entered into a herd simulation model for six northern Australian breeding properties that spay females to enhance their marketing options. After the data were validated by management, alternative management strategies were modelled using current market prices and most likely herd outcomes. The model predicted a close relationship between the average sale value of cows, the total herd sales and the gross margin/adult equivalent. Keeping breeders out of the herd to fatten generally improves their sale value, and this can be cost-effective, despite the lower number of progeny produced and the subsequent reduction in total herd sales. Furthermore, if the price of culled cows exceeds the price of culled heifers, provided there are sufficient replacement pregnant heifers available to maintain the breeder herd nucleus, substantial gains in profitability can be obtained by decreasing the age at which cows are culled from the herd. Generalised recommendations on improving reproductive performance are not necessarily the most cost-effective strategy to improve breeder herd profitability. Judicious use of simulation models is essential to help develop the best turnoff strategies for females and to improve station profitability.

  11. Animal Production Performance and Herd Management in Suckling Farms on Réunion Island

    J.P. Choisis

    2008-02-01

    Full Text Available In Réunion, because of the insularity and the small size of farms, improving cattle farm productivity involves increas­ing technical management aspects. To analyze relationships between herd management practices and animal perform­ances, a survey was conducted in ten suckling farms, located in the Highlands, from 1999 to 2002. Three sets of 4, 8 and 3 variables, respectively, were thus extracted from the moni­toring database: animal performances (calving interval, fertil­ity rate, body weight at standard age, live meat production, farmers’ practices (grazing time per hectare and paddock, time interval between two passages, paddock size, stocking rate, feed complementation of weaned animals and lactating cows, culling rate, and environment (rainfall, herbage production, body condition score of cows. An analysis of co-inertia was carried out on the first two tables to analyze relationships between animal production performances and practices. A significant correlation was observed between the two tables. The results of the co-inertia analysis were interpreted for each farm. Beyond specific constraints, they revealed proximities between farms and herd management based on various strat­egies, which were relevant with the observed performances. A STATICO analysis was performed to assess relationships between performance parameters and environment parameters for the four studied years. It revealed that there was a stable costructure between the environment and performance tables. This suggests that practices had a highly structuring effect on animal production and that some system adjustments miti­gated the climate effects.

  12. Bacteriological etiology and treatment of mastitis in Finnish dairy herds.

    Vakkamäki, Johanna; Taponen, Suvi; Heikkilä, Anna-Maija; Pyörälä, Satu

    2017-05-25

    The Finnish dairy herd recording system maintains production and health records of cows and herds. Veterinarians and farmers register veterinary treatments in the system. Milk samples for microbiological analysis are routinely taken from mastitic cows. The laboratory of the largest dairy company in Finland, Valio Ltd., analyzes most samples using real-time PCR. This study addressed pathogen-specific microbiological data and treatment and culling records, in combination with cow and herd characteristics, from the Finnish dairy herd recording system during 2010-2012. The data derived from 240,067 quarter milk samples from 93,529 dairy cows with mastitis; 238,235 cows from the same herds served as the control group. No target pathogen DNA was detected in 12% of the samples. In 49% of the positive samples, only one target species and in 19%, two species with one dominant species were present. The most common species in the samples with a single species only were coagulase-negative staphylococci (CNS) (43%), followed by Staphylococcus aureus (21%), Streptococcus uberis (9%), Streptococcus dysgalactiae (8%), Corynebacterium bovis (7%), and Escherichia coli (5%). On average, 36% of the study cows and 6% of the control cows had recorded mastitis treatments during lactation. The corresponding proportions were 16 and 6% at drying-off. For more than 75% of the treatments during lactation, diagnosis was acute clinical mastitis. In the milk samples from cows with a recorded mastitis treatment during lactation, CNS and S. aureus were most common, followed by streptococci. Altogether, 48% of the cows were culled during the study. Mastitis was reported as the most common reason to cull; 49% of study cows and 18% of control cows were culled because of mastitis. Culling was most likely if S. aureus was detected in the milk sample submitted during the culling year. The PCR test has proven to be an applicable method also for large-scale use in bacterial diagnostics. In the present

  13. Molecular aspects of antibody-antigen interactions : size reduction of a herpes simplex virus neutralizing antibody and its antigen

    Schellekens, Gerardus Antonius

    1996-01-01

    Antibody molecules, produced as a response against foreign substances, interact with their antigen in a very specific manner. Antibodies with a predetermined specificity (monoclonal antibodies) can be produced and are widely used in medicine and science as indicator molecules. Genetic engineering of

  14. Interactions of animal age and particle size with deposition and retention of inhaled 51Cr-labeled microspheres

    Hackett, P.L.; Sikov, M.R.; Skiens, W.E.; Cannon, W.C.; Hess, J.O.; Hall, D.

    1980-01-01

    Newborn, juvenile, weanling, and adult rats were exposed to aerosols of 51 Cr-labeled microspheres with AMADs of 0.91, 1.4, 2.3, 3.4, and 4.4 μm. Alveolar deposition was negligible in newborn rats for all particle sizes, and decreased to less than 6% at an AMAD of 2.3 μm in juveniles and weanlings, and an AMAD of 3.4 μm in adults

  15. Interdigital dermatitis, heel horn erosion, and digital dermatitis in 14 Norwegian dairy herds

    Knappe-Poindecker, M.; Gilhuus, M.; Jensen, Tim Kåre

    2013-01-01

    The aim of this study was to assess infectious foot diseases, including identification and characterization of Dichelobacter nodosus and Treponema spp., in herds having problems with interdigital dermatitis (ID) and heel horn erosion (E) and in control herds expected to have few problems. We also......, with a prevalence of 50.4% in problem herds compared with 26.8% in control herds. Heel horn erosion was recorded in 34.8% of the cows in problem herds compared with 22.1% in control herds. Dichelobacter nodosus was detected in 97.1% of the cows with ID, in 36.4% with E, in all cows with both ID and E, in all cows...

  16. Epidemiological Investigations of Four Cowpox Virus Outbreaks in Alpaca Herds, Germany

    Prkno, Almut; Hoffmann, Donata; Goerigk, Daniela; Kaiser, Matthias; van Maanen, Anne Catherine Franscisca; Jeske, Kathrin; Jenckel, Maria; Pfaff, Florian; Vahlenkamp, Thomas W.; Beer, Martin; Ulrich, Rainer G.; Starke, Alexander; Pfeffer, Martin

    2017-01-01

    Four cowpox virus (CPXV) outbreaks occurred in unrelated alpaca herds in Eastern Germany during 2012–2017. All incidents were initially noticed due to severe, generalized, and finally lethal CPXV infections, which were confirmed by testing of tissue and serum samples. As CPXV-infection has been described in South American camelids (SACs) only three times, all four herds were investigated to gain a deeper understanding of CPXV epidemiology in alpacas. The different herds were investigated twic...

  17. Influence of species, size and relative abundance on the outcomes of competitive interactions between brook trout and juvenile coho salmon

    Thornton, Emily J; Duda, Jeff; Quinn, Thomas P.

    2016-01-01

    Resource competition between animals is influenced by a number of factors including the species, size and relative abundance of competing individuals. Stream-dwelling animals often experience variably available food resources, and some employ territorial behaviors to increase their access to food. We investigated the factors that affect dominance between resident, non-native brook trout and recolonizing juvenile coho salmon in the Elwha River, WA, USA, to see if brook trout are likely to disrupt coho salmon recolonization via interference competition. During dyadic laboratory feeding trials, we hypothesized that fish size, not species, would determine which individuals consumed the most food items, and that species would have no effect. We found that species, not size, played a significant role in dominance; coho salmon won 95% of trials, even when only 52% the length of their brook trout competitors. As the pairs of competing fish spent more time together during a trial sequence, coho salmon began to consume more food, and brook trout began to lose more, suggesting that the results of early trials influenced fish performance later. In group trials, we hypothesized that group composition and species would not influence fish foraging success. In single species groups, coho salmon consumed more than brook trout, but the ranges overlapped. Brook trout consumption remained constant through all treatments, but coho salmon consumed more food in treatments with fewer coho salmon, suggesting that coho salmon experienced more intra- than inter-specific competition and that brook trout do not pose a substantial challenge. Based on our results, we think it is unlikely that competition from brook trout will disrupt Elwha River recolonization by coho salmon.

  18. Characterization of PEI-coated superparamagnetic iron oxide nanoparticles for transfection: Size distribution, colloidal properties and DNA interaction

    Steitz, Benedikt [Laboratory of Powder Technology, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); Hofmann, Heinrich [Laboratory of Powder Technology, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); Kamau, Sarah W. [Institute of Veterinary Biochemistry and Molecular Biology, University of Zuerich, Zurich (Switzerland); Hassa, Paul O. [Institute of Veterinary Biochemistry and Molecular Biology, University of Zuerich, Zurich (Switzerland); Hottiger, Michael O. [Institute of Veterinary Biochemistry and Molecular Biology, University of Zuerich, Zurich (Switzerland); Rechenberg, Brigitte von [Musculoskeletal Research Unit, Equine Hospital, Vetsuisse Faculty Zurich, University of Zurich, Winterthurerstr. 260, 8057 Zurich (Switzerland); Hofmann-Amtenbrink, Magarethe [MatSearch, Chemin Jean Pavillard 14, 1009 Pully (Switzerland); Petri-Fink, Alke [Laboratory of Powder Technology, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland)]. E-mail: alke.fink@epfl.ch

    2007-04-15

    Superparamagnetic iron oxide nanoparticles (SPIONs) were coated with polyethylenimine. Here, we briefly describe the synthesis as well as DNA:PEI:SPION complexes and the characterization of the compounds according to their particle size, {zeta}-potential, morphology, DNA complexing ability, magnetic sedimentation, and colloidal stability. PEI coating of SPIONs led to colloidally stable beads even in high salt concentrations over a wide pH range. DNA plasmids and PCR products encoding for green fluorescent protein were associated with the described beads. The complexes were added to cells and exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency.

  19. Family size, cognitive outcomes, and familial interaction in stable, two-parent families: United States, 1997-2002.

    Sandberg, John; Rafail, Patrick

    2014-10-01

    Measures of children's time use, particularly with parents and siblings, are used to evaluate three hypotheses in relation to the vocabulary and mathematical skills development: (1) the resource dilution hypothesis, which argues that parental and household resources are diluted in larger families; (2) the confluence hypothesis, which suggests that the intellectual milieu of families is lowered with additional children; and (3) the admixture ("no effect") hypothesis, which suggests that the negative relationship between family size and achievement is an artifact of cross-sectional research resulting from unobserved heterogeneity. Each hypothesis is tested using within-child estimates of change in cognitive scores over time with the addition of new children to families.

  20. Characterization of PEI-coated superparamagnetic iron oxide nanoparticles for transfection: Size distribution, colloidal properties and DNA interaction

    Steitz, Benedikt; Hofmann, Heinrich; Kamau, Sarah W.; Hassa, Paul O.; Hottiger, Michael O.; Rechenberg, Brigitte von; Hofmann-Amtenbrink, Magarethe; Petri-Fink, Alke

    2007-01-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) were coated with polyethylenimine. Here, we briefly describe the synthesis as well as DNA:PEI:SPION complexes and the characterization of the compounds according to their particle size, ζ-potential, morphology, DNA complexing ability, magnetic sedimentation, and colloidal stability. PEI coating of SPIONs led to colloidally stable beads even in high salt concentrations over a wide pH range. DNA plasmids and PCR products encoding for green fluorescent protein were associated with the described beads. The complexes were added to cells and exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency

  1. Genotype-specific risk factors for Staphylococcus aureus in Swiss dairy herds with an elevated yield-corrected herd somatic cell count.

    Berchtold, B; Bodmer, M; van den Borne, B H P; Reist, M; Graber, H U; Steiner, A; Boss, R; Wohlfender, F

    2014-01-01

    Bovine mastitis is a frequent problem in Swiss dairy herds. One of the main pathogens causing significant economic loss is Staphylococcus aureus. Various Staph. aureus genotypes with different biological properties have been described. Genotype B (GTB) of Staph. aureus was identified as the most contagious and one of the most prevalent strains in Switzerland. The aim of this study was to identify risk factors associated with the herd-level presence of Staph. aureus GTB and Staph. aureus non-GTB in Swiss dairy herds with an elevated yield-corrected herd somatic cell count (YCHSCC). One hundred dairy herds with a mean YCHSCC between 200,000 and 300,000cells/mL in 2010 were recruited and each farm was visited once during milking. A standardized protocol investigating demography, mastitis management, cow husbandry, milking system, and milking routine was completed during the visit. A bulk tank milk (BTM) sample was analyzed by real-time PCR for the presence of Staph. aureus GTB to classify the herds into 2 groups: Staph. aureus GTB-positive and Staph. aureus GTB-negative. Moreover, quarter milk samples were aseptically collected for bacteriological culture from cows with a somatic cell count ≥150,000cells/mL on the last test-day before the visit. The culture results allowed us to allocate the Staph. aureus GTB-negative farms to Staph. aureus non-GTB and Staph. aureus-free groups. Multivariable multinomial logistic regression models were built to identify risk factors associated with the herd-level presence of Staph. aureus GTB and Staph. aureus non-GTB. The prevalence of Staph. aureus GTB herds was 16% (n=16), whereas that of Staph. aureus non-GTB herds was 38% (n=38). Herds that sent lactating cows to seasonal communal pastures had significantly higher odds of being infected with Staph. aureus GTB (odds ratio: 10.2, 95% CI: 1.9-56.6), compared with herds without communal pasturing. Herds that purchased heifers had significantly higher odds of being infected with

  2. Veterinary dairy herd health management in Europe: constraints and perspectives.

    Cannas da Silva, J; Noordhuizen, J P T M; Vagneur, M; Bexiga, R; Gelfert, C C; Baumgartner, W

    2006-03-01

    The nature of veterinary work in dairy health management in Europe has changed over the past years and will change even more dramatically in the near future. The consumers and the media show increasing concern about animal welfare, safety of products of animal origin and traceability of animal products. Farmers in Europe have to produce under strict, often expensive and laborious regulations, while still commercially competing with farmers outside the EU and not subject to the same rules. Veterinarians should adapt their knowledge and skills to the new challenges and developments of the dairy sector. Dairy farmers nowadays ask for support in areas that go beyond clinical activities: environmental protection, welfare, nutrition, grassland management, economics and business management. Bovine practitioners should be able to advise in many different areas and subjects--that is the challenge to our profession. Veterinary education with regards to cattle health management should start with individual animal clinical work, which constitutes the basis of herd health advisory programmes. The bovine practitioner should then look beyond that and regard the herd as the unit. Each diseased cow or group of cows should be detected early enough to avoid financial losses or such losses should be prevented altogether by detecting and managing risk factors contributing to disease occurrence. Herd health and production management programmes represent the first level to optimise dairy farm performance. Expansions to that should further be considered, comprising both animal health and welfare issues, as well as food safety and public health issues. The latter could be addressed by quality risk management programmes following the HACCP-principles. Cattle veterinarians should follow recent developments and invest in new skills and knowledge in order to maintain their usefulness to the modern dairy farmer. Finally we are convinced that the cattle practitioner should evolve into this

  3. Migratory herds of wildebeests and zebras indirectly affect calf survival of giraffes.

    Lee, Derek E; Kissui, Bernard M; Kiwango, Yustina A; Bond, Monica L

    2016-12-01

    In long-distance migratory systems, local fluctuations in the predator-prey ratio can exhibit extreme variability within a single year depending upon the seasonal location of migratory species. Such systems offer an opportunity to empirically investigate cyclic population density effects on short-term food web interactions by taking advantage of the large seasonal shifts in migratory prey biomass.We utilized a large-mammal predator-prey savanna food web to evaluate support for hypotheses relating to the indirect effects of "apparent competition" and "apparent mutualism" from migratory ungulate herds on survival of resident megaherbivore calves, mediated by their shared predator. African lions ( Panthera leo ) are generalist predators whose primary, preferred prey are wildebeests ( Connochaetes taurinus ) and zebras ( Equus quagga ), while lion predation on secondary prey such as giraffes ( Giraffa camelopardalis ) may change according to the relative abundance of the primary prey species.We used demographic data from five subpopulations of giraffes in the Tarangire Ecosystem of Tanzania, East Africa, to test hypotheses relating to direct predation and indirect effects of large migratory herds on calf survival of a resident megaherbivore. We examined neonatal survival via apparent reproduction of 860 adult females, and calf survival of 449 giraffe calves, during three precipitation seasons over 3 years, seeking evidence of some effect on neonate and calf survival as a consequence of the movements of large herds of migratory ungulates.We found that local lion predation pressure (lion density divided by primary prey density) was significantly negatively correlated with giraffe neonatal and calf survival probabilities. This supports the apparent mutualism hypothesis that the presence of migratory ungulates reduces lion predation on giraffe calves.Natural predation had a significant effect on giraffe calf and neonate survival, and could significantly affect giraffe

  4. Random within-herd variation in financial performance and time to financial steady-state following management changes in the dairy herd

    Kristensen, Erling Lundager; Østergaard, Søren; Krogh, Mogens Agerbo

    2008-01-01

    The manager of a dairy herd and the affiliated consultants constantly need to judge whether financial performance of the production system is satisfactory and whether financial performance relates to real (systematic) effects of changes in management. This is no easy task because the dairy herd...... is a very complex system. Thus, it is difficult to obtain empirical data that allows a valid estimation of the random (within-herd) variation in financial performance corrected for management changes. Thus, simulation seems to be the only option. This study suggests that much caution must be recommended...

  5. Studies of interaction of amines with TOPO/TOP capped CdSe quantum dots: Role of crystallite size and oxidation potential

    Sharma, Shailesh N.; Sharma, Himani; Singh, Gurmeet; Shivaprasad, S.M.

    2008-01-01

    This work reports the interaction of aliphatic (triethyl amine, butyl amine) and aromatic amines (PPD, aniline) with CdSe quantum dots of varied sizes. The emission properties and lifetime values of CdSe quantum dots were found to be dependent on the oxidation potential of amines and crystallite sizes. Smaller CdSe quantum dots (size ∼5 nm) ensure better surface coverage of amines and hence higher quenching efficiency of amines could be realized as compared to larger CdSe quantum dots (size ∼14 nm). Heterogeneous quenching of amines due to the presence of accessible and inaccessible set of CdSe fluorophores is indicated. PPD owing to its lowest oxidation potential (∼0.26 V) has been found to have higher quenching efficiency as compared to other amines TEA and aniline having oxidation potentials ∼0.66 and >1.0 V, respectively. Butyl amine on the other hand, plays a dual role: its post-addition acts as a quencher for smaller and enhances emission for larger CdSe quantum dots, respectively. The beneficial effect of butyl amine in enhancing emission intensity could be attributed to enhance capping effect and better passivation of surface-traps

  6. Herd protection effect of N95 respirators in healthcare workers.

    Chen, Xin; Chughtai, Abrar Ahmad; MacIntyre, Chandini Raina

    2017-12-01

    Objective To determine if there was herd protection conferred to unprotected healthcare workers (HCWs) by N95 respirators worn by colleagues. Methods Data were analysed from a prospective cluster randomized clinical trial conducted in Beijing, China between 1 December 2008 and 15 January 2009. A minimum compliance level (MCL) of N95 respirators for prevention of clinical respiratory illness (CRI) was set based on various compliance cut-offs. The CRI rates were compared between compliant (≥MCL) and non-compliant (protection from use of N95 respirators by colleagues within a hospital ward.

  7. Pertussis: herd immunity and vaccination coverage in St Lucia.

    Cooper, E; Fitch, L

    1983-11-12

    In a single complete epidemic in St Lucia, an island too small to support constant clinical pertussis, the pertussis case rates in small communities (villages and small towns) with differing levels of vaccination coverage of young children were compared. The association between greater vaccination coverage and greater herd immunity was clear, despite the imperfect protection given to individuals. An analysis in terms of population dynamics is evidence against the theory that endemic subclinical pertussis maintains transmission in a highly vaccinated population. We suggest that with a homogeneous vaccination coverage of 80% of 2-year-old children pertussis might be eradicated from the island, and that this is a practicable experiment.

  8. Infection dynamics of Lawsonia intracellularis in pig herds

    Stege, H.; Jensen, Tim Kåre; Møller, Kristian

    2004-01-01

    shedding of L. intracellularis was assessed by real time-PCR and sero-conversion by an indirect immunofluorescence antibody test (IFAT). Clinical disease was not reported but infection was present in all herds and the PCR assay indicated infection in 75% of pigs examined. Most L. intracellularis infected....... Relative to the bacterial shedding, the onset of sero-conversion was a little delayed, in general, most pigs had sero-converted 2 weeks after the first shedding. Once sero-converted, 92% of the pigs remained sero-positive over the entire survey period....

  9. Co-management of the Porcupine Caribou Herd

    Albert Peter

    1996-01-01

    Full Text Available The success of a co-management organization rests with the user communities. Over the years members of the Porcupine Caribou Management Board have observed that it is the knowledge and concerns held by the people in the communities which are affected by caribou management policies, that provide the greatest inspiration to the Board. In return, the Board must never lose sight of its primary objective which is to manage and conserve the Porcupine Caribou Herd by incorporating native participation at every level of decision-making.

  10. Spatial and temporal changes in seasonal range attributes in a declining barren-ground caribou herd

    John A. Virgl

    2017-05-01

    Full Text Available From 1996 to 2015 the Bathurst caribou herd has declined from approximately 349,000 to 20,000 animals. Aboriginal traditional knowledge (TK has recently observed the later arrival of the herd below the treeline, an attribute of the autumn range. Science also predicts that seasonal range attributes (e.g., area, location likely vary with population size, and perhaps climate. We used Aboriginal TK and science to identify several seasonal range attributes that were ex­amined for changes through time (decreasing population abundance. Attributes of seasonal ranges for female Bathurst caribou were calculated using satellite radio-collar data from January 1996 through October 2013. Climate data from CircumArctic Rangifer Monitoring and Assessment Network were analyzed for trends from 1979 to 2009. Analyses showed a significant decrease in the area of post-calving and autumn ranges, but no changes in winter and spring ranges. Results supported Aboriginal TK that female caribou have shifted the autumn range farther from the treeline and moved into the forest later in the year. Analysis of climate variables found no trends at the spatio-temporal scale of the post-calving to autumn ranges. Working hypotheses to explain these patterns, which are not mutually exclusive, include reduced predation risk, increased use of core areas at lower population density, and greater utilization of areas of taiga where arboreal and ground lichen availability and accessibility are relatively higher than in the forest. This analysis demonstrates how including Aboriginal TK can lead to stronger connections and results, with potential to provide new and different insights for further investigations.

  11. Temporal variation and interaction of full size spectrum Alcian blue stainable materials and water quality parameters in a reservoir.

    Thuy, Nguyen Thi; Lin, Justin Chun-Te; Juang, Yaju; Huang, Chihpin

    2015-07-01

    This paper reports on the fate of different fractions of Alcian blue (AB) stainable material in Pao-Shan reservoir, Taiwan, in a one-year study (2013-2014) and an intensive study during phytoplankton bloom (2014). The interactions between the fractions, including AB stained particles, particle and colloidal transparent exopolymer particles (pTEP and cTEP), dissolved acid polysaccharide (dAPS), and their relationship to other water quality parameters were analyzed. The Flow Cytometer and Microscope (FlowCAM) was for first time used to characterize AB stained particles. The results of the one-year study likely showed relationships of pTEP concentration to phytoplankton count and chlorophyll a, while in the intensive study, AB stained particles abundance and pTEP concentration were correlated neither phytoplankton count nor chlorophyll a, but strongly positively correlated with some phytoplankton species' abundance. The difference indicates that sampling frequency and phytoplankton composition should be addressed for studying the links between AB stained fractions and phytoplankton. The interaction between different AB stained fractions further suggests that the majority of AB stained particles and pTEP would be directly generated by some phytoplankton species, whereas their abiotic generation by cTEP or dAPS may only have contributed partly to their formation. This differs from previous studies which generally posited that pTEP are mainly formed abiotically from dissolved precursors. Successful application of FlowCAM for visualization of AB stained particles recommends this technique by which particle morphologies can be conserved and morphological features of particle can be simultaneously elucidated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Biosecurity and animal disease management in organic and conventional Swedish dairy herds: a questionnaire study.

    Emanuelson, Ulf; Sjöström, Karin; Fall, Nils

    2018-04-12

    Good animal health is a notion that is germane to organic dairy production, and it is expected that such herds would pay significant attention on the health of their animals. However, it is not known if the applied animal disease management is actually more adequate in organic dairy cattle herds than in conventional dairy herds. A questionnaire study on biosecurity and animal disease management activities was therefore conducted among Swedish farmers with organic and conventional dairy cattle herds. A total of 192 useable questionnaires were returned; response rates of 30.3 and 20.2% for organic and conventional farmers, respectively. Herd characteristics of the two herd types were very similar, except that pipeline/tie-stall systems were less common in organic farms and that organic farmers had a higher education level than their conventional counterparts. Also, very few systematic differences in general or specific disease management activities were observed between the two types of farms. The main exceptions being how milk from cows during antibiotic treatment was used, views on policy actions in relation to antibiotic use, and attitudes towards calling for veterinary support. Using milk from cows during antibiotic treatment was more common in conventional herds, although it was mainly given to bull calves. Farmers of organic herds were more positive to policy actions to reduce the use and need for antibiotics, and they reported waiting longer before contacting a veterinarian for calves with diarrhoea and cows with subclinical mastitis. The stated biosecurity and animal disease management was relatively equal in Swedish organic and conventional dairy herds. Our results thus indicate that animal health is as important in conventionally managed dairy herds in Sweden as in organically managed herds.

  13. Humic acids and their interactions with metallic elements: Cu II, Eu III, Th IV, U VI: contribution of size exclusion chromatography method and research of complexation models

    Lesourd-Moulin, V.

    1986-04-01

    The interest given to natural organic matter (humic and fulvic acids) as complexing agents of metallic ions in soils and natural waters becomes more and more important in environmental area. Cation - humic matter interactions have a great importance, a better understanding of the contribution of these substances in natural media specially towards radioactive elements with long life time. Interactions are studied by a chromatographic technique of gel filtration: the dynamic equilibrium method is based on the separation of the formed complex humic macromolecule - metallic ion and the free metallic ion, which due to its size penetrates totally in the pores of the gel. Separation mechanisms of the chromatographic support and the contribution of each parameter, are studied as a function of the buffer nature, its concentration, the PH, the gel porosity and the valence of the metallic cation. This study led to the determination of the appropriate experimental conditions for each cation. A study of metallic binding with humic acid has been undertaken with Cu 2+ , Eu 3+ , Th 4+ , Uo 2 2+ . These elements, except copper, have been chosen for their properties similar to the transuranic elements. Different samples of humic acids (commercial, podzolic soil, rendzine soil) are also studied. A deeper research of europium - humic acid interactions by means of different treatment models (discrete or gaussian models) has been undertaken in order to determine the number, the binding site strength and the global interaction constants [fr

  14. Unrecognized circulation of SAT 1 foot-and-mouth disease virus in cattle herds around Queen Elizabeth National Park in Uganda.

    Dhikusooka, Moses Tefula; Ayebazibwe, Chrisostom; Namatovu, Alice; Belsham, Graham J; Siegismund, Hans Redlef; Wekesa, Sabenzia Nabalayo; Balinda, Sheila Nina; Muwanika, Vincent B; Tjørnehøj, Kirsten

    2016-01-06

    Foot-and-mouth disease (FMD) is endemic in Uganda in spite of the control measures used. Various aspects of the maintenance and circulation of FMD viruses (FMDV) in Uganda are not well understood; these include the role of the African buffalo (Syncerus caffer) as a reservoir for FMDV. To better understand the epidemiology of FMD at the livestock-wildlife-interface, samples were collected from young, unvaccinated cattle from 24 pastoral herds that closely interact with wildlife around Queen Elizabeth National Park in Uganda, and analysed for evidence of FMDV infection. In total, 37 (15%) of 247 serum samples had detectable antibodies against FMDV non-structural proteins (NSPs) using a pan-serotypic assay. Within these 37 sera, antibody titres ≥ 80 against the structural proteins of serotypes O, SAT 1, SAT 2 and SAT 3 were detected by ELISA in 5, 7, 4 and 3 samples, respectively, while neutralizing antibodies were only detected against serotype O in 3 samples. Two FMDV isolates, with identical VP1 coding sequences, were obtained from probang samples from clinically healthy calves from the same herd and are serotype SAT 1 (topotype IV (EA-I)). Based on the VP1 coding sequences, these viruses are distinct from previous cattle and buffalo SAT 1 FMDV isolates obtained from the same area (19-30% nucleotide difference) and from the vaccine strain (TAN/155/71) used within Uganda (26% nucleotide difference). Eight herds had only one or a few animals with antibodies against FMDV NSPs while six herds had more substantial evidence of prior infection with FMDV. There was no evidence for exposure to FMDV in the other ten herds. The two identical SAT 1 FMDV VP1 sequences are distinct from former buffalo and cattle isolates from the same area, thus, transmission between buffalo and cattle was not demonstrated. These new SAT 1 FMDV isolates differed significantly from the vaccine strain used to control Ugandan FMD outbreaks, indicating a need for vaccine matching studies. Only

  15. Estimating genetic effect sizes under joint disease-endophenotype models in presence of gene-environment interactions

    Alexandre eBureau

    2015-07-01

    Full Text Available Effects of genetic variants on the risk of complex diseases estimated from association studies are typically small. Nonetheless, variants may have important effects in presence of specific levels of environmental exposures, and when a trait related to the disease (endophenotype is either normal or impaired. We propose polytomous and transition models to represent the relationship between disease, endophenotype, genotype and environmental exposure in family studies. Model coefficients were estimated using generalized estimating equations and were used to derive gene-environment interaction effects and genotype effects at specific levels of exposure. In a simulation study, estimates of the effect of a genetic variant were substantially higher when both an endophenotype and an environmental exposure modifying the variant effect were taken into account, particularly under transition models, compared to the alternative of ignoring the endophenotype. Illustration of the proposed modeling with the metabolic syndrome, abdominal obesity, physical activity and polymorphisms in the NOX3 gene in the Quebec Family Study revealed that the positive association of the A allele of rs1375713 with the metabolic syndrome at high levels of physical activity was only detectable in subjects without abdominal obesity, illustrating the importance of taking into account the abdominal obesity endophenotype in this analysis.

  16. Uniform two-dimensional square assemblies from conjugated block copolymers driven by π–π interactions with controllable sizes

    Han, Liang; Wang, Meijing; Jia, Xiangmeng; Chen, Wei; Qian, Hujun; He, Feng

    2018-02-28

    Two-dimensional (2-D) micro- and nano- architectures are attractive because of their unique properties caused by their ultrathin and flat morphologies. However, the formation of 2-D supramolecular highly symmetrical structures with considerable control is still a major challenge. Here, we presented a simple approach for the preparation of regular and homogeneous 2-D fluorescent square noncrystallization micelles with conjugated diblock copolymers PPV12-b-P2VPn through a process of dissolving-cooling-aging. The scale of the formed micelles could be controlled by the ratio of PPV/P2VP blocks and the concentration of the solution. The forming process of the platelet square micelles was analyzed by UV-Vis, DLS and SLS, while the molecular arrangement was characterized by GIXD. The results revealed that the micelles of PPV12-b-P2VPn initially form 1-D structures and then grow into 2-D structures in solution, and the growth is driven by intermolecular π-π interactions with the PPV12 blocks. The formation of 2-D square micelles is induced by herringbone arrangement of the molecules, which is closely related to the presence of the branched alkyl chains attached to conjugated PPV12 cores.

  17. Simulated Annealing-Based Krill Herd Algorithm for Global Optimization

    Gai-Ge Wang

    2013-01-01

    Full Text Available Recently, Gandomi and Alavi proposed a novel swarm intelligent method, called krill herd (KH, for global optimization. To enhance the performance of the KH method, in this paper, a new improved meta-heuristic simulated annealing-based krill herd (SKH method is proposed for optimization tasks. A new krill selecting (KS operator is used to refine krill behavior when updating krill’s position so as to enhance its reliability and robustness dealing with optimization problems. The introduced KS operator involves greedy strategy and accepting few not-so-good solutions with a low probability originally used in simulated annealing (SA. In addition, a kind of elitism scheme is used to save the best individuals in the population in the process of the krill updating. The merits of these improvements are verified by fourteen standard benchmarking functions and experimental results show that, in most cases, the performance of this improved meta-heuristic SKH method is superior to, or at least highly competitive with, the standard KH and other optimization methods.

  18. Herd prevalence of Salmonella enterica infections in Danish slaughter pigs determined by microbiological testing

    Baggesen, Dorte Lau; Wegener, Henrik Caspar; Bager, Flemming

    1996-01-01

    As a part of a nationwide programme to survey and control salmonella in pig herds, a microbiological survey of 1363 pig herds was performed in Denmark. A total of 13 468 slaughter pigs were examined at slaughter by culture of 5 g of caecal contents. Overall, 30 different serotypes of Salmonella...

  19. Antibiotic use in dairy herds in the Netherlands from 2005 to 2012

    Kuipers, A.; Koops, W.J.; Wemmenhove, H.

    2016-01-01

    The aim of this study was to examine the variation in antibiotic use and the effects of external factors on trends in antibiotic use at the herd level by using the number of daily dosages as an indicator for antibiotic use. For this purpose, antibiotic use was analyzed in 94 dairy herds in the

  20. Metabolic parameters and blood leukocyte profiles in cows from herds with high or low mastitis incidence.

    Holtenius, K; Persson Waller, K; Essén-Gustavsson, B; Holtenius, P; Hallén Sandgren, C

    2004-07-01

    The objective of this study was to determine whether there were differences in metabolic parameters and blood leukocyte profiles between cows in herds with high or low yearly mastitis incidence. In this study, 271 cows from 20 high yielding dairy herds were examined. According to the selection criteria, all herds had low somatic cell counts. Ten of the selected herds represented low mastitis treatment incidence (LMI) and ten herds had high mastitis treatment incidence (HMI). The farms were visited once and blood samples were taken from each cow that was in the interval from three weeks before to 15 weeks after parturition. The eosinophil count was significantly lower among cows from the HMI herds in the period from four weeks to 15 weeks after parturition. The plasma concentrations of beta-hydroxybutyrate, glucose, insulin and urea did not differ between groups, but the concentration of nonesterified fatty acids was significantly higher among HMI cows during the period three weeks after parturition. The concentration of the amino acid tryptophan in plasma was significantly lower among the HMI cows prior to parturition. Glutamine was significantly lower in cows from HMI herds during the first three weeks after parturition. Arginine was consistently lower in HMI cows, although the decrease was only significant during the period from four to fifteen weeks after parturition. The results suggest that there were differences in the metabolism and immune status between herds with high or low yearly mastitis treatment incidence indicating an increased metabolic stress in HMI cows.

  1. 9 CFR 78.9 - Cattle from herds not known to be affected.

    2010-01-01

    ... same individual, and (A) The cattle being moved originate from a herd in which (1) All the cattle were... affected may be moved interstate without further restriction. Female cattle which are not test eligible and are from herds not known to be affected may be moved interstate only in accordance with § 78.10 of...

  2. Occurrence and strain diversity of thermophilic campylobacters in cattle of different age groups in dairy herds

    Nielsen, Eva M.

    2002-01-01

    . Serotype 2 was especially prevalent among calves (68% of the positive calves). In eight of the 20 positive herds, all isolates had the same sero- and PFGE type while, in the other herds, two to five different types were isolated. Conclusions: Significant differences were found between age groups...

  3. Bovine tuberculosis and its risk factors among dairy cattle herds in ...

    Simple random sampling technique was applied to select dairy herds from the available sample frame. A total of. 1279 cattle were ... Statistical significance was assumed if the confidence interval (CI) did not include one among .... Table 3: Bivariate and multivariate logistic regression analysis for potential herd risk factors at ...

  4. Characteristics of the USA dairy herd as related to management and demographic elements

    The data characteristics of the United States dairy herd related to animals enrolled in milk recording (dairy herd improvement) are the basic foundation and important influencers for the management and genetic progress achieved in a population or animal production unit. The amount, characteristics ...

  5. Use of herd management programmes to improve the reproductive performance of dairy cattle.

    McDougall, S; Heuer, C; Morton, J; Brownlie, T

    2014-05-01

    There has been a long history of herd health and production management programmes in many dairy industries around the world, but evidence for the efficacy of such programmes is limited. In response to a perceived decline in fertility of dairy cows, a herd reproductive management programme (InCalf) was introduced in New Zealand in 2007. This programme uses a management cycle approach that includes an assessment of the current herd status, identification of areas for improvement, development of a plan, implementation of this plan and finally a review process. The programme uses facilitators who work with farmers either in a one-to-one manner or in a formalised group setting that involves a series of meetings over a 12-month period (the farmer action group). The hypothesis that involvement in a reproductive management programme would improve herd reproductive performance was tested using a herd-level controlled randomised study (the National Herd Fertility Study) involving herds in four geographic regions of New Zealand over 2 years. Within each region, herds were ranked on the basis of the 6-week in-calf rate (i.e. the proportion of the herd pregnant in the first 6 weeks of the seasonal breeding programme) in the year preceding commencement of the study and then randomly assigned to be involved in a farmer action group or left as untreated controls. The key outcome variable of the study was the 6-week in-calf rate. Pregnancy diagnosis was undertaken at 12 weeks after the start of the seasonal breeding programme, which allowed determination of conception dates and hence calculation of the 6-week in-calf rate. Additional measurements including heifer live weight and body condition score (pre-calving and pre-mating) were undertaken to test whether treatment resulted in measurable changes in some of the key determinants of herd reproductive performance. Involvement in the farmer action group of InCalf resulted in a 2 percentage point increase in the 6-week in-calf rate

  6. Effect of cation size and charge on the interaction between silica surfaces in 1:1, 2:1, and 3:1 aqueous electrolytes.

    Dishon, Matan; Zohar, Ohad; Sivan, Uri

    2011-11-01

    Application of two complementary AFM measurements, force vs separation and adhesion force, reveals the combined effects of cation size and charge (valency) on the interaction between silica surfaces in three 1:1, three 2:1, and three 3:1 metal chloride aqueous solutions of different concentrations. The interaction between the silica surfaces in 1:1 and 2:1 salt solutions is fully accounted for by ion-independent van der Waals (vdW) attraction and electric double-layer repulsion modified by cation specific adsorption to the silica surfaces. The deduced ranking of mono- and divalent cation adsorption capacity (adsorbability) to silica, Mg(2+) cation bare size as well as cation solvation energy but does not correlate with hydrated ionic radius or with volume or surface ionic charge density. In the presence of 3:1 salts, the coarse phenomenology of the force between the silica surfaces as a function of salt concentration resembles that in 1:1 and 2:1 electrolytes. Nevertheless, two fundamental differences should be noticed. First, the attraction between the silica surfaces is too large to be attributed solely to vdW force, hence implying an additional attraction mechanism or gross modification of the conventional vdW attraction. Second, neutralization of the silica surfaces occurs at trivalent cation concentrations that are 3 orders of magnitude smaller than those characterizing surface neutralization by mono- and divalent cations. Consequently, when trivalent cations are added to our cation adsorbability series the correlation with bare ion size breaks down abruptly. The strong adsorbability of trivalent cations to silica contrasts straightforward expectations based on ranking of the cationic solvation energies, thus suggesting a different adsorption mechanism which is inoperative or weak for mono- and divalent cations.

  7. Investor herds and oil prices evidence in the Gulf Cooperation Council (GCC equity markets

    Talat Ulussever

    2017-09-01

    Full Text Available This paper scrutinizes the effect of crude oil prices on herd behavior among investors in the Gulf Cooperation Council (GCC stock markets. Using firm level data from Saudi Arabia, Qatar, Oman, Kuwait, Bahrain, Dubai and Abu Dhabi stock exchanges, we examine equity return dispersions within industry portfolios and test whether investor herds exist in these markets. We then assess whether crude oil price movements have any effect on the investment behavior of traders in the aforementioned markets. Our findings reveal significant evidence supporting herd behavior in all GCC equity markets with the exception of Oman and Qatar, more consistently during periods of market losses. Furthermore, we find significant oil price effects on herd behavior in these markets, particularly during periods of extreme positive changes in the price of oil. Our findings suggest that investors’ tendency to act as a herd in the said markets is significantly affected by the developments in the oil market.

  8. A descriptive epidemiological study of mastitis in 12 Irish dairy herds

    Barrett Damien J

    2005-01-01

    Full Text Available Factors relating to the occurrence of mastitis were studied on 12 Irish dairy herds with histories of elevated somatic cell count (SCC and/or increased incidence of clinical mastitis cases. Milk recording data were analysed, housing conditions and calving areas were examined; dry cow therapy, clinical mastitis records, milking technique and aspects of milking machine function were assessed. Herds with a ratio of less than 110 cubicles per 100 cows were more likely to experience environmental mastitis. Herds with inadequate calving facilities, where cows spent prolonged periods on straw bedding, were likely to acquire environmental mastitis. In the majority of the herds, the selection of dry cow therapy lacked adequate planning. The majority of farmers took no action to reduce pain experienced by cows suffering mastitis. Deficiencies in parlour hygiene were evident in all herds experiencing elevation in SCC.

  9. Effect of herd cues and product involvement on bidder online choices.

    Chen, Yi-Fen; Wang, Ya-Ju

    2010-08-01

    Previous works have shown that consumers are influenced by others in decision making. Herd behavior is common in situations in which consumers infer product quality from other consumer choices and incorporate that information into their own decision making. This research presents two studies examining herd effect and the moderating role of product involvement on bidder choices in online auctions. The two studies addressed the influence on bidder online choices of herd cues frequently found in online auctions, including feedback ratings and number of questions and answers. The experimental results demonstrated that bidders use online herd cues when making decisions in online auctions. Additionally, the effects of herd cues on bidder online choices were stronger in high-involvement than low-involvement participants. Results and implications are discussed.

  10. Associations of Neospora caninum seropositivity with gestation number and pregnancy outcome in Danish dairy herds

    Jensen, Anette Møllegaard; Bjorkman, C.; Kjeldsen, A.M.

    1999-01-01

    The prevalence and distribution of seropositivity towards the protozoan parasite Neospora caninum were studied in single blood samples from 1561 cows from 31 Danish dairy herds. Blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test, Seropre......The prevalence and distribution of seropositivity towards the protozoan parasite Neospora caninum were studied in single blood samples from 1561 cows from 31 Danish dairy herds. Blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test......, Seroprevalence in 15 herds with previous abortions assigned to neosporosis ranged from I% to 58%, with a mean frequency of 22%. In eight out of 16 herds without a history of N. caninum related abortions, no seroreactors were found. In the remaining eight herds, the seroprevalence ranged from 6% to 59...

  11. Problems in maintenance of herd health associated with acid forming emissions

    Kostuch, M.

    1992-01-01

    The effects of sour gas plant emissions on dairy herds are described. A veterinarian establishing a practice in Rocky Mountain House, Alberta, found that dairy herds in that area suffered from a disproportionately higher occurrence of health problems than Minnesota herds with similar types of management. These problems are postulated to result from acid-forming emissions from two large sour gas plants in the area (the Ram River and Gulf Strachan plants). Health problems found in dairy cattle in the Rocky Mountain House area were: unthriftiness, increased susceptibility to infectious diseases, reproductive problems, and 'downer' animals (cows unable to stand up unassisted). Problems related to the reproductive organs were the most apparent. Clinical observations of problems in dairy herds are described. Since the levels of emissions from the plants have decreased, incidence of problems in dairy herds has also decreased. 1 ref., 2 figs

  12. Management, operational, animal health, and economic characteristics of large dairy herds in 4 states in the Upper Midwest of the United States.

    Evink, T L; Endres, M I

    2017-11-01

    Recent trends in dairy farm structure in the United States have included a decreasing number of farms, although farm size has increased, especially the share of milk production from very large herds (>2,500 cows). The objectives of this observational study were to describe common management practices; to characterize labor and operational structure; to measure some aspects of animal health, including lameness, hock lesions, mortality, and mastitis incidence; and to summarize cost of production on farms with more than 2,500 cows in 4 states in the Upper Midwest of the United States. The study included 15 dairy farms in Minnesota, Wisconsin, Iowa, and South Dakota. Farms were visited twice, once each year, and on-farm herd records were collected for those 2 yr. On-farm herd records were used to investigate mortality, culling, pregnancy rate, and clinical mastitis incidence. At least 1 high-producing pen of mature cows and 1 pen of fresh cows were scored for locomotion. Likewise, at least 1 pen of high-producing mature cows was scored for cleanliness and hock lesions. Median herd size was 3,975 cows (range = 2,606-13,266). Milk sold per employee was 1,120,745 kg and the number of cows per employee was 105. Eighty percent of the farms had Holstein cows, 13% had Jersey, and 7% had Jersey-Holstein crosses. All farms used artificial insemination as the sole form of breeding and 100% of the farms used hormonal synchronization or timed artificial insemination programs in their reproductive protocols; 21-d pregnancy rate was 21.7%. Median lameness prevalence was 18.3% and median severe lameness prevalence was 5.1%. Median hock lesion prevalence was 17.4% and median severe hock lesion prevalence was 1.9%; mortality rate was 7.4%. Clinical mastitis incidence was 62.5 cases per 100 cow-years. Feed costs accounted for approximately 53% of the total cost of producing milk, followed by labor at 11%, interest and depreciation expenses at 10%, and replacement costs at 9.5%. Herds in

  13. Could information about herd immunity help us achieve herd immunity? Evidence from a population representative survey experiment.

    Arnesen, Sveinung; Bærøe, Kristine; Cappelen, Cornelius; Carlsen, Benedicte

    2018-05-01

    Immunisation causes dramatic reductions in morbidity and mortality from infectious diseases; however, resistance to vaccination is nonetheless widespread. An understudied issue - explored here - is whether appeals to collective as opposed to individual benefits of vaccination encourage people to vaccinate. Knowledge of this is important not least with respect to the design of public health campaigns, which often lack information about the collective benefits of vaccination. Using a between-subjects experimental survey design, we test whether information about the effects of herd immunity influences people's decision to vaccinate. A representative sample of Norwegians was confronted with a hypothetical scenario in which a new and infectious disease is on its way to Norway. The sample was split in three - a control group and two treatment groups. The one treatment group was provided information about collective benefits of vaccination; the other was provided information about the individual benefits of vaccination. Both treatments positively affect people's decision to vaccinate; however, informing about the collective benefits has an even stronger effect than informing about the individual benefits. Our results suggest that people's decision about whether to vaccinate and thus contribute to herd immunity is influenced by concern for others. Thus, stressing the collective benefits of vaccination could increase the effectiveness of health campaigns.

  14. Herd characteristics and management practices associated with bulk tank milk quality of dairy herds in southeastern Brazil.

    Cortinhas, Cristina Simões; Botaro, Bruno Garcia; de Macedo, Susana Nori; Dos Santos, Marcos Veiga

    2018-04-30

    This study identified the association of management practices and herd characteristics with milk quality of bulk tanks in southeastern, Brazil. Milk samples were collected weekly during 8 weeks from 63 dairy herds. Bulk tanks were evaluated for total bacteria (TBC), preliminary incubation (PIC), pasteurization (PC), coliform (CC), and somatic cell counts (SCC). Associations found were type of milking system utilized in the farm with TBC, PIC, and SCC; the use of gloves for milking with TBC and PIC; sanitation of milking equipment prior to milking with PC and CC; strip cup testing of cows with PC; teat washing prior to milking with SCC; pre-milking teat disinfection with TBC and CC; post-dipping with TBC and SCC; and the alkaline-acid washing procedure of milking equipment with PIC and PC. The regression analysis explained the variation of bulk tank PC (- 0.47 log cfu/mL) due to the adoption of strip cup test (P = 0.036) and, by 0.366 log cfu/mL due to alkaline and acid washing of milking equipment (P = 0.036). Herringbone milking systems adopted on farms represented a change of - 0.11 log cfu/mL on the log SCC (P = 0.048). Findings may provide a guideline to prioritize efforts aimed at improving milk quality at the farm level in Brazil.

  15. Consequence of changes in herd size and densities for the contingency planning

    Christiansen, Lasse Engbo; Hisham Beshara Halasa, Tariq; Boklund, Anette

    2012-01-01

    The objective of the current work was to evaluate whether the effects and control of foot-and-mouth disease (FMD) spread would differ following the structural changes to the Danish agricultural sector from now until 2030. Following the predicted structural changes, a new farm file was created, re...

  16. INTERACT

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions ...

  17. Latent class analysis of bulk tank milk PCR and ELISA testing for herd level diagnosis of Mycoplasma bovis

    Nielsen, Per Kantsø; Petersen, Mette Bisgaard; Nielsen, Liza Rosenbaum

    2015-01-01

    of this study was to evaluate the herd-level diagnostic performance of an indirect ELISA test by comparison to a real-time PCR test when diagnosing M. bovis in cattle herds of bulk tank milk. Bulk tank milk samples from Danish dairy herds (N=3437) were analysed with both the antibody detecting BIO K 302 M...

  18. Inclusion of the value of herd immunity in economic evaluations of vaccines. A systematic review of methods used

    Nymark, Liv Solvår; Sharma, T; Miller, A

    2017-01-01

    human-transmissible diseases from 1976 to 2015. Of these, 172 (28%) included herd immunity. While 4% of studies included herd immunity in 2001, 53% of those published in 2015 did this. Pneumococcal, human papilloma and rotavirus vaccines represented the majority of studies (63%) considering herd...

  19. Chronic lead poisoning in a herd of mute swans

    Simpson, V.R.; Hunt, A.E.; French, M.C.

    1979-01-01

    Lead poisoning due to the ingestion of lead fishing shot was shown to be the cause of death of a number of mute swans Cygnus olor Gmelin. The area in which they were feeding was shown to be heavily contaminated with fishing shot. The results of clinical, histopathological, haematological and analytical examinations are reported. The kidneys of the dead birds contained from 350 to 6650 ..mu..g/g DM of lead and blood lead levels in the remainder of the herd were greatly elevated, rising to 3290 ..mu..g/100 ml. Consistently elevated liver levels of iron and zinc and a marked loss of body weight were all directly proportional to the increase in kidney lead concentration. 17 references, 10 figures, 4 tables.

  20. Prophylactic and metaphylactic antimicrobial use in Belgian fattening pig herds.

    Callens, Bénédicte; Persoons, Davy; Maes, Dominiek; Laanen, Maria; Postma, Merel; Boyen, Filip; Haesebrouck, Freddy; Butaye, Patrick; Catry, Boudewijn; Dewulf, Jeroen

    2012-09-01

    The monitoring of antimicrobial use is an essential step to control the selection and spread of antimicrobial resistance. Between January and October 2010 data on prophylactic and metaphylactic antimicrobial use were collected retrospectively on 50 closed or semi-closed pig herds. Ninety-three percent of the group treatments were prophylactic whereas only 7% were methaphylactic. The most frequently used antimicrobials orally applied at group level were colistin (30.7%), amoxicillin (30.0%), trimethoprim-sulfonamides (13.1%), doxycycline (9.9%) and tylosin (8.1%). The most frequently applied injectable antimicrobials were tulathromycin (45.0%), long acting ceftiofur (40.1%) and long acting amoxicillin (8.4%). The treatment incidences (TI) based on the used daily dose pig (UDD(pig) or the actually administered dose per day per kg pig of a drug) for all oral and injectable antimicrobial drugs was on average 200.7 per 1000 pigs at risk per day (min=0, max=699.0), while the TI based on the animal daily dose pig (ADD(pig) or the national defined average maintenance dose per day per kg pig of a drug used for its main indication) was slightly higher (average=235.8, min=0, max=1322.1). This indicates that in reality fewer pigs were treated with the same amount of antimicrobials than theoretically possible. Injectable products were generally overdosed (79.5%), whereas oral treatments were often underdosed (47.3%). In conclusion, this study shows that prophylactic group treatment was applied in 98% of the visited herds and often includes the use of critically important and broad-spectrum antimicrobials. In Belgium, the guidelines for prudent use of antimicrobials are not yet implemented. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Trends in udder health and emerging mastitogenic pathogens in South African dairy herds

    I.M. Petzer

    2009-05-01

    Full Text Available The aim of this study was to retrospectively analyse the results of milk samples obtained from South African dairy herds during the period 1996 to April 2007 in order to identify possible trends in isolates of microorganisms and their pathogenicity under field conditions. Milk samples were obtained from 7 of the 9 provinces in South Africa where there are low numbers of dairy cows. Although there is scientific limitation to a country wide survey, such as the variation in herd size, management skills, parity, milk yield, milking frequency and other parameters, the size of this database helps to give a fair indication of general udder health in South Africa. Cytology and routine bacteriology were performed on 379 000 milk samples of lactating cows and bacteriology on 11 946 samples from non-lactating cows. According to the results obtained, mastitis did not decrease in South Africa over the test period. The prevalence of mastitis and teat canal infection was lowest in 2002. Mastitis and teat canal infection increased from 2002 to 2006 from 8.1 % and 24.1 % to 15.4 and 30.0 % respectively. The percentage of mastitogenic pathogens isolated from cows over these years also varied. Previously unknown or almost eradicated mastitogenic pathogens such as αβ haemolytic Staphylococcus aureus which is thought to be of human origin, Streptococcus agalactiae and Enterococcus canis were responsible for numerous mastitis outbreaks seen in the test samples. Coagulase-negative staphylococci were the most frequently isolated bacteria in milk samples from both lactating and dry cows, followed by Staphylococcus aureus and Streptococcus agalactiae. Although Staphylococcus aureus remained the principal mastitogenic pathogen in South Africa, owing to its chronic nature and resultant economic losses, most cases of mastitis were caused by coagulase-negative staphylococci. This finding increases the importance of coagulase-negative staphylococci (formerly described as a

  2. Accuracy of Estimation of Graft Size for Living-Related Liver Transplantation: First Results of a Semi-Automated Interactive Software for CT-Volumetry

    Mokry, Theresa; Bellemann, Nadine; Müller, Dirk; Lorenzo Bermejo, Justo; Klauß, Miriam; Stampfl, Ulrike; Radeleff, Boris; Schemmer, Peter; Kauczor, Hans-Ulrich; Sommer, Christof-Matthias

    2014-01-01

    Objectives To evaluate accuracy of estimated graft size for living-related liver transplantation using a semi-automated interactive software for CT-volumetry. Materials and Methods Sixteen donors for living-related liver transplantation (11 male; mean age: 38.2±9.6 years) underwent contrast-enhanced CT prior to graft removal. CT-volumetry was performed using a semi-automated interactive software (P), and compared with a manual commercial software (TR). For P, liver volumes were provided either with or without vessels. For TR, liver volumes were provided always with vessels. Intraoperative weight served as reference standard. Major study goals included analyses of volumes using absolute numbers, linear regression analyses and inter-observer agreements. Minor study goals included the description of the software workflow: degree of manual correction, speed for completion, and overall intuitiveness using five-point Likert scales: 1–markedly lower/faster/higher for P compared with TR, 2–slightly lower/faster/higher for P compared with TR, 3–identical for P and TR, 4–slightly lower/faster/higher for TR compared with P, and 5–markedly lower/faster/higher for TR compared with P. Results Liver segments II/III, II–IV and V–VIII served in 6, 3, and 7 donors as transplanted liver segments. Volumes were 642.9±368.8 ml for TR with vessels, 623.8±349.1 ml for P with vessels, and 605.2±345.8 ml for P without vessels (Pvolumetry performed with P can predict accurately graft size for living-related liver transplantation while improving workflow compared with TR. PMID:25330198

  3. Applying an international CAPM to herding behaviour model for integrated stock markets

    Najmudin Najmudin

    2017-12-01

    Full Text Available Development of financial globalization in the form of stock market integration experiences a trend which is getting stronger. The analysis models in the field of finance and investments should be able to adjust to these developments. This adjustment includes the models used to detect the existence of herding behavior. All this time, the herding behavior model of individual stocks towards market consensus has been referring to CAPM theory. The basic assumption of CAPM is that financial assets at a domestic stock market are segmented from the financial assets’ movement at the global market. Therefore, this paper aims to provide an alternative view in the form of an international herding model that should be applied in the context of an integrated stock market. The model was created with reference to the international CAPM. This paper combined ICAPM method and international CSAD model to identify herding for eight stock markets, the sample period being from January 2003 to December 2016. The result found that for segmented stock markets, represented by China and the Philippines, herding happened for both overall the sample period and the market crisis period. In addition, for the integrated stock markets, represented by Indonesia, Japan, Malaysia, Singapore, Thailand, and the UK, herding behavior was only found during the market crisis period. Therefore, classification of market integrations should be considered in assessing the herding behaviour at stock markets.

  4. Managerial and environmental determinants of clinical mastitis in Danish dairy herds

    Houe Hans

    2008-02-01

    Full Text Available Abstract Background Several management and environmental factors are known as contributory causes of clinical mastitis in dairy herd. The study objectives were to describe the structure of herd-specific mastitis management and environmental factors and to assess the relevance of these herd-specific indicators to mastitis incidence rate. Methods Disease reports from the Danish Cattle Data Base and a management questionnaire from 2,146 herds in three Danish regions were analyzed to identify and characterize risk factors of clinical mastitis. A total of 94 (18 continuous and 76 discrete management and production variables were screened in separate bivariate regression models. Variables associated with mastitis incidence rate at a p-value Results Three latent factors (quality of labor, region of Denmark and claw trimming, and quality of outdoor holding area were identified from 14 variables. Daily milk production per cow, claw disease, quality of labor and region of Denmark were found to be significantly associated with mastitis incidence rate. A common multiple regression analysis with backward and forward selection procedures indicated there were 9 herd-specific risk factors. Conclusion Though risk factors ascertained by farmer-completed surveys explained a small percentage of the among-herd variability in crude herd-specific mastitis rates, the study suggested that farmer attitudes toward mastitis and lameness treatment were important determinants for mastitis incidence rate. Our factor analysis identified one significant latent factor, which was related to labor quality on the farm.

  5. Understanding herding based on a co-evolutionary model for strategy and game structure

    Wang, Tao; Huang, Keke; Cheng, Yuan; Zheng, Xiaoping

    2015-01-01

    Highlights: •We model herding effect in emergency from perspective of evolutionary game theory. •Rational subpopulation survives only when the game parameter is significantly large. •Herding effect may arise if the relative rewarding for rational agents is small. •Increasing the relative rewarding for rational agents will prevent herding effect. •The evolution result is unstable if the game parameter approaches critical points. -- Abstract: So far, there has been no conclusion on the mechanism for herding, which is often discussed in the academia. Assuming escaping behavior of individuals in emergency is rational rather than out of panic according to recent findings in social psychology, we investigate the behavioral evolution of large crowds from the perspective of evolutionary game theory. Specifically, evolution of the whole population divided into two subpopulations, namely the co-evolution of strategy and game structure, is numerically simulated based on the game theoretical models built and the evolutionary rule designed, and a series of phenomena including extinction of one subpopulation and herding effect are predicted in the proposed framework. Furthermore, if the rewarding for rational agents becomes significantly larger than that for emotional ones, herding effect will disappear. It is exciting that some phase transition points with interesting properties for the system can be found. In addition, our model framework is able to explain the fact that it is difficult for mavericks to prevail in society. The current results of this work will be helpful in understanding and restraining herding effect in real life

  6. Selenium status in cattle herds in Wallonia (Belgium: overview and health management

    Youcef Mehdi

    2014-12-01

    Full Text Available Aim: Monitoring was performed in order to determine the Selenium (Se status of cattle herds in different agricultural areas in Wallonia (Belgium. Materials and Methods: The study included 114 heifers and 184 cows (82 dairy and 102 beef cows from 66 cattle farms situated in Wallonia. The Se status was assessed by measuring the glutathion peroxydase in red cells and converting it to the equivalent Se blood content. Results: The average blood concentrations of Se were very low. The Ardennes region was an area where the lowest Se status was recorded. The highest levels of Se in dairy cows and beef cows were recorded respectively in the limoneuse region and Famenne areas. The Se content in beef herds was lower compared with that of dairy herds (35 vs. 56 μg/L, p<0.01. Conclusion: On average over all the regions, 87% of animals were classified as deficient and only 13% of the animals were classified as adequate. The heifers from both dairy and beef herds in Wallonia exhibited a deficiency in Se classified as moderate to severe. The beef herds showed larger deficiencies compared with the dairy herds. Selenium deficiency can be prevented by ensuring adequate supplementation of deficient animals in Se deficient regions. An increased consumption of vitamin-mineral supplements, the use of Se-enriched fertilizers and ingredients containing high levels of Se can help to reduce or correct deficiencies recorded in cattle herds in Wallonia.

  7. Work-Related Musculoskeletal Symptoms and Job Factors Among Large-Herd Dairy Milkers.

    Douphrate, David I; Nonnenmann, Matthew W; Hagevoort, Robert; Gimeno Ruiz de Porras, David

    2016-01-01

    Dairy production in the United States is moving towards large-herd milking operations, resulting in an increase in task specialization and work demands. The objective of this project was to provide preliminary evidence of the association of a number of specific job conditions that commonly characterize large-herd parlor milking operations with work-related musculoskeletal symptoms (MSS). A modified version of the Standardized Nordic Questionnaire was administered to assess MSS prevalence among 450 US large-herd parlor workers. Worker demographics and MSS prevalences were generated. Prevalence ratios were also generated to determine associations of a number of specific job conditions that commonly characterize large-herd parlor milking operations with work-related MSS. Work-related MSS are prevalent among large-herd parlor workers, since nearly 80% report 12-month prevalences of one or more symptoms, which are primarily located in the upper extremities, specifically shoulders and wrist/hand. Specific large-herd milking parlor job conditions are associated with MSS in multiple body regions, including performing the same task repeatedly, insufficient rest breaks, working when injured, static postures, adverse environmental conditions, and reaching overhead. These findings support the need for administrative and engineering solutions aimed at reducing exposure to job risk factors for work-related MSS among large-herd parlor workers.

  8. Size-dependent plastic deformation characteristics in He-irradiated nanostructured Cu/Mo multilayers: Competition between dislocation-boundary and dislocation-bubble interactions

    Zhang, J.Y.; Zeng, F.L.; Wu, K.; Wang, Y.Q.; Liang, X.Q.; Liu, G.; Zhang, G.J.; Sun, J.

    2016-01-01

    Nanoindentation methodology was used to investigate the plastic deformation characteristics, including the hardness (H), strain rate sensitivity (SRS, m) and activation volume (V * ), of Cu/Mo nanostructured metallic multilayers (NMMs) with equal layer thickness (h) spanning from 10 to 200 nm before and after He-implantation at room temperature. Compared with the as-deposited Cu/Mo NMMs, the irradiated Cu/Mo samples exhibited the enhanced hardness particularly at great h, which is caused by the bubble-hardening effect. Unlike the as-deposited Cu/Mo NMMs displayed a monotonic increase in SRS (or a monotonic decrease in activation volume) with reducing h, the irradiated Cu/Mo samples manifested an unexpected non-monotonic variation in SRS as well as in activation volume. It was clearly unveiled that the SRS of irradiated Cu/Mo firstly decreased with reducing h down to a critical size of ~50 nm and subsequently increased with further reducing h, leaving a minimum value at the critical h. These phenomena are rationalized by considering a competition between dislocation-boundary and dislocation-bubble interactions. A thermally activated model based on the depinning process of bowed-out partial dislocations was employed to quantitatively account for the size-dependent SRS of Cu/Mo NMMs before and after irradiation. Our findings not only provide fundamental understanding of the effects of radiation-induced defects on plastic characteristics of NMMs, but also offer guidance for their microstructure sensitive design for performance optimization at extremes.

  9. Size-dependent physicochemical and mechanical interactions in battery paste anodes of Si-microwires revealed by Fast-Fourier-Transform Impedance Spectroscopy

    Hansen, Sandra; Quiroga-González, Enrique; Carstensen, Jürgen; Adelung, Rainer; Föll, Helmut

    2017-05-01

    Perfectly aligned silicon microwire arrays show exceptionally high cycling stability with record setting (high) areal capacities of 4.25 mAh cm-2. Those wires have a special, modified length and thickness in order to perform this good. Geometry and sizes are the most important parameters of an anode to obtain batteries with high cycling stability without irreversible losses. The wires are prepared with a unique etching fabrication method, which allows to fabricate wires of very precise sizes. In order to investigate how good randomly oriented silicon wires perform in contrast to the perfect order of the array, the wires are embedded in a paste. This study reveals the fundamental correlation between geometry, mechanics and charge transfer kinetics of silicon electrodes. Using a suitable RC equivalent circuit allows to evaluate data from cyclic voltammetry and simultaneous FFT-Impedance Spectroscopy (FFT-IS), yielding in time-resolved resistances, time constants, and their direct correlation to the phase transformations. The change of the resistances during lithiation and delithiation correlates to kinetics and charge transfer mechanisms. This study demonstrates how the mechanical and physiochemical interactions at the silicon/paste interface inside the paste electrodes lead to void formation around silicon and with it to material loss and capacity fading.

  10. Studies on herd-immunity and primary versus secondary infection of VHSV in challenge and vaccination trials with rainbow trout

    Lorenzen, Ellen; Kjær, Torben Egil; Lorenzen, Niels

    as well as selective breeding, i.e. the more non-susceptible individuals in a population, the lower the risk of disease among susceptible individuals. Thus as part of a recent field trial with a VHS-DNA-vaccine vaccinated as well as naïve fish from a Danish fish farm were brought to the laboratory......Abstract for Scofda meeting 4-5.11.09 Studies on herd-immunity effect and primary versus secondary infection of VHSV by Ellen Lorenzen, Torben Eigil Kjær & Niels Lorenzen, National Veterinary Laboratory, Århus The phenomenon of “herd-immunity” is one of the basal principles behind vaccination...... at a size of 24g to be subjected to an experimental challenge with VHSV. The setup included 7 aquaria with 100 fish in each: 2 aquaria with 100 vaccinated fish (+VHS-challenge), 2 aquaria with 100 naïve fish (+ VHS-challenge), 2 aquaria with 50 vaccinated + 50 naïve fish (+VHS-challenge), and 1 aquarium...

  11. Modeling the decline of the Porcupine Caribou Herd, 1989-1998: the importance of survival vs. recruitment

    Stephen M. Arthur

    2003-04-01

    Full Text Available The Porcupine caribou (Rangifer tarandus granti herd increased from approximately 100 000 animals during the 1970s to 178 000 in 1989, then declined to 129 000 by 1998. Our objective was to model the dynamics of this herd and investigate the potential that lower calf recruitment, as was observed during 1991-1993, produced the observed population changes. A deterministic model was prepared using estimates of birth and survival rates that reproduced the pattern of population growth from 1971-1989. Then, parameters were changed to simulate effects of lower calf recruitment and adult survival. Reducing recruitment for 3 years caused an immediate reduction in population size, but the population began to recover in 5-6 years. Even a dramatic temporary reduction in recruitment did not explain the continuing decline after 1995. In contrast, a slight but persistent reduction in adult survival caused a decline that closely followed the observed pattern. This suggests that survival of adults, and perhaps calves, has declined since the late 1980s.

  12. Individual and interacting effects of pCO2 and temperature on Emiliania huxleyi calcification: study of the calcite production, the coccolith morphology and the coccosphere size

    K. Sabbe

    2010-05-01

    Full Text Available The impact of ocean acidification and increased water temperature on marine ecosystems, in particular those involving calcifying organisms, has been gradually recognised. We examined the individual and combined effects of increased pCO2 (180 ppmV CO2, 380 ppmV CO2 and 750 ppmV CO2 corresponding to past, present and future CO2 conditions, respectively and temperature (13 °C and 18 °C during the exponential growth phase of the coccolithophore E. huxleyi using batch culture experiments. We showed that cellular production rate of Particulate Organic Carbon (POC increased from the present to the future CO2 treatments at 13 °C. A significant effect of pCO2 and of temperature on calcification was found, manifesting itself in a lower cellular production rate of Particulate Inorganic Carbon (PIC as well as a lower PIC:POC ratio at future CO2 levels and at 18 °C. Coccosphere-sized particles showed a size reduction with both increasing temperature and CO2 concentration. The influence of the different treatments on coccolith morphology was studied by categorizing SEM coccolith micrographs. The number of well-formed coccoliths decreased with increasing pCO2 while temperature did not have a significant impact on coccolith morphology. No interacting effects of pCO2 and temperature were observed on calcite production, coccolith morphology or on coccosphere size. Finally, our results suggest that ocean acidification might have a larger adverse impact on coccolithophorid calcification than surface water warming.

  13. Herd- and cow-level risk factors associated with subclinical mastitis in dairy farms from the High Plains of the northern Antioquia, Colombia.

    Ramírez, N F; Keefe, G; Dohoo, I; Sánchez, J; Arroyave, O; Cerón, J; Jaramillo, M; Palacio, L G

    2014-07-01

    Mastitis is the main disease entity affecting dairy farms in the Colombian High Plains of northern Antioquia, Colombia. However, no previous epidemiologic studies have determined the characteristics that increase the risk of infection in this region, where manual milking is still the prevailing system of milking. A 24-mo longitudinal study was designed to identify the predominant mastitis pathogens and important herd- and cow-level risk factors. Monthly visits were made to 37 commercial dairy farms to collect herd- and cow-level data and milk samples. Herd size varied from 6 to 136 cows (mean 37.0, median 29). Herd-level factors included type of milking system (manual or mechanical) and a range of management practices recommended by the National Mastitis Council (Madison, WI) to prevent mastitis. Individual cow-level risk factors included parity, stage of lactation, breed, udder hygiene, and lameness. A logistic regression analysis was used to investigate associations between herd- and cow-level risk factors with the presence of subclinical mastitis and infection caused by Streptococcus agalactiae at the quarter level. A quarter was considered to have subclinical mastitis if it had a positive California Mastitis Test and was subsequently confirmed to have a somatic cell count of ≥200,000 cells/mL. Any cow with one or more quarters with subclinical mastitis was considered to have subclinical mastitis at the cow level. Using 17,622 cow observations, the mean prevalence of subclinical mastitis at the cow level was 37.2% (95% confidence interval: 31.2, 43.3) for the first month and did not substantially change throughout the study. The predominant microorganisms isolated from quarters meeting the subclinical mastitis definition were contagious pathogens, including Strep. agalactiae (34.4%), Corynebacterium spp. (13.2%), and Staphylococcus aureus (8.0%). Significant variables associated with subclinical mastitis risk at the quarter level included being a purebred

  14. Risk factors associated with Neospora caninum abortion in Ontario Holstein dairy herds.

    Hobson, J C; Duffield, T F; Kelton, D; Lissemore, K; Hietala, S K; Leslie, K E; McEwen, B; Peregrine, A S

    2005-02-28

    The objective of this epidemiological study was to identify risk factors for Neospora caninum-related abortions in Ontario Holstein dairy herds. A total of 88 herds, consisting of 5080 cattle, and utilizing Dairy Herd Improvement (DHI) services, were divided into three groups. Case (n = 30) and first control (n = 31) herds were selected from 1998 and 1999 fetal abortion submissions to the Animal Health Laboratory, University of Guelph, that were histopathologically positive or negative, respectively, for N. caninum. A second control group (n = 27) was selected from multiple sources of herds sampled within the previous 4 years that had a low seroprevalence (recorded information on housing, animal species present, manure management, reproduction, biosecurity practices, wildlife observations, peri-parturient cow management, herd disease history and nutrition. Production and other herd parameters were obtained from DHI records. Logistic regression indicated that the following parameters were positively associated with a N. caninum abortion in a herd: the N. caninum herd seroprevalence (OR = 1.1), the total number of dogs on a farm (OR = 2.8), the frequency that dogs were observed defecating in mangers (OR = 2.8), the number of horses on a farm (OR = 3.1), the observed annual rate of retained fetal membranes (OR = 1.2) and the observed annual rate of cows returning to estrus after pregnancy confirmation (OR = 1.2). Factors negatively associated were the frequency of stray cats and wild canids observed on a farm (OR = 0.4 and OR = 0.7, respectively) and the housing of heifers on loafing packs (a housing pen divided into feed manger, scrape alley and bedded pack areas, OR = 0.1).

  15. Epidemiological Investigations of Four Cowpox Virus Outbreaks in Alpaca Herds, Germany

    Almut Prkno

    2017-11-01

    Full Text Available Four cowpox virus (CPXV outbreaks occurred in unrelated alpaca herds in Eastern Germany during 2012–2017. All incidents were initially noticed due to severe, generalized, and finally lethal CPXV infections, which were confirmed by testing of tissue and serum samples. As CPXV-infection has been described in South American camelids (SACs only three times, all four herds were investigated to gain a deeper understanding of CPXV epidemiology in alpacas. The different herds were investigated twice, and various samples (serum, swab samples, and crusts of suspicious pox lesions, feces were taken to identify additionally infected animals. Serum was used to detect CPXV-specific antibodies by performing an indirect immunofluorescence assay (iIFA; swab samples, crusts, and feces were used for detection of CPXV-specific DNA in a real-time PCR. In total, 28 out of 107 animals could be identified as affected by CPXV, by iIFA and/or PCR. Herd seroprevalence ranged from 16.1% to 81.2%. To investigate the potential source of infection, wild small mammals were trapped around all alpaca herds. In two herds, CPXV-specific antibodies were found in the local rodent population. In the third herd, CPXV could be isolated from a common vole (Microtus arvalis found drowned in a water bucket used to water the alpacas. Full genome sequencing and comparison with the genome of a CPXV from an alpaca from the same herd reveal 99.997% identity, providing further evidence that the common vole is a reservoir host and infection source of CPXV. Only in the remaining fourth herd, none of the trapped rodents were found to be CPXV-infected. Rodents, as ubiquitous reservoir hosts, in combination with increasingly popular alpacas, as susceptible species, suggest an enhanced risk of future zoonotic infections.

  16. Epidemiological Investigations of Four Cowpox Virus Outbreaks in Alpaca Herds, Germany.

    Prkno, Almut; Hoffmann, Donata; Goerigk, Daniela; Kaiser, Matthias; van Maanen, Anne Catherine Franscisca; Jeske, Kathrin; Jenckel, Maria; Pfaff, Florian; Vahlenkamp, Thomas W; Beer, Martin; Ulrich, Rainer G; Starke, Alexander; Pfeffer, Martin

    2017-11-18

    Four cowpox virus (CPXV) outbreaks occurred in unrelated alpaca herds in Eastern Germany during 2012-2017. All incidents were initially noticed due to severe, generalized, and finally lethal CPXV infections, which were confirmed by testing of tissue and serum samples. As CPXV-infection has been described in South American camelids (SACs) only three times, all four herds were investigated to gain a deeper understanding of CPXV epidemiology in alpacas. The different herds were investigated twice, and various samples (serum, swab samples, and crusts of suspicious pox lesions, feces) were taken to identify additionally infected animals. Serum was used to detect CPXV-specific antibodies by performing an indirect immunofluorescence assay (iIFA); swab samples, crusts, and feces were used for detection of CPXV-specific DNA in a real-time PCR. In total, 28 out of 107 animals could be identified as affected by CPXV, by iIFA and/or PCR. Herd seroprevalence ranged from 16.1% to 81.2%. To investigate the potential source of infection, wild small mammals were trapped around all alpaca herds. In two herds, CPXV-specific antibodies were found in the local rodent population. In the third herd, CPXV could be isolated from a common vole ( Microtus arvalis ) found drowned in a water bucket used to water the alpacas. Full genome sequencing and comparison with the genome of a CPXV from an alpaca from the same herd reveal 99.997% identity, providing further evidence that the common vole is a reservoir host and infection source of CPXV. Only in the remaining fourth herd, none of the trapped rodents were found to be CPXV-infected. Rodents, as ubiquitous reservoir hosts, in combination with increasingly popular alpacas, as susceptible species, suggest an enhanced risk of future zoonotic infections.

  17. Population ecology of two woodland caribou herds in the southern Yukon

    Richard Farnell

    1996-01-01

    Full Text Available Since the mid 1980's, the Aishihik herd of woodland caribou (Rangifer tarandus caribou declined from approximately 1500 to 583 animals. During the same period a nearby herd, the Wolf Lake Herd increased from approximately 664 to 1249 animals. This paper compares aspects of the ecology of these two herds to determine how these relationships conform to a general model of caribou population ecology described by Seip (1992. Comparisons include caribou demographic characteristics and distribution patterns, predator densities, abundance of alternate prey, human hunting and snow depth on caribou winter range. Ecological differences between herds were apparent in the ratio of prime bulls to cows, the abundance of moose (Alces alces, the occurrence of coyotes (Canis latrans, late winter snow conditions, and access to hunting. We hypothesize that the Wolf Lake herd was able to grow because wolves {Canis lupus preyed mainly on the relatively abundant moose population. A highly clumped winter caribou distribution may have further reduced the impact of wolf predation on the Wolf Lake herd. In contrast, the decline of the Aishihik herd was accompanied by a relative scarcity of moose, few prime aged caribou bulls probably due to a more liberal trophy harvest, and wider late-winter dispersion that offered wolves greater access to caribou. The decline may have been exaggerated by the peak in the snowshoe hare (Lepus americanus cycle which may have temporarily improved wolf pup survival. We suspect that moose are normally the primary prey of wolves in the Yukon and that a decline in moose eventually results in their being too scarce to offer an economical prey choice, prompting a prey switch to caribou. Results of our analyses conform incompletely to Seip's (1992 model for woodland caribou population ecology, particularly because the Wolf Lake herd prospered where moose were relatively abundant.

  18. Assessment of the interaction between straw size and thawing rate and its impact on in vitro quality of post-thaw goat semen

    Francisco Silvestre Brilhante Bezerra

    2012-03-01

    Full Text Available The objective of this study was to analyze interactions between different straw sizes and thawing rates on the post-thaw goat semen parameters. Twenty-one ejaculates (seven per animal were collected from three stud bucks by using an artificial vagina. After evaluation, the semen was extended in Tris-egg yolk-glycerol and packed in 0.25 and 0.50 mL straws, followed by storage in liquid nitrogen. Thawing was performed using two different rates: 37 ºC/1 min and 55 ºC/7 s. The interaction between the 0.5-mL straw and the thawing rate of 55 ºC/7 s promoted higher progressive motility. When the effect of straws alone was analyzed, it was verified that the use of the 0.50 mL straw promoted better conservation than the 0.25 mL one for progressive motility and acrosomal integrity, after the frozen-thawing procedures. Optimal results for progressive motility were achieved when goat semen was frozen in 0.5 mL straws and thawed in water at 55 ºC/7 s.

  19. Object individuation is invariant to attentional diffusion: Changes in the size of the attended region do not interact with object-substitution masking.

    Goodhew, Stephanie C; Edwards, Mark

    2016-12-01

    When the human brain is confronted with complex and dynamic visual scenes, two pivotal processes are at play: visual attention (the process of selecting certain aspects of the scene for privileged processing) and object individuation (determining what information belongs to a continuing object over time versus what represents two or more distinct objects). Here we examined whether these processes are independent or whether they interact. Object-substitution masking (OSM) has been used as a tool to examine such questions, however, there is controversy surrounding whether OSM reflects object individuation versus substitution processes. The object-individuation account is agnostic regarding the role of attention, whereas object-substitution theory stipulates a pivotal role for attention. There have been attempts to investigate the role of attention in OSM, but they have been subject to alternative explanations. Here, therefore, we manipulated the size of the attended region, a pure and uncontaminated attentional manipulation, and examined the impact on OSM. Across three experiments, there was no interaction. This refutes the object-substitution theory of OSM. This, in turn, tell us that object-individuation is invariant the distribution of attention. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Exchange bias properties of 140 nm-sized dipolarly interacting circular dots with ultrafine IrMn and NiFe layers

    Spizzo, F., E-mail: spizzo@fe.infn.it [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Tamisari, M. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Dipartimento di Fisica e Geologia and CNISM, Università di Perugia, I-06123 Perugia (Italy); Chinni, F.; Bonfiglioli, E. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Gerardino, A. [Istituto di Fotonica e Nanotecnologie, CNR, I-00156 Roma (Italy); Barucca, G. [Dipartimento SIMAU, Università Politecnica delle Marche, I-60131 Ancona (Italy); Bisero, D.; Fin, S.; Del Bianco, L. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy)

    2016-02-15

    We studied the exchange bias effect in an array of IrMn(3 nm)/NiFe(3 nm) circular dots (size ~140 nm and center-to-center distance ~200 nm, as revealed by microscopy analyses), prepared on a large area (3×3 mm{sup 2}) by electron beam lithography and lift-off, using dc sputtering deposition. Hysteresis loops were measured by SQUID magnetometer at increasing values of temperature T (in the 5–300 K range) after cooling from 300 K down to 5 K in zero field (ZFC mode) and in a saturating magnetic field (FC mode). The exchange bias effect disappears above T~200 K and, at each temperature, the exchange field H{sub EX} measured in ZFC is substantially lower than the FC one. Micromagnetic calculations indicate that, at room temperature, each dot is in high-remanence ground state, but magnetic dipolar interactions establish a low-remanence configuration of the array as a whole. Hence, at low temperature, following the ZFC procedure, the exchange anisotropy in the dot array is averaged out, tending to zero. However, even the FC values of H{sub EX} and of the coercivity H{sub C} are definitely smaller compared to those measured in a reference continuous film with the same stack configuration (at T=5 K, H{sub EX}~90 Oe and H{sub C}~180 Oe in the dots and H{sub EX}~1270 Oe and H{sub C}~860 Oe in the film). Our explanation is based on the proven glassy magnetic nature of the ultrathin IrMn layer, implying the existence of magnetic correlations among the spins, culminating in a collective freezing below T~100 K. We propose, also by the light of micromagnetic simulations, that the small dot size imposes a spatial constraint on the magnetic correlation length among the IrMn spins so that, even at the lowest temperature, their thermal stability, especially at the dot border, is compromised. - Highlights: • Exchange bias in 140 nm-sized IrMn(3 nm)/NiFe(3 nm) dots much weaker than in a film. • Glassy magnetic nature of the IrMn phase and collective spin freezing at T<100 K

  1. Exchange bias properties of 140 nm-sized dipolarly interacting circular dots with ultrafine IrMn and NiFe layers

    Spizzo, F.; Tamisari, M.; Chinni, F.; Bonfiglioli, E.; Gerardino, A.; Barucca, G.; Bisero, D.; Fin, S.; Del Bianco, L.

    2016-01-01

    We studied the exchange bias effect in an array of IrMn(3 nm)/NiFe(3 nm) circular dots (size ~140 nm and center-to-center distance ~200 nm, as revealed by microscopy analyses), prepared on a large area (3×3 mm"2) by electron beam lithography and lift-off, using dc sputtering deposition. Hysteresis loops were measured by SQUID magnetometer at increasing values of temperature T (in the 5–300 K range) after cooling from 300 K down to 5 K in zero field (ZFC mode) and in a saturating magnetic field (FC mode). The exchange bias effect disappears above T~200 K and, at each temperature, the exchange field H_E_X measured in ZFC is substantially lower than the FC one. Micromagnetic calculations indicate that, at room temperature, each dot is in high-remanence ground state, but magnetic dipolar interactions establish a low-remanence configuration of the array as a whole. Hence, at low temperature, following the ZFC procedure, the exchange anisotropy in the dot array is averaged out, tending to zero. However, even the FC values of H_E_X and of the coercivity H_C are definitely smaller compared to those measured in a reference continuous film with the same stack configuration (at T=5 K, H_E_X~90 Oe and H_C~180 Oe in the dots and H_E_X~1270 Oe and H_C~860 Oe in the film). Our explanation is based on the proven glassy magnetic nature of the ultrathin IrMn layer, implying the existence of magnetic correlations among the spins, culminating in a collective freezing below T~100 K. We propose, also by the light of micromagnetic simulations, that the small dot size imposes a spatial constraint on the magnetic correlation length among the IrMn spins so that, even at the lowest temperature, their thermal stability, especially at the dot border, is compromised. - Highlights: • Exchange bias in 140 nm-sized IrMn(3 nm)/NiFe(3 nm) dots much weaker than in a film. • Glassy magnetic nature of the IrMn phase and collective spin freezing at T<100 K • Confinement of IrMn magnetic

  2. Reproductive management of dairy herds in New Zealand: attitudes, priorities and constraints perceived by farmers managing seasonal-calving, pasture-based herds in four regions.

    Brownlie, T S; Weir, A M; Tarbotton, I; Morton, J M; Heuer, C; McDougall, S

    2011-01-01

    To examine attitudes, priorities, and constraints pertaining to herd reproductive management perceived by farmers managing seasonal-calving, pasture-based dairy herds in four regions of New Zealand, and to explore how these varied with demographic and biophysical factors. Key decision makers (KDM) on 133 dairy herds in four dairy regions (Waikato, Taranaki, and north and south Canterbury) were interviewed between May and July 2009. They were asked to provide demographic and biophysical data about the farm, and to rate their attitude in relation to their own personality traits, management issues and priorities, and likely constraints affecting reproductive performance in their herds. Associations between demographic factors and attitudes, priorities and constraints were analysed using univariable and multivariable proportional-odds regression models. Farms in the regions studied in the South Island were larger, had larger herds and more staff than farms in the regions studied in the North Island. The farms in the South Island were more likely to be owned by a corporation, managed by younger people or people who had more education, and the herds were more likely to be fed a higher percentage of supplementary feed. The majority of KDM rated the current genetics, milksolids performance and reproductive performance of their herds as high or very high, and >70% believed that the reproductive performance had remained the same or improved over the preceding 3 years. Despite this, improving reproductive performance was the most highly rated priority for the next 3 years. The constraints considered most likely to have affected reproductive performance in the last 2 years were anoestrous cows, protracted calving periods, and low body condition scores; those considered least likely were artificial breeding and heat detection. Of the variables examined related to attitudes, priorities and likely constraints, there were significant differences between region for 10/40, and with

  3. Reducing use of antimicrobials - experiences from an intervention study in organic dairy herds in Denmark

    Bennedsgaard, Torben Werner; Klaas, Ilka Christine; Vaarst, Mette

    2010-01-01

    , the project herds were smaller with lower production and had half the incidence rate of mastitis treatment than the organic herds from other dairies before the start of the project. The incidence rate of mastitis treatments was reduced considerably from 20 treatments per 100 cow years to 10 treatments per 100...... cow years after the project period. Somatic cell count (SCC) and scores for acute and chronic intramammary infections did not change significantly during the study period, and milk production increased at the same rate as in the other herd groups. The incidence rate of mastitis treatments...

  4. Cost of Mastitis in Scottish Dairy Herds with Low and High Subclinical Mastitis Problems

    YALÇIN, Cengiz

    2000-01-01

    The aim of this study was to estimate the cost of mastitis and the contribution of each cost component of mastitis to the total mastitis induced cost in herds with low and high levels of subclinical mastitis under Scottish field conditions. It was estimated that mastitis cost £140 per cow/year to the average Scottish dairy farmer in 1996. However, this figure was as low as £69 per cow/year in herds with lower levels of subclinical mastitis, and as high as £228 cow/year in herds with high s...

  5. Herd diagnosis of low pathogen diarrhoea in growing pigs – a pilot study

    Pedersen, Ken Steen; Johansen, Markku; Angen, Øystein

    2014-01-01

    be demonstrated in a small number of pigs within the treated group (low pathogen diarrhoea). Termination of antibiotic batch medication in herds suffering from such diarrhoea could potentially reduce the consumption of antibiotics in the pig industry. The objective of the present pilot study was to suggest...... criteria for herd diagnosis of low pathogen diarrhoea in growing pigs. Data previously collected from 20 Danish herds were used to create a case series of clinical diarrhoea outbreaks normally subjected to antibiotic treatment. In the present study, these diarrhoea outbreaks were classified as low pathogen...... (diagnosis of low pathogen diarrhoea were...

  6. Risk factors for changing test classification in the Danish surveillance program for Salmonella in dairy herds

    Nielsen, Lennarth Ravn; Warnick, L. D.; Greiner, M.

    2007-01-01

    test positive to negative, whereas the breed and neighbor factors were not found to be important for small herds. Organic production was associated with remaining test positive, but not with becoming test positive. The results emphasize the importance of external and internal biosecurity measures....... The objective of this study was to evaluate risk factors for changing from test negative to positive, which was indicative of herds becoming infected from one quarter of the year to the next, and risk factors for changing from test positive to negative, which was indicative of herds recovering from infection...

  7. Bovine respiratory syncytial virus (BRSV) pneumonia in beef calf herds despite vaccination

    Larsen, Lars Erik; Tegtmeier, C.; Pedersen, E.

    2001-01-01

    to the outbreak. The clinical signs comprised nasal discharge, pyrexia, cough and increased respiratory rates. A total of 28 calves died in the 2 herds. The laboratory investigations revealed that BRSV was involved and probably initiated both outbreaks. Furthermore, the serological results suggested...... beef herds failed to protect the calves against severe or even fatal BRSV mediated respiratory disease 2 months later.......The present report describes the clinical, pathological, serological and virological findings in calves from 2 larger Danish beef herds experiencing outbreaks of pneumonia. The calves had been vaccinated with an inactivated bovine respiratory syncytial virus (BRSV) vaccine 2 months prior...

  8. Herd specific risk factors for Mycoplasma hyopneumoniae infections in suckling pigs at the age of weaning.

    Nathues, Heiko; Woeste, Henrike; Doehring, Stefanie; Fahrion, Anna S; Doherr, Marcus G; Beilage, Elisabeth grosse

    2013-04-12

    Mycoplasma hyopneumoniae is the etiologic agent of enzootic pneumonia mainly occurring in fattening pigs. It is assumed that horizontal transmission of the pathogen during nursery and growing phase starts with few suckling pigs vertically infected by the sow. The aim of the present study was the exploration of the herd prevalence of M. hyopneumoniae infections in suckling pigs followed by an investigation of various herd specific factors for their potential of influencing the occurrence of this pathogen at the age of weaning. In this cross-sectional study, 125 breeding herds were examined by taking nasal swabs from 20 suckling pigs in each herd. In total, 3.9% (98/2500) of all nasal swabs were tested positive for M. hyopneumoniae by real-time PCR. Piglets tested positive originated from 46 different herds resulting in an overall herd prevalence of 36.8% (46/125) for M. hyopneumoniae infection in pigs at the age of weaning. While the herds were epidemiologically characterized, the risk for demonstration of M. hyopneumoniae was significantly increased, when the number of purchased gilts per year was more than 120 (OR: 5.8), and when the number of farrowing pens per compartment was higher than 16 (OR: 3.3). In herds with a planned and segregated production, where groups of sows entered previously emptied farrowing units, the risk for demonstration of M. hyopneumoniae in piglets was higher in herds with two or four weeks between batches than in herds with one or three weeks between batches (OR: 2.7). In this cross-sectional study, several risk factors could be identified enhancing the probability of breeding herds to raise suckling pigs already infected with M. hyopneumoniae at the time of weaning. Interestingly, some factors (farrowing rhythm, gilt acclimatisation issues) were overlapping with those also influencing the seroprevalences among sows or the transmission of the pathogen between older age groups. Taking the multifactorial character of enzootic pneumonia

  9. The Role of Herd Behaviour in Determining the Investor‘s Monday Irrationality

    Rayenda Brahmana; Chee Wooi Hooy; Zamri Ahmad

    2012-01-01

    With regards to determining whether herding is spontaneous and irrational behavior causing the Day-of-the-week anomaly, this paper intersects the Christie and Huang (1995) herd behaviour model with French's (1980) Day-of-the-week model in several layers of tests. We use firm-level data and investigate the return dispersion of 846 Bursa Malaysia stocks during 1990–2010. This paper found the herd behaviour is the determinant for investor’s Monday irrationality, especially in small caps indu...

  10. Effects of herd origin, AI stud and sire identification on genetic evaluation of Holstein Friesian bulls

    Giovanni Bittante; Paolo Carnier; Luigi Gallo Gallo; Riccardo Dal Zotto; Martino Cassandro

    2010-01-01

    The purpose of this study was to estimate the effects of herd origin of bull, AI stud and sire identification number (ID)  on official estimated breeding values (EBV) for production traits of Holstein Friesian proven bulls. The data included 1,005  Italian Holstein-Friesian bulls, sons of 76 sires, born in 100 herds and progeny tested by 10 AI studs. Bulls were required  to have date of first proof between September 1992 and September 1997, to be born in a herd with at least on...

  11. Evaluation of the surveillance program of Streptococcus agalactiae in Danish dairy herds

    Andersen, H. J.; Pedersen, L. H.; Aarestrup, Frank Møller

    2003-01-01

    The aim of this study was to evaluate the Danish surveillance program of Streptococcus agalactiae in dairy herds with respect to 1) fluctuation over time of the presence of S. agalactiae in bulk tank milk, 2) sensitivity and specificity of the bacteriological method used, and 3) contamination...... the isolates. Streptococcus agalactiae was found in eight of 96 herds in which S. agalactiae had never previously been found during the surveillance program. Streptococcus agalactiae was not found in all seven sampling rounds in any of the eight herds. Comparing the approved method with supplemental findings...

  12. Preferential Interactions between ApoE-containing Lipoproteins and Aβ Revealed by a Detection Method that Combines Size Exclusion Chromatography with Non-Reducing Gel-shift

    LaDu, Mary Jo; Munson, Gregory W.; Jungbauer, Lisa; Getz, Godfrey S.; Reardon, Catherine A.; Tai, Leon M.; Yu, Chunjiang

    2012-01-01

    The association between apolipoprotein E (apoE) and amyloid-β peptide (Aβ) may significantly impact the function of both proteins, thus affecting the etiology of Alzheimer’s disease (AD). However, apoE/Aβ interactions remain fundamentally defined by the stringency of the detection method. Here we use size exclusion chromatography (SEC) as a non-stringent approach to the detection of apoE/Aβ interactions in solution, specifically apoE and both endogenous and exogenous Aβ from plasma, CSF and astrocyte conditioned media. By SEC analysis, Aβ association with plasma and CNS lipoproteins is apoE-dependent. While endogenous Aβ elutes to specific human plasma lipoproteins distinct from those containing apoE, it is the apoE-containing lipoproteins that absorb excess amounts of exogenous Aβ40. In human CSF, apoE, endogenous Aβ and phospholipid elute in an almost identical profile, as do apoE, exogenous Aβ and phospholipid from astrocyte conditioned media. Combining SEC fractionation with subsequent analysis for SDS-stable apoE/Aβ complex reveals that apoE-containing astrocyte lipoproteins exhibit the most robust interactions with Aβ. Thus, standardization of the methods for detecting apoE/Aβ complex is necessary to determine its functional significance in the neuropathology characteristic of AD. Importantly, a systematic understanding of the role of apoE-containing plasma and CNS lipoproteins in Aβ homeostasis could potentially contribute to identifying a plasma biomarker currently over-looked because it has multiple components. PMID:22138302

  13. Incorporation of aurochs into a cattle herd in Neolithic Europe: single event or breeding?

    Schibler, Jörg; Elsner, Julia; Schlumbaum, Angela

    2014-07-01

    Domestication is an ongoing process continuously changing the lives of animals and humans and the environment. For the majority of European cattle (Bos taurus) genetic and archaeozoological evidence support initial domestication ca. 11'000 BP in the Near East from few founder aurochs (Bos primigenius) belonging to the mitochondrial DNA T macro-haplogroup. Gene flow between wild European aurochs of P haplogroup and domestic cattle of T haplogroup, coexisting over thousands of years, appears to have been sporadic. We report archaeozoological and ancient DNA evidence for the incorporation of wild stock into a domestic cattle herd from a Neolithic lake-dwelling in Switzerland. A complete metacarpus of a small and compact adult bovid is morphologically and genetically a female. With withers height of ca. 112 cm, it is comparable in size with small domestic cattle from contemporaneous sites in the area. The bone is directly dated to 3360-3090 cal BC and associated to the Horgen culture, a period of the secondary products revolution. The cow possessed a novel mtDNA P haplotype variant of the European aurochs. We argue this is either a single event or, based on osteological characteristics of the Horgen cattle, a rare instance of intentional breeding with female aurochs.

  14. CrossRef Experimental verification of the HERD prototype at CERN SPS

    Dong, Yongwei; Wang, Junjing; Xu, Ming; Albergo, Sebastiano; Ambroglini, Filippo; Ambrosi, Giovanni; Azzarello, Philipp; Bai, Yonglin; Bao, Tianwei; Baldini, Luca; Battiston, Roberto; Bernardini, Paolo; Chen, Zhen; D'Alessandro, Raffaello; Duranti, Matteo; D'Urso, Domenico; Fusco, Piergiorgio; Gao, Jiarui; Gao, Xiaohui; Gargano, Fabio; Giglietto, Nicola; Hu, Bingliang; Li, Ran; Li, Yong; Liu, Xin; Loparco, Francesco; Lu, Junguang; Marsella, Giovanni; Mazziotta, Mario N; De Mitri, Ivan; Mori, Nicola; Orsi, Silvio; Oscar, Adriani; Pearce, Mark; Pohl, Martin; Ryde, Felix; Shi, Dalian; Spillantini, Piero; Su, Meng; Sun, Xin; Surdo, Antonio; Walter, Roland; Wang, Bo; Wang, Le; Wang, Ruijie; Wang, Zhigang; Wu, Bobing; Wu, Xin; Yan, Peng; Zhang, Li; Zhang, Shuangnan

    2016-01-01

    The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic light house program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. Beam test with a HERD prototype, to verify the HERD specifications and the reading out method of wavelength shifting fiber and image intensified CCD, was taken at CERN SPS in November, 2015. The prototype is composed of an array of 5*5*10 LYSO crystals, which is 1/40th of the scale of HERD calorimeter. Experimental results on the performances of the calorimeter are discussed. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  15. The cost of a case of subclinical ketosis in Canadian dairy herds.

    Gohary, Khaled; Overton, Michael W; Von Massow, Michael; LeBlanc, Stephen J; Lissemore, Kerry D; Duffield, Todd F

    2016-07-01

    The objective of this study was to develop a model to estimate the cost of a case of subclinical ketosis (SCK) in Canadian dairy herds. Costs were derived from the default inputs, and included increased clinical disease incidence attributable to SCK, $76; longer time to pregnancy, $57; culling and death in early lactation attributable to SCK, $26; milk production loss, $44. Given these figures, the cost of 1 case of SCK was estimated to be $203. Sensitivity analysis showed that the estimated cost of a case of SCK was most sensitive to the herd-level incidence of SCK and the cost of 1 day open. In conclusion, SCK negatively impacts dairy herds and losses are dependent on the herd-level incidence and factors included in the calculation.

  16. Risk factors and epidemiological characteristics of new neonatal porcine diarrhoea syndrome in four Danish herds

    Kongsted, Hanne; Toft, Nils; Nielsen, Jens Peter

    2014-01-01

    , which is un-responsive to antibiotics and not associated with known pathogens. The aetiology behind the syndrome is unknown, and specific risk factors predisposing piglets to develop NNPDS also remain to be determined. The study evaluated sow and piglet-level risk factors for developing NNPDS......-65%) of piglets born by mature sows. In total of 26% of piglets had liquid faeces on the day of birth. Approximately half of these piglets developed NNPDS. In the majority of cases (50-70% of cases within herds) symptoms started on the second or third day of life. Piglets in Herd 1 had 12.8 times higher...... probability of developing NNPDS than piglets in Herd 4. First parity piglets had a 4.1 higher probability of developing NNPDS than piglets born by mature sows. Birth weight and faecal consistency on the day of birth were minor risk factors, each significant within one herd. Conclusions: The most important...

  17. Spread of Staphylococcus aureus resistant to penicillin and tetracycline within and between dairy herds

    Waage, S.; Bjorland, J.; Caugant, D. A.

    2002-01-01

    One hundred and seven bovine isolates of penicillin and tetracycline resistant Staphylococcus aureus, recovered from 25 different dairy herds in various parts of Norway, were characterized using antimicrobial susceptibility testing, multilocus enzyme electrophoresis, ribotyping, plasmid analysis ...

  18. Extensive sequence divergence among bovine respiratory syncytial viruses isolated during recurrent outbreaks in closed herds

    Larsen, Lars Erik; Tjørnehøj, Kirsten; Viuff, B.

    2000-01-01

    and veal calf production units) in different years and from all confirmed outbreaks in Denmark within a short period. The results showed that identical viruses were isolated within a herd during outbreaks and that viruses from recurrent infections varied by up to 11% in sequence even in closed herds......The nucleotides coding for the extracellular part of the G glycoprotein and the full SH protein of bovine respiratory syncytial virus (BRSV) were sequenced from viruses isolated from numerous outbreaks of BRSV infection. The isolates included viruses isolated from the same herd (closed dairy farms....... It is possible that a quasispecies variant swarm of BRSV persisted in some of the calves in each herd and that a new and different highly fit virus type (master and consensus sequence) became dominant and spread from a single animal in connection with each new outbreak. Based on the high level of diversity...

  19. Identification of atypical porcine pestivirus infection in swine herds in China.

    Zhang, K; Wu, K; Liu, J; Ge, S; Xiao, Y; Shang, Y; Ning, Z

    2017-08-01

    Atypical porcine pestivirus (APPV) have been detected in swine herds from the USA, Germany, the Netherlands, Spain and most recently in Austria, suggesting a wide geographic distribution of this novel virus. Here, for the first time, we reported APPV infection in swine herds in China. Newborn piglets from two separate swine herds in Guangdong province were found showing typical congenital tremors in July and August 2016. RT-PCR, sequencing and phylogenetic analysis showed APPV infection occurred. Phylogenetic analysis showed that Chinese APPV strains, GD1 and GD2, formed independent branch from the USA, Germany and the Netherlands. Nucleotide identities between members of the APPV ranged between 83.1% and 83.5%, and this showed APPV is highly diverse. It is apparent that this provides the first molecular evidence of APPV infection in swine herds in China. © 2017 Blackwell Verlag GmbH.

  20. An Investigation into the Etiological Agents of Swine Dysentery in Australian Pig Herds.

    Tom La

    Full Text Available Swine dysentery (SD is a mucohemorrhagic colitis, classically seen in grower/finisher pigs and caused by infection with the anaerobic intestinal spirochete Brachyspira hyodysenteriae. More recently, however, the newly described species Brachyspira hampsonii and Brachyspira suanatina have been identified as causing SD in North America and/or Europe. Furthermore, there have been occasions where strains of B. hyodysenteriae have been recovered from healthy pigs, including in multiplier herds with high health status. This study investigated whether cases of SD in Australia may be caused by the newly described species; how isolates of B. hyodysenteriae recovered from healthy herds compared to isolates from herds with disease; and how contemporary isolates compare to those recovered in previous decades, including in their plasmid gene content and antimicrobial resistance profiles. In total 1103 fecal and colon samples from pigs in 97 Australian herds were collected and tested. Of the agents of SD only B. hyodysenteriae was found, being present in 34 (35.1% of the herds, including in 14 of 24 (58% herds that had been considered to be free of SD. Multilocus sequence typing applied to 96 isolates from 30 herds and to 53 Australian isolates dating from the 1980s through the early 2000s showed that they were diverse, distinct from those reported in other countries, and that the 2014/16 isolates generally were different from those from earlier decades. These findings provided evidence for ongoing evolution of B. hyodysenteriae strains in Australia. In seven of the 20 herds where multiple isolates were available, two to four different sequence types (STs were identified. Isolates with the same STs also were found in some herds with epidemiological links. Analysis of a block of six plasmid virulence-associated genes showed a lack of consistency between their presence or absence and their origin from herds currently with or without disease; however

  1. Evaluation of two dairy herd reproductive performance indicators that are adjusted for voluntary waiting period

    Löf Emma

    2012-01-01

    Full Text Available Abstract Background Overall reproductive performance of dairy herds is monitored by various indicators. Most of them do not consider all eligible animals and do not consider different management strategies at farm level. This problem can be alleviated by measuring the proportion of pregnant cows by specific intervals after their calving date or after a fixed time period, such as the voluntary waiting period. The aim of this study was to evaluate two reproductive performance indicators that consider the voluntary waiting period at the herd. The two indicators were: percentage of pregnant cows in the herd after the voluntary waiting period plus 30 days (PV30 and percentage of inseminated cows in the herd after the voluntary waiting period plus 30 days (IV30. We wanted to assess how PV30 and IV30 perform in a simulation of herds with different reproductive management and physiology and to compare them to indicators of reproductive performance that do not consider the herd voluntary waiting period. Methods To evaluate the reproductive indicators we used the SimHerd-program, a stochastic simulation model, and 18 scenarios were simulated. The scenarios were designed by altering the reproductive management efficiency and the status of reproductive physiology of the herd. Logistic regression models, together with receiver operating characteristics (ROC, were used to examine how well the reproductive performance indicators could discriminate between herds of different levels of reproductive management efficiency or reproductive physiology. Results The logistic regression models with the ROC analysis showed that IV30 was the indicator that best discriminated between different levels of management efficiency followed by PV30, calving interval, 200-days not-in calf-rate (NotIC200, in calf rate at100-days (IC100 and a fertility index. For reproductive physiology the ROC analysis showed that the fertility index was the indicator that best discriminated

  2. Size-dependent plastic deformation characteristics in He-irradiated nanostructured Cu/Mo multilayers: Competition between dislocation-boundary and dislocation-bubble interactions

    Zhang, J.Y.; Zeng, F.L.; Wu, K.; Wang, Y.Q.; Liang, X.Q.; Liu, G., E-mail: lgsammer@mail.xjtu.edu.cn; Zhang, G.J.; Sun, J., E-mail: junsun@mail.xjtu.edu.cn

    2016-09-15

    Nanoindentation methodology was used to investigate the plastic deformation characteristics, including the hardness (H), strain rate sensitivity (SRS, m) and activation volume (V{sup *}), of Cu/Mo nanostructured metallic multilayers (NMMs) with equal layer thickness (h) spanning from 10 to 200 nm before and after He-implantation at room temperature. Compared with the as-deposited Cu/Mo NMMs, the irradiated Cu/Mo samples exhibited the enhanced hardness particularly at great h, which is caused by the bubble-hardening effect. Unlike the as-deposited Cu/Mo NMMs displayed a monotonic increase in SRS (or a monotonic decrease in activation volume) with reducing h, the irradiated Cu/Mo samples manifested an unexpected non-monotonic variation in SRS as well as in activation volume. It was clearly unveiled that the SRS of irradiated Cu/Mo firstly decreased with reducing h down to a critical size of ~50 nm and subsequently increased with further reducing h, leaving a minimum value at the critical h. These phenomena are rationalized by considering a competition between dislocation-boundary and dislocation-bubble interactions. A thermally activated model based on the depinning process of bowed-out partial dislocations was employed to quantitatively account for the size-dependent SRS of Cu/Mo NMMs before and after irradiation. Our findings not only provide fundamental understanding of the effects of radiation-induced defects on plastic characteristics of NMMs, but also offer guidance for their microstructure sensitive design for performance optimization at extremes.

  3. Accuracy of estimation of graft size for living-related liver transplantation: first results of a semi-automated interactive software for CT-volumetry.

    Theresa Mokry

    Full Text Available To evaluate accuracy of estimated graft size for living-related liver transplantation using a semi-automated interactive software for CT-volumetry.Sixteen donors for living-related liver transplantation (11 male; mean age: 38.2±9.6 years underwent contrast-enhanced CT prior to graft removal. CT-volumetry was performed using a semi-automated interactive software (P, and compared with a manual commercial software (TR. For P, liver volumes were provided either with or without vessels. For TR, liver volumes were provided always with vessels. Intraoperative weight served as reference standard. Major study goals included analyses of volumes using absolute numbers, linear regression analyses and inter-observer agreements. Minor study goals included the description of the software workflow: degree of manual correction, speed for completion, and overall intuitiveness using five-point Likert scales: 1--markedly lower/faster/higher for P compared with TR, 2--slightly lower/faster/higher for P compared with TR, 3--identical for P and TR, 4--slightly lower/faster/higher for TR compared with P, and 5--markedly lower/faster/higher for TR compared with P.Liver segments II/III, II-IV and V-VIII served in 6, 3, and 7 donors as transplanted liver segments. Volumes were 642.9±368.8 ml for TR with vessels, 623.8±349.1 ml for P with vessels, and 605.2±345.8 ml for P without vessels (P<0.01. Regression equations between intraoperative weights and volumes were y = 0.94x+30.1 (R2 = 0.92; P<0.001 for TR with vessels, y = 1.00x+12.0 (R2 = 0.92; P<0.001 for P with vessels, and y = 1.01x+28.0 (R2 = 0.92; P<0.001 for P without vessels. Inter-observer agreement showed a bias of 1.8 ml for TR with vessels, 5.4 ml for P with vessels, and 4.6 ml for P without vessels. For the degree of manual correction, speed for completion and overall intuitiveness, scale values were 2.6±0.8, 2.4±0.5 and 2.CT-volumetry performed with P can predict accurately graft

  4. Evaporation of liquid droplets of nano- and micro-meter size as a function of molecular mass and intermolecular interactions: experiments and molecular dynamics simulations.

    Hołyst, Robert; Litniewski, Marek; Jakubczyk, Daniel

    2017-09-13

    Transport of heat to the surface of a liquid is a limiting step in the evaporation of liquids into an inert gas. Molecular dynamics (MD) simulations of a two component Lennard-Jones (LJ) fluid revealed two modes of energy transport from a vapour to an interface of an evaporating droplet of liquid. Heat is transported according to the equation of temperature diffusion, far from the droplet of radius R. The heat flux, in this region, is proportional to temperature gradient and heat conductivity in the vapour. However at some distance from the interface, Aλ, (where λ is the mean free path in the gas), the temperature has a discontinuity and heat is transported ballistically i.e. by direct individual collisions of gas molecules with the interface. This ballistic transport reduces the heat flux (and consequently the mass flux) by the factor R/(R + Aλ) in comparison to the flux obtained from temperature diffusion. Thus it slows down the evaporation of droplets of sizes R ∼ Aλ and smaller (practically for sizes from 10 3 nm down to 1 nm). We analyzed parameter A as a function of interactions between molecules and their masses. The rescaled parameter, A(k B T b /ε 11 ) 1/2 , is a linear function of the ratio of the molecular mass of the liquid molecules to the molecular mass of the gas molecules, m 1 /m 2 (for a series of chemically similar compounds). Here ε 11 is the interaction parameter between molecules in the liquid (proportional to the enthalpy of evaporation) and T b is the temperature of the gas in the bulk. We tested the predictions of MD simulations in experiments performed on droplets of ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol. They were suspended in an electrodynamic trap and evaporated into dry nitrogen gas. A changes from ∼1 (for ethylene glycol) to approximately 10 (for tetraethylene glycol) and has the same dependence on molecular parameters as obtained for the LJ fluid in MD simulations. The value of x = A

  5. Relative contribution of decreased productivity and survival to recent changes in the demographic trend of the Rivière George Caribou Herd

    M. Crête

    1996-01-01

    Full Text Available The Rivière George caribou herd (RGCH was numerically low during the middle part of the century but apparently erupted in the sixties and the seventies. Puberty was early and pregnancy rate was high among RGCH females from 1973 until the mid-eighties when fecundity decreased significantly, in particular among sub-adults; productivity remained low in 1992. Autumn calf:female ratios reflected this trend in pregnancy, exceeding 50 calves: 100 cows between 1973 and 1983, but dropping thereafter progressively to a low of 24 in 1992. In 1993, this ratio rebounded back to 42. Annual adult survival rate of radio-collared females was high (0.95 at the beginning of the monitoring in 1984, but exhibited a variable but declining trend until 1992. Simulations were conducted to estimate the demographic trend of the RGCH between 1984 and 1992, using annual survival rates of radio-collared animals and annual autumn calffemale ratios to estimate calf production. Age structure played a minor role in estimating the finite rate of increase (Lamda. According to the simulations, the RGCH increased in size until 1987, and showed a slight decrease thereafter. The herd should have decreased by 12-15% between 1988 and 1993, according to the simulations. Productivity first caused a decline in Lamda, but in recent years decreased survival contributed slightly more than productivity to the reduction in Lamda. Estimation of the herd size by means of aerial censuses in 1976, 1984, 1988 and 1993 suggested a similar pattern in demographic trend, differences being statistically meaningless. We speculated on the future of the RGCH, that could have erupted after many decades of unfavourable weather. The herd will exhibit a rapid descent to low numbers if wolves show a numerical response to current caribou abundance, or if lichen availability on the winter range decreases due to competition with the adjacent and increasing Rivière aux Feuilles herd; otherwise it will exhibit

  6. Geographical distribution of salmonella infected pig, cattle and sheep herds in Sweden 1993-2010

    Skog Lars

    2011-10-01

    Full Text Available Abstract Background The Swedish salmonella control programme covers the entire production chain, from feed to food. All salmonella serotypes are notifiable. On average, less than 20 cases of salmonella in food-producing animals are reported every year. In some situations, the cases would be expected to cluster geographically. The aim of this study was to illustrate the geographic distribution of the salmonella cases detected in pigs, cattle and sheep. Methods Data on all herds with pigs, cattle and sheep found to be infected with salmonella during the time period from 1993 to 2010 were obtained from the Swedish Board of Agriculture. Using the ArcGIS software, various maps were produced of infected herds, stratified on animal species as well as salmonella serotype. Based on ocular inspection of all maps, some were collapsed and some used separately. Data were also examined for temporal trends. Results No geographical clustering was observed for ovine or porcine cases. Cattle herds infected with Salmonella Dublin were mainly located in the southeast region and cattle herds infected with Salmonella Typhimurium in the most southern part of the country. Some seasonal variation was seen in cattle, but available data was not sufficient for further analyses. Conclusions Analyses of data on salmonella infected herds revealed some spatial and temporal patterns for salmonella in cattle. However, despite using 18 years' of data, the number of infected herds was too low for any useful statistical analyses.

  7. Monitoring indices of cow comfort in free-stall-housed dairy herds.

    Cook, N B; Bennett, T B; Nordlund, K V

    2005-11-01

    Indices of cow comfort are used widely by consultants in the dairy industry, with a general understanding that they are representative of lying behavior. This study examines the influence of stall base type (sand or a geotextile mattress filled with rubber crumbs) and time of measurement on 4 indices of comfort collected at hourly intervals in 12 herds, aligned by morning and afternoon milking. Stall base type significantly influenced all indices of comfort. For example, the least squares mean (SE) cow comfort index (proportion of cows touching a stall that are lying down) was 0.76 (0.015) in herds with mattresses compared with 0.86 (0.015) in herds with sand stalls. Significant hourly variation was also identified suggesting that timing of measurement is important. None of the indices of cow comfort derived from the high-yielding group pen was associated with the mean 24-h lying time of 10 sentinel cows whose time budgets were known in each herd. However, the cow comfort index was associated with the herd mean 24-h stall standing time, with the strongest relationships occurring 2 h before the morning and afternoon milking, when stall base type did not significantly influence the association. When measured at these times, we recommend use of the stall standing index (proportion of cows touching a stall that are standing), with values greater than 0.20 being associated with abnormally long herd mean stall standing times greater than 2 h/d.

  8. Blood parameters in Swedish dairy herds with high or low incidence of displaced abomasum or ketosis.

    Stengärde, Lena; Holtenius, Kjell; Emanuelson, Ulf; Hultgren, Jan; Niskanen, Rauni; Tråvén, Madeleine

    2011-10-01

    Sixty dairy herds were studied to investigate the association between long-term incidence of displaced abomasum and clinical ketosis and body condition score and blood profiles, including parameters estimating energy metabolism and hepatic lipidosis in the periparturient period and early lactation. Blood samples were taken around parturition and in early lactation from cows without apparent clinical symptoms of metabolic disorders. A difference in metabolism between high and low incidence herds was shown post-partum by a lower metabolic index (the revised Quantitative Insulin Sensitivity Check Index, RQUICKI), and tendencies for higher concentrations of glucose, insulin and non-esterified fatty acids in the high incidence herds. High incidence herds had more cows and produced on average 1400kg energy-corrected milk per cow per year more than the low incidence herds. No differences were found in parameters reflecting liver cell damage. In the first 3weeks post-partum the RQUICKI was a more sensitive marker of herds with a high incidence of displaced abomasum and clinical ketosis than any of the individual parameters, but further research is needed before practical applications of the RQUICKI can be foreseen. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. CAUSES OF DISPOSAL OF MURRAH BUFFALO FROM AN ORGANISED HERD

    S. Taraphder

    2011-07-01

    Full Text Available The present study comprised of 602 disposal records of adult Murrah buffaloes , spread over a period of 16 years from 1985 to 2000 at NDRI, Karnal, Haryana. Analysed data showed that the reproductive problems (38.62, low milk production (24.01 and udder problems (22.76 were the three major reasons of culling in adult Murrah buffaloes . The culling of cows due to involuntary reason (reproductive problems, udder problems and locomotive disorders accounted for nearly 63.68 percent of total culling in Murrah buffaloes in the NDRI herd. The data revealed that maximum mortality occurred due to digestive problems accounting for 30.89 percent followed by cardio-vascular problems (26.02 percent, respiratory problems (21.14 percent, parasitic problems (8.13 percent and uro-genital problems (5.69 percent. The results showed that there is a scope for further improvement in production and reproductive efficiency through better monitoring of reproduction and udder health status of the buffaloes. The high involuntary culling rate not only makes the dairy enterprises economically less profitable but also reduces the genetic improvement by lowering the selection differential for milk production.

  10. GENETIC CHANGES FOR PERFORMANCE TRAITS IN SLOVENIAN PIG NUCLEUS HERDS

    Špela Malovrh

    2000-06-01

    Full Text Available In Slovenian pig nucleus herds, the genetic trends for performance traits in boars were investigated using mixed model methodology. Altogether, data sets from four farms with test stations consisted of 60709 records for five breeds: Swedish Landrace (SL, Large White (LW, Duroc (D, Pietrain (P, and German Landrace (GL boars from years 1975 to 1999. Separate analyses were performed for each farm using the PEST package. Breed, season, and weight on test within breed were fixed effects, while common litter environment and additive genetic effect were treated as random. Genetic trends for days on test from 30 to 100 kg (DoT30100, feed conversion efficiency from 30 to 100 kg (FCE30100, and ultrasonically measured backfat thickness (BF100 were expressed as linear regression of the averages of predicted breeding values on the year of birth. Estimates for genetic changes varied between farms and breeds from +0.0046 to –0.374 day, +0.0019 to – 0.013, and +0.262 to –0.221 mm per year for DoT30100, FCE30100, and BF100, respectively.

  11. [Multiresistant Brachyspira hyodysenteriae in a Dutch sow herd].

    Duinhof, T F; Dierikx, C M; Koene, M G J; van Bergen, M A P; Mevius, D J; Veldman, K T; van Beers-Schreurs, H M G; de Winne, R T J A

    This case study describes the isolation ofa multiresistant strain ofBrachyspira hyodysenteriae in April 2007 in a Dutch sow herd with recurrent diarrhoea. Examination of faecal samples taken from 7-month-old breeding gilts with diarrhoea revealed the presence of resistance against tiamulin, lincomycin, tylosin, doxycycline, and tylvalosin (the active substance in Aivlosin) in four of five samples. Tiamulin resistance has not been reported in The Netherlands before. The repeated use of tiamulin on the affected farm was assumed to be the main cause of the development of resistance to the drug. The farmer was advised to adopt a medication strategy and to implement management practices that would prevent an ongoing cycle of infection on the farm. It is important that the Dutch swine industry appreciates that tiamulin-resistant strains of B. hyodysenteriae may be found on other farms as well. The appropriate and prudent use of antibiotics is essential in order to prevent the development of resistance against the last option left to cure B. hyodysenteriae infections: valnemulin.

  12. Disease Recording Systems and Herd Health Schemes for Production Diseases

    Østerås O

    2001-03-01

    Full Text Available Disease recording of cattle is compulsory in Sweden and Norway. Sweden and Denmark also have mandatory disease recording for swine, whereas Finland and Norway only have compulsory recording of infectious diseases. Both compulsory and voluntary systems are databased, the first ones developed in the 1970's. Disease recording at pig slaughtering is somewhat older. The veterinary practitioner, and often also the farmer, can report treated cases as well as fertility disturbances to the systems. Disease recording at slaughter is carried out by veterinarians and inspection officers. The databases are handled by the veterinary authorities or the agricultural organisations in each country. Costs are defrayed by the authorities and/or the agricultural industry. The farmers receive periodic reports. Data are stored for three to ten years, often longer. Affiliation to animal health schemes for cattle or swine is voluntary. In Sweden and Denmark (cattle they are run within the scope of government regulations. Affiliation to animal health programmes may also be demanded by organisations within the agricultural industry. These organisations are also responsible for the administration of the programmes. Costs to take part in herd health schemes are covered by the farmers themselves. In certain cases, grants are received from agricultural organisations, authorities, or the European Union. Recording of diseases and the format of animal health schemes in the Nordic countries are described here in order to illustrate the possibilities to compare data between countries.

  13. Financial aspects of veterinary herd health management programmes.

    Ifende, V I; Derks, M; Hooijer, G A; Hogeveen, H

    2014-09-06

    Veterinary herd health management (VHHM) programmes have been shown to be economically effective in the past. However, no current information is available on costs and benefits of these programmes. This study compared economics and farm performance between participants and non-participants in VHHM programmes in 1013 dairy farms with over 40 cows. Milk Production Registration (MPR) data and a questionnaire concerning VHHM were used. Based on the level of participation in VHHM (as indicated in the questionnaire), costs of the programmes were calculated using a normative model. The economic value of the production effects was similarly calculated using normative modelling based on MPR data. Participants in VHHM had a better performance with regard to production, but not with regard to reproduction. Over 90 per cent of the VHHM participants were visited at least once every six weeks and most participants discussed at least three topics. In most farms, the veterinarian did the pregnancy checks as part of the VHHM programmes. There was a benefit to cost ratio of about five per cow per year for VHHM participants, and a mean difference in net returns of €30 per cow per year after adjusting for the cost of the programme. This portrays that participation in a VHHM programme is cost-efficient. There is, however, much unexplained variation in the net returns, possibly due to diverse approaches by veterinarians towards VHHM or by other factors not included in this analysis, like nutritional quality or management abilities of the farmer. British Veterinary Association.

  14. Assessment of herd management on organic and conventional dairy farms in the United States.

    Stiglbauer, K E; Cicconi-Hogan, K M; Richert, R; Schukken, Y H; Ruegg, P L; Gamroth, M

    2013-02-01

    The objective of this study was to evaluate management characteristics on organic and similarly sized conventional dairy farms located in New York, Wisconsin, and Oregon. Data from 192 organic farms (ORG), 64 conventional nongrazing farms (CON-NG), and 36 conventional grazing farms (CON-GR) were collected during farm visits and were size-matched and analyzed. The average lactation number of animals on ORG and CON-GR farms was 2.6 lactations, which was greater than that on CON-NG farms (2.3 lactations). A greater percentage of first-lactation heifers were found on conventional farms than on ORG farms. Facilities used by adult animals, including housing and milking facilities, did not differ among the grazing systems. Cattle on conventional farms were fed approximately twice as much grain as cattle on ORG farms and had greater milk production. Little difference was found for the average reported somatic cell count and standard plate count, suggesting that milk quality is not dependent on grazing system. Milking procedures were similar across all 3 grazing systems, indicating that an industry standard now exists for milking and that milk quality problems will need to be addressed with other management problems in mind. Although some disease prevention measures were commonly utilized on ORG farms, such as keeping a closed herd and having a written record of treatments administered to the animals, the use of outside support and vaccinations were found to be less prevalent on organic farms than on conventional farms. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. A longitudinal study investigating the prevalence of Staphylococcus aureus genotype B in seasonally communal dairy herds.

    Voelk, V; Graber, H U; van den Borne, B H P; Sartori, C; Steiner, A; Bodmer, M; Haerdi-Landerer, M C

    2014-07-01

    Staphylococcus aureus is a major mastitis-causing pathogen. Various genotypes have been recently identified in Switzerland but Staph. aureus genotype B (GTB) was the only genotype associated with high within-herd prevalence. The risk of introducing this Staph. aureus genotype into a herd may be increased by frequent animal movements. This may also be the case when cows from different herds of origin are commingled and share their milking equipment for a limited period of time. The aim of the present study was to determine the prevalence of Staph. aureus GTB in seasonally communal dairy herds before and after a summer period when dairy farming is characterized by mixing cows from different herds of origin in 1 communal operation. In addition, the environment was investigated to identify potential Staph. aureus GTB reservoirs relevant for transmission of the disease. A total of 829 cows from 110 herds of origin in 9 communal operations were included in the study. Composite milk samples were collected from all cows during the first or second milking after arrival at the communal operation and again shortly before the end of the season. Swab samples from the environment, involved personnel, and herding dogs present were collected before the cows arrived. At the end of the season, sampling of personnel was repeated. All samples were analyzed for the presence of Staph. aureus GTB using an established quantitative PCR. At the beginning of the season, Staph. aureus GTB-positive cows were identified in 7 out of 9 communal operations and the within-communal operation prevalence ranged from 2.2 to 38.9%. At the second sampling, all communal operations were Staph. aureus GTB positive, showing within-communal operation prevalence from 1 to 72.1%. The between-herd of origin prevalence increased from 27.3 to 56.6% and the cow-level prevalence increased from 11.2% at the beginning of the season to 29.6% at the end of the season. On 3 different communal operations, Staph. aureus

  16. Molecular epidemiology and strain-specific characteristics of Streptococcus agalactiae at the herd and cow level.

    Mahmmod, Y S; Klaas, I C; Katholm, J; Lutton, M; Zadoks, R N

    2015-10-01

    Host-adaptation of Streptococcus agalactiae subpopulations has been described whereby strains that are commonly associated with asymptomatic carriage or disease in people differ phenotypically and genotypically from those causing mastitis in dairy cattle. Based on multilocus sequence typing (MLST), the most common strains in dairy herds in Denmark belong to sequence types (ST) that are also frequently found in people. The aim of this study was to describe epidemiological and diagnostic characteristics of such strains in relation to bovine mastitis. Among 1,199 cattle from 6 herds, cow-level prevalence of S. agalactiae was estimated to be 27.4% based on PCR and 7.8% based on bacteriological culture. Quarter-level prevalence was estimated at 2.8% based on bacteriological culture. Per herd, between 2 and 26 isolates were characterized by pulsed-field gel electrophoresis (PFGE) and MLST. Within each herd, a single PFGE type and ST predominated, consistent with a contagious mode of transmission or point source infection within herds. Evidence of within-herd evolution of S. agalactiae was detected with both typing methods, although ST belonged to a single clonal complex (CC) per herd. Detection of CC23 (3 herds) was associated with significantly lower approximate count (colony-forming units) at the quarter level and significantly lower cycle threshold value at the cow level than detection of CC1 (2 herds) or CC19 (1 herd), indicating a lower bacterial load in CC23 infections. Median values for the number of infected quarters and somatic cell count (SCC) were numerically but not significantly lower for cows infected with CC23 than for cows with CC1 or CC19. For all CC, an SCC threshold of 200,000 cells/mL was an unreliable indicator of infection status, and prescreening of animals based on SCC as part of S. agalactiae detection and eradication campaigns should be discouraged. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights

  17. Milk quality assurance for paratuberculosis: simulation of within-herd infection dynamics and economicsof within-herd infection dynamics and economics

    Weber, M.F.; Nielen, M.; Velthuis, A.G.J.; Roermund, van H.J.W.

    2008-01-01

    bulk milk quality assurance programme for Mycobacterium avium subsp. paratuberculosis (Map) in dairy herds was simulated with a stochastic simulation model (JohneSSim). The aim of this study was to evaluate the epidemiological and economic effects of preventive management measures and various test

  18. Clinical and laboratory studies on herds affected with postweaning multisystemic wasting syndrome in Denmark, France, Spain, and Sweden: Disease progression and a proposal for herd case definition

    Grau-Roma, L.; Baekbo, P.; Rose, N.

    2012-01-01

    , a significant increase in postweaning mortality, compared to the historical background in the herd, must be observed in association with clinical signs compatible with PMWS. Secondly, PMWS must be diagnosed in at least one of three to five necropsied pigs concurrently with the increase in mortality. Ruling out...

  19. The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape: A Large-Scale Genome-Wide Interaction Study.

    Thomas W Winkler

    2015-10-01

    Full Text Available Genome-wide association studies (GWAS have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI, a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age- and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT Consortium. Each study tested the association of up to ~2.8M SNPs with BMI and WHRadjBMI in four strata (men ≤50y, men >50y, women ≤50y, women >50y and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE, sex-specific effects (G x SEX or age-specific effects that differed between men and women (G x AGE x SEX. For BMI, we identified 15 loci (11 previously established for main effects, four novel that showed significant (FDR<5% age-specific effects, of which 11 had larger effects in younger (<50y than in older adults (≥50y. No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.

  20. Study of the interaction between the indentation size effect and Hall-Petch effect with spherical indenters on annealed polycrystalline copper

    Hou, X D; Bushby, A J; Jennett, N M

    2008-01-01

    Methods to obtain tensile stress-strain properties of materials from a practically non-destructive indentation test are of great industrial interest. Nanoindentation is a good candidate. However, to do this successfully, indentation size effects must be accounted for. An indentation size effect with spherical indenters has been shown for a range of fcc metals with relatively large grain size (Spary et al 2006 Phil. Mag. 86 5581-93); the increase in yield stress being proportional to the inverse cube root of indenter radius. Here, we investigate these differences further and present results for the indentation size effect with spherical indenters on Cu samples with a range of different grain sizes from 1 μm to single crystal. The important experimental control parameter, of the relative size of the indentation compared with the grain size, is also explored by using indenters of different radii on the different grain sized samples. When the grain size, d, is less than 6 times the radius of the projected contact area, a, a Hall-Petch-like behaviour is observed superimposed on the indentation size effect. For d > 6a the indentation size effect dominates. The two effects may be combined by addition in quadrature. This new parametric function is able to predict the indentation pressure in annealed copper given input values of indenter radius and grain size

  1. Warming Climate and Changing Societies - a Challenge or an Opportunity for Reindeer Herding?

    Käyhkö, J.; Horstkotte, T.; Kivinen, S.; Vehmas, J.; Oksanen, L.; Forbes, B. C.; Johansen, B.; Jepsen, J. U.; Markkola, A.; Pulliainen, J.; Olofsson, J.; Oksanen, T.; Utsi, T. A.; Korpimäki, E.; Menard, C.; Ericson, L.

    2015-12-01

    The Arctic region will warm more rapidly than the global mean, influencing dramatically the northern ecosystems. Simultaneously, our societies transform towards urbanized, highly educated, service-based culture, where a decreasing population will gain its livelihood from primary production. We study various ecosystem interactions in a changing climate and integrate these with reindeer husbandry and the indigenous Sámi culture dependent on it1. Potential climate impacts include the transformation of arctic-alpine tundra to dense scrubland with conceivable consequences to reindeer husbandry, but also global warming due to decreasing albedo. The social-ecological system (SES) of reindeer husbandry includes administrative and ecological processes that do not always correspond (Figure 1). Consequently, management priorities and administration may conflict with local social and ecological processes, bringing about risks of environmental degradation, loss of biodiversity and defeat of traditional livelihoods. We hypothesize the plausibility to support the indigenous reindeer herding livelihood against rapid external changes by utilizing the migratory reindeer grazing system of the Sámi as a management tool for sustaining the high-albedo tundra and mitigating global warming. Our first-of-a-kind satellite-based high resolution vegetation map covering Northern Fennoscandia allows detailed management plans. Our ecological research demonstrates the important role of herbivory on arctic vegetation communities. Interactive workshops with reindeer herders offer indigenous knowledge of state and changes of the ecosystems, and reflect the threats and expectations of the herders. We are currently building models of the complex social-ecological system of Northern Fennoscandia and will report the first findings of the exercise. 1 www.ncoetundra.utu.fi Figure 1. The scales of administrative and ecological processes do not always coincide. This may bring about challenges in managing

  2. Spatial and temporal patterns of pig herds diagnosed with Postweaning Multisystemic Wasting Syndrome (PMWS) during the first two years of its occurrence in Denmark

    Vigre, Håkan; Bækbo, P.; Jorsal, Sven Erik Lind

    2005-01-01

    two years after the first herd was diagnosed, and we tested for spatial and spatio-temporal clustering using scan statistics. The study population consisted of pig herds that during the study period (October 2001 - September 2003) performed diagnostic submissions to the two major veterinary diagnostic......The clinical syndrome Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs has emerged globally during the last decade. In October 2001, the first pig herd diagnosed with PMWS was reported in Denmark, and since then the number of herds diagnosed with PMWS has increased markedly. The etiology...... laboratories in Denmark (6724 herds). Of these, 277 herds were diagnosed with PMWS. Two statistically significant spatial clusters of herds diagnosed with PMWS were identified. These clusters included 11% and 8% of the study herds, respectively. Within these two clusters the relative risk for a herd...

  3. Financial effect of bovine Johne's disease in beef cattle herds in Australia.

    Webb Ware, J K; Larsen, J W A; Kluver, P

    2012-04-01

    To assess the financial effect of programs for controlling bovine Johne's disease (BJD) in beef herds. A spreadsheet simulation model of a self-replacing beef herd in south-eastern Australia selling 400-kg steers at 15 months old. The model calculated the monthly cash flow, and net present value (NPV) of cumulative cash flow, over 10 years. Four main control options were compared: (1) a base herd (no action to control the disease), (2) test and cull, and (3) partial and (4) total destocking. It was assumed that BJD was eradicated after 3 and 5 years with total and partial destocking, respectively, and not eradicated with a test and cull program. Scenarios were compared for both commercial and stud enterprises. If there was no discount on the sale price of cattle in commercial herds, deaths from BJD had to exceed 5% before the NPV of partial or total destocking was similar to taking no action to control the disease over a 10-year period. When cattle sales incurred a 10% discount, deaths had to exceed 1% before the destocking strategies would break even after 10 years. Control options for BJD should be carefully planned on an individual herd basis, as significant production and financial risks accompany destocking programs. Eradication will only be more profitable in the longer term, compared with living with the disease, when discounts on the sale of stock from infected herds are high. This can occur with the selling of store cattle or breeders. In stud herds, BJD will usually cause the total failure of the business. © 2012 The Authors. Australian Veterinary Journal © 2012 Australian Veterinary Association.

  4. Streptococcus agalactiae in the environment of bovine dairy herds--rewriting the textbooks?

    Jørgensen, H J; Nordstoga, A B; Sviland, S; Zadoks, R N; Sølverød, L; Kvitle, B; Mørk, T

    2016-02-29

    Many free-stall bovine dairy herds in Norway fail to eradicate Streptococcus agalactiae despite long-term control measures. In a longitudinal study of 4 free-stall herds with automatic milking systems (AMS), milk and extramammary sites were sampled 4 times with 1-2 month intervals. Composite milk, rectal- and vaginal swabs were collected from dairy cows; rectal swabs from heifers and young stock; rectal- and tonsillar swabs from calves; and environmental swabs from the AMS, the floors, cow beds, watering and feeding equipment. A cross sectional study of 37 herds was also conducted, with 1 visit for environmental sampling. Fifteen of the herds were known to be infected with S. agalactiae while the remaining 22 had not had evidence of S. agalactiae mastitis in the preceding 2 years. All samples were cultured for S. agalactiae, and selected isolates (n=54) from positive herds were genotyped by Multi Locus Sequence Typing (MLST). Results show that the bovine gastrointestinal tract and the dairy cow environment are reservoirs of S. agalactiae, and point to the existence of 2 transmission cycles; a contagious transmission cycle via the milking machine and an oro-fecal transmission cycle, with drinking water as the most likely vehicle for transmission. Ten sequence types were identified, and results suggest that strains differ in their ability to survive in the environment and transmit within dairy herds. Measures to eradicate S. agalactiae from bovine dairy herds should take into account the extra-mammary reservoirs and the potential for environmental transmission of this supposedly exclusively contagious pathogen. Copyright © 2016. Published by Elsevier B.V.

  5. Determining the Ratio of Animal Species in the Herd of Pre-Class Societies

    Stegantsev Mark A.

    2013-09-01

    Full Text Available The article is devoted to the methodology of research of domestic animals herd composition in ancient societies, based on the materials of Late Bronze and Early Iron Age sites located in the Western part of forest-steppe and steppe of Western Siberia and Northern Kazakhstan. The theoretical portion of the article demonstrates that percentage composition of the ancient herd can be restored only by taking into account the early maturation of the domestic ungulates forming its component part. The values of their early maturation depend on the distribution of animals by age. The formulas, derived through herd models developed, make it possible to determine the required distribution, based on the number of animal units of different ages in osteological collections. They are not affected by the type of herd reproduction. The application of the derived formulas in order to determine the early maturation of large and small cattle, and horses in the settlements of certain cultures in forest, forest-steppe and steppe zones, has confirmed the adequacy of the model in explaining the archaeological data. It has also been shown that economic specialization of successive Late Bronze and Early Iron Age cultures in the region was determined mainly by the horse. The study of different methods of determining ancient herd composition has made it possible to come to the following conclusion. The method of transition from identifiable bones in the excavation to the number of animal units corresponding to them, and then, by determining early maturation of different species, to their ratio in the ancient herd, has an absolute priority as compared to the method of transition from the identifiable bones directly to herd composition.

  6. The effect of herd formation among healthcare investors on health sector growth in China.

    Lulin, Zhou; Antwi, Henry Asante; Wang, Wenxin; Yiranbon, Ethel; Marfo, Emmanuel Opoku; Acheampong, Patrick

    2016-07-19

    China has become the world's second largest healthcare market based on a recent report by the World Health Organization. Eventhough China achieved universal health insurance coverage in 2011, representing the largest expansion of insurance coverage in human history achieved; health inequality remains endemic in China. Lessons from the effect of market crisis on health equity in Europe and other places has reignited interest in exploring the potential healthcare market aberrations that can trigger distributive injustice in healthcare resource allocation among China's provinces. Recently, many healthcare investors in China have become more concerned about capital preservation, and are responding by abandoning long term investments strategies in healthcare. This investment withdrawal en mass is perceived to be influenced by herding tendencies and can trigger or consolidate endemic health inequality. Our study simultaneously employs four testing models (two state spaced models and two return dispersion models) to establish the existence of procyclical (herding) behavior among the stocks and its health equity implications. These are applied to a large set of data to compare and contrast results of herd formation among investors in fourteen healthcare sectors in China. The study reveals that apart from the cross sectional standard deviation (CSSD) model, the remaining two models and our augmented state space model yields significant evidence of herding in all subsectors of the healthcare market. We also find that the herding effect is more prominent during down movements of the market. Herding behavior may lead to contemporaneous loss of investor confidence and capital withdrawal and thereby deprive the healthcare sector of the much needed capital for expansion. Thus there may be obvious delay in efforts to bridge the gap in access to healthcare facilities, medical support services, medical supplies, pharmaceuticals, biotechnology, diagnostic substances, medical

  7. Metabolic profiles in five high-producing Swedish dairy herds with a history of abomasal displacement and ketosis

    Stengärde Lena

    2008-08-01

    Full Text Available Abstract Background Body condition score and blood profiles have been used to monitor management and herd health in dairy cows. The aim of this study was to examine BCS and extended metabolic profiles, reflecting both energy metabolism and liver status around calving in high-producing herds with a high incidence of abomasal displacement and ketosis and to evaluate if such profiles can be used at herd level to pinpoint specific herd problems. Methods Body condition score and metabolic profiles around calving in five high-producing herds with high incidences of abomasal displacement and ketosis were assessed using linear mixed models (94 cows, 326 examinations. Cows were examined and blood sampled every three weeks from four weeks ante partum (ap to nine weeks postpartum (pp. Blood parameters studied were glucose, fructosamine, non-esterified fatty acids (NEFA, insulin, β-hydroxybutyrate, aspartate aminotransferase, glutamate dehydrogenase, haptoglobin and cholesterol. Results All herds had overconditioned dry cows that lost body condition substantially the first 4–6 weeks pp. Two herds had elevated levels of NEFA ap and three herds had elevated levels pp. One herd had low levels of insulin ap and low levels of cholesterol pp. Haptoglobin was detected pp in all herds and its usefulness is discussed. Conclusion NEFA was the parameter that most closely reflected the body condition losses while these losses were not seen in glucose and fructosamine levels. Insulin and cholesterol were potentially useful in herd profiles but need further investigation. Increased glutamate dehydrogenase suggested liver cell damage in all herds.

  8. Metabolic profiles in five high-producing Swedish dairy herds with a history of abomasal displacement and ketosis

    Stengärde, Lena; Tråvén, Madeleine; Emanuelson, Ulf; Holtenius, Kjell; Hultgren, Jan; Niskanen, Rauni

    2008-01-01

    Background Body condition score and blood profiles have been used to monitor management and herd health in dairy cows. The aim of this study was to examine BCS and extended metabolic profiles, reflecting both energy metabolism and liver status around calving in high-producing herds with a high incidence of abomasal displacement and ketosis and to evaluate if such profiles can be used at herd level to pinpoint specific herd problems. Methods Body condition score and metabolic profiles around calving in five high-producing herds with high incidences of abomasal displacement and ketosis were assessed using linear mixed models (94 cows, 326 examinations). Cows were examined and blood sampled every three weeks from four weeks ante partum (ap) to nine weeks postpartum (pp). Blood parameters studied were glucose, fructosamine, non-esterified fatty acids (NEFA), insulin, β-hydroxybutyrate, aspartate aminotransferase, glutamate dehydrogenase, haptoglobin and cholesterol. Results All herds had overconditioned dry cows that lost body condition substantially the first 4–6 weeks pp. Two herds had elevated levels of NEFA ap and three herds had elevated levels pp. One herd had low levels of insulin ap and low levels of cholesterol pp. Haptoglobin was detected pp in all herds and its usefulness is discussed. Conclusion NEFA was the parameter that most closely reflected the body condition losses while these losses were not seen in glucose and fructosamine levels. Insulin and cholesterol were potentially useful in herd profiles but need further investigation. Increased glutamate dehydrogenase suggested liver cell damage in all herds. PMID:18687108

  9. Applied biotechnology for improving fertility of herds in Argentina

    Mongiardino, M.E.; Dick, A.R.; Murray, R.; Ramos, G.; Balbiani, G.; Maciel, M.

    1990-01-01

    In an attempt to find methods to shorten the calving to conception interval of dairy cattle in Argentina, three research projects were carried out: (1) use of hormonal treatments in the early post-partum period to increase fertility in non-cycling cows; (2) treatments to increase the fertility of cycling cows; and (3) management systems to improve the efficiency of oestrus detection. In non-cycling cows, fewer services per conception and earlier pregnancies were obtained when a progesterone suppository was placed intravaginally (PRID treatment) 24-31 days post-partum. No statistical reduction in days open was observed, however, because of the great variability in response within groups. GnRH injection given 24 and 25 days post-partum did not improve reproductive indices. In cycling cows, clitoral massage after AI did not enhance fertility, while GnRH 14 days post-service resulted in pregnancy rates of 68.4% compared with 25% in the control group. In an attempt to improve the efficiency of oestrus detection successive periods of either 10 or 14 days of 'heat' observation followed by similar periods of no observation, combined with the systematic use of an oestrus synchronizer (cloprostenol), resulted in the same reproductive performance as in control cows observed continuously but with a saving of 50% in time spent in oestrus detection. In a seasonally bred herd, a reduction of 12 days in interval to conception and subsequent improvement in milk produced in the following season were obtained by synchronizing oestrus at the start of the breeding season with a norgestomet implant followed by a prostaglandin injection one day before implant removal. In repeat breeders, a second implant 9 days and 21 days later was found to be effective. (author). 24 refs, 2 figs, 4 tabs

  10. Analytical study of index-coupled herd behavior in financial markets

    Berman, Yonatan; Shapira, Yoash; Schwartz, Moshe

    2016-12-01

    Herd behavior in financial markets had been investigated extensively in the past few decades. Scholars have argued that the behavioral tendency of traders and investors to follow the market trend, notably reflected in indices both on short and long time scales, is substantially affecting the overall market behavior. Research has also been devoted to revealing these behaviors and characterizing the market herd behavior. In this paper we present a simple herd behavior model for the dynamics of financial variables by introducing a simple coupling mechanism of stock returns to the index return, deriving analytic expressions for statistical properties of the returns. We found that several important phenomena in the stock market, namely the correlations between stock market returns and the exponential decay of short-term autocorrelations, are derived from our model. These phenomena have been given various explanations and theories, with herd market behavior being one of the leading. We conclude that the coupling mechanism, which essentially encapsulates the herd behavior, indeed creates correlation and autocorrelation. We also show that this introduces a time scale to the system, which is the characteristic time lag between a change in the index and its effect on the return of a stock.

  11. Assessing, and understanding, European organic dairy farmers' intentions to improve herd health.

    Jones, P J; Sok, J; Tranter, R B; Blanco-Penedo, I; Fall, N; Fourichon, C; Hogeveen, H; Krieger, M C; Sundrum, A

    2016-10-01

    Many believe the health status of organic dairy herds in Europe should be improved to meet consumers' and legislators' expectations to improve animal welfare. This paper reports on a study in four countries that examined dairy farmers' intentions towards improving the health status of their organic herds through the use of the Theory of Planned Behaviour. It was found that farmers across the countries were positive about taking additional preventative measures to improve the health status of their herds. They believed this would not only improve herd physical performance, such as milk yield and fertility, but also achieve greater cost effectiveness and improved job satisfaction for them. Most study farmers would implement a tailored package of improvement measures designed by the study team with higher uptake most likely being by younger farmers, those who make greater use of veterinarians and professional advisory services, and those supplying specialist milk-marketing chains. Furthermore, farmers will be most likely to take-up additional health promotion if compatible with their everyday activities and if they have strong business performance goals aimed at maximising the physical performance of the herd. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Herd-specific random regression carcass profiles for beef cattle after adjustment for animal genetic merit.

    Englishby, Tanya M; Moore, Kirsty L; Berry, Donagh P; Coffey, Mike P; Banos, Georgios

    2017-07-01

    Abattoir data are an important source of information for the genetic evaluation of carcass traits, but also for on-farm management purposes. The present study aimed to quantify the contribution of herd environment to beef carcass characteristics (weight, conformation score and fat score) with particular emphasis on generating finishing herd-specific profiles for these traits across different ages at slaughter. Abattoir records from 46,115 heifers and 78,790 steers aged between 360 and 900days, and from 22,971 young bulls aged between 360 and 720days, were analysed. Finishing herd-year and animal genetic (co)variance components for each trait were estimated using random regression models. Across slaughter age and gender, the ratio of finishing herd-year to total phenotypic variance ranged from 0.31 to 0.72 for carcass weight, 0.21 to 0.57 for carcass conformation and 0.11 to 0.44 for carcass fat score. These parameters indicate that the finishing herd environment is an important contributor to carcass trait variability and amenable to improvement with management practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Niat Melakukan Pencatatan Akuntansi pada Usaha Kecil Menengah: Pengetahuan Akuntansi ataukah Herding?

    Yohanes Hendri Andhika

    2017-11-01

    Full Text Available Indonesian SMEs exhibit low intention to prepare accounting records. Previous studies suggest that the level of accounting knowledge is positively associated with the intention to prepare accounting records, but none of them discusses the likely effect of the Indonesian collectivism culture on the intention to prepare accounting records. Accordingly, this study adds the role of herding behavior in explaining the SMEs’ intention to prepare accounting records. Using SMEs in Salatiga as our respondents, our study shows that both herding behavior and accounting knowledge positively affect the intention to prepare accounting records. Abstrak Realitas UKM di Indonesia menunjukkan rendahnya niat melakukan pencatatan akuntansi. Penelitian-penelitian sebelumnya lebih melihat bagaimana niat untuk melakukan pencatatan dikaitkan dengan pengetahuan akuntansi. Namun, dengan melihat latar belakang budaya masyarakat Indonesia yang kolektivisme, maka penelitian ini menambahkan variable perilaku herding dalam kaitannya dengan niat melakukan pencatatan. Tujuan dari penelitian ini adalah menguji pengaruh antara pengetahuan akuntansi dan perilaku herding terhadap niat melakukan pencatatan akuntansi. Penelitian dilakukan pada UKM yang berada di Kota Salatiga. Pengambilan sampel menggunakan metode convenience sampling. Hasil pengujian menunjukkan perilaku herding dan pengetahuan akuntansi berpengaruh positif terhadap kemauan dalam membuat pencatatan keuangan.

  14. Effect of calving interval and parity on milk yield per feeding day in Danish commercial dairy herds.

    Lehmann, J O; Fadel, J G; Mogensen, L; Kristensen, T; Gaillard, C; Kebreab, E

    2016-01-01

    The idea of managing cows for extended lactations rather than lactations of the traditional length of 1 yr primarily arose from observations of increasing problems with infertility and cows being dried off with high milk yields. However, it is vital for the success of extended lactation practices that cows are able to maintain milk yield per feeding day when the length of the calving interval (CInt) is increased. Milk yield per feeding day is defined as the cumulated lactation milk yield divided by the sum of days between 2 consecutive calvings. The main objective of this study was to investigate the milk production of cows managed for lactations of different lengths, and the primary aim was to investigate the relationship between CInt, parity, and milk yield. Five measurements of milk yield were used: energy-corrected milk (ECM) yield per feeding day, ECM yield per lactating day, cumulative ECM yield during the first 305 d of lactation, as well as ECM yield per day during early and late lactation. The analyses were based on a total of 1,379 completed lactations from cows calving between January 2007 and May 2013 in 4 Danish commercial dairy herds managed for extended lactation for several years. Herd-average CInt length ranged from 414 to 521 d. The herds had Holstein, Jersey, or crosses between Holstein, Jersey, and Red Danish cows with average milk yields ranging from 7,644 to 11,286 kg of ECM per cow per year. A significant effect of the CInt was noted on all 5 measurements of milk yield, and this effect interacted with parity for ECM per feeding day, ECM per lactating day and ECM per day during late lactation. The results showed that cows were at least able to produce equivalent ECM per feeding day with increasing CInt, and that first- and second-parity cows maintained ECM per lactating day. Cows with a CInt between 17 and 19 mo produced 476 kg of ECM more during the first 305 d compared with cows with a CInt of less than 13 mo. Furthermore, early

  15. Study of the chemical interaction between the beryllium powders of different particles size and the air in the temperature range 500-1000degC form the viewpoint of ITER safety

    Davydov, D.A. [State Scientific Center of Russian Federation, Moscow (Russian Federation); Konovalov, Y.V.; Gorokhov, V.A.; Levin, V.B.; Chekhlatov, G.M.; Khomutov, A.M.

    1998-01-01

    Under an effect of some factors characteristic for the ITER- operating condition a dense beryllium facing plasma can transit into various forms, changing its structural states. As a result of the bombardment of beryllium plasma facing components by ion fluxes, the production of a dust including the particles from a few micrometers to a few millimeters in size is possible. The specific features in the behaviour of various beryllium forms under emergency conditions are of an essential interest from the viewpoint of ITER safety. Some grades of powders of different average particles size (14-31 micron) have been produced in a given study, and their chemical interaction at high temperatures with air (500-1100degC), test duration effects simulating the emergency situation at ITER in the first approximation have been studied. The temperature dependence of beryllium powders (different particles size after disc abrased) interaction with air in the temperature range 500-1000degC at the exposure of 5 hours long for each temperature and kinetic dependence of interaction of these powders with air at 800degC for the exposure from half an hour to 7 hours long were studied. An analysis of granulometric weight fraction in the metallic and oxidized beryllium powders with different particles size has been done by the photosedimentational technique with the instrument `Analysette-20`. Construction of a mathematical model for the chemical interaction of beryllium powders with air at high temperatures have been carried out. (author)

  16. Herd-level prevalence and incidence of porcine epidemic diarrhoea virus (PEDV) and porcine deltacoronavirus (PDCoV) in swine herds in Ontario, Canada.

    Ajayi, T; Dara, R; Misener, M; Pasma, T; Moser, L; Poljak, Z

    2018-04-01

    Porcine epidemic diarrhoea virus (PEDV) and porcine deltacoronavirus (PDCoV) were first identified in Canada in 2014. Surveillance efforts have been instrumental in controlling both diseases. In this study, we provide an overview of surveillance components for the two diseases in Ontario (Canada), as well as PEDV and PDCoV incidence and prevalence measures. Swine herds located in the Province of Ontario, of any type, whose owners agreed to participate in a voluntary industry-led disease control programme (DCP) and with associated diagnostic or epidemiological information about the two swine coronaviruses, were eligible to be included for calculation of disease frequency at the provincial level. PEDV and PDCoV data stored in the industry DCP database were imported into the R statistical software and analysed to produce weekly frequency of incidence counts and prevalence counts, in addition to yearly herd-level incidence risk and prevalence between 2014 and 2016. The yearly herd-level incidence risk of PEDV, based on industry data, was 13.5%, 3.0% and 1.4% (95% CI: 11.1-16.2, 2.0-4.2, 0.8-2.3), while the yearly herd-level incidence risk of PDCoV was 1.1%, 0.3%, and 0.1% (95% CI: 0.5-2.2, 0.1-0.9, 0.0-0.5), for 2014, 2015 and 2016, respectively. Herd-level prevalence estimates for PEDV in the last week of 2014, 2015 and 2016 were 4.4%, 2.3% and 1.4%, respectively (95% CI: 3.1-6.0, 1.5-3.3, 0.8-2.2), while herd-level prevalence estimates for PDCoV in the last week of 2014, 2015 and 2016 were 0.5%, 0.2% and 0.2%, respectively (95% CI: 0.1-1.2, 0.0-0.6, 0.0-0.6). Collectively, our results point to low and decreasing incidence risk and prevalence for PEDV and PDCoV in Ontario, making both diseases possible candidates for disease elimination at the provincial level. © 2018 Blackwell Verlag GmbH.

  17. Canadian National Dairy Study: Herd-level milk quality.

    Bauman, C A; Barkema, H W; Dubuc, J; Keefe, G P; Kelton, D F

    2018-03-01

    The objective of this study was to estimate Canadian national milk quality parameters and estimate the bulk tank milk (BTM) prevalence of 4 mastitis pathogens, Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, and Prototheca spp., on Canadian dairy farms. A questionnaire was sent to all Canadian dairy producers. Of the 1,062 producers who completed the questionnaire, 374 producers from across the country were visited and milking hygiene was assessed. Farm-level milk quality data for all Canadian dairy producers was collected from the provincial marketing boards and combined with the questionnaire and farm visit data. In addition, a BTM sample was collected either during the farm visit or by the marketing board in November of 2015 and was tested for 4 major mastitis pathogens using the PathoProof Mastitis Major 4 PCR Assay (Thermo Fisher Scientific Inc., Waltham, MA). Apparent herd-level prevalence was 46% for S. aureus, 6% for Prototheca spp., 0% for M. bovis, and 0% for Strep. agalactiae. Due to the low prevalence of M. bovis and Strep. agalactiae and a lack of significant factors associated with farms testing positive for Prototheca spp., an association analysis could only be carried out for Staph. aureus-positive farms. Factors associated with Staph. aureus-positive farms were not fore-stripping cows before milking (odds ratio = 1.87), milking with a pipeline system (odds ratio = 2.21), and stall bases made of a rubberized surface (mats and mattresses), whereas protective factors were using blanket dry cow therapy (odds ratio = 0.49) and applying a tag or visible mark on cows known to have chronic mastitis infections (odds ratio = 0.45). The Canadian national production-weighted geometric mean somatic cell count was determined to be 208,000 cells/mL. This is the first national dairy study conducted in Canada. Participating farms had higher milk yield; were more likely to have a loose housing system, parlor, or automated milking system; and had

  18. Parasites of sheep herding dogs in central Germany.

    Rehbein, Steffen; Kaulfuß, Karl-heinz; Visser, Martin; Sommer, Maria Franziska; Grimm, Felix; Silaghi, Cornelia

    2016-01-01

    This paper reports on endoparasite infections diagnosed in 2012 by standard coproscopical techniques and coproantigen Giardia ELISA in 165 dogs used for sheep herding in 36 farms in central Germany. The overall prevalence of dogs with evidence of endoparasite infections was 27.3% (95% CI 20.6-34.7). The most frequently identified faecal forms were those of ascarids (Toxocara, 6.7%; Toxascaris 3.6%), hookworms (5.5%) and taeniid cestodes (4.2%), followed by those of Trichuris whipworms (3.0%), Capillaria aerophila (1.8%), Angiostrongylus and Crenosoma lungworms (1.2% each) and Cystoisospora canis coccidians (0.6%). Molecular identification demonstrated the seven dogs shedding taeniid eggs positive for Taenia (T.) species tapeworms (five, T. hydatigena; one, T. ovis; one Taenia sp.). Screening of the faeces with the coproantigen ELISA revealed Giardia specific antigen in 5.5% of the samples. The majority of the dogs had evidence of single endoparasite infections (22.4%) while evidence for infection with two or three parasites concurrently was found in six (3.6%) and two (1.2%) of the dogs, respectively. Dogs ≤ 1 year (n = 19) were parasitized more frequently (p < 0.05) with overall gastrointestinal parasites (63.2% vs. 20.5%), ascarids (36.8% vs. 6.8%) and Giardia spp. (21.1% vs. 3.4%) than older dogs (n = 146). Dogs which had been wormed within six months of examination tested less frequently positive for gastrointestinal helminths compared to dogs not wormed (11.1% vs. 25.0%; p = 0.0567). In addition, ear swabs taken from 43 sheep dogs in 2012 were examined, and Otodectes cynotis mites were extracted from one dog. Identification of ectoparasites collected by full body search and combing from 113 sheep dogs in the years 2011 to 2013 revealed infestation of fleas and ticks (each up to five specimens per dog) on 13 and 108 dogs, respectively, with nine dogs carrying both fleas and ticks. Archaeopsylla erinacei, Ctenocephalides (C) canis, C. felis and Pulex irritans

  19. Herding: a new phenomenon affecting medical decision-making in multiple sclerosis care? Lessons learned from DIScUTIR MS.

    Saposnik, Gustavo; Maurino, Jorge; Sempere, Angel P; Ruff, Christian C; Tobler, Philippe N

    2017-01-01

    Herding is a phenomenon by which individuals follow the behavior of others rather than deciding independently on the basis of their own private information. A herding-like phenomenon can occur in multiple sclerosis (MS) when a neurologist follows a therapeutic recommendation by a colleague even though it is not supported by best practice clinical guidelines. Limited information is currently available on the role of herding in medical care. The objective of this study was to determine the prevalence (and its associated factors) of herding in the management of MS. We conducted a study among neurologists with expertise in MS care throughout Spain. Participants answered questions regarding the management of 20 case scenarios commonly encountered in clinical practice and completed 3 surveys and 4 experimental paradigms based on behavioral economics. The herding experiment consisted of a case scenario of a 40-year-old woman who has been stable for 3 years on subcutaneous interferon and developed a self-limited neurological event. There were no new magnetic resonance imaging (MRI) lesions. Her neurological examination and disability scores were unchanged. She was advised by an MS neurologist to switch from interferon to fingolimod against best practice guidelines. Multivariable logistic regression analysis was conducted to evaluate factors associated with herding. Out of 161 neurologists who were invited to participate, 96 completed the study (response rate: 60%). Herding was present in 75 (78.1%), having a similar prevalence in MS experts and general neurologists (68.8% vs 82.8%; P =0.12). In multivariate analyses, the number of MS patients seen per week was positively associated with herding (odds ratio [OR] 1.08, 95% CI 1.01-1.14). Conversely, physician's age, gender, years of practice, setting of practice, or risk preferences were not associated with herding. Herding was a common phenomenon affecting nearly 8 out of 10 neurologists caring for MS patients. Herding may

  20. Interspecific Interactions and the Scope for Parent-Offspring Conflict: High Mite Density Temporarily Changes the Trade-Off between Offspring Size and Number in the Burying Beetle, Nicrophorus vespilloides.

    Ornela De Gasperin

    Full Text Available Parents have a limited amount of resources to invest in reproduction and commonly trade-off how much they invest in offspring size (or quality versus brood size. A negative relationship between offspring size and number has been shown in numerous taxa and it underpins evolutionary conflicts of interest between parents and their young. For example, previous work on vertebrates shows that selection favours mothers that produce more offspring, at the expense of individual offspring size, yet favours offspring that have relatively few siblings and therefore attain a greater size at independence. Here we analyse how this trade-off is temporarily affected by stochastic variation in the intensity of interspecific interactions. We examined the effect of the mite Poecilochirus carabi on the relationship between offspring size and number in the burying beetle, Nicrophorus vespilloides. We manipulated the initial number of mites in the reproductive event (by introducing either no mites, 4 mites, 10 mites, or 16 mites, and assessed the effect on the brood. We found a similar trade-off between offspring size and number in all treatments, except in the '16 mite' treatment where the correlation between offspring number and size flattened considerably. This effect arose because larvae in small broods failed to attain a high mass by dispersal. Our results show that variation in the intensity of interspecific interactions can temporarily change the strength of the trade-off between offspring size and number. In this study, high densities of mites prevented individual offspring from attaining their optimal weight, thus potentially temporarily biasing the outcome of parent-offspring conflict in favour of parents.

  1. Interspecific Interactions and the Scope for Parent-Offspring Conflict: High Mite Density Temporarily Changes the Trade-Off between Offspring Size and Number in the Burying Beetle, Nicrophorus vespilloides.

    De Gasperin, Ornela; Kilner, Rebecca M

    2016-01-01

    Parents have a limited amount of resources to invest in reproduction and commonly trade-off how much they invest in offspring size (or quality) versus brood size. A negative relationship between offspring size and number has been shown in numerous taxa and it underpins evolutionary conflicts of interest between parents and their young. For example, previous work on vertebrates shows that selection favours mothers that produce more offspring, at the expense of individual offspring size, yet favours offspring that have relatively few siblings and therefore attain a greater size at independence. Here we analyse how this trade-off is temporarily affected by stochastic variation in the intensity of interspecific interactions. We examined the effect of the mite Poecilochirus carabi on the relationship between offspring size and number in the burying beetle, Nicrophorus vespilloides. We manipulated the initial number of mites in the reproductive event (by introducing either no mites, 4 mites, 10 mites, or 16 mites), and assessed the effect on the brood. We found a similar trade-off between offspring size and number in all treatments, except in the '16 mite' treatment where the correlation between offspring number and size flattened considerably. This effect arose because larvae in small broods failed to attain a high mass by dispersal. Our results show that variation in the intensity of interspecific interactions can temporarily change the strength of the trade-off between offspring size and number. In this study, high densities of mites prevented individual offspring from attaining their optimal weight, thus potentially temporarily biasing the outcome of parent-offspring conflict in favour of parents.

  2. The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape: A Large-Scale Genome-Wide Interaction Study

    T.W. Winkler (Thomas W.); A.E. Justice (Anne); M.J. Graff (Maud J.L.); Barata, L. (Llilda); M.F. Feitosa (Mary Furlan); Chu, S. (Su); J. Czajkowski (Jacek); T. Esko (Tõnu); M. Fall (Magnus); T.O. Kilpeläinen (Tuomas); Y. Lu (Yingchang); R. Mägi (Reedik); E. Mihailov (Evelin); T.H. Pers (Tune); Rüeger, S. (Sina); A. Teumer (Alexander); G.B. Ehret (Georg); T. Ferreira (Teresa); N.L. Heard-Costa (Nancy); J. Karjalainen (Juha); V. Lagou (Vasiliki); A. Mahajan (Anubha); Neinast, M.D. (Michael D.); I. Prokopenko (Inga); J. Simino (Jeannette); T.M. Teslovich (Tanya M.); R. Jansen; H.J. Westra (Harm-Jan); C.C. White (Charles); D. Absher (Devin); T.S. Ahluwalia (Tarunveer Singh); S. Ahmad (Shafqat); E. Albrecht (Eva); A.C. Alves (Alexessander Couto); Bragg-Gresham, J.L. (Jennifer L.); A.J. de Craen (Anton); J.C. Bis (Joshua); A. Bonnefond (Amélie); G. Boucher (Gabrielle); G. Cadby (Gemma); Y.-C. Cheng (Yu-Ching); Chiang, C.W. (Charleston W K); G. Delgado; A. Demirkan (Ayşe); N. Dueker (Nicole); N. Eklund (Niina); G. Eiriksdottir (Gudny); J. Eriksson (Joel); B. Feenstra (Bjarke); K. Fischer (Krista); F. Frau (Francesca); T.E. Galesloot (Tessel); F. Geller (Frank); A. Goel (Anuj); M. Gorski (Mathias); T.B. Grammer (Tanja); S. Gustafsson (Stefan); Haitjema, S. (Saskia); J.J. Hottenga (Jouke Jan); J.E. Huffman (Jennifer); A.U. Jackson (Anne); K.B. Jacobs (Kevin); A. Johansson (Åsa); M. Kaakinen (Marika); M.E. Kleber (Marcus); J. Lahti (Jari); I.M. Leach (Irene Mateo); Lehne, B. (Benjamin); Liu, Y. (Youfang); K.S. Lo; M. Lorentzon (Mattias); J. Luan (Jian'An); P.A. Madden (Pamela); M. Mangino (Massimo); B. McKnight (Barbara); Medina-Gomez, C. (Carolina); K.L. Monda (Keri); M.E. Montasser (May E.); G. Müller (Gabriele); M. Müller-Nurasyid (Martina); I.M. Nolte (Ilja); Panoutsopoulou, K. (Kalliope); L. Pascoe (Laura); L. Paternoster (Lavinia); N.W. Rayner (Nigel William); F. Renström (Frida); Rizzi, F. (Federica); L.M. Rose (Lynda); Ryan, K.A. (Kathy A.); P. Salo (Perttu); S. Sanna (Serena); H. Scharnagl (Hubert); Shi, J. (Jianxin); A.V. Smith (Albert Vernon); L. Southam (Lorraine); A. Stancáková (Alena); V. Steinthorsdottir (Valgerdur); R.J. Strawbridge (Rona); Sung, Y.J. (Yun Ju); I. Tachmazidou (Ioanna); T. Tanaka (Toshiko); G. Thorleifsson (Gudmar); S. Trompet (Stella); N. Pervjakova (Natalia); J.P. Tyrer (Jonathan); L. Vandenput (Liesbeth); S.W. Van Der Laan (Sander W.); N. van der Velde (Nathalie); J. van Setten (Jessica); J.V. van Vliet-Ostaptchouk (Jana); N. Verweij (Niek); E. Vlachopoulou (Efthymia); L. Waite (Lindsay); S.R. Wang (Sophie); Z. Wang (Zhaoming); S.H. Wild (Sarah); C. Willenborg (Christina); J.F. Wilson (James); A. Wong (Andrew); Yang, J. (Jian); L. Yengo (Loic); L.M. Yerges-Armstrong (Laura); Yu, L. (Lei); W. Zhang (Weihua); Zhao, J.H. (Jing Hua); E.A. Andersson (Ehm Astrid); S.J.L. Bakker (Stephan); D. Baldassarre (Damiano); Banasik, K. (Karina); Barcella, M. (Matteo); Barlassina, C. (Cristina); C. Bellis (Claire); P. Benaglio (Paola); J. Blangero (John); M. Blüher (Matthias); Bonnet, F. (Fabrice); L.L. Bonnycastle (Lori); H.A. Boyd (Heather); M. Bruinenberg (M.); Buchman, A.S. (Aron S.); H. Campbell (Harry); Y.D. Chen (Y.); P.S. Chines (Peter); S. Claudi-Boehm (Simone); J.W. Cole (John W.); F.S. Collins (Francis); E.J.C. de Geus (Eco); L.C.P.G.M. de Groot (Lisette); M. Dimitriou (Maria); J. Duan (Jubao); S. Enroth (Stefan); E. Eury (Elodie); A.-E. Farmaki (Aliki-Eleni); N.G. Forouhi (Nita); N. Friedrich (Nele); P.V. Gejman (Pablo); B. Gigante (Bruna); N. Glorioso (Nicola); A. Go (Attie); R.F. Gottesman (Rebecca); J. Gräßler (Jürgen); H. Grallert (Harald); N. Grarup (Niels); Gu, Y.-M. (Yu-Mei); L. Broer (Linda); A.C. Ham (Annelies); T. Hansen (T.); T.B. Harris (Tamara); C.A. Hartman (Catharina A.); Hassinen, M. (Maija); N. Hastie (Nick); A.T. Hattersley (Andrew); A.C. Heath (Andrew); A.K. Henders (Anjali); D.G. Hernandez (Dena); H.L. Hillege (Hans); O.L. Holmen (Oddgeir); G.K. Hovingh (Kees); J. Hui (Jennie); Husemoen, L.L. (Lise L.); Hutri-Kähönen, N. (Nina); P.G. Hysi (Pirro); T. Illig (Thomas); P.L. de Jager (Philip); S. Jalilzadeh (Shapour); T. Jorgensen (Torben); J.W. Jukema (Jan Wouter); Juonala, M. (Markus); S. Kanoni (Stavroula); M. Karaleftheri (Maria); K.T. Khaw; L. Kinnunen (Leena); T. Kittner (Thomas); W. Koenig (Wolfgang); I. Kolcic (Ivana); P. Kovacs (Peter); Krarup, N.T. (Nikolaj T.); W. Kratzer (Wolfgang); Krüger, J. (Janine); Kuh, D. (Diana); M. Kumari (Meena); T. Kyriakou (Theodosios); C. Langenberg (Claudia); L. Lannfelt (Lars); C. Lanzani (Chiara); V. Lotay (Vaneet); L.J. Launer (Lenore); K. Leander (Karin); J. Lindström (Jaana); A. Linneberg (Allan); Liu, Y.-P. (Yan-Ping); S. Lobbens (Stéphane); R.N. Luben (Robert); V. Lyssenko (Valeriya); S. Männistö (Satu); P.K. Magnusson (Patrik); W.L. McArdle (Wendy); C. Menni (Cristina); S. Merger (Sigrun); L. Milani (Lili); Montgomery, G.W. (Grant W.); A.P. Morris (Andrew); N. Narisu (Narisu); M. Nelis (Mari); K.K. Ong (Ken); A. Palotie (Aarno); L. Perusse (Louis); I. Pichler (Irene); M.G. Pilia (Maria Grazia); A. Pouta (Anneli); Rheinberger, M. (Myriam); Ribel-Madsen, R. (Rasmus); Richards, M. (Marcus); K.M. Rice (Kenneth); T.K. Rice (Treva K.); C. Rivolta (Carlo); V. Salomaa (Veikko); A.R. Sanders (Alan); M.A. Sarzynski (Mark A.); S. Scholtens (Salome); R.A. Scott (Robert); W.R. Scott (William R.); S. Sebert (Sylvain); S. Sengupta (Sebanti); B. Sennblad (Bengt); T. Seufferlein (Thomas); A. Silveira (Angela); P.E. Slagboom (Eline); J.H. Smit (Jan); T. Sparsø (Thomas); K. Stirrups (Kathy); R.P. Stolk (Ronald); H.M. Stringham (Heather); Swertz, M.A. (Morris A.); A.J. Swift (Amy); A.C. Syvänen; S.-T. Tan (Sian-Tsung); B. Thorand (Barbara); A. Tönjes (Anke); Tremblay, A. (Angelo); E. Tsafantakis (Emmanouil); P.J. van der Most (Peter); U. Völker (Uwe); M.-C. Vohl (Marie-Claude); J.M. Vonk (Judith); M. Waldenberger (Melanie); Walker, R.W. (Ryan W.); R. Wennauer (Roman); E. Widen; G.A.H.M. Willemsen (Gonneke); T. Wilsgaard (Tom); A.F. Wright (Alan); M.C. Zillikens (Carola); S. Van Dijk (Suzanne); N.M. van Schoor (Natasja); F.W. Asselbergs (Folkert); P.I.W. de Bakker (Paul); J.S. Beckmann (Jacques); J.P. Beilby (John); D.A. Bennett (David A.); R.N. Bergman (Richard); S.M. Bergmann (Sven); C.A. Böger (Carsten); B.O. Boehm (Bernhard); E.A. Boerwinkle (Eric); D.I. Boomsma (Dorret); S.R. Bornstein (Stefan); E.P. Bottinger (Erwin); C. Bouchard (Claude); J.C. Chambers (John); S.J. Chanock (Stephen); D.I. Chasman (Daniel); F. Cucca (Francesco); D. Cusi (Daniele); G.V. Dedoussis (George); J. Erdmann (Jeanette); K. Hagen (Knut); D. Evans; U. de Faire (Ulf); M. Farrall (Martin); L. Ferrucci (Luigi); I. Ford (Ian); L. Franke (Lude); P.W. Franks (Paul); P. Froguel (Philippe); R.T. Gansevoort (Ron); C. Gieger (Christian); H. Grönberg (Henrik); V. Gudnason (Vilmundur); U. Gyllensten (Ulf); P. Hall (Per); A. Hamsten (Anders); P. van der Harst (Pim); C. Hayward (Caroline); M. Heliovaara (Markku); C. Hengstenberg (Christian); A.A. Hicks (Andrew); A. Hingorani (Aroon); A. Hofman (Albert); Hu, F. (Frank); H.V. Huikuri (Heikki); K. Hveem (Kristian); A. James (Alan); Jordan, J.M. (Joanne M.); A. Jula (Antti); M. Kähönen (Mika); E. Kajantie (Eero); S. Kathiresan (Sekar); L.A.L.M. Kiemeney (Bart); M. Kivimaki (Mika); P. Knekt; H. Koistinen (Heikki); J.S. Kooner (Jaspal S.); S. Koskinen (Seppo); J. Kuusisto (Johanna); W. Maerz (Winfried); N.G. Martin (Nicholas); M. Laakso (Markku); T.A. Lakka (Timo); T. Lehtimäki (Terho); G. Lettre (Guillaume); D.F. Levinson (Douglas); W.H.L. Kao (Wen); M.L. Lokki; Mäntyselkä, P. (Pekka); M. Melbye (Mads); A. Metspalu (Andres); B.D. Mitchell (Braxton); F.L. Moll (Frans); J.C. Murray (Jeffrey); A.W. Musk (Arthur); M.S. Nieminen (Markku); I. Njølstad (Inger); C. Ohlsson (Claes); A.J. Oldehinkel (Albertine); B.A. Oostra (Ben); C. Palmer (Cameron); J.S. Pankow (James); G. Pasterkamp (Gerard); N.L. Pedersen (Nancy); O. Pedersen (Oluf); B.W.J.H. Penninx (Brenda); M. Perola (Markus); A. Peters (Annette); O. Polasek (Ozren); P.P. Pramstaller (Peter Paul); Psaty, B.M. (Bruce M.); Qi, L. (Lu); T. Quertermous (Thomas); Raitakari, O.T. (Olli T.); T. Rankinen (Tuomo); R. Rauramaa (Rainer); P.M. Ridker (Paul); J.D. Rioux (John); F. Rivadeneira Ramirez (Fernando); J.I. Rotter (Jerome I.); I. Rudan (Igor); H.M. den Ruijter (Hester ); J. Saltevo (Juha); N. Sattar (Naveed); Schunkert, H. (Heribert); P.E.H. Schwarz (Peter); A.R. Shuldiner (Alan); J. Sinisalo (Juha); H. Snieder (Harold); T.I.A. Sørensen (Thorkild); T.D. Spector (Timothy); Staessen, J.A. (Jan A.); Stefania, B. (Bandinelli); U. Thorsteinsdottir (Unnur); M. Stumvoll (Michael); J.-C. Tardif (Jean-Claude); E. Tremoli (Elena); J. Tuomilehto (Jaakko); A.G. Uitterlinden (André); M. Uusitupa (Matti); A.L.M. Verbeek; S.H.H.M. Vermeulen (Sita); J. Viikari (Jorma); Vitart, V. (Veronique); H. Völzke (Henry); P. Vollenweider (Peter); G. Waeber (Gérard); M. Walker (Mark); H. Wallaschofski (Henri); N.J. Wareham (Nick); H. Watkins (Hugh); E. Zeggini (Eleftheria); A. Chakravarti (Aravinda); Clegg, D.J. (Deborah J.); L.A. Cupples (Adrienne); P. Gordon-Larsen (Penny); C.E. Jaquish (Cashell); D.C. Rao (Dabeeru C.); Abecasis, G.R. (Goncalo R.); T.L. Assimes (Themistocles); I.E. Barroso (Inês); S.I. Berndt (Sonja); M. Boehnke (Michael); P. Deloukas (Panagiotis); C.S. Fox (Caroline); L. Groop (Leif); D. Hunter (David); E. Ingelsson (Erik); R.C. Kaplan (Robert); McCarthy, M.I. (Mark I.); K.L. Mohlke (Karen); J.R. O´Connell; Schlessinger, D. (David); D.P. Strachan (David); J-A. Zwart (John-Anker); C.M. van Duijn (Cornelia); J.N. Hirschhorn (Joel); C.M. Lindgren (Cecilia M.); I.M. Heid (Iris); K.E. North (Kari); I.B. Borecki (Ingrid); Z. Kutalik (Zoltán); R.J.F. Loos (Ruth)

    2015-01-01

    textabstractGenome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ

  3. Serum progesterone radioimmunoassay (RIA) for evaluation of reproductive performance of dairy herds

    Sula, F.; Stefanllari, K.; Lamce, Th.

    1996-01-01

    This publication summarizes the principal application of P 4-RIA of blood which helped to determine the time for onset of sexual functions after parturition, the incidence of silent oestrus, and the correct timing of service. Progesterone profiles showed that cows in this herd ovulated considerably later than 35+/-7 days after calving, which is the value reported for many other herds of dairy cows. The percentage of cows in oestrus was found 66% within 60 days post-partum while the incidence of silent oestrus was 20%. The correct timing of service is 85%. According to this study, the major causes for the lowered reproductive efficiency in this herd were found to be the delayed onset of post-partum ovarian activity and the incidence of silent oestrus. 9 refs. 3 tabs

  4. A longitudinal study of serological patterns of respiratory infections in nine infected Danish swine herds

    Andreasen, Margit; Nielsen, Jens; Bækbo, Poul

    2000-01-01

    Sixteen litters of seven pigs from each of nine Danish farrow-to-finish herds were followed to investigate the serological patterns caused by natural infection with Mycoplasma hyponeumoniae, Pasteurella multocida toxin and Actinobacillus pleuroneumoniae serotypes 2, 5-7, 12. In seven of the herds......, pigs were followed as two separate cohorts started 4 weeks apart, and in two herds only one cohort was followed. A total of 999 pigs were included in the study. The pigs were blood sampled at weaning and subsequently every fourth week until slaughter. All pigs were examined for antibodies against M....... hyopneumoniae (enzyme-linked immunosorbent assay), P. multocida toxin (enzyme-linked immunosorbent assay) and A. pleuropneumoniae serotypes 2, 5-7, 12 (complement-fixation tests). The most-common pattern (28%) of seroconversion was that of pigs first seroconverting to A. pleuropneumoniae serotype 2, followed...

  5. Optimization of surveillance opf Bovine Viral Diarrhea in Danish dairy herds

    Foddai, Alessandro

    dairy herds (e.g. after import of infected cattle) could be more difficult to detect compared to the past, due to the lower prevalence of antibody positive milking cows and the (expected) higher dilution of antibodies in bigger milk containers. Therefore, an evaluation and an eventual optimization...... ELISA (Rønsholt et al., 1997; Bitsch et al., 1997) and the SVANOVIR ELISA (Juntti at al., 1987; Niskanen, 1993) were compared on milk and serum samples. The prevalence of antibody positive milking cows, which can be detected by each of those tests, was estimated by diluting positive individual milk...... ELISA could detect a lower prevalence of antibody positive cows compared to the Danish blocking ELISA (0.78% vs. 50%). Hence, the former could detect newly infected herds shortly after infection when only few milking cows have seroconverted in the herd. In blood, the two tests performed similarly. Thus...

  6. Determining the optimal number of individual samples to pool for quantification of average herd levels of antimicrobial resistance genes in Danish pig herds using high-throughput qPCR

    Clasen, Julie; Mellerup, Anders; Olsen, John Elmerdahl

    2016-01-01

    The primary objective of this study was to determine the minimum number of individual fecal samples to pool together in order to obtain a representative sample for herd level quantification of antimicrobial resistance (AMR) genes in a Danish pig herd, using a novel high-throughput qPCR assay...

  7. Effect of lactation therapy on Staphylococcus aureus transmission dynamics in two commercial dairy herds.

    Barlow, John W; Zadoks, Ruth N; Schukken, Ynte H

    2013-02-11

    Treatment of subclinical mastitis during lactation can have both direct (individual animal level) and indirect (population level) effects. With a few exceptions, prior research has focused on evaluating the direct effects of mastitis treatment, and to date no controlled field trials have been conducted to test whether beneficial indirect effects of lactation treatment strategies targeting subclinical mastitis can be demonstrated on commercial dairy farms. Furthermore, there is limited knowledge on the impact of such interventions on the population dynamics of specific bacterial strains. The purpose of this study was to test the hypothesis that lactation therapy targeting S. aureus subclinical intramammary infection reduces transmission of S. aureus strains within dairy herds. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to determine strain specific infection dynamics in treated and control groups in a split herd trial conducted on 2 commercial dairy farms. The direct effect of 8 days intramammary lactation therapy with pirlimycin hydrochloride was demonstrated by an increased proportion of cure and a reduction in duration of infection in quarters receiving treatment compared to untreated controls. The indirect effect of lactation therapy was demonstrated by reduction of new S. aureus intramammary infections (IMI) caused by the dominant strain type in both herds. Strain typing of representative isolates taken over the duration of all IMI, including pre- and post-treatment isolates, provided more precise estimates of new infection, cure, and re-infection rates. New S. aureus infections in recovered susceptible quarters and the emergence of a new strain type in one herd influenced incidence measures. In addition to demonstrating positive direct effects of lactation therapy, this study provides evidence that treatment of subclinical S. aureus mastitis during lactation can have indirect effects including preventing new IMI and

  8. Effect of lactation therapy on Staphylococcus aureus transmission dynamics in two commercial dairy herds

    Barlow John W

    2013-02-01

    Full Text Available Abstract Background Treatment of subclinical mastitis during lactation can have both direct (individual animal level and indirect (population level effects. With a few exceptions, prior research has focused on evaluating the direct effects of mastitis treatment, and to date no controlled field trials have been conducted to test whether beneficial indirect effects of lactation treatment strategies targeting subclinical mastitis can be demonstrated on commercial dairy farms. Furthermore, there is limited knowledge on the impact of such interventions on the population dynamics of specific bacterial strains. The purpose of this study was to test the hypothesis that lactation therapy targeting S. aureus subclinical intramammary infection reduces transmission of S. aureus strains within dairy herds. Pulsed-field gel electrophoresis (PFGE and multilocus sequence typing (MLST were used to determine strain specific infection dynamics in treated and control groups in a split herd trial conducted on 2 commercial dairy farms. Results The direct effect of 8 days intramammary lactation therapy with pirlimycin hydrochloride was demonstrated by an increased proportion of cure and a reduction in duration of infection in quarters receiving treatment compared to untreated controls. The indirect effect of lactation therapy was demonstrated by reduction of new S. aureus intramammary infections (IMI caused by the dominant strain type in both herds. Strain typing of representative isolates taken over the duration of all IMI, including pre- and post-treatment isolates, provided more precise estimates of new infection, cure, and re-infection rates. New S. aureus infections in recovered susceptible quarters and the emergence of a new strain type in one herd influenced incidence measures. Conclusion In addition to demonstrating positive direct effects of lactation therapy, this study provides evidence that treatment of subclinical S. aureus mastitis during lactation can

  9. Comparison of Coxiella burnetii shedding in milk of dairy bovine, caprine, and ovine herds.

    Rodolakis, A; Berri, M; Héchard, C; Caudron, C; Souriau, A; Bodier, C C; Blanchard, B; Camuset, P; Devillechaise, P; Natorp, J C; Vadet, J P; Arricau-Bouvery, N

    2007-12-01

    The shedding of Coxiella burnetii in bovine, caprine, and ovine milk was measured using PCR, in 3 herds for each species, the bulk tank milk samples of which were positive at the time of their selection. Milk samples of 95 cows, 120 goats, and 90 ewes were sampled over 16 wk, as was the bulk tank milk. The shedding of C. burnetii in vaginal mucus and feces was checked at the beginning of the experiment and 2 mo later. The clinical signs in the selected herds as well as the duration and the shedding routes differed among the 3 species. The cows were asymptomatic and shed C. burnetii almost exclusively in milk. In one of the caprine herds, abortions due to C. burnetii were reported. The goats excreted the bacteria mainly in milk. In contrast, the ewes, which came from flocks with abortions due to Q fever (C. burnetii infection), shed the bacteria mostly in feces and in vaginal mucus. This could explain why human outbreaks of Q fever are more often related to ovine flocks than to bovine herds. These excretions did not seem more frequent when the samples were taken close to parturition. The samples were taken from 0 to 421 d after parturition in bovine herds and from 5 to 119 d and 11 to 238 d after parturition in the caprine and ovine herds, respectively. The shedding in milk was sometimes intermittent, and several animals shed the bacteria but were negative by ELISA: 80% of the ewes were seronegative, underscoring the lack of sensitivity of the ELISA tests available for veterinary diagnosis. The detection of antibodies in milk seems more sensitive than it is in serum.

  10. Different Mycobacterium avium subsp. paratuberculosis MIRU-VNTR patterns coexist within cattle herds.

    van Hulzen, K J E; Heuven, H C M; Nielen, M; Hoeboer, J; Santema, W J; Koets, A P

    2011-03-24

    A better understanding of the biodiversity of Mycobacterium avium subsp. paratuberculosis (MAP) offers more insight in the epidemiology of paratuberculosis and therefore may contribute to the control of the disease. The aim of this study was to investigate the genetic diversity in bovine MAP isolates using PCR-based methods detecting genetic elements called Variable-Number Tandem Repeats (VNTRs) and Mycobacterial Interspersed Repetitive Units (MIRUs) to determine if multiple MAP strains can coexist on farms with endemic MAP infection. For 52 temporal isolates originating from infected cattle from 32 commercial dairy herds with known trading history, MIRU-VNTR analysis was applied at 10 loci of which six showed variation. Within the group of 52 isolates, 17 different MIRU-VNTR patterns were detected. One MIRU-VNTR pattern was found in 29 isolates, one pattern in four isolates, one pattern in three isolates, two times one MIRU-VNTR pattern was found occurring in two isolates, and 12 patterns were found only once. Eleven herds provided multiple isolates. In five herds a single MIRU-VNTR pattern was detected among multiple isolates whereas in six herds more than one pattern was found. This study confirms that between dairy farms as well as within dairy farms, infected animals shed MAP with different MIRU-VNTR patterns. Analysis of trading history and age within herds indicated that cows born within the same birth cohort can be infected with MAP strains exhibiting variations in the number of MIRU-VNTR repeats. These data indicate that such multiple genotypes of MAP can coexist within one herd. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Medicated early weaning to obtain pigs free from pathogens endemic in the herd of origin.

    Alexander, T J; Thornton, K; Boon, G; Lysons, R J; Gush, A F

    1980-02-09

    A field trial was conducted to assess the value of medicated early weaning for obtaining pigs free from some of the pathogens endemic in their herd of origin. The trial comprised 51 sows from a closed herd, which were farrowed in an isolated farrowing house in seven separate groups. The sows in each group were bred at the same time and induced to farrow on the same day. Their thriftiest piglets were weaned at five days of age and moved to an isolated early-weaning unit. At about six weeks of age they were moved to one of three isolated grow-out units where they were held to slaughter weight. Sows in five of the groups were dosed with high levels of tiamulin and trimethoprim-sulphonamide preparations from their entry into the farrowing house until their biggest piglets were weaned. Their piglets were dosed with similar drugs from birth until 10 days of age. The first and seventh groups of sows and their litters were not medicated. Tests were carried out on pigs aged five to 11 weeks, on slaughter pigs, and on pigs which died or were killed at different ages, for Mycoplasma hyopneumoniae, Bordetella bronchiseptica and colonic treponemes, which were readily detectable in the herd of origin. No evidence could be found of mycoplasma or bordetella. Colonic treponemes were recovered from some of the pigs at slaughter, but not from younger pigs. Thirty-seven boars and gilts from the medicated groups were introduced into 11 herds thought to be free of enzootic pneumonia and 13 were introduced into three herds which had enzootic pneumonia. No subsequent signs of enzootic pneumonia were noted in 10 of the enzootic pneumonia-free herds.

  12. Effects of herd management practices on somatic cell counts in an arid climate

    Ali Sadeghi-Sefidmazgi; Farahnaz Rayatdoost-Baghal

    2014-01-01

    The objective of this study was to evaluate associations between average lactation somatic cell counts (SCC) and herd management practices in an arid climate. A total of 38,530 average lactation SCC records for 10,216 Holstein cows gathered on 25 dairy farms from January 2009 to October 2012 in Isfahan (Iran) were analyzed. Average lactation SCC (cells × 1,000) was 250.79 ranging from 90.31 to 483.23 cells/mL across investigated farms. Herd-level management factors associated with average lac...

  13. Claw and limb disorders in 12 Norwegian beef-cow herds.

    Fjeldaas, Terje; Nafstad, Ola; Fredriksen, Bente; Ringdal, Grethe; Sogstad, Ase M

    2007-09-24

    The main aim of the study was to assess the prevalence of claw and limb disorders in Norwegian beef-cow herds. Twenty-six herds with >or=15 cow-years were selected by computerized systematic assignment from the three most beef cattle-dense regions of Norway. The study population consisted of 12 herds with 28 heifers and 334 cows. The animals were trimmed and examined once by claw trimmers during the late winter and spring of 2003. The seven claw trimmers had been taught diagnosing and recording of claw lesions. Environment, feeding and management routines, age and breed, culling and carcass characteristics were also recorded. Lameness was recorded in 1.1% of the animals, and only in hind claws. Pericarpal swellings were recorded in one animal and peritarsal lesions in none. In total, claw and limb disorders including lameness were recorded in 29.6% of the animals, 4.1% with front and 28.2% with hind limb disorders, respectively. Most lesions were mild. Laminitis-related claw lesions were recorded in 18.0% of the animals and infectious lesions in 16.6%. The average claw length was 84 mm in front claws and 89 mm in hind claw. Both laminitis-related and infectious claw lesions were more prevalent with increasing age. Carcasses from animals with claw and limb disorders were on average 34 kg heavier than carcasses from animals without such disorders (p = 0.02). Our results also indicate association between some management factors and claw lesions. The study shows that the prevalence of lameness was low in 12 Norwegian beef-cow herds compared to beef-cattle herds in other countries and also that there were less claw and limb disorders in these herds compared to foreign dairy-cattle herds. The prevalence of lameness and white-line fissures was approximately the same as in Norwegian dairy herds whereas less dermatitis, heel-horn erosions, haemorrhages of the sole and the white line and sole ulcers were recorded.

  14. Sole disorders in conventionally managed and organic dairy herds using different housing systems

    Vaarst, Mette; Hindhede, Jens; Enevoldsen, Carsten

    1998-01-01

    Records of claw trimmings were analyzed in seven organic and six conventional Danish herds (a total of 974 cows). The housing systems represented were tie stall systems, loose housing system with slatted floor (one organic herd), and deep litter systems (deep straw bedding). Occurrence of sole...... stage from 61 to 120 d post partum in cows of other dual purpose breeds was positively associated with the presence of sole ulcer in one leg only in first parity cows. The time of year for claw trimming was a risk factor for acute haemorrhage in first parity cows, with the period from December...

  15. Cow and herd variation in milk urea nitrogen concentrations in lactating dairy cattle.

    Aguilar, M; Hanigan, M D; Tucker, H A; Jones, B L; Garbade, S K; McGilliard, M L; Stallings, C C; Knowlton, K F; James, R E

    2012-12-01

    Milk urea nitrogen (MUN) is correlated with N balance, N intake, and dietary N content, and thus is a good indicator of proper feeding management with respect to protein. It is commonly used to monitor feeding programs to achieve environmental goals; however, genetic diversity also exists among cows. It was hypothesized that phenotypic diversity among cows could bias feed management decisions when monitoring tools do not consider genetic diversity associated with MUN. The objective of the work was to evaluate the effect of cow and herd variation on MUN. Data from 2 previously published research trials and a field trial were subjected to multivariate regression analyses using a mixed model. Analyses of the research trial data showed that MUN concentrations could be predicted equally well from diet composition, milk yield, and milk components regardless of whether dry matter intake was included in the regression model. This indicated that cow and herd variation could be accurately estimated from field trial data when feed intake was not known. Milk urea N was correlated with dietary protein and neutral detergent fiber content, milk yield, milk protein content, and days in milk for both data sets. Cow was a highly significant determinant of MUN regardless of the data set used, and herd trended to significance for the field trial data. When all other variables were held constant, a percentage unit change in dietary protein concentration resulted in a 1.1mg/dL change in MUN. Least squares means estimates of MUN concentrations across herds ranged from a low of 13.6 mg/dL to a high of 17.3 mg/dL. If the observed MUN for the high herd were caused solely by high crude protein feeding, then the herd would have to reduce dietary protein to a concentration of 12.8% of dry matter to achieve a MUN concentration of 12 mg/dL, likely resulting in lost milk production. If the observed phenotypic variation is due to genetic differences among cows, genetic choices could result in

  16. Claw and limb disorders in 12 Norwegian beef-cow herds

    Ringdal Grethe

    2007-09-01

    Full Text Available Abstract Background The main aim of the study was to assess the prevalence of claw and limb disorders in Norwegian beef-cow herds. Methods Twenty-six herds with ≥15 cow-years were selected by computerized systematic assignment from the three most beef cattle-dense regions of Norway. The study population consisted of 12 herds with 28 heifers and 334 cows. The animals were trimmed and examined once by claw trimmers during the late winter and spring of 2003. The seven claw trimmers had been taught diagnosing and recording of claw lesions. Environment, feeding and management routines, age and breed, culling and carcass characteristics were also recorded. Results Lameness was recorded in 1.1% of the animals, and only in hind claws. Pericarpal swellings were recorded in one animal and peritarsal lesions in none. In total, claw and limb disorders including lameness were recorded in 29.6% of the animals, 4.1% with front and 28.2% with hind limb disorders, respectively. Most lesions were mild. Laminitis-related claw lesions were recorded in 18.0% of the animals and infectious lesions in 16.6%. The average claw length was 84 mm in front claws and 89 mm in hind claw. Both laminitis-related and infectious claw lesions were more prevalent with increasing age. Carcasses from animals with claw and limb disorders were on average 34 kg heavier than carcasses from animals without such disorders (p = 0.02. Our results also indicate association between some management factors and claw lesions. Conclusion The study shows that the prevalence of lameness was low in 12 Norwegian beef-cow herds compared to beef-cattle herds in other countries and also that there were less claw and limb disorders in these herds compared to foreign dairy-cattle herds. The prevalence of lameness and white-line fissures was approximately the same as in Norwegian dairy herds whereas less dermatitis, heel-horn erosions, haemorrhages of the sole and the white line and sole ulcers were

  17. Associations between biosecurity practices and bovine digital dermatitis in Danish dairy herds

    Oliveira, Victor Henrique Silva de; Sørensen, Jan Tind; Thomsen, Peter T.

    2017-01-01

    as negative or positive for DD at the hind legs during milking in the milking parlor. Information about biosecurity was obtained through questionnaires addressed to farmers, on-farm observations, and information from the Danish Cattle Database (www.seges.dk). These assessment tools covered potential infection...... among cows and herds were 24 and 97%, respectively; the within-herd DD prevalence ranged from 0 to 56%. Poor external biosecurity measures associated with higher prevalence of DD were recent animal purchase, access to pasture, lack of boots available for visitors, farm staff working at other dairy farms...

  18. Effects of herd origin, AI stud and sire identification on genetic evaluation of Holstein Friesian bulls

    Giovanni Bittante

    2010-01-01

    Full Text Available The purpose of this study was to estimate the effects of herd origin of bull, AI stud and sire identification number (ID  on official estimated breeding values (EBV for production traits of Holstein Friesian proven bulls. The data included 1,005  Italian Holstein-Friesian bulls, sons of 76 sires, born in 100 herds and progeny tested by 10 AI studs. Bulls were required  to have date of first proof between September 1992 and September 1997, to be born in a herd with at least one other  bull and to have sire and dam with official EBV when bull was selected for progeny testing. Records of sires with only one  son were also discarded. The dependent variable analyzed was the official genetic evaluation for a “quantity and quality  of milk” index (ILQ. The linear model to predict breeding values of bulls included the fixed class effects of herd origin of  bull, AI testing organization, birth year of bull, and estimated breeding values of sire and dam, both as linear covariates.  The R2of the model was 45% and a significant effect was found for genetic merit of sire (P   for herd origin of bull (P   nificant. The range of herd origin effect was 872 kg of ILQ. However, in this study, the causes of this result were not  clear; it may be due to numerous factors, one of which may be preferential treatment on dams of bulls. Analyses of resid-  uals on breeding value of proven bulls for ILQ showed a non significant effect of sire ID, after adjusting for parent aver-  age, herd origin effect and birth year effect. Although the presence of bias in genetic evaluation of dairy bulls is not evi-  dent, further research is recommended firstly to understand the reasons of the significant herd origin effect, secondly to  monitor and guarantee the greatest accuracy and reliability of genetic evaluation procedures. 

  19. Nation-wide Salmonella enterica surveillance and control in Danish slaughter swine herds

    Mousing, Jan; Jensen, P.T.; Halgaard, C.

    1997-01-01

    ranging from four to more than 60 swine are obtained quarterly at the abattoir. A meat sample from each pig is frozen, and meat juice (harvested after thawing) is examined for specific antibodies against S. enterica using an indirect enzyme-linked immunosorbent assay (ELISA). The ELISA combines several S...... during 1995 ranged from a mean of 2.9% in smaller herds (101-200 swine slaughtered per year) to 6.1% in relatively large herds (more than 5000 swine slaughtered per year)....

  20. 76 FR 6322 - Brucellosis Class Free States and Certified Brucellosis-Free Herds; Revisions to Testing and...

    2011-02-04

    ... reclassification of any Class Free State or area to a lower status if two or more herds are found to have.... APHIS-2009-0083] RIN 0579-AD22 Brucellosis Class Free States and Certified Brucellosis-Free Herds... Class Free States. This action will allow interested persons additional time to prepare and submit...

  1. Population dynamics of swine influenza virus in farrow-to-finish and specialised finishing herds in the Netherlands

    Loeffen, W.L.A.; Hunneman, W.A.; Quak, J.; Verheijden, J.H.M.; Stegeman, J.A.

    2009-01-01

    Influenza virus infections with subtypes H1N1, H3N2 and H1N2 are very common in domestic pigs in Europe. Data on possible differences of population dynamics in finishing pigs in farrow-to-finish herds and in specialised finishing herds are, however, scarce. The presence of sows and weaned piglets on

  2. Short communication: Genetic lag represents commercial herd genetic merit more accurately than the 4-path selection model.

    Dechow, C D; Rogers, G W

    2018-05-01

    Expectation of genetic merit in commercial dairy herds is routinely estimated using a 4-path genetic selection model that was derived for a closed population, but commercial herds using artificial insemination sires are not closed. The 4-path model also predicts a higher rate of genetic progress in elite herds that provide artificial insemination sires than in commercial herds that use such sires, which counters other theoretical assumptions and observations of realized genetic responses. The aim of this work is to clarify whether genetic merit in commercial herds is more accurately reflected under the assumptions of the 4-path genetic response formula or by a genetic lag formula. We demonstrate by tracing the transmission of genetic merit from parents to offspring that the rate of genetic progress in commercial dairy farms is expected to be the same as that in the genetic nucleus. The lag in genetic merit between the nucleus and commercial farms is a function of sire and dam generation interval, the rate of genetic progress in elite artificial insemination herds, and genetic merit of sires and dams. To predict how strategies such as the use of young versus daughter-proven sires, culling heifers following genomic testing, or selective use of sexed semen will alter genetic merit in commercial herds, genetic merit expectations for commercial herds should be modeled using genetic lag expectations. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Ethological investigations on a herd of plains zebra in a safari park: Time-budgets, reproduction and food competition

    Schilder, M.B.H.; Boer, P.L.

    The social organization of a herd of 25 plains zebras under safari park conditions and the time-budgets of 18 individuals from this herd were investigated. The zebras had organized themselves in harem groups. Stallions appeared to spend more time acting socially than did other sex-age classes and

  4. A Multi-level hierarchic Markov process with Bayesian updating for herd optimization and simulation in dairy cattle

    Demeter, R.M.; Kristensen, A.R.; Dijkstra, J.; Oude Lansink, A.G.J.M.; Meuwissen, M.P.M.; Arendonk, van J.A.M.

    2011-01-01

    Herd optimization models that determine economically optimal insemination and replacement decisions are valuable research tools to study various aspects of farming systems. The aim of this study was to develop a herd optimization and simulation model for dairy cattle. The model determines

  5. The Heritage of Herding and Southern Homicide: Examining the Ecological Foundations of the Code of Honor Thesis

    Baller, Robert D.; Zevenbergen, Matthew P.; Messner, Steven F.

    2009-01-01

    The authors examine the ecological foundations of the thesis of a "code of honor" as an explanation for southern homicide. Specifically, they consider the effects of indicators of ethnic groups that migrated from herding economies (the Scotch-Irish), cattle and pig herding, and the relative importance of agricultural production across…

  6. Effects on goat milk quality of the presence of Mycoplasma spp. in herds without symptoms of contagious agalactia.

    de la Fe, Christian; Sánchez, Antonio; Gutierrez, Aldo; Contreras, Antonio; Carlos Corrales, Juan; Assunçao, Patricia; Poveda, Carlos; Poveda, José B

    2009-02-01

    This study was designed to assess the possible effects of mycoplasmas on the quality of milk produced by goat herds in a contagious agalactia (CA) endemic area with absence of classical symptoms. Several factors related to milk quality (percentages of fat, total protein, lactose and total solids, standard plate counts (SPC) and presence of Staphylococcus aureus) were compared in mycoplasma-infected and non-infected herds. To define the CA status of 26 herds on the island of Lanzarote (Spain), where CA is endemic, 570 individual milk samples and 266 bulk tank milk (BTM) samples were microbiologically analysed for the presence of Mycoplasma spp. A herd was considered infected by mycoplasmas when at least a sample (individual or BTM) was positive. BTM samples were also used to determine milk quality parameters. Mycoplasma infection was confirmed in 13 herds. A total of 31, 10 and 11 strains of Mycoplasma mycoides subsp. mycoides LC (MmmLC), Mp. agalactiae and Mp. capricolum subsp. capricolum were isolated. No significant differences were observed between the least square means of the variables fat, total protein, lactose and total solids or SPC recorded for the infected v. non-infected herds. The Staph. aureus status of a herd was also found to be independent of the presence of Mycoplasma spp. Our findings indicate that neither the presence of mycoplasmas in a goat herd with absence of classical symptoms seem to compromise the quality of the BTM.

  7. Effect of interparticle interactions on size determination of zirconia and silica based systems – A comparison of SAXS, DLS, BET, XRD and TEM

    Pabisch, Silvia; Feichtenschlager, Bernhard; Kickelbick, Guido; Peterlik, Herwig

    2012-01-01

    The aim of this work is a systematic comparison of size characterisation methods for two completely different model systems of oxide nanoparticles, i.e. amorphous spherical silica and anisotropic facet-shaped crystalline zirconia. Size and/or size distribution were determined in a wide range from 5 to 70 nm using small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), nitrogen sorption (BET), X-ray diffraction (XRD) and transmission electron microscopy (TEM). A nearly perfect coincidence was observed only for SAXS and TEM for both types of particles. For zirconia nanoparticles considerable differences between different measurement methods were observed. PMID:22347721

  8. Animal interactions and the emergence of territoriality.

    Luca Giuggioli

    2011-03-01

    Full Text Available Inferring the role of interactions in territorial animals relies upon accurate recordings of the behaviour of neighbouring individuals. Such accurate recordings are rarely available from field studies. As a result, quantification of the interaction mechanisms has often relied upon theoretical approaches, which hitherto have been limited to comparisons of macroscopic population-level predictions from un-tested interaction models. Here we present a quantitative framework that possesses a microscopic testable hypothesis on the mechanism of conspecific avoidance mediated by olfactory signals in the form of scent marks. We find that the key parameters controlling territoriality are two: the average territory size, i.e. the inverse of the population density, and the time span during which animal scent marks remain active. Since permanent monitoring of a territorial border is not possible, scent marks need to function in the temporary absence of the resident. As chemical signals carried by the scent only last a finite amount of time, each animal needs to revisit territorial boundaries frequently and refresh its own scent marks in order to deter possible intruders. The size of the territory an animal can maintain is thus proportional to the time necessary for an animal to move between its own territorial boundaries. By using an agent-based model to take into account the possible spatio-temporal movement trajectories of individual animals, we show that the emerging territories are the result of a form of collective animal movement where, different to shoaling, flocking or herding, interactions are highly heterogeneous in space and time. The applicability of our hypothesis has been tested with a prototypical territorial animal, the red fox (Vulpes vulpes.

  9. Within- and between-herd prevalence variation of Mycobacterium avium subsp. paratuberculosis infection among control programme herds in Denmark (2011-2013)

    Verdugo, Cristobal; Toft, Nils; Nielsen, Søren

    2015-01-01

    estimates. Bayesian posterior probabilities were computed in order to compare prevalence between the years. A total of 665,700 samples were included in the study, from 221,914, 224,040, and 220,466 cows sourced from 1138, 1112, and 1059 herds in years 2011, 2012, and 2013, respectively. In that period, HTP...... estimates of 0.92 (95% posterior probability interval (PPI), 0.87-0.96), 0.78 (95% PPI, 0.74-0.83), and 0.75 (95% PPI, 0.71-0.78) were recorded, respectively. Low TP were observed, with population mean estimates of 0.08 (95% PPI, 0.07-0.08), 0.07 (95% PPI, 0.07-0.08), and 0.07 (95% PPI, 0.......06-0.07) for the three consecutive years. Statistically-important differences were recorded for HTP and population mean TP estimates between years, indicating a trend for a decreasing level of MAP infection at both herd and animal level. Model results showed that MAP infection was widespread among the Dairy cattle herds...

  10. Comparison of the antimicrobial consumption in weaning pigs in Danish sow herds with different vaccine purchase patterns during 2013

    Temtem, Carolina; Kruse, Amanda Brinch; Nielsen, Liza Rosenbaum

    2016-01-01

    Background: There is growing concern about development of antimicrobial resistance due to use of antimicrobials (AMs) in livestock production. Identifying efficient alternatives, including vaccination, is a priority. The objective of this study was to compare the herd-level amount of AMs prescribed...... for weaner pigs, between Danish sow herds using varying combinations of vaccines against Porcine Circovirus Type 2 (PCV2), Mycoplasma hyopneumoniae (MYC) and Lawsonia intracellularis (LAW). It was hypothesised that herds purchasing vaccines, use these to prevent disease, and hence reduce their AM consumption......, compared to herds purchasing fewer or no vaccines against these pathogens. Data summarised over year 2013 were obtained from the Danish Central Husbandry Register and the Danish VetStat database, in which prescriptions of medication are recorded. All one-site indoor pig herds with >50 sows and >200 weaners...

  11. Evaluation of milk yield losses associated with Salmonella antibodies in bulk tank milk in bovine dairy herds

    Nielsen, T D; Green, L E; Kudahl, Anne Margrethe Braad

    2012-01-01

    The effect of Salmonella on milk production is not well established in cattle. The objective of this study was to investigate whether introduction of Salmonella into dairy cattle herds was associated with reduced milk yield and determine the duration of any such effect. Longitudinal data from 2005...... through 2009 were used, with data from 12 mo before until 18 mo after the estimated date of infection. Twenty-eight case herds were selected based on an increase in the level of Salmonella-specific antibodies in bulk-tank milk from ... was randomly allocated to the control herds. Hierarchical mixed effect models with the outcome test-day yield of energy-corrected milk (ECM)/cow were used to investigate daily milk yield before and after the estimated herd infection date for cows in parities 1, 2, and 3+. Control herds were used to evaluate...

  12. Association between placentome size, measured using transrectal ultrasonography, and gestational age in cattle

    Adeyinka, F.D.; Laven, R.A.; Lawrence, K.E.; Bosch, van den M.; Blankenvoorde, G.; Parkinson, T.J.

    2014-01-01

    AIM: The aim of this study was to estimate whether fetal age could be accurately estimated using placentome size. METHODS: Fifty-eight cows with confirmed conception dates in two herds were used for the study. The length of the long axis and cross-sectional area of placentomes close to the cervix

  13. Seasonal activity of the Denali caribou herd, Alaska

    Rodney D. Boertje

    1985-05-01

    Full Text Available Activity of female and young caribou in the Denali herd was studied from June 1978 through April 1980 to help assess the food availability/nutritional status of this reduced population. No nutritional stress was evident as inferred by the greater activity of Denali caribou in late winter compared with starving caribou in West Greenland and by the low proportion of time spent grazing in spring compared with reindeer on overgrazed ranges in Norway. Also, low proportions of time were spent running from insects due to relatively few insects and a high availability of insect-relief sites. A low proportion of time was spent cratering due to windswept conditions. Activity budgets calculated from complete active-rest cycles and accompanied by the duration of active and rest periods may be useful indicators of relative food availability/nutritional status, particularly in late winter/early spring. Duration of active periods is presumably most strongly related to rumen fill, and, thus, food availability. Duration of rest periods was not significantly different among seasons (P<0.05, except when insects, rutting bulls, and, presumably, mushroom-searching altered active-rest cycles.Sesongmessige svingninger av aktiviteten i Denali karibu-flokk, Alaska.Abstract in Norwegian / Sammendrag: Aktiviteten hos simler og ungdyr i Denali karibouflokk ble studert fra juni 1978 til utgangen av april 1980 som hjelpemiddel for å bestemme næringstilbud/ernæringsstatus i denne reduserte karibustamme. Ingen ernæringsmessig stress var åpenbar, noe som kan utledes av den større aktivitet hos Denali karibu på senvinteren sammenlignet med sultende karibu i Vest-Grønland samt den lave andel av beiting sammenlignet med rein på overbelastede beiter i Norge. Videre ble en lav andel av tiden brukt til å rømme fra insekter, fordi insektplagen var relativt liten og at det var lett adgang til områder der dyrene kunne befri seg fra insektene. Graving krevde også liten andel

  14. Dairy farms testing positive for Mycobacterium avium ssp. paratuberculosis have poorer hygiene practices and are less cautious when purchasing cattle than test-negative herds.

    Wolf, R; Barkema, H W; De Buck, J; Orsel, K

    2016-06-01

    Mycobacterium avium ssp. paratuberculosis (MAP), the causative agent of Johne's disease, is present on most dairy farms in Alberta, causing economic losses and presenting a potential public health concern. The objective of this cross-sectional study was to identify risk factors for Alberta dairy herds being MAP-positive based on environmental samples (ES). Risk assessments were conducted and ES were collected on 354 Alberta dairy farms (62% of eligible producers) voluntarily participating in the Alberta Johne's Disease Initiative. In univariate logistic regression, risk factors addressing animal and pen hygiene, as well as the use of feeding equipment to remove manure and manure application on pastures, were all associated with the number of positive ES. Furthermore, based on factor analysis, risk factors were clustered and could be summarized as 4 independent factors: (1) animal, pen, and feeder contamination; (2) shared equipment and pasture contamination; (3) calf diet; and (4) cattle purchase. Using these factor scores as independent variables in multivariate logistic regression models, a 1-unit increase in animal, pen, and feeder contamination resulted in 1.31 times higher odds of having at least 1 positive ES. Furthermore, a 1-unit increase in cattle purchase also resulted in 1.31 times the odds of having at least 1 positive ES. Finally, a 100-cow increase in herd size resulted in an odds ratio of 2.1 for having at least 1 positive ES. In conclusion, cleanliness of animals, pens, and feeders, as well as cattle purchase practices, affected risk of herd infection with MAP. Therefore, improvements in those management practices should be the focus of effective tools to control MAP on dairy farms. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Management practices from questionnaire surveys in herds with very low somatic cell score through a national mastitis program in France.

    Barnouin, J; Chassagne, M; Bazin, S; Boichard, D

    2004-11-01

    French dairy herds (n = 534) were enrolled in the National 'Zero Mastitis Objective' Program to highlight management practices characterizing very low somatic cell score (SCS) herds. The herds studied were stratified into 2 groups. The first group (LOW) included herds within the first 5 percentiles and the second group (MED) herds within the 50 to 55 percentiles of herds on the basis of mean SCS for the 36 mo preceding the program. Potential explanatory variables, collected through questionnaire surveys, were analyzed using multistep logistic regression models. Twenty-six variables were significant factors in the final models, in which 18 were considered as primary factors for very low SCS. The probability for a herd belonging to the LOW group was associated with: (1) regular use of teat spraying; (2) herdsman precise in his techniques; (3) less than 1 person-year used at activities other than dairy herd; (4) teat dipping after mammary infusion at dry off; (5) heifers kept in a calving pen around parturition; (6) cows locked in feed-line lockups after milking; (7) dry cows with prepartum Ca restriction; (8) heifers on a nondamp pasture; (9) cows culled when at least one damaged teat; (10) heifers at pasture not drinking water from a river; and (11) disinfecting teat ends with alcohol before intramammary infusion at dry off. The probability for a herd belonging to the MED group was associated with: (1) milking cows housed in a straw yard; (2) checking heifers for mastitis only beginning at 2-wk prepartum; (3) no mastitis treatment when at least one clot was observed in milk at successive milkings; (4) distance of herdsman's house to cowshed >300 m; (5) only dirty teats washed before milking; (6) free access of cows from pasture to cowshed during bad weather; and (7) more than 18% of spring calvings. The variables associated with very low SCS should be applied as part of a thorough mastitis-control program adapted to each herd.

  16. Spatiotemporal patterns, annual baseline and movement-related incidence of Streptococcus agalactiae infection in Danish dairy herds: 2000-2009.

    Mweu, Marshal M; Nielsen, Søren S; Halasa, Tariq; Toft, Nils

    2014-02-01

    Several decades after the inception of the five-point plan for the control of contagious mastitis pathogens, Streptococcus agalactiae (S. agalactiae) persists as a fundamental threat to the dairy industry in many countries. A better understanding of the relative importance of within- and between-herd sources of new herd infections coupled with the spatiotemporal distribution of the infection, may aid in effective targeting of control efforts. Thus, the objectives of this study were: (1) to describe the spatiotemporal patterns of infection with S. agalactiae in the population of Danish dairy herds from 2000 to 2009 and (2) to estimate the annual herd-level baseline and movement-related incidence risks of S. agalactiae infection over the 10-year period. The analysis involved registry data on bacteriological culture of all bulk tank milk samples collected as part of the mandatory Danish S. agalactiae surveillance scheme as well as live cattle movements into dairy herds during the specified 10-year period. The results indicated that the predicted risk of a herd becoming infected with S. agalactiae varied spatiotemporally; the risk being more homogeneous and higher in the period after 2005. Additionally, the annual baseline risks yielded significant yet distinctive patterns before and after 2005 - the risk of infection being higher in the latter phase. On the contrary, the annual movement-related risks revealed a non-significant pattern over the 10-year period. There was neither evidence for spatial clustering of cases relative to the population of herds at risk nor spatial dependency between herds. Nevertheless, the results signal a need to beef up within-herd biosecurity in order to reduce the risk of new herd infections. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Spatiotemporal patterns, annual baseline and movement-related incidence of Streptococcus agalactiae infection in Danish dairy herds: 2000–2009

    Mweu, Marshal M.; Nielsen, Søren S.; Hisham Beshara Halasa, Tariq

    2014-01-01

    -herd sources of new herd infections coupled with the spatiotemporal distribution of the infection, may aid in effective targeting of control efforts. Thus, the objectives of this study were: (1) to describe the spatiotemporal patterns of infection with S. agalactiae in the population of Danish dairy herds from...

  18. Relationships between milk mid-IR predicted gastro-enteric methane production and the technical and financial performance of commercial dairy herds.

    Delhez, P; Wyzen, B; Dalcq, A-C; Colinet, F G; Reding, E; Vanlierde, A; Dehareng, F; Gengler, N; Soyeurt, H

    2017-12-22

    Considering economic and environmental issues is important in ensuring the sustainability of dairy farms. The objective of this study was to investigate univariate relationships between lactating dairy cow gastro-enteric methane (CH4) production predicted from milk mid-IR (MIR) spectra and technico-economic variables by the use of large scale and on-farm data. A total of 525 697 individual CH4 predictions from milk MIR spectra (MIR-CH4 (g/day)) of milk samples collected on 206 farms during the Walloon milk recording scheme were used to create a MIR-CH4 prediction for each herd and year (HYMIR-CH4). These predictions were merged with dairy herd accounting data. This allowed a simultaneous study of HYMIR-CH4 and 42 technical and economic variables for 1024 herd and year records from 2007 to 2014. Pearson correlation coefficients (r) were used to assess significant relationships (P<0.05). Low HYMIR-CH4 was significantly associated with, amongst others, lower fat and protein corrected milk (FPCM) yield (r=0.18), lower milk fat and protein content (r=0.38 and 0.33, respectively), lower quantity of milk produced from forages (r=0.12) and suboptimal reproduction and health performance (e.g. longer calving interval (r=-0.21) and higher culling rate (r=-0.15)). Concerning economic results, low HYMIR-CH4 was significantly associated with lower gross margin per cow (r=0.19) and per litre FPCM (r=0.09). To conclude, this study suggested that low lactating dairy cow gastro-enteric CH4 production tended to be associated with more extensive or suboptimal management practices, which could lead to lower profitability. The observed low correlations suggest complex interactions between variables due to the use of on-farm data with large variability in technical and management practices.

  19. Prevalence of purulent vaginal discharge in dairy herds depends on timing but not method of detection

    A review of existing literature was conducted to determine the prevalence of purulent vaginal discharge (PVD) in dairy herds around the world and detection methodologies that influence prevalence estimates. Four databases (PubMed, Google Scholar, Web of Science, and Scopus) were queried with the sea...

  20. Studies on genetic diversity of bovine viral diarrhea viruses in Danish cattle herds

    Nagy, Abdou; Fahnøe, Ulrik; Rasmussen, Thomas Bruun

    2014-01-01

    Scandinavian countries have successfully pursued bovine viral diarrhea virus (BVDV) eradication without the use of vaccines. In Denmark, control and eradication of BVDV were achieved during the last two decades, but occasionally new BVDV infections are detected in some Danish cattle herds. The aim...