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Sample records for sheep flocks electronic

  1. Radiocaesium variability in upland sheep flocks

    Beresford, N.A

    2002-07-01

    Following the 1986 Chernobyl accident large areas of uplands in the United Kingdom were contaminated by radiocaesium. Consequently, the level of radiocaesium in the tissues of some sheep exceeded 1000 Bq kg{sup -1} fresh weight This is the limit adopted within the UK above which meat cannot enter the food chain. In 1986, restrictions were placed on the movement and slaughter of sheep in areas of west Cumbria, north Wales and Scotland. Whilst the number of farms under restriction has reduced considerably, some still remain restricted in 2002. Although a number of workers had noted considerable variability between the radiocaesium activities of individuals within sheep flocks there had been no analyses of causal effects. The work described here, combined studies on three upland farms within west Cumbria with controlled feeding experiments, to systematically assess the parameters which may contribute to such variability. Results from all three farms demonstrate a temporally consistent ranking of the {sup 137}Cs activity concentration of individual sheep within the study flocks. As there was also a correlation between the {sup 137}Cs activity concentration of ewes and their pre-weaned lambs it is likely that the same ewes are producing lambs in excess of the intervention limit in subsequent years. It is difficult to generalise as to which factors will contribute to {sup 137}Cs variability within a given upland flock; factors contributing to variation were not consistent between the study farms. However, the location grazed and/or vegetation selected by animals was a causal factor to the observed variability at all three farms. The transfer of radiocaesium from the diet to muscle of sheep was found to be determined by live-weight change and dry matter intake. Subsequent studies have suggested that protein turnover may be a potential mechanism for the relationship between dry matter intake and radiocaesium transfer. This hypothesis is supported by current understanding

  2. Radiocaesium variability in upland sheep flocks

    Beresford, N.A.

    2002-01-01

    Following the 1986 Chernobyl accident large areas of uplands in the United Kingdom were contaminated by radiocaesium. Consequently, the level of radiocaesium in the tissues of some sheep exceeded 1000 Bq kg -1 fresh weight This is the limit adopted within the UK above which meat cannot enter the food chain. In 1986, restrictions were placed on the movement and slaughter of sheep in areas of west Cumbria, north Wales and Scotland. Whilst the number of farms under restriction has reduced considerably, some still remain restricted in 2002. Although a number of workers had noted considerable variability between the radiocaesium activities of individuals within sheep flocks there had been no analyses of causal effects. The work described here, combined studies on three upland farms within west Cumbria with controlled feeding experiments, to systematically assess the parameters which may contribute to such variability. Results from all three farms demonstrate a temporally consistent ranking of the 137 Cs activity concentration of individual sheep within the study flocks. As there was also a correlation between the 137 Cs activity concentration of ewes and their pre-weaned lambs it is likely that the same ewes are producing lambs in excess of the intervention limit in subsequent years. It is difficult to generalise as to which factors will contribute to 137 Cs variability within a given upland flock; factors contributing to variation were not consistent between the study farms. However, the location grazed and/or vegetation selected by animals was a causal factor to the observed variability at all three farms. The transfer of radiocaesium from the diet to muscle of sheep was found to be determined by live-weight change and dry matter intake. Subsequent studies have suggested that protein turnover may be a potential mechanism for the relationship between dry matter intake and radiocaesium transfer. This hypothesis is supported by current understanding of protein-dry matter

  3. Prevalence of Coxiella burnetii in clinically healthy German sheep flocks

    Hilbert Angela

    2012-03-01

    Full Text Available Abstract Background Current epidemiological data on the situation of Coxiella (C. burnetii infections in sheep are missing, making risk assessment and the implementation of counteractive measures difficult. Using the German state of Thuringia as a model example, the estimated sero-, and antigen prevalence of C. burnetii (10% and 25%, respectively was assessed at flock level in 39/252 randomly selected clinically healthy sheep flocks with more than 100 ewes and unknown abortion rate. Results The CHECKIT™ Q-fever Test Kit identified 11 (28% antibody positive herds, whereas real-time PCR revealed the presence of C. burnetii DNA in 2 (5% of the flocks. Multiple-locus variable number of tandem repeats analysis of 9 isolates obtained from one flock revealed identical profiles. All isolates contained the plasmid QpH1. Conclusions The results demonstrate that C. burnetii is present in clinically inconspicuous sheep flocks and sporadic flare-ups do occur as the notifications to the German animal disease reporting system show. Although C. burnetii infections are not a primary veterinary concern due to the lack of significant clinical impact on animal health (with the exception of goats, the eminent zoonotic risk for humans should not be underestimated. Therefore, strategies combining the interests of public and veterinary public health should include monitoring of flocks, the identification and culling of shedders as well as the administration of protective vaccines.

  4. Acute coenurosis of dairy sheep from 11 flocks in Greece.

    Giadinis, N D; Psychas, V; Polizopoulou, Z; Papadopoulos, E; Papaioannou, N; Komnenou, A Th; Thomas, A-L; Petridou, E J; Kritsepi-Konstantinou, M; Lafi, S Q; Brellou, G D

    2012-07-01

    A syndrome of acute neurological dysfunction with increased mortality was observed in lambs of 10 dairy sheep flocks and adult animals in one flock in Central and Northern Greece. Each farmer completed a questionnaire regarding the management and feeding of their flocks. In seven of the 11 flocks the affected animals were grazing pasture, while in the remaining four flocks (5, 8, 9, 10) the animals were fed alfalfa hay (Medicago sativa) and concentrates indoors. A follow-up study of the affected flocks was conducted during the next 12 months. Of 42 sheep with acute coenurosis that were examined, the most prominent neurological abnormalities were ataxia, depression, blindness, scoliosis, coma and dysmetria. Except for the four sheep that were comatose, all other animals had normal body temperatures and their appetites remained normal or were slightly decreased. Haematological findings of 15 examined sheep were within normal limits. The affected sheep were subject to euthanasia. A histopathological examination was performed in 13 cases. Faecal samples from dogs associated with these flocks were negative for taeniid infections. During the following 12 months cases of chronic coenurosis in these flocks were observed. In the 42 animals that were necropsied, the main gross findings were cystic formations between 0.5-1 cm in diameter with translucent walls that were seen lying free on the leptomeninges or partly penetrating the brain tissue, sterile microabscecess and brain necrosis. Histopathological evaluation of tissue sections of 13 brains showed multifocal purulent or pyogranulomatous meningoencephalitis, accompanied by eosinophilic infiltrations. No bacteria were isolated following bacterial culture of brain tissue Parasitological examination of the cysts from five cases revealed whitish specks on the transparent cyst wall and germination membrane representing the scolices. Acute coenurosis was diagnosed in all cases studied. Acute coenurosis can be one of the

  5. Brucellosis outbreak in a flock of seventeen sheep in Zaria | Onoja ...

    This work is a case report of brucellosis in a flock of sheep in Zaria. The flock comprised of seventeen Yankasa sheep, 14 ewes and 3 rams, with history of 2 recent cases of abortion, a presented case of uterine prolapse and 3 cases of carpal hygroma (1st and 2nd sheep bilaterally and the 3rd sheep left unilaterally).

  6. Fatal systemic cladosporiosis in a merino sheep flock.

    Haligur, Mehmet; Ozmen, Ozlem; Dorrestein, Gerry M

    2010-12-01

    Systemic cladosporiosis is described in 25 merino sheep from a flock consisting 250 animals. The fungal pneumonia appeared after an intensive antibiotic treatment, because of a respiratory system disorder. The pen of the flock was humid and crowded, and animals had signs of respiratory distress, coughing, fever and anorexia. All of the ill animals died, and necropsy was performed on 10 sheep. The lesions were characterized by a multifocal pyogranulomatous pneumonia and an abomasitis. Severe hemorrhages were observed in the lungs. At the histopathological examination, severe vasculitis with thrombosis was observed in various organs, especially in the lungs and abomasums, suggestive for a hematogenous dissemination of the infection in these organs. Numerous PAS-positive fungal elements were seen in the pyogranulomatous foci. Dark green fungal colonies were seen in the blood agar and Sabouraud dextrose agar that were identified as Cladosporium cladosporioides. This report highlights that phaeohyphomycosis can cause a severe systemic and fatal disease in merino sheep under insufficient management conditions.

  7. Radiocaesium activity in sheep: variation within flocks and with time

    Pearce, J.; Moss, B.W.; Colgan, P.A.; Scully, B.J.

    1990-01-01

    The radiocaesium levels in sheep, assessed by in vivo monitoring, increased rapidly and in a parallel manner in both lambs and ewes grazing upland pasture in Ireland known to be contaminated with post-Chernobyl fallout for at least 10 weeks after the animals were moved on to this pasture. Considerable variability was noted in the individual animal radiocaesium values within all the flocks studied. A comparison of the radiocaesium contents of some flocks in 1987, 1988 and 1989 show similar values for the different years. (author)

  8. Prevalence of and risk factors associated with ovine progressive pneumonia in Wyoming sheep flocks.

    Gerstner, Shelley; Adamovicz, Jeffrey J; Duncan, John V; Laegreid, William W; Marshall, Katherine L; Logan, James R; Schumaker, Brant A

    2015-10-15

    To determine the prevalence of antibodies against small ruminant lentivirus (SRLV), the causative agent of ovine progressive pneumonia (OPP), and to identify risk factors associated with OPP in Wyoming sheep flocks. Cross-sectional study. 1,415 sheep from 54 flocks in Wyoming. Flocks were surveyed as part of the National Animal Health Monitoring System (NAHMS) 2011 sheep study. Serum samples obtained from sheep in Wyoming were analyzed for anti-SRLV antibodies by use of a competitive-inhibition ELISA. The prevalence of seropositive animals overall and within each flock was calculated. Respective associations between flock OPP status and various demographic and management variables were assessed. The estimated prevalence of sheep seropositive for anti-SRLV antibodies and OPP-infected flocks in Wyoming was 18.0% and 47.5%, respectively. Within OPP-infected flocks, the prevalence of seropositive sheep ranged from 3.9% to 96%. Flocks maintained on nonfenced range were more likely to be infected with OPP than were flocks maintained on fenced range (OR, 3.4; 95% confidence interval, 1.1 to 10.7). The estimated prevalence of OPP-infected flocks in Wyoming did not vary substantially from that at the regional or national level reported in the NAHMS 2001 sheep study. Compared with results of the NAHMS 2011 sheep study, Wyoming producers were more familiar with OPP than were other US sheep producers, but only 61% of Wyoming producers surveyed reported being very or somewhat familiar with the disease. Results indicated that OPP is prevalent in many Wyoming sheep flocks, which suggested that continued efforts are necessary to increase producer knowledge about the disease and investigate practices to minimize economic losses associated with OPP.

  9. Epidemiological characteristics of classical scrapie outbreaks in 30 sheep flocks in the United Kingdom.

    K Marie McIntyre

    Full Text Available Most previous analyses of scrapie outbreaks have focused on flocks run by research institutes, which may not reflect the field situation. Within this study, we attempt to rectify this deficit by describing the epidemiological characteristics of 30 sheep flocks naturally-infected with classical scrapie, and by exploring possible underlying causes of variation in the characteristics between flocks, including flock-level prion protein (PrP genotype profile. In total, the study involved PrP genotype data for nearly 8600 animals and over 400 scrapie cases.We found that most scrapie cases were restricted to just two PrP genotypes (ARQ/VRQ and VRQ/VRQ, though two flocks had markedly different affected genotypes, despite having similar underlying genotype profiles to other flocks of the same breed; we identified differences amongst flocks in the age of cases of certain PrP genotypes; we found that the age-at-onset of clinical signs depended on peak incidence and flock type; we found evidence that purchasing infected animals is an important means of introducing scrapie to a flock; we found some evidence that flock-level PrP genotype profile and flock size account for variation in outbreak characteristics; identified seasonality in cases associated with lambing time in certain flocks; and we identified one case that was homozygous for phenylalanine at codon 141, a polymorphism associated with a very high risk of atypical scrapie, and 28 cases that were heterozygous at this codon.This paper presents the largest study to date on commercially-run sheep flocks naturally-infected with classical scrapie, involving 30 study flocks, more than 400 scrapie cases and over 8500 PrP genotypes. We show that some of the observed variation in epidemiological characteristics between farms is related to differences in their PrP genotype profile; although much remains unexplained and may instead be attributed to the stochastic nature of scrapie dynamics.

  10. Worm control practice against gastro-intestinal parasites in Norwegian sheep and goat flocks

    2011-01-01

    Background Anthelmintic treatment is the most common way of controlling nematode infections in ruminants. However, several countries have reported anthelmintic resistance (AR), representing a limitation for sustainable small ruminant production. The knowledge regarding worm control management represents a baseline to develop a guideline for preventing AR. The aim of the present study was therefore to improve our knowledge about the worm control practices in small ruminant flocks in Norway. Methods A questionnaire survey regarding worm control practices was performed in small ruminant flocks in Norway. Flocks were selected from the three main areas of small ruminant farming, i.e. the coastal, inland and northern areas. A total of 825 questionnaires, comprising 587 sheep flocks (return rate of 51.3%) and 238 goat flocks (52.6%) were included. Results The results indicated that visual appraisal of individual weight was the most common means of estimating the anthelmintic dose used in sheep (78.6%) and goat (85.1%) flocks. The mean yearly drenching rate in lambs and ewes were 2.5 ± 1.7 and 1.9 ± 1.1, respectively, whereas it was 1.0 (once a year) in goats. However, these figures were higher in sheep in the coastal area with a rate of 3.4 and 2.2 in lambs and ewes, respectively. Benzimidazoles were the predominant anthelmintic class used in sheep flocks (64.9% in 2007), whereas benzimidazoles and macrocyclic lactones were both equally used in dairy goat flocks. In the period of 2005-2007, 46.3% of the sheep flocks never changed the anthelmintic class. The dose and move strategy was practiced in 33.2% of the sheep flocks. Conclusions The present study showed that inaccurate weight calculation gives a risk of under-dosing in over 90% of the sheep and goat flocks in Norway. Taken together with a high treatment frequency in lambs, a lack of anthelmintic class rotation and the common use of a dose-and-move strategy, a real danger for development of anthelmintic resistance

  11. Worm control practice against gastro-intestinal parasites in Norwegian sheep and goat flocks

    Vatn Synnøve

    2011-05-01

    Full Text Available Abstract Background Anthelmintic treatment is the most common way of controlling nematode infections in ruminants. However, several countries have reported anthelmintic resistance (AR, representing a limitation for sustainable small ruminant production. The knowledge regarding worm control management represents a baseline to develop a guideline for preventing AR. The aim of the present study was therefore to improve our knowledge about the worm control practices in small ruminant flocks in Norway. Methods A questionnaire survey regarding worm control practices was performed in small ruminant flocks in Norway. Flocks were selected from the three main areas of small ruminant farming, i.e. the coastal, inland and northern areas. A total of 825 questionnaires, comprising 587 sheep flocks (return rate of 51.3% and 238 goat flocks (52.6% were included. Results The results indicated that visual appraisal of individual weight was the most common means of estimating the anthelmintic dose used in sheep (78.6% and goat (85.1% flocks. The mean yearly drenching rate in lambs and ewes were 2.5 ± 1.7 and 1.9 ± 1.1, respectively, whereas it was 1.0 (once a year in goats. However, these figures were higher in sheep in the coastal area with a rate of 3.4 and 2.2 in lambs and ewes, respectively. Benzimidazoles were the predominant anthelmintic class used in sheep flocks (64.9% in 2007, whereas benzimidazoles and macrocyclic lactones were both equally used in dairy goat flocks. In the period of 2005-2007, 46.3% of the sheep flocks never changed the anthelmintic class. The dose and move strategy was practiced in 33.2% of the sheep flocks. Conclusions The present study showed that inaccurate weight calculation gives a risk of under-dosing in over 90% of the sheep and goat flocks in Norway. Taken together with a high treatment frequency in lambs, a lack of anthelmintic class rotation and the common use of a dose-and-move strategy, a real danger for development of

  12. Development of pneumonia in desert bighorn sheep after exposure to a flock of exotic wild and domestic sheep.

    Callan, R J; Bunch, T D; Workman, G W; Mock, R E

    1991-03-15

    From 1986 to 1989, 5 desert bighorn sheep (3 Ovis canadensis mexicana and 2 O c nelsoni), ranging in age from 2 to 3 years, were exposed to a flock of exotic wild and domestic sheep to potentially achieve naturally acquired pneumonia. Pasteurella multocida was isolated from nasal samples from 4 of 6 sheep randomly sampled from the flock. Bighorn sheep were exposed individually and each exposure period was a trial. Treatment before and after exposure varied and included combinations of alpha interferon, antibiotics, anti-inflammatory drugs, and vaccines. Treatments were chosen on the basis of recommendations of others for treating pneumonia in desert bighorn sheep as well as our own experience in sheep and cattle. Regardless of treatment used, bighorn sheep in trials 1 to 4 developed signs of pneumonia within 10 to 14 days of exposure. Bighorn sheep in trials 1 to 3 died within 11 to 17 days of initial exposure. In trial 4, the bighorn sheep was isolated from the carrier sheep for treatment of pneumonia on day 14 and died on day 30. Pasteurella multocida was isolated from lung tissue in 3 of the 4 bighorn sheep. On the basis of results of trials 1 to 4, a more in depth clinical study was conducted in trial 5. Nasal and blood specimens were collected prior to and during trial 5 for bacteriologic culturing and serologic testing for bovine viral diarrhea virus, infectious bovine rhinotracheitis, parainfluenza-3 virus, and respiratory syncytial virus.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Q fever: baseline monitoring of a sheep and a goat flock associated with human infections.

    Eibach, R; Bothe, F; Runge, M; Fischer, S F; Philipp, W; Ganter, M

    2012-11-01

    Animal losses due to abortion and weak offspring during a lambing period amounted up to 25% in a goat flock and up to 18% in a sheep flock kept at an experimental station on the Swabian Alb, Germany. Fifteen out of 23 employees and residents on the farm tested positive for Coxiella burnetii antibodies by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence assay. Ninety-four per cent of the goats and 47% of the sheep were seropositive for C. burnetii by ELISA. Blood samples of 8% of goats and 3% of sheep were PCR positive. C. burnetii was shed by all tested animals through vaginal mucus, by 97% of the goats and 78% of the sheep through milk, and by all investigated sheep through faeces (PCR testing). In this outbreak human and animal infection were temporally related suggesting that one was caused by the other.

  14. Detection of antibodies against Chlamydophila abortus in Costa Rican sheep flocks

    R. Villagra-Blanco

    2015-09-01

    Full Text Available A total of 359 sheep samples from 15 flocks were analyzed for the presence of antibodies against Chlamydophila abortus using a commercial Enzyme linked Immunosorbent Assay (ELISA. Antibodies were detected in 19 (5.29% sheep from 12 (80% flocks. Seropositive animals were found in all analyzed regions (Central, Chorotega, Atlantic Huetar, North Huetar and Central Pacific determining prevalence between 0.28% and 4.4%, and intra-flock positivity between 3.7% and 25.0%. The survey revealed two risk factors associated with seropositivity; introducing animals (males and females, embryos, or semen from other farms or from abroad without any sanitary certification, and flocks not having quarantine areas or separated boxes for diseased animals. No clinical signs of disease were observed in positive seroreactors. C. abortus seems to be present in Costa Rica in a very low prevalence in sheep flocks. Further studies, to isolate the bacteria are required. Finally, implementation of control measures to prevent the spread of C. abortus is recommended.

  15. Detection of antibodies against Chlamydophila abortus in Costa Rican sheep flocks

    Villagra-Blanco, R.; Dolz, G.; Montero-Caballero, D.; Romero-Zúñiga, J.J.

    2015-01-01

    A total of 359 sheep samples from 15 flocks were analyzed for the presence of antibodies against Chlamydophila abortus using a commercial Enzyme linked Immunosorbent Assay (ELISA). Antibodies were detected in 19 (5.29%) sheep from 12 (80%) flocks. Seropositive animals were found in all analyzed regions (Central, Chorotega, Atlantic Huetar, North Huetar and Central Pacific) determining prevalence between 0.28% and 4.4%, and intra-flock positivity between 3.7% and 25.0%. The survey revealed two risk factors associated with seropositivity; introducing animals (males and females), embryos, or semen from other farms or from abroad without any sanitary certification, and flocks not having quarantine areas or separated boxes for diseased animals. No clinical signs of disease were observed in positive seroreactors. C. abortus seems to be present in Costa Rica in a very low prevalence in sheep flocks. Further studies, to isolate the bacteria are required. Finally, implementation of control measures to prevent the spread of C. abortus is recommended. PMID:26623377

  16. Dynamics of a scrapie outbreak in a flock of Romanov sheep-estimation of transmission parameters

    Hagenaars, T.H.J.; Donelly, C.A.; Ferguson, N.M.; Anderson, R.M.

    2003-01-01

    Knowledge of epidemiological mechanisms and parameters underlying scrapie transmission in sheep flocks remains very limited at present. Here we introduce a method for fitting stochastic transmission models to outbreak data to estimate bounds on key transmission parameters. We apply this method to

  17. Comparison of strategies for substantiating freedom from scrapie in a sheep flock.

    Durand, Benoit; Martinez, Marie-José; Calavas, Didier; Ducrot, Christian

    2009-04-30

    The public health threat represented by a potential circulation of bovine spongiform encephalopathy agent in sheep population has led European animal health authorities to launch large screening and genetic selection programmes. If demonstrated, such a circulation would have dramatic economic consequences for sheep breeding sector. In this context, it is important to evaluate the feasibility of qualification procedures that would allow sheep breeders demonstrating their flock is free from scrapie. Classical approaches, based on surveys designed to detect disease presence, do not account for scrapie specificities: the genetic variations of susceptibility and the absence of live diagnostic test routinely available. Adapting these approaches leads to a paradoxical situation in which a greater amount of testing is needed to substantiate disease freedom in genetically resistant flocks than in susceptible flocks, whereas probability of disease freedom is a priori higher in the former than in the latter. The goal of this study was to propose, evaluate and compare several qualification strategies for demonstrating a flock is free from scrapie. A probabilistic framework was defined that accounts for scrapie specificities and allows solving the preceding paradox. Six qualification strategies were defined that combine genotyping data, diagnostic tests results and flock pedigree. These were compared in two types of simulated flocks: resistant and susceptible flocks. Two strategies allowed demonstrating disease freedom in several years, for the majority of simulated flocks: a strategy in which all the flock animals are genotyped, and a strategy in which only founders animals are genotyped, the flock pedigree being known. In both cases, diagnostic tests are performed on culled animals. The less costly strategy varied according to the genetic context (resistant or susceptible) and to the relative costs of a genotyping exam and of a diagnostic test. This work demonstrates that

  18. Factors contributing to radiocaesium variability in upland sheep flocks in west Cumbria (United Kingdom)

    Beresford, N.A.; Barnett, C.L.; Wright, S.M.; Howard, B.J.; Crout, N.M.J.

    2007-01-01

    Following the Chernobyl accident in 1986, restrictions were placed on the movement and slaughter of sheep within upland areas of the UK because radiocaesium activity concentrations in their meat exceeded 1000 Bq kg -1 fresh weight. Some farms remain under restriction in 2007. From 1991 to 1993 detailed studies were conducted on three sheep farms within the restricted area of west Cumbria to systematically assess the various parameters which may contribute to the observed variability in radiocaesium activity concentrations within sheep flocks. This paper reports the spatial variation in soil and vegetation activity concentrations across the grazed areas at these farms and determines the influence of grazing behaviour on variability in 137 Cs activity concentrations between individual sheep within the flocks. Together with previously reported results, these new data are used to draw conclusions on the factors determining variability within the three flocks. However, the factors are too site specific to be able to generalise the findings to other farms within the restricted areas of the UK

  19. Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity

    Joulié, A.; Laroucau, K.; Bailly, X.; Prigent, M.; Gasqui, P.; Lepetitcolin, E.; Blanchard, B.; Rousset, E.; Sidi-Boumedine, K.; Jourdain, E.

    2015-01-01

    Q fever is a worldwide zoonosis caused by Coxiella burnetii. Domestic ruminants are considered to be the main reservoir. Sheep, in particular, may frequently cause outbreaks in humans. Because within-flock circulation data are essential to implementing optimal management strategies, we performed a follow-up study of a naturally infected flock of dairy sheep. We aimed to (i) describe C. burnetii shedding dynamics by sampling vaginal mucus, feces, and milk, (ii) assess circulating strain divers...

  20. The potential for improving welfare standards and productivity in United Kingdom sheep flocks using veterinary flock health plans.

    Scott, P R; Sargison, N D; Wilson, D J

    2007-05-01

    Data from industry sources detailing variable costs in 2003 revealed that the average farmer keeping 1000 lowland ewes in the United Kingdom spent 3500 UK pounds annually on veterinary fees and medicines. Despite such expenditure, psoroptic mange and cutaneous myiasis are common in the UK, resistance to one or more anthelmintic group is not only common but increasing in frequency and distribution, and abortion outbreaks caused by Toxoplasma gondii and Chlamydophila abortus are frequently reported by veterinary laboratories. Welfare concerns also arise from farmers' intransigence towards tail docking and castration in lambs (mutilations), reported market forces necessitating long distance road transportation to slaughter plants, and an unwillingness to employ veterinary surgeons for obstetrical problems. The spread of sheep scab in the UK over the past decade illustrates the failure of flock owners to effect rudimentary biosecurity and disease control measures. A first step towards improving the health and welfare of sheep would be the immediate implementation of basic good husbandry practices, including ectoparasiticide treatment for sheep scab eradication, prophylaxis for cutaneous myiasis in selected lambs, and appropriate vaccination strategies for clostridial diseases and certain abortion agents. There would also be money from within current farm expenditure to provide veterinary attention for obstetrical problems affecting up to 2% of ewes per annum. Planned use of ecto- and endoparasiticides is urgently needed to maintain the efficacy of these unique drugs.

  1. Rituals Cows or just another flock of Sheep?

    Bangsgaard, Pernille

    or body-parts and any special treatment of the bones, such as cutting, skinning and painting. In order to contextualise the faunal deposits I have also included information concerning the cemeteries, the graves, the small finds and the gender and age of the deceased. In the SJE assemblages three types...... of deposits could be identified, these include complete sheep deposited next to the dead, cut cattle skulls as well as large deposits of decorated sheep and goat skulls, the two latter located on or near the original surface of the cemetery. In the following fifth chapter information regarding from a number...

  2. Chernobyl derived activity in sheep: variation within a single flock and with time

    Walters, B.

    1988-01-01

    The continuous monitoring of the caesium contents of sheep grazing a high fell in Cumbria, UK, is described. The technique of in-vivo monitoring, using portable NaI crystal detectors, is shown to be robust and capable of producing accurate quantitative data. Results are presented from the monitoring of 100 sheep at fortnightly intervals over a period of 13 weeks. The peak average activity (1300 Bq kg -1 ) was reached five weeks after introduction of the sheep to grazing land with up to 2000 Bq kg -1 in herbage. Activity had fallen, on average, to 68% of the peak value after eight weeks. The variation in activity between individual sheep is large and usually symmetrically distributed. The temporal trend of activity in the whole flock is a combination of the many disparate individual trends. The technique has allowed the variation between animals and individual time trends to be followed. (author)

  3. Economics of vaccinating extensively managed sheep flocks against Bluetongue disease

    Bluetongue is a serious and recurring threat to sheep producers throughout the world. In the western United States, bluetongue virus (BTV) is transmitted by biting midges in late summer and early autumn, just before lambs are sent to market. No vaccine is currently sold for the most common serotype ...

  4. Deletion variant near ZNF389 is associated with control of ovine lentivirus in multiple sheep flocks

    White, S N; Mousel, M R; Reynolds, J O; Herrmann-Hoesing, L M; Knowles, D P

    2014-01-01

    Ovine lentivirus (OvLV) is a macrophage-tropic lentivirus found in many countries that causes interstitial pneumonia, mastitis, arthritis and cachexia in sheep. There is no preventive vaccine and no cure, but breed differences suggest marker-assisted selective breeding might improve odds of infection and control of OvLV post-infection. Although variants in TMEM154 have consistent association with odds of infection, no variant in any gene has been associated with host control of OvLV post-infection in multiple animal sets. Proviral concentration is a live-animal diagnostic measure of OvLV control post-infection related to severity of OvLV-induced lesions. A recent genome-wide association study identified a region including four zinc finger genes associated with proviral concentration in one Rambouillet flock. To refine this region, we tested additional variants and identified a small insertion/deletion variant near ZNF389 that showed consistent association with proviral concentration in three animal sets (P sheep from multiple locations and management conditions. Strikingly, one flock had exceptionally high prevalence (>87%, including yearlings) and mean proviral concentration (>950 copies/μg), possibly due to needle sharing. The best estimate of proviral concentration by genotype, obtained from all 1310 OvLV-positive animals tested, showed insertion homozygotes had less than half the proviral concentration of other genotypes (P sheep flocks. PMID:24303974

  5. Ovine and Caprine Brucellosis (Brucella melitensis in Aborted Animals in Jordanian Sheep and Goat Flocks

    Assadullah Samadi

    2010-01-01

    Full Text Available Two hundred and fifty five biological samples were collected from 188 animals (81 sheep and 107 goats during the lambing season from September 2009 to April 2010 from the Mafraq region of Jordan. Sampled animals belonged to 93 sheep and goat flocks that had abortion cases in the region. One hundred and seven (41.9% biological samples were positive for the omp2 primers that were able to identify all Brucella species in the collected samples which were obtained from 86 aborted animals (86/188=45.7%. Using the B. melitensis insertion sequence 711 (IS711 primers on the 107 omp2 positive samples, only 61 confirmed to be positive for B. melitensis. These positive samples were obtained from 28 sheep and 33 goats. The prevalence rate of B. melitensis was 27.1% (51/188 among aborted animals. For differentiation between vaccine strain and field strain infection, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP method using PstI endonuclease enzyme was used. Vaccination with Rev-1 in the last year (OR=2.92, CI: 1.1–7.7 and grazing at common pasture (OR=2.78, CI: 1.05–7.36 were statistically significant (P≤.05 risk factors positively associated with the occurrence of brucellosis in sheep and goat flocks.

  6. Increased Toxoplasma gondii positivity relative to age in 125 Scottish sheep flocks; evidence of frequent acquired infection

    2011-01-01

    Toxoplasma gondii seroprevalence was determined in 3333 sheep sera from 125 distinct sheep flocks in Scotland, with the majority of flocks being represented by 27 samples, which were collected between July 2006 and August 2008. The selected farms give a representative sample of 14 400 sheep holdings identified in the Scottish Government census data from 2004. Overall T. gondii seroprevalence, at individual sheep level, was determined to be 56.6%; each flock tested, had at least a single positive animal and in four flocks all ewes tested positive. The seroprevalence of sheep increased from 37.7% in one year old stock to 73.8% in ewes that were older than six years, showing that acquired infections during the life of the animals is frequent and that environmental contamination by T. gondii oocysts must be significant. The median within-flock seroprevalence varied significantly across Scotland, with the lowest seroprevalence of 42.3% in the South and the highest seroprevalence of 69.2% in the far North of Scotland and the Scottish Islands, while the central part of Scotland had a seroprevalence of 57.7%. This distribution disequilibrium may be due to the spread and survival of oocysts on pasture and lambing areas. A questionnaire accompanying sampling of flocks identified farms that used Toxovax®, a commercial vaccine that protects sheep from abortion due to T. gondii infection. Only 24.7% of farmers used the vaccine and the vaccine did not significantly affect the within flock seroprevalence for T. gondii. The implications for food safety and human infection are discussed. PMID:22189159

  7. Seroprevalence of Q fever in sheep and goat flocks with a history of abortion in Iran between 2011 and 2012

    Javad Asadi

    2013-06-01

    Full Text Available The purpose of this study was to estimate the seroprevalence of Coxiella burnetii infection in sheep and goat flocks with a history of abortion in different areas of Iran. One thousand and one hundred ovine and 180 caprine samples from 43 sheep and goat flocks in four counties located in the Northeast (Mashhad, Central (Isfahan, Western (Arak, and Southwest (Shiraz Iran were collected randomly between March 2011 and April 2012. The CHEKIT Q fever ELISA kit was used to identify specific antibodies against C. burnetii in sheep and goats. The results showed that the overall seroprevalence of C. burnetii in sheep and goats was 19.5% and 27.2%, respectively. There was a significant difference in seropositivity between sheep and goats (P<0.05. Central Iran significantly had the highest prevalence among the studied areas, especially in goat coxiellosis (23.8% and 40.8% in sheep and goats, respectively. The lowest prevalence in sheep was 12.8% in Northeast Iran while in Western Iran C. burnetii antibodies were absent in goats. The higher prevalence of Q fever in Central Iran may be partly due to persistent favourable conditions to spread C. burnetii in this area including drought and dust storms that originated from neighbouring Iraq and Kuwait. In conclusion, the present study demonstrated the relatively high prevalence of Q fever in sheep and goat flocks with a history of abortion. Therefore, Q fever could be responsible for considerable numbers of ovine and caprine abortions in Iran.

  8. Artificial immune system and sheep flock algorithms for two-stage fixed-charge transportation problem

    Kannan, Devika; Govindan, Kannan; Soleimani, Hamed

    2014-01-01

    In this paper, we cope with a two-stage distribution planning problem of supply chain regarding fixed charges. The focus of the paper is on developing efficient solution methodologies of the selected NP-hard problem. Based on computational limitations, common exact and approximation solution...... approaches are unable to solve real-world instances of such NP-hard problems in a reasonable time. These approaches involve cumbersome computational steps in real-size cases. In order to solve the mixed integer linear programming model, we develop an artificial immune system and a sheep flock algorithm...

  9. Sheep farmer opinions on the current and future role of veterinarians in flock health management on sheep farms: A qualitative study

    Kaler, Jasmeet; Green, L.E.

    2013-01-01

    A 2009 UK Government report on veterinary expertise in food animal production highlighted that there was insufficient herd health expertise among veterinarians and lack of appropriate business models to deliver veterinary services to the livestock sector. Approximately two thirds of sheep farmers only contact their veterinarian for emergencies and one fifth have all year round contact. The aim of the current study was to understand sheep farmers’ perception, the current and future role of veterinarians in flock health management using qualitative methodology. The eligibility criteria were male farmers with a flock size of at least 200 adult sheep. Seven focus groups of farmers (n = 45) stratified by three regions and two age groups (≤50 and >50) were conducted. Thematic analysis of the discussions indicated that most farmers considered and used their veterinarian as a fire-fighter, whilst other advice was gathered free of charge when the veterinarian was on the farm for other reasons (typically seeing cattle) or by telephone. A small group of farmers were using their veterinarian or a sheep consultant proactively with regular contact and found this financially beneficial. Farmers indicated that the key barriers to using a veterinarian proactively were inconsistent service, high turnover of veterinarians, lack of expertise of sheep farming among veterinarians and concern about independence of advice. Although economics was also mentioned as a key barrier to using veterinarians more proactively, most farmers did not know where they gained and lost income from their flock; there was heavy reliance on the single farm payment scheme (SPS) and very few farmers kept records from which they could investigate where there were inefficiencies in production. Overall sheep farmers considered sheep farming complex and that each farm was unique and that they themselves were the experts to manage their flock. We conclude that there is an impasse: veterinarians might need to

  10. Detection of Salmonella Carriers in Sheep and Goat Flocks of Bushehr and Lorestan Provinces, Iran

    Hossein Esmaeili

    2017-01-01

    Full Text Available Background:    Salmonellosis is an infectious and a food-borne disease of humans and animals. The initial source of the infection is the intestinal tracts of birds and other animals. Apparently healthy animals can become subclinical carriers and persistently shed Salmonella in their feces which can act as a reservoir for the pathogen. The aim of this study is to detect the carriers of Salmonella among apparently healthy sheep and goat flocks of Bushehr and Lorestan provinces, Iran.Methods:    A total of 389 fecal samples were aseptically collected from the rectum of apparently healthy sheep and goat flocks of Bushehr and Lorestan provinces. Bacteriological culture was conducted using selenite cystine, Rappaport–Vassiliadis, brilliant green and xylose lysine deoxycholate agar. Suspected colonies were inoculated in to TSI, peptone water, Simmon’s Citrate, Urea medium and MRVP. Sero-groups were detected by antisera.              Results:    Two samples from 189 samples (1.05% were positive for Salmonella in Bushehr province. Salmonella abortusovis and Salmonella typhimurium were detected following serotyping. No Salmonella carriers were detected in Lorestan province.Conclusion:    As the rate of carriers of Salmonella was low, the risk of food-borne salmonellosis due to consumption of small ruminant's meat is low, especially in the condition of well cooked meat. Since S. abortusovis was detected, strategies of prevention and control of abortion due to this agent must be taken to reduce the economic losses. Moreover, the presence of S. typhimurium is a hazard to public health and people who have close contact to sheep and goats.

  11. Radiocaesium variability within sheep flocks. Relationships between the 137Cs activity concentrations of individual ewes within a flock and between ewes and their progeny

    Beresford, N.A.; Barnett, C.L.; Crout, N.M.J.; Morris, C.C.

    1995-01-01

    As a consequence of radiocaesium deposition following the Chernobyl accident the movement and slaughter of sheep were restricted within some upland areas of the United Kingdom. Considerable variability in the radiocaesium activity concentrations between individual sheep within flocks has been recorded. This paper reports studies conducted to investigate the reasons for this within flock variability on three farms in the restricted area of west Cumbria. On each farm, study sheep were selected and live-monitored over the period 1991-93. Results from all three study farms showed a correlation in the 137 Cs activity concentration of individual sheep on different monitoring occasions. This observation suggested that a few sheep on each farm are likely to be responsible for the continuation of restrictions on many of the affected holdings. Comparisons between monitoring data obtained in summer and autumn months were better correlated than those involving data collected in the winter and spring. Prior to weaning there was a linear relationship between the 137 Cs levels in the muscle of a lamb and that in the muscle of its dam. Given these observations it is suggested that, in successive years, ewes identified as consistently having high radiocaesium levels in their muscle will produce lambs which will also have comparatively high levels of radiocaesium; the limited data available support this hypothesis. However, no relationship between the 137 Cs activity concentration of a ewe and its lamb was evident post-weaning, thereby discounting any possibility of an inherited effect. On one of the farms a significant difference was found between the 137 Cs activity concentration of different breeds of sheep

  12. An improved sheep flock heredity algorithm for job shop scheduling and flow shop scheduling problems

    Chandramouli Anandaraman

    2011-10-01

    Full Text Available Job Shop Scheduling Problem (JSSP and Flow Shop Scheduling Problem (FSSP are strong NP-complete combinatorial optimization problems among class of typical production scheduling problems. An improved Sheep Flock Heredity Algorithm (ISFHA is proposed in this paper to find a schedule of operations that can minimize makespan. In ISFHA, the pairwise mutation operation is replaced by a single point mutation process with a probabilistic property which guarantees the feasibility of the solutions in the local search domain. A Robust-Replace (R-R heuristic is introduced in place of chromosomal crossover to enhance the global search and to improve the convergence. The R-R heuristic is found to enhance the exploring potential of the algorithm and enrich the diversity of neighborhoods. Experimental results reveal the effectiveness of the proposed algorithm, whose optimization performance is markedly superior to that of genetic algorithms and is comparable to the best results reported in the literature.

  13. Discrepant epidemiological patterns between classical and atypical scrapie in sheep flocks under French TSE control measures.

    Fediaevsky, Alexandre; Gasqui, Patrick; Calavas, Didier; Ducrot, Christian

    2010-09-01

    The occurrence of secondary cases of atypical and classical scrapie was examined in 340 outbreaks of atypical and 296 of classical sheep scrapie detected in France during active surveillance programmes between 2002 and 2007. The prevalence of atypical scrapie in these flocks was 0.05% under selective culling and 0.07% under intensified monitoring i.e. not significantly different from that detected during active surveillance of the general population (P>0.5), whereas these figures were much higher for classical scrapie (3.67% and 0.25%, respectively, Pclassical scrapie but were not more efficient than active surveillance in detecting cases of atypical scrapie. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Anthelmintic-resistant nematodes in Irish commercial sheep flocks- the state of play

    Good Barbara

    2012-12-01

    Full Text Available Abstract Anthelmintic resistance has been reported in most sheep producing countries. Prior to the mid 1990s, reports of anthelmintic resistance in Ireland were sparse and focused on benzimidazole, one of the three classes of anthelmintic available during this period. This evidence for efficacy issues on Irish farms combined with awareness that anthelmintic resistance was increasingly being reported in other countries prompted the need for more comprehensive investigations on Irish farms. Faecal egg count reduction and micro-agar larval development tests were employed to investigate resistance to benzimidazole, levamisole and macrocyclic lactone. There is compelling evidence for resistance to both benzimidazole (>88% of flocks and levamisole (>39% of flocks. Resistance of nematode populations to macrocyclic lactone was suspected on a small number of farms (11% but needs to be confirmed. The recent introduction of two new classes of anthelmintics, after over a 25 year interval, together with the evidence that anthelmintic resistance is reported within a relatively short time following the introduction of a new anthelmintic compound means that the challenge to the industry is immediate. Actions are urgently required to manage anthelmintic resistance so as to prolong the lifespan of anthelmintics.

  15. Models to capture the potential for disease transmission in domestic sheep flocks.

    Schley, David; Whittle, Sophie; Taylor, Michael; Kiss, Istvan Zoltan

    2012-09-15

    Successful control of livestock diseases requires an understanding of how they spread amongst animals and between premises. Mathematical models can offer important insight into the dynamics of disease, especially when built upon experimental and/or field data. Here the dynamics of a range of epidemiological models are explored in order to determine which models perform best in capturing real-world heterogeneities at sufficient resolution. Individual based network models are considered together with one- and two-class compartmental models, for which the final epidemic size is calculated as a function of the probability of disease transmission occurring during a given physical contact between two individuals. For numerical results the special cases of a viral disease with a fast recovery rate (foot-and-mouth disease) and a bacterial disease with a slow recovery rate (brucellosis) amongst sheep are considered. Quantitative results from observational studies of physical contact amongst domestic sheep are applied and results from the differently structured flocks (ewes with newborn lambs, ewes with nearly weaned lambs and ewes only) compared. These indicate that the breeding cycle leads to significant changes in the expected basic reproduction ratio of diseases. The observed heterogeneity of contacts amongst animals is best captured by full network simulations, although simple compartmental models describe the key features of an outbreak but, as expected, often overestimate the speed of an outbreak. Here the weights of contacts are heterogeneous, with many low weight links. However, due to the well-connected nature of the networks, this has little effect and differences between models remain small. These results indicate that simple compartmental models can be a useful tool for modelling real-world flocks; their applicability will be greater still for more homogeneously mixed livestock, which could be promoted by higher intensity farming practices. Copyright © 2012

  16. Factors affecting the reproductive performance of Awassi sheep flocks in north-east of Jordan: an epidemiological study.

    Lafi, S Q; Talafha, A Q; Giadinis, N; Kalaitzakis, E; Pourliotis, K; Panousis, N

    2009-12-01

    A prospective cohort study was conducted using 32 randomly selected Awassi sheep flocks to identify factors hypothesized to be associated with the occurrence of pregnancy, twinning and fetal loss between August 2005 and May 2006 in the region of Al-Safawi (northeast of Jordan). Vitamins A and E and selenium concentrations were determined on 448 blood samples. Using the forward selection procedure of the logistic regression module, models with statistically significant risk factors (P loss. Serum vitamin A concentration levels were associated with pregnancy (OR = 2.26, 2.48), twinning (OR = 6.49, 17.74) and fetal loss (OR = 0.13, 0.19). Primiparous ewes were 48% less likely to become pregnant than fourth or higher parity ewes. The likelihood of twinning increased significantly in ewes up to the third parity. Ewes that were fed 700-900 g barley, 250-300 g wheat-bran per head per day and grazed on vegetables residues were 4.15 times more likely to have twins than ewes that were fed 600 g barley and 200 g wheat-bran per head per day. Fetal loss in first and second parity ewes was about 3 times more likely than that in third or higher-parity ewes. Ewes pregnant with twins were about 14 times more likely to have fetal loss than ewes carrying single fetus. Pregnant ewes of the stationary flocks were 37% less likely to have fetal loss than ewes of the semi-nomadic flocks. These results demonstrate that stationary Awassi sheep flocks had higher pregnancy and twinning rates and less pregnancy loss. Supplementation of vitamin A, providing sufficient quantity of dry feed and increasing ram: ewe ratio for primiparous ewes of semi-nomadic flocks is essential to improve Awassi sheep reproductive performance.

  17. Ovine progressive pneumonia provirus levels are unaffected by the prion 171R allele in an Idaho sheep flock.

    Harrington, Robert D; Herrmann-Hoesing, Lynn M; White, Stephen N; O'Rourke, Katherine I; Knowles, Donald P

    2009-01-22

    Selective breeding of sheep for arginine (R) at prion gene (PRNP) codon 171 confers resistance to classical scrapie. However, other effects of 171R selection are uncertain. Ovine progressive pneumonia/Maedi-Visna virus (OPPV) may infect up to 66% of a flock thus any affect of 171R selection on OPPV susceptibility or disease progression could have major impact on the sheep industry. Hypotheses that the PRNP 171R allele is 1) associated with the presence of OPPV provirus and 2) associated with higher provirus levels were tested in an Idaho ewe flock. OPPV provirus was found in 226 of 358 ewes by quantitative PCR. The frequency of ewes with detectable provirus did not differ significantly among the 171QQ, 171QR, and 171RR genotypes (p > 0.05). Also, OPPV provirus levels in infected ewes were not significantly different among codon 171 genotypes (p > 0.05). These results show that, in the flock examined, the presence of OPPV provirus and provirus levels are not related to the PRNP 171R allele. Therefore, a genetic approach to scrapie control is not expected to increase or decrease the number of OPPV infected sheep or the progression of disease. This study provides further support to the adoption of PRNP 171R selection as a scrapie control measure.

  18. Ovine progressive pneumonia provirus levels are unaffected by the prion 171R allele in an Idaho sheep flock

    Herrmann-Hoesing Lynn M

    2009-01-01

    Full Text Available Abstract Selective breeding of sheep for arginine (R at prion gene (PRNP codon 171 confers resistance to classical scrapie. However, other effects of 171R selection are uncertain. Ovine progressive pneumonia/Maedi-Visna virus (OPPV may infect up to 66% of a flock thus any affect of 171R selection on OPPV susceptibility or disease progression could have major impact on the sheep industry. Hypotheses that the PRNP 171R allele is 1 associated with the presence of OPPV provirus and 2 associated with higher provirus levels were tested in an Idaho ewe flock. OPPV provirus was found in 226 of 358 ewes by quantitative PCR. The frequency of ewes with detectable provirus did not differ significantly among the 171QQ, 171QR, and 171RR genotypes (p > 0.05. Also, OPPV provirus levels in infected ewes were not significantly different among codon 171 genotypes (p > 0.05. These results show that, in the flock examined, the presence of OPPV provirus and provirus levels are not related to the PRNP 171R allele. Therefore, a genetic approach to scrapie control is not expected to increase or decrease the number of OPPV infected sheep or the progression of disease. This study provides further support to the adoption of PRNP 171R selection as a scrapie control measure.

  19. Vaccination delays maedi-visna lentivirus infection in a naturally-infected sheep flock

    Gudnadóttir Margrét

    2013-01-01

    Full Text Available Abstract Background The Maedi-Visna (MV lentivirus causes two slowly progressive eventually fatal diseases of sheep, Maedi, a progressive interstitial pneumonia, and Visna, a progressive demyelinating disease of the central nervous system. Other lentiviruses also cause fatal slow infections in their natural hosts, e.g. the HIV virus in humans. Results of experimental vaccination against any lentivirus where vaccinees are challenged by natural routes, may therefore be of general interest. From 1991–1998 experiments with formalin-inactivated whole Maedi-Visna virus vaccine were carried out in the Department of Microbiology at the University of Iceland. Western Blot tests showed good immune response to all major proteins of the virus. When aluminium hydroxide was added to the vaccine all vaccinees developed neutralizing antibodies to the vaccine strain at titers 1/8 – 1/256. After housing 5 twin pairs, one twin in each pair vaccinated, the other unvaccinated, with infected sheep for 4 years, all the unvaccinated twins became infected, but only 2 of their vaccinated siblings as confirmed by virus cultivation experiments on tissues from their lungs spleens lymph nodes and choroid plexuses. Results One twin in each of 40 female twin pairs, born into a Maedi-Visna-infected sheep flock and kept under natural farming conditions in Cyprus, was vaccinated at birth, 3 weeks and 3 months, with formalin-inactivated whole Maedi-Visna lentivirus vaccine adjuvanted with aluminium hydroxide. 17 mothers of the twins were seronegative, 13 seroconverting and 10 had old infection. Of 17 vaccinees born to seronegative mothers 9 were uninfected at 28 months, but only 2 of their unvaccinated siblings. Of 13 unvaccinated twins born to seroconverting mothers, 12 caught infection during their first 10 weeks, but only 4 of their vaccinated siblings. Vaccination had no effects on 10 vaccinees born to mothers with long-standing Maedi-Visna infections and broad andibody

  20. Mutations in Ovis aries TMEM154 are associated with lower small ruminant lentivirus proviral concentration in one sheep flock.

    Alshanbari, F A; Mousel, M R; Reynolds, J O; Herrmann-Hoesing, L M; Highland, M A; Lewis, G S; White, S N

    2014-08-01

    Small ruminant lentivirus (SRLV), also called ovine progressive pneumonia virus or maedi-visna, is present in 24% of US sheep. Like human immunodeficiency virus, SRLV is a macrophage-tropic lentivirus that causes lifelong infection. The production impacts from SRLV are due to a range of disease symptoms, including pneumonia, arthritis, mastitis, body condition wasting and encephalitis. There is no cure and no effective vaccine for preventing SRLV infection. However, breed differences in prevalence and proviral concentration indicate a genetic basis for susceptibility to SRLV. Animals with high blood proviral concentration show increased tissue lesion severity, so proviral concentration represents a live animal test for control post-infection in terms of proviral replication and disease severity. Recently, it was found that sheep with two copies of TMEM154 haplotype 1 (encoding lysine at position 35) had lower odds of SRLV infection. In this study, we examined the relationship between SRLV control post-infection and variants in two genes, TMEM154 and CCR5, in four flocks containing 1403 SRLV-positive sheep. We found two copies of TMEM154 haplotype 1 were associated with lower SRLV proviral concentration in one flock (P < 0.02). This identified the same favorable diplotype for SRLV control post-infection as for odds of infection. However, frequencies of haplotypes 2 and 3 were too low in the other three flocks to test. The CCR5 promoter deletion did not have consistent association with SRLV proviral concentration. Future work in flocks with more balanced allele frequencies is needed to confirm or refute TMEM154 association with control of SRLV post-infection. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Animal Genetics published by John Wiley & Sons Ltd on behalf of Stichting International Foundation for Animal Genetics.

  1. Evaluation of risk factors of prevalence of leptospirosis in sheep flocks

    M Imandar

    2012-02-01

    Full Text Available Leptospirosis  is  a  worldwide  bacterial  zoonoses  that  its  main  source  are  wild animals  and  rodents  That  leptospirals  excrete  in  their  urine. This  disease  causes  fever, hemoglobinuria, jaundice, abortion, mastitis, reduced  milk  production, reproductive  disorders  and  death  in  cattle, that  major  complications  in  sheep  are  abortion  and  pyelonephritis. The  purpose  of  this  study  is the  evaluation  of   risk  factors  for  leptospirosis  disease  and  its  association  with  high  prevalence  of  infection  in  the  sheep  flocks. Accordingly, 260 serum samples were collected from 20 flocks of  sheep. Then  with  microscopic  agglutination  test (MAT using  6  live  antigen  Leptospira  interrogans  include  Pomona , canicola, icterohaemorrhagiae, gryppotyphoza, ballum  and  hardjo  was  studied. MAT  test  results  of  the  serum  samples  showed  the  contamination  was  28.46%. Most  contamination  of  the  samples  was  allocated  to  sheep  who  lived  in  swampy  areas, so  that  70.28%  of  positive   samples  were  included. 56.25%  of  positive  samples  among  the  samples  showed  positive  reaction  with  serotype canicola. On the other hand, 76.56%  of  the  positive  samples  belonged  to  animals  which  in  their  environment, rodents   in  very  large  numbers  were  observed. The  sheep  that  kept  in moist  and  wet  environment  to  be  had  60%  of  positive  samples , and  finally  the  highest frequency  of  positive  animals  were  ranged  among  ages  3  to  6  years  old, the  incidence  of  the  disease  increased  in  older  animals. By  attention  to  the  results, increasing  of  age, living  in  swampy  and  wet  bed, being  infectious  dogs  in  side  of  flocks and  also  very  large

  2. Coxiella burnetii Circulation in a Naturally Infected Flock of Sheep: Individual Follow-Up of Antibodies in Serum and Milk.

    Joulié, A; Rousset, E; Gasqui, P; Lepetitcolin, E; Leblond, A; Sidi-Boumedine, K; Jourdain, E

    2017-07-01

    The control of Q fever, a zoonotic disease caused by the Coxiella burnetii bacterium, remains a scientific challenge. Domestic ruminants are considered the main reservoir, shedding C. burnetii essentially through parturition products during abortion or birth. Sheep are particularly frequently associated with human outbreaks, but there are insufficient field data to fully understand disease dynamics and to instigate efficient control measures. A longitudinal follow-up study of a naturally infected sheep flock was performed (i) to investigate relationships between seropositivity and bacterial shedding in the vaginal mucus, (ii) to describe the kinetics of antibodies, including responses to vaccination, (iii) to monitor maternal antibodies in ewe lambs, and (iv) to compare serological results for milk and serum samples. For 8 months, we collected blood samples every 3 weeks from 11 aborting and 26 nonaborting dairy ewes, 20 nonaborting suckler ewes, and 9 ewe lambs. Individual milk samples were also obtained from lactating females. All serum and milk samples were tested by enzyme-linked immunosorbent assay (ELISA), whereas vaginal swabs were tested by quantitative PCR. We found that some dairy females did not seroconvert despite shedding C. burnetii in their vaginal mucus. Overall, antibody levels in adult females were found to remain stable over time, with exceptions during the mating and lambing periods. Maternal antibodies decreased during the first month after birth. Interestingly, antibody levels in milk were correlated with those in serum. This study provides valuable field data that will help improve Q fever surveillance and within-flock management measures. IMPORTANCE Field data are necessary to improve the surveillance, diagnosis, and sanitary management of Q fever in livestock. Here, we provide extensive serological data obtained from serum and milk samples from infected and vaccinated ewes belonging to a naturally infected flock of sheep. We show that

  3. Estimates of genetic parameters, genetic trends, and inbreeding in a crossbred dairy sheep research flock in the United States.

    Murphy, T W; Berger, Y M; Holman, P W; Baldin, M; Burgett, R L; Thomas, D L

    2017-10-01

    For the past 2 decades, the Spooner Agriculture Research Station (ARS) of the University of Wisconsin-Madison operated the only dairy sheep research flock in North America. The objectives of the present study were to 1) obtain estimates of genetic parameters for lactation and reproductive traits in dairy ewes, 2) estimate the amount of genetic change in these traits over time, and 3) quantify the level of inbreeding in this flock over the last 20 yr. Multiple-trait repeatability models (MTRM) were used to analyze ewe traits through their first 6 parities. The first MTRM jointly analyzed milk (180-d-adjusted milk yield [180d MY]), fat (180-d-adjusted fat yield [180d FY]), and protein (180-d-adjusted protein yield [180d PY]) yields adjusted to 180 d of lactation; number of lambs born per ewe lambing (NLB); and lactation average test-day somatic cell score (LSCS). A second MTRM analyzed 180d MY, NLB, LSCS, and percentage milk fat (%F) and percentage milk protein (%P). The 3 yield traits were moderately heritable (0.26 to 0.32) and strongly genetically correlated (0.91 to 0.96). Percentage milk fat and %P were highly heritable (0.53 and 0.61, respectively) and moderately genetically correlated (0.61). Milk yield adjusted to 180 d was negatively genetically correlated with %F and %P (-0.31 and -0.34, respectively). Ewe prolificacy was not significantly ( > 0.67) genetically correlated with yield traits, %P, or LSCS but lowly negatively correlated with %F (-0.26). Lactation somatic cell score was unfavorably genetically correlated with yield traits (0.28 to 0.39) but not significantly ( > 0.09) correlated with %F, %P, and NLB. Within-trait multiple-trait models through the first 4 parities revealed that 180d MY, 180d FY, 180d PY, %F, and %P were strongly genetically correlated across parity (0.67 to 1.00). However, the genetic correlations across parity for NLB and LSCS were somewhat lower (0.51 to 0.96). Regressing predicted breeding values for 180d MY, without and with

  4. A "shotgun" method for tracing the birth locations of sheep from flock tags, applied to scrapie surveillance in Great Britain.

    Birch, Colin P D; Del Rio Vilas, Victor J; Chikukwa, Ambrose C

    2010-09-01

    Movement records are often used to identify animal sample provenance by retracing the movements of individuals. Here we present an alternative method, which uses the same identity tags and movement records as are used to retrace movements, but ignores individual movement paths. The first step uses a simple query to identify the most likely birth holding for every identity tag included in a database recording departures from agricultural holdings. The second step rejects a proportion of the birth holding locations to leave a list of birth holding locations that are relatively reliable. The method was used to trace the birth locations of sheep sampled for scrapie in abattoirs, or on farm as fallen stock. Over 82% of the sheep sampled in the fallen stock survey died at the holding of birth. This lack of movement may be an important constraint on scrapie transmission. These static sheep provided relatively reliable birth locations, which were used to define criteria for selecting reliable traces. The criteria rejected 16.8% of fallen stock traces and 11.9% of abattoir survey traces. Two tests provided estimates that selection reduced error in fallen stock traces from 11.3% to 3.2%, and in abattoir survey traces from 8.1% to 1.8%. This method generated 14,591 accepted traces of fallen stock from samples taken during 2002-2005 and 83,136 accepted traces from abattoir samples. The absence or ambiguity of flock tag records at the time of slaughter prevented the tracing of 16-24% of abattoir samples during 2002-2004, although flock tag records improved in 2005. The use of internal scoring to generate and evaluate results from the database query, and the confirmation of results by comparison with other database fields, are analogous to methods used in web search engines. Such methods may have wide application in tracing samples and in adding value to biological datasets. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

  5. Coxiella burnetii, the agent of Q fever, in domestic sheep flocks from Wyoming, United States.

    Loftis, Amanda D; Reeves, Will K; Miller, Myrna M; Massung, Robert F

    2012-03-01

    Coxiella burnetii, the agent of Q fever, is an intracellular bacterial pathogen. It has a nearly cosmopolitan distribution. We conducted a serological survey of domestic sheep herds for infections with C. burnetii in Wyoming following reports of abortion and open ewes. Based on the serologic evidence, there was no link between reproductive problems and exposure to C. burnetii. However, the overall prevalence of C. burnetii in WY sheep was 7%, which indicates that the agent is present in the environment and could pose a threat to public health.

  6. Risk factors and impacts of clinical and subclinical mastitis in commercial meat-producing sheep flocks in Quebec, Canada.

    Arsenault, Julie; Dubreuil, Pascal; Higgins, Robert; Bélanger, Denise

    2008-11-17

    We conducted a prospective observational study on clinical and subclinical mastitis in 30 commercial meat-producing sheep flocks from 2 regions of the province of Quebec, Canada. A total of 2,792 ewes selected in late gestation were followed from lambing to weaning of lambs. The incidence of clinical mastitis for the total lactation period (average of 58 days) ranged among flocks from 0 to 6.6%, with a median of 1.2%. The most frequently isolated bacteria from the cases of clinical mastitis, in pure or mixed culture, were Mannheimia haemolytica (26%), Staphylococcus aureus (23%), and coagulase-negative staphylococci (17%). Incidence of clinical mastitis was higher in ewes that gave birth to 3 or more lambs and from the Estrie region, and was associated with an increase in ewe mortality, an increase in lamb mortality at the litter level, and a decrease in lamb's weaning weight for lambs born in multiple litter size or from ewes >or=4 years old. Among 354 selected ewes with clinically normal udder at the end of lactation, 28.8% had potentially pathogenic bacteria isolated from milk. The most prevalent bacteria were S. aureus (9.3%) and coagulase-negative staphylococci (9.3%). The risk of having a positive culture in at least one half was different between the two regions. Prevalence of ewes (n=261) with California Mastitis Test (CMT) positive result in at least one half was 24.1 and 14.9% using a cut-off of >or=1+ and >or=2+, respectively. Prevalence of culture-positive udder halves was 11.7% for CMT-negative compared with 53.6% for CMT 3+ halves. CMT status was positively associated with the isolation of coagulase-negative staphylococci, M. haemolytica, S. aureus, and various Streptococcus species, but not with other isolated bacteria. Additionally, prevalence of CMT-positive halves was higher in ewes from the Estrie region, aged of >or=4 years versus 1 year, having clinical mastitis previously detected in the lactation and/or with low body condition score. Lamb

  7. Atypical outbreak of acute coenurosis by Taenia multiceps in a sheep flock.

    Pintus, Davide; Varcasia, Antonio; Dessì, Giorgia; Tamponi, Claudia; Manunta, Maria Lucia; Carboni, Giovanni Antonio; Cancedda, Maria Giovanna; Ligios, Ciriaco; Scala, Antonio

    2018-06-01

    Herein, we examined the brain of adult ewes and lambs less than 30 days old which were found affected by neurological signs in a flock located in Sardinia (Italy). Gross anatomo-pathological examination of all brains of the animals revealed multiple linear reddish-yellow foci of necrotic purulent inflammation due to oncosphere migration. Histologically, we confirmed a multifocal pyo-granulomatous meningo-encephalitis both in ewes and in lambs, confirming acute coenurosis. Morphological examination and DNA sequencing identified the Taenia multiceps we isolated as Tm1 strain. This report describes for the first time a natural acute coenurosis infection in suckling lambs under 30 days of age.

  8. A method for hardening or curing adhesives for flocking thermally sensitive substrata by means of an electron-beam

    Nablo, S.V.; Fussa, A.D.

    1975-01-01

    The invention relates to a method for hardening or curing adhesives for flocking thermally sensitive substrata by means of an electron-beam. That method consists in accurately adjusting the parameters of irradiation by an electron-beam and the beam velocity so as to obtain, a very rapid hardening of adhesives used for fixing flocking materials, or the like, to thermally sensitive substrate. That can be applied to hardening or curing adhesives for flocking thermally-sensitive substrata which normally restrict the hardening rate [fr

  9. Business Students Flock to Courses on Electronic Commerce.

    Mangan, Katherine S.

    1999-01-01

    Business schools across the country are specializing in electronic commerce, in which teams of students create online businesses available on the Internet only to participating institutions. The courses offer students an opportunity to see how an online retailing business is conducted, including creating and maintaining Web sites, advertising…

  10. Genetic trend for growth and wool performance in a closed flock of Bharat Merino sheep at sub temperate region of Kodai hills, Tamil Nadu.

    Mallick, P K; Thirumaran, S M K; Pourouchottamane, R; Rajapandi, S; Venkataramanan, R; Nagarajan, G; Murali, G; Rajendiran, A S

    2016-03-01

    The study was conducted at Southern Regional Research Center, ICAR-Central Sheep and Wool Research Institute (CSWRI), Mannavanur, Kodaikanal, Tamil Nadu to estimate genetic trends for birth weight (BWT), weaning weight (3WT), 6 months weight (6WT), and greasy fleece weight (GFY) in a Bharat Merino (BM) flock, where selection was practiced for 6WT and GFY. The data for this study represents a total of 1652 BM lambs; progeny of 144 sires spread over 15 years starting from 2000 to 2014, obtained from the BM flock of ICAR-SRRC (CSWRI), Mannavanur, Kodaikanal, Tamil Nadu, India. The genetic trends were calculated by regression of average predicted breeding values using software WOMBAT for the traits BWT, 3WT, 6WT and GFY versus the animal's birth year. The least square means were 3.28±0.02 kg, 19.08±0.23 kg, 25.00±0.35 kg and 2.13±0.07 kg for BWT, 3WT, 6WT and GFY, respectively. Genetic trends were positive and highly significant (p<0.01) for BWT, while the values for 3WT, 6WT and GFY though positive, were not significant. The estimates of genetic trends in BWT, 3WT, 6WT and GFY were 5 g, 0.8 g, 7 g and 0.3 g/year gain and the fit of the regression shows 55%, 22%, 42% and 12% coefficient of determination with the regressed value, respectively. In this study, estimated mean predicted breeding value (kg) in BWT and 3WT, 6WT and GFY were 0.067, 0.008, 0.036 and -0.003, respectively. Estimates of genetic trends indicated that there was a positive genetic improvement in all studied traits and selection would be effective for the improvement of body weight traits and GFY of BM sheep.

  11. Coxiella burnetii Circulation in a Naturally Infected Flock of Sheep: Individual Follow-Up of Antibodies in Serum and Milk

    Joulié, A.; Rousset, E.; Gasqui, P.; Lepetitcolin, E.; Leblond, A.; Sidi-Boumedine, K.; Jourdain, E.

    2017-01-01

    The control of Q fever, a zoonotic disease caused by the Coxiella burnetii bacterium, remains a scientific challenge. Domestic ruminants are considered the main reservoir, shedding C. burnetii essentially through parturition products during abortion or birth. Sheep are particularly frequently associated with human outbreaks, but there are insufficient field data to fully understand disease dynamics and to instigate efficient control measures. A longitudinal follow-up study of a naturally infe...

  12. Drivers for precision livestock technology adoption: A study of factors associated with adoption of electronic identification technology by commercial sheep farmers in England and Wales.

    Lima, Eliana; Hopkins, Thomas; Gurney, Emma; Shortall, Orla; Lovatt, Fiona; Davies, Peers; Williamson, George; Kaler, Jasmeet

    2018-01-01

    The UK is the largest lamb meat producer in Europe. However, the low profitability of sheep farming sector suggests production efficiency could be improved. Although the use of technologies such as Electronic Identification (EID) tools could allow a better use of flock resources, anecdotal evidence suggests they are not widely used. The aim of this study was to assess uptake of EID technology, and explore drivers and barriers of adoption of related tools among English and Welsh farmers. Farm beliefs and management practices associated with adoption of this technology were investigated. A total of 2000 questionnaires were sent, with a response rate of 22%. Among the respondents, 87 had adopted EID tools for recording flock information, 97 intended to adopt it in the future, and 222 neither had adopted it, neither intended to adopt it. Exploratory factor analysis (EFA) and multivariable logistic regression modelling were used to identify farmer beliefs and management practices significantly associated with adoption of EID technology. EFA identified three factors expressing farmer's beliefs-external pressure and negative feelings, usefulness and practicality. Our results suggest farmer's beliefs play a significant role in technology uptake. Non-adopters were more likely than adopters to believe that 'government pressurise farmers to adopt technology'. In contrast, adopters were significantly more likely than non-adopters to see EID as practical and useful (p≤0.05). Farmers with higher information technologies literacy and intending to intensify production in the future were significantly more likely to adopt EID technology (p≤0.05). Importantly, flocks managed with EID tools had significantly lower farmer- reported flock lameness levels (p≤0.05). These findings bring insights on the dynamics of adoption of EID tools. Communicating evidence of the positive effects EID tools on flock performance and strengthening farmer's capability in use of technology are likely

  13. Drivers for precision livestock technology adoption: A study of factors associated with adoption of electronic identification technology by commercial sheep farmers in England and Wales

    Hopkins, Thomas; Gurney, Emma; Shortall, Orla; Lovatt, Fiona; Davies, Peers; Williamson, George; Kaler, Jasmeet

    2018-01-01

    The UK is the largest lamb meat producer in Europe. However, the low profitability of sheep farming sector suggests production efficiency could be improved. Although the use of technologies such as Electronic Identification (EID) tools could allow a better use of flock resources, anecdotal evidence suggests they are not widely used. The aim of this study was to assess uptake of EID technology, and explore drivers and barriers of adoption of related tools among English and Welsh farmers. Farm beliefs and management practices associated with adoption of this technology were investigated. A total of 2000 questionnaires were sent, with a response rate of 22%. Among the respondents, 87 had adopted EID tools for recording flock information, 97 intended to adopt it in the future, and 222 neither had adopted it, neither intended to adopt it. Exploratory factor analysis (EFA) and multivariable logistic regression modelling were used to identify farmer beliefs and management practices significantly associated with adoption of EID technology. EFA identified three factors expressing farmer’s beliefs–external pressure and negative feelings, usefulness and practicality. Our results suggest farmer’s beliefs play a significant role in technology uptake. Non-adopters were more likely than adopters to believe that ‘government pressurise farmers to adopt technology’. In contrast, adopters were significantly more likely than non-adopters to see EID as practical and useful (p≤0.05). Farmers with higher information technologies literacy and intending to intensify production in the future were significantly more likely to adopt EID technology (p≤0.05). Importantly, flocks managed with EID tools had significantly lower farmer- reported flock lameness levels (p≤0.05). These findings bring insights on the dynamics of adoption of EID tools. Communicating evidence of the positive effects EID tools on flock performance and strengthening farmer’s capability in use of

  14. INVIVO DEGRADATION OF PROCESSED DERMAL SHEEP COLLAGEN EVALUATED WITH TRANSMISSION ELECTRON-MICROSCOPY

    VANWACHEM, PB; VANLUYN, MJA; NIEUWENHUIS, P; KOERTEN, HK; DAMINK, LO; TENHOOPEN, H; FEIJEN, J

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  15. In vivo degradation of processed dermal sheep collagen evaluated with transmission electron microscopy

    van Wachem, P.B.; van Luyn, M.J.A.; Nieuwenhuis, P.; Koerten, H.K.; Olde damink, L.H.H.; Olde-Damink, L.; ten Hoopen, Hermina W.M.; Feijen, Jan

    1991-01-01

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  16. A comparison of the efficacy of three intervention trial types: postal, group, and one-to-one facilitation, prior management and the impact of message framing and repeat messages on the flock prevalence of lameness in sheep.

    Grant, Claire; Kaler, Jasmeet; Ferguson, Eamonn; O'Kane, Holly; Green, Laura Elizabeth

    2018-01-01

    The aim of this study was to evaluate the effectiveness of three knowledge-transfer intervention trial types (postal, group, one-to-one) to promote best practice to treat sheep with footrot. Further aims were to investigate whether farmer behaviour (i.e. management of lameness) before the trial was associated with uptake of best practice and whether the benefits of best practice framed positively or negatively influenced change in behaviour. The intervention was a message developed from evidence and expert opinion. It was entitled "Six steps to sound sheep" and promoted (1) catch sheep within three days of becoming lame, (2) inspect feet without foot trimming, (3) correctly diagnose the cause, (4) treat sheep lame with footrot or interdigital dermatitis with antibiotic injection and spray without foot trimming, (5) record the identity of treated sheep, (6) cull repeatedly lame sheep. In 2013, 4000 randomly-selected English sheep farmers were sent a questionnaire, those who responded were recruited to the postal (1081 farmers) or one-to-one intervention (32 farmers) trials. A random sample of 400 farmers were invited to join the group trial; 78 farmers participated. A follow-up questionnaire was sent to all participants in summer 2014. There were 72%, 65% and 91% useable responses for the postal, group and one-to-one trials respectively. In both 2013 and 2014, the prevalence of lameness was lower in flocks managed by LC1 farmers than LC2 and LC3 farmers. Between 2013 and 2014, the reduction in geometric mean (95% CI) period prevalence of lameness, proportional between flock reduction in lameness and within flock reduction in lameness was greatest in the one-to-one (7.6% (7.1-8.2%) to 4.3% (3.6-5.0%), 35%, 72%) followed by the group (4.5% (3.9-5.0%) to 3.1% (2.4-3.7%), 27%, 55%) and then the postal trial (from 3.5% (3.3-3.7%) to 3.2% (3.1-3.4%), 21%, 43%). There was a marginally greater reduction in lameness in farmers using most of Six steps but slow to treat lame

  17. Sheep internal parasites on Rab and Pag

    Relja Beck

    2010-01-01

    Full Text Available The purpose of our research was to determine which groups and species of internal parasites endanger the health of sheep on the islands of Rab and Pag. The research was carried out in 10 flocks on both islands taking the fresh dung out of 30% of the total number of sheep in each flock. It was ascertained that the gastrointestinal parasites and protozoa of Eimeria genus are present in most flocks on both islands. The presence of the fluke Dicrocoelium dendriticum was ascertained in considerably larger number of flocks on the island of Rab than on the island of Pag. On the other hand, the presence of parasites of Moniezia and Nematodirus genus was ascertained in larger number of flocks on the island of Pag. In two flocks on Rab parasites of Protostrongylus genus were ascertained while on the island of Pag they were not found in any flock.

  18. Farmers' practices and factors associated with the prevalence of all lameness and lameness attributed to interdigital dermatitis and footrot in sheep flocks in England in 2004.

    Kaler, J; Green, L E

    2009-11-01

    The aim of this study was to investigate whether the risk factors associated with all causes of lameness in sheep differed from those associated with the lesion specific causes of lameness, interdigital dermatitis (ID) and footrot (FR). A total of 809 randomly selected English sheep farmers participated in a postal survey in 2005. Data were requested on their management of lameness in 2004 and whether this had changed from 2003 and the prevalence of all lameness, and lameness caused by ID and FR. The farmer ability to recognise ID and FR was assessed from their responses to a written and pictorial description. On 443 farms where both ID and FR were correctly named by the farmer, the mean prevalence of all lameness, and lameness caused by ID and FR were 10.0% (95% CI: 8.9, 10.8), 6.5% (95% CI: 5.8, 7.3) and 3.1% (95% CI: 2.8, 3.6), respectively. The mean prevalence of all lameness on all 809 farms was not significantly different at 10.2% (95% CI: 9.2, 11.0). The data were analysed using negative binomial regression models with the three outcomes farmer estimated prevalence of all lameness and lameness caused by ID or FR in 2004. Farmers who changed management of sheep between 2003 and 2004 were excluded from the analysis, thus all fixed effects were the farmers' managements in 2003 and 2004 to ensure that the management was in place for at least one year before the prevalence estimates. Routine foot trimming>or=once/year compared with no routine foot trimming was significantly associated with an increased prevalence of all lameness (prevalence ratio (PR)=1.34), ID (PR=1.50) and FR (PR=1.35). Footbathing was also significantly associated with increased prevalence of all lameness (PR=1.67), ID (PR=1.68) and FR (PR=1.76). A stocking density of >8 ewes/ha was associated with a significantly increased prevalence of all lameness (PR=1.26) and ID (PR=1.39). There was a significantly lower prevalence of FR (PR=0.73; PR=0.70, respectively) on farms in the North East and

  19. A rapid method of predicting radiocaesium concentrations in sheep from activity levels in faeces

    McGee, E.J.; Synnott, H.J.; Colgan, P.A.; Keatinge, M.J.

    1994-01-01

    The use of faecal samples taken from sheep flocks as a means of predicting radiocaesium concentrations in live animals was studied. Radiocaesium levels in 1726 sheep from 29 flocks were measured using in vivo techniques and a single faecal sample taken from each flock was also analysed. A highly significant relationship was found to exist between mean flock activity and activity in the corresponding faecal samples. Least-square regression yielded a simple model for predicting mean flock radiocaesium concentrations based on activity levels in faecal samples. A similar analysis of flock maxima and activity levels in faeces provides an alternative model for predicting the expected within-flock maximum radiocaesium concentration. (Author)

  20. Sheep Feed and Scrapie, France

    Philippe, Sandrine; Ducrot, Christian; Roy, Pascal; Remontet, Laurent; Jarrige, Nathalie

    2005-01-01

    Scrapie is a small ruminant, transmissible spongiform encephalopathy (TSE). Although in the past scrapie has not been considered a zoonosis, the emergence of bovine spongiform encephalopathy, transmissible to humans and experimentally to sheep, indicates that risk exists for small ruminant TSEs in humans. To identify the risk factors for introducing scrapie into sheep flocks, a case-control study was conducted in France from 1999 to 2000. Ninety-four case and 350 control flocks were matched by location and main breed. Three main hypotheses were tested: direct contact between flocks, indirect environmental contact, and foodborne risk. Statistical analysis was performed by using adjusted generalized linear models with the complementary log-log link function, considering flock size as an offset. A notable effect of using proprietary concentrates and milk replacers was observed. The risk was heterogeneous among feed factories. Contacts between flocks were not shown to be a risk factor. PMID:16102318

  1. Livestock mortality and offtake in sheep and goat flocks of livestock owners making use of services offered by paravets in West Afghanistan.

    Bartels, Chris J M; Fakhri, A Qader; Shams, M Hamed; Briscoe, Raymond P; Schreuder, Bram E C

    2017-10-01

    reference category. In conclusion, we demonstrated significant improvement of health and production parameters in small ruminants' flocks of owners making use of the services of the DCA-trained paravets, emphasizing the importance of this sustainable and effective system of private veterinary service delivery in Afghanistan. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Encephalitic Sarcocystosis and its Prophylactic Treatment in Sheep

    ÖZMEN, Özlem; ŞAHİNDURAN, Şima; HALIGÜR, Mehmet; YUKARI, Bayram Ali; DORRESTEIN, Gerry M.

    2014-01-01

    The aim of this study was to examine the clinical and pathological findings in sheep naturally infected with severe encephalitic sarcocystosis and to evaluate the prophylactic effect of amprolium on the disease. From a flock of approximately 350 animals, 10 sheep were referred to the Veterinary Faculty Clinic with neurological symptoms that developed during the previous 2 weeks. These 10 sheep were clinically and pathologically examined, and the remaining animals in the flock without neurolog...

  3. Hydrodynamics of Turning Flocks

    Yang, Xingbo; Marchetti, M. Cristina

    2014-01-01

    We present a hydrodynamic model of flocking that generalizes the familiar Toner-Tu equations to incorporate turning inertia of well-polarized flocks. The continuum equations controlled by only two dimensionless parameters, orientational inertia and alignment strength, are derived by coarse graining the inertial spin model recently proposed by Cavagna et al. The interplay between orientational inertia and bend elasticity of the flock yields anisotropic spin waves that mediate the propagation o...

  4. Sero-prevalence study of bluetongue infection in sheep and goats in ...

    tion channels, muddy areas and fecal runoff areas around farms and habitats for them ... susceptible than native African sheep (Davies and Walker, 1974; Howell, 1979; ..... ity in sheep flocks in North West Frontier Province, Pakistan. Prev. Vet.

  5. In vivo and in vitro effects of imidacloprid on sheep keds (Melophagus ovinus): a light and electron microscopic study.

    Mehlhorn, H; D'Haese, J; Mencke, N; Hansen, O

    2001-04-01

    The effects of imidacloprid (Advantage) on sheep keds (Melophagus ovinus Linne 1758) were studied in vivo and in vitro by means of direct observation (monitored on video tape) and by light and electron microscopy. It was found that: 1. Imidacloprid acted rapidly on all motile stages of the sheep keds. Within 3-4 min after exposure they became immobile and their legs and the abdomen started tetanic trembling movements for 15-30 min, leading to death. 2. The compound is apparently taken up by the body, since it also acted on those sheep keds that had been exclusively exposed to imidacloprid-contaminated filter papers. 3. The compound is available and active for more than 1 month in the wool of sheep; even rainfall does not reduce its efficacy. Body contact between treated mother sheep and their lambs protects them from infestation with these ectoparasites. 4. The compound initiates an ultimately lethal destruction of the ganglia, nerve chords and related muscle fibers, as can be seen in electron micrographs.

  6. Within-Flock Population Dynamics of Dichelobacter nodosus

    Laura E. Green

    2017-04-01

    Full Text Available Footrot causes 70–90% of lameness in sheep in Great Britain. With approximately 5% of 18 million adult sheep lame at any one time, it costs the UK sheep industry £24–84 million per year. The Gram-negative anaerobe Dichelobacter nodosus is the causative agent, with disease severity influenced by bacterial load, virulence, and climate. The aim of the current study was to characterize strains of D. nodosus isolated by culture of swabs from healthy and diseased feet of 99 ewes kept as a closed flock over a 10-month period and investigate persistence and transmission of strains within feet, sheep, and the flock. Overall 268 isolates were characterized into strains by serogroup, proline–glycine repeat (pgr status, and multi-locus variable number tandem repeat analysis (MLVA. The culture collection contained 87 unique MLVA profiles and two major MLVA complexes that persisted over time. A subset of 189 isolates tested for the virulence marker aprV2 were all positive. The two MLVA complexes (76 and 114 comprised 62 and 22 MLVA types and 237 and 28 isolates, respectively. Serogroups B, and I, and pgrB were associated with MLVA complex 76, whereas serogroups D and H were associated with MLVA complex 114. We conclude that within-flock D. nodosus evolution appeared to be driven by clonal diversification. There was no association (P > 0.05 between serogroup, pgr, or MLVA type and disease state of feet. Strains of D. nodosus clustered within sheep and were transmitted between ewes over time. D. nodosus was isolated at more than one time point from 21 feet, including 5 feet where the same strain was isolated on two occasions at an interval of 1–33 weeks. Collectively, our results indicate that D. nodosus strains persisted in the flock, spread between sheep, and possibly persisted on feet over time.

  7. Sheep lymph-nodes as a biological indicator of environmental exposure to fluoro-edenite

    Ledda, Caterina; Loreto, Carla; Pomara, Cristoforo; Rapisarda, Giuseppe; Fiore, Maria; Ferrante, Margherita; Bracci, Massimo; Santarelli, Lory; Fenga, Concettina; Rapisarda, Venerando

    2016-01-01

    A significantly increased incidence of pleural mesothelioma in Biancavilla (Sicily, Italy) has been attributed to exposure to fluoro-edenite (FE), a fibrous amphibole extracted from a local stone quarry. The lymph-nodes draining the pulmonary lobes of sheep grazing around the town were examined, to gain insights into fibre diffusion. The pasture areas of six sheep flocks lying about 3 km from Biancavilla were located using the global positioning system. The cranial tracheobronchial and one middle mediastinal lymph-node as well as four lung tissue samples were collected from 10 animals from each flock and from 10 control sheep for light and scanning electron microscopy (SEM) examination. The lymph-nodes from exposed sheep were enlarged and exhibited signs of anthracosis. Histologically, especially at the paracortical level, they showed lymph-follicle hyperplasia with large reactive cores and several macrophages (coniophages) containing grey-brownish particulate interspersed with elements with a fibril structure, forming aggregates of varying dimensions (coniophage nodules). Similar findings were detected in some peribronchiolar areas of the lung parenchyma. SEM examination showed that FE fibres measured 8–41 µm in length and 0.4–1.39 µm in diameter in both lymph-nodes and lung tissue. Monitoring of FE fibres in sheep lymph-nodes using appropriate techniques can help set up environmental pollution surveillance. - Highlights: • Lymph-nodes draining sheep lung were used to assess environmental fluoro-edenite exposure. • Monitoring fluoro-edenite fibres in sheep lung nodes can provide pollution surveillance. • Our findings document a risk of fluoro-edenite fibre inhalation a few kilometres from the source. • Sheep appear to be a valuable bioindicator species.

  8. Sheep lymph-nodes as a biological indicator of environmental exposure to fluoro-edenite

    Ledda, Caterina, E-mail: cledda@unict.it [Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, Catania (Italy); Hygiene and Public Health, Department of Medical Sciences, Surgical and Advanced Technologies “GF Ingrassia”, University of Catania, Catania (Italy); Loreto, Carla [Human Anatomy and Histology, Department of Bio-Medical Sciences, University of Catania, Catania (Italy); Pomara, Cristoforo [Department of Anatomy, School of Medicine, University of Malta, Msida (Malta); Rapisarda, Giuseppe [Department of Veterinary Medicine, ASP Catania, Catania (Italy); Fiore, Maria; Ferrante, Margherita [Hygiene and Public Health, Department of Medical Sciences, Surgical and Advanced Technologies “GF Ingrassia”, University of Catania, Catania (Italy); Bracci, Massimo; Santarelli, Lory [Occupational Medicine, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, Ancona (Italy); Fenga, Concettina [Occupational Medicine, Department of the Environment, Safety, Territory, Food and Health Sciences, University of Messina, Messina (Italy); Rapisarda, Venerando [Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, Catania (Italy)

    2016-05-15

    A significantly increased incidence of pleural mesothelioma in Biancavilla (Sicily, Italy) has been attributed to exposure to fluoro-edenite (FE), a fibrous amphibole extracted from a local stone quarry. The lymph-nodes draining the pulmonary lobes of sheep grazing around the town were examined, to gain insights into fibre diffusion. The pasture areas of six sheep flocks lying about 3 km from Biancavilla were located using the global positioning system. The cranial tracheobronchial and one middle mediastinal lymph-node as well as four lung tissue samples were collected from 10 animals from each flock and from 10 control sheep for light and scanning electron microscopy (SEM) examination. The lymph-nodes from exposed sheep were enlarged and exhibited signs of anthracosis. Histologically, especially at the paracortical level, they showed lymph-follicle hyperplasia with large reactive cores and several macrophages (coniophages) containing grey-brownish particulate interspersed with elements with a fibril structure, forming aggregates of varying dimensions (coniophage nodules). Similar findings were detected in some peribronchiolar areas of the lung parenchyma. SEM examination showed that FE fibres measured 8–41 µm in length and 0.4–1.39 µm in diameter in both lymph-nodes and lung tissue. Monitoring of FE fibres in sheep lymph-nodes using appropriate techniques can help set up environmental pollution surveillance. - Highlights: • Lymph-nodes draining sheep lung were used to assess environmental fluoro-edenite exposure. • Monitoring fluoro-edenite fibres in sheep lung nodes can provide pollution surveillance. • Our findings document a risk of fluoro-edenite fibre inhalation a few kilometres from the source. • Sheep appear to be a valuable bioindicator species.

  9. External and internal modulators of sheep reproduction.

    Blache, Dominique; Bickell, Samantha L

    2011-12-01

    Several factors such as season, genetics, social interaction and metabolic status control or modulate the reproductive capacity of sheep. In addition to these well-studied factors in sheep, the influence of emotional reactivity on the reproductive success of sheep has started to be investigated over the last two decades. In this paper, after briefly reviewing the impact of classical factors affecting reproduction in sheep, we define emotional reactivity and the expression of its inter-individual variability, named temperament. Then, following a description of the protocol to measure temperament in sheep and discussion on the heritability of temperament traits, we illustrate how this selection affects the reproductive biology of sheep. We will be mainly using results obtained from a unique flock of sheep selected for low or high emotional reactivity. In conclusion, we propose that energy partitioning could be one of the mechanisms by which selection for temperament in sheep affects the different steps of the reproductive cycle.

  10. Flocking through disorder

    Morin, Alexandre; Desreumaux, Nicolas; Caussin, Jean-Baptiste; Bartolo, Denis

    How do flocks, herds and swarms proceed through disordered environments? This question is not only crucial to animal groups in the wild, but also to virtually all applications of collective robotics, and active materials composed of synthetic motile units. In stark contrast, appart from very rare exceptions, our physical understanding of flocking has been hitherto limited to homogeneous media. Here we explain how collective motion survives to geometrical disorder. To do so, we combine experiments on motile colloids cruising through random microfabricated obstacles, and analytical theory. We explain how disorder and bending elasticity compete to channel the flow of polar flocks along sparse river networks akin those found beyond plastic depinning in driven condensed matter. Further increasing disorder, we demonstrate that collective motion is suppressed in the form of a first-order phase transition generic to all polar active materials.

  11. Tibiotarsal arthrodesis in a Moufflon sheep.

    Ferguson, J G; Farrow, C S; Haigh, J C

    1978-11-01

    Restraint of a mature Moufflon sheep resulted in severe fracture and luxation of a previously osteoarthritic tibiotarsal joint. Arthrodesis was accomplished by means of internal pin fixation and an external fiberglass cast. After 3 months of hospitalization, the ram was returned to the original flock. Competition for dominance within the flock resulted in physical trauma to the ram. Seven months after surgery, the ram sustained a fractured ulna and died from exposure.

  12. Coordinated Behaviour in Pigeon Flocks

    Yomosa, Makoto; Mizuguchi, Tsuyoshi; V?s?rhelyi, G?bor; Nagy, M?t?

    2015-01-01

    We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i) the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii) during ...

  13. Topological Sound and Flocking on Curved Surfaces

    Suraj Shankar

    2017-09-01

    Full Text Available Active systems on curved geometries are ubiquitous in the living world. In the presence of curvature, orientationally ordered polar flocks are forced to be inhomogeneous, often requiring the presence of topological defects even in the steady state because of the constraints imposed by the topology of the underlying surface. In the presence of spontaneous flow, the system additionally supports long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. We analytically compute the steady-state profile of an active polar flock on a two-sphere and a catenoid, and show that curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface (the equator or the neck, respectively. These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering.

  14. Topological Sound and Flocking on Curved Surfaces

    Shankar, Suraj; Bowick, Mark J.; Marchetti, M. Cristina

    2017-07-01

    Active systems on curved geometries are ubiquitous in the living world. In the presence of curvature, orientationally ordered polar flocks are forced to be inhomogeneous, often requiring the presence of topological defects even in the steady state because of the constraints imposed by the topology of the underlying surface. In the presence of spontaneous flow, the system additionally supports long-wavelength propagating sound modes that get gapped by the curvature of the underlying substrate. We analytically compute the steady-state profile of an active polar flock on a two-sphere and a catenoid, and show that curvature and active flow together result in symmetry-protected topological modes that get localized to special geodesics on the surface (the equator or the neck, respectively). These modes are the analogue of edge states in electronic quantum Hall systems and provide unidirectional channels for information transport in the flock, robust against disorder and backscattering.

  15. Chronic intoxication with copper in sheep: prophylaxis and treatment

    Tomov, A

    1964-01-01

    In the period 1961-1962 chronic intoxication of sheep with copper was observed on 7 farms, the number of sheep totaling about 9000. In one of the flocks intoxication occurred after feeding the sheep for a long time with aftermath collected from orchards which had been sprinkled with copper compounds. The aftermath was proven to contain from 11 to 17 mg. per cent of copper. The other flocks were put to pasture in vineyards after the grapes had been gathered. Intoxication in these flocks was caused by vineleaves. No accumulation of copper through the soil was established in the investigated fresh grass found in the vineyards and which the sheep had also grazed. From 36 to 81 mg. per cent of copper was established in the livers of dead sheep. In order to protect the sheep from this intoxication, 100-200 mg. of ammonium or sodium molybdate and 5-10 g. of sodium sulfate were used in the case of each sheep daily for 2-3 weeks. The concentrated fodder of the sheep was moistened with an aqueous solution of these compounds. A very good prophylactic effect was obtained. At the same time oats, maize, oilcakes and others, which constitute a fodder rich in fats, were eliminated from the food rations of the sheep. The above substances, given at larger doses simultaneously with vitamin B/sub 12/ were also used for the treatment of diseased sheep, and of 10 ill sheep, 7 recovered.

  16. Both gas chromatography and an electronic nose reflect chemical polymorphism of juniper shrubs browsed or avoided by sheep.

    Markó, Gábor; Novák, Ildikó; Bernáth, Jeno; Altbäcker, Vilmos

    2011-07-01

    Chemical polymorphism may contribute to variation in browsing damage by mammalian herbivores. Earlier, we demonstrated that essential oil concentration in juniper, Juniperus communis, was negatively associated with herbivore browsing. The aim of the present study was to characterize the volatile chemical composition of browsed and non-browsed J. communis. By using either gas chromatography with flame ionization detection (GC-FID) or an electronic nose device, we could separate sheep-browsed or non-browsed juniper shrubs by their essential oil pattern and complex odor matrix. The main components of the essential oil from J. communis were monoterpenes. We distinguished three chemotypes, dominated either by α-pinene, sabinene, or δ-3-carene. Shrubs belonging to the α-pinene- or sabinene-dominated groups were browsed, whereas all individuals with the δ-3-carene chemotype were unused by the local herbivores. The electronic nose also separated the browsed and non-browsed shrubs indicating that their odor matrix could guide sheep browsing. Responses of sheep could integrate the post-ingestive effects of plant secondary metabolites with sensory experience that stems from odor-phytotoxin interactions. Chemotype diversity could increase the survival rate in the present population of J. communis as certain shrubs could benefit from relatively better chemical protection against the herbivores.

  17. Recognition of lameness and decisions to catch for inspection among sheep farmers and specialists in GB

    Green LE

    2008-10-01

    Full Text Available Abstract Background Epidemiological studies have used farmer estimates of the prevalence of lameness in their flocks. This assumes that farmers can identify lame sheep. Eight movie clips of sheep with locomotion from sound to moderately lame were used to investigate the ability of farmers and sheep specialists to recognise lame sheep. Each participant was asked to complete a form and indicate, for each movie clip, whether they thought the sheep was lame and whether they would catch it if it was the only lame sheep or if 2 – 5, 6 – 10 or > 10 sheep were equally lame. The farmers' responses were compared with their estimates of flock lameness prevalence and the interval between observing a lame sheep and catching it. Results 178 farmers and 54 sheep specialists participated. Participants could identify even mildly lame sheep but made a separate decision on whether to catch them. This decision was dependent on the severity of lameness and the number of sheep lame in a group. Those who said they would catch the first lame sheep in a group were significantly more likely to catch mildly lame sheep (farmer-reported median prevalence of lameness 5% (IQR: 2%–6%. In contrast, farmers who waited for several sheep to be lame indicated that they would only catch more severely lame sheep (farmer reported median flock lameness 11% (IQR: 9%–15%. Approximately 15% of farmers did not catch individual lame sheep (farmer reported median flock lameness 15% (IQR: 10%–15%. The flock prevalence of lameness increased as time to treatment increased and time to treatment was positively correlated with only catching more severely lame sheep. Conclusion If movie-clips are similar to the flock situation, farmers and specialists can recognise even mildly lame sheep but vary in their management from prompt treatment of the first lame sheep in a group to no individual sheep treatments. The former practices would be appropriate to minimise transmission of footrot, a

  18. Environmental study of nylon flocking process.

    Burkhart, J; Piacitelli, C; Schwegler-Berry, D; Jones, W

    1999-05-14

    Environmental measurements for a variety of gas, particulate, and microbiological agents have been made in order to characterize exposures associated with the nylon flocking process. Of all agents measured, particulate is the predominant exposure. Levels of total particulate ranged from O.1 to 240 mg/m3 (x = 11.4 mg/m3). Average respirable particulate was 2.2 mg/m3, ranging from 0.5 to 39.9 mg/m3. Highest levels of particulates were found in the flocking room, and direct reading dust measurements indicate that the highest peak exposures are associated with "blowdown" (a cleaning procedure used between flocking runs). The nature of the airborne particles was investigated using polarized light and scanning electron microscopy. Air samples were found to contain flock particles (fibers nominally 10-15 microm in diameter by about 1000 microm in length) and a variety of respirable particles types, several of which were linked directly to the process. Of special interest were elongated respirable particles, which by microscopic analysis, complemented with melting-point determination, were found to be shreds of nylon.

  19. Genetic trends of selection for pelt traits in Karakul sheep I. Direct ...

    Genetic trends of selection for pelt traits in Karakul sheep. I. Direct ... development in the Karakul Wereestimated with the Animal Model in four selection lines and in a control flock over ..... Selection experiments in laboratory and domestic.

  20. An ecologic study comparing distribution of Pasteurella trehalosi and Mannheimia haemolytica between Sierra Nevada bighorn sheep, White Mountain bighorn sheep, and domestic sheep.

    Tomassini, Letizia; Gonzales, Ben; Weiser, Glen C; Sischo, William

    2009-10-01

    The prevalence and phenotypic variability of Pasteurella and Mannheimia isolates from Sierra Nevada bighorn sheep (Ovis canadensis sierrae), White Mountain bighorn sheep (Ovis canadensis nelsoni), and domestic sheep (Ovis aries) from California, USA, were compared. The White Mountain bighorn sheep population had a recent history of pneumonia-associated mortality, whereas the Sierra Nevada bighorn sheep population had no recent history of pneumonia-associated mortality. The domestic sheep flocks were pastured in areas geographically near both populations but were not known to have direct contact with either bighorn sheep population. Oropharyngeal swab samples were collected from healthy domestic and bighorn sheep and cultured to characterize bacterial species, hemolysis, biogroups, and biovariants. Pasteurella trehalosi and Mannheimia haemolytica were detected in all of the study populations, but the relative proportion of each bacterial species differed among sheep populations. Pasteurella trehalosi was more common than M. haemolytica in the bighorn sheep populations, whereas the opposite was true in domestic sheep. Mannheimia haemolytica was separated into 11 biogroups, and P. trehalosi was characterized into two biogroups. Biogroup distributions for M. haemolytica and P. trehalosi differed among the three populations; however, no difference was detected for the distribution of P. trehalosi biogroups between the Sierra Nevada bighorn sheep and domestic sheep. The prevalence odds ratios (pOR) for the distribution of M. haemolytica biogroups suggested little difference between White Mountain bighorn sheep and domestic sheep compared with Sierra Nevada bighorn sheep and domestic sheep, although these comparisons had relatively large confidence intervals for the point estimates. Hemolytic activity of the isolates was not different among the sheep populations for M. haemolytica but was different for P. trehalosi. No clear evidence of association was found in the

  1. Flocking ferromagnetic colloids.

    Kaiser, Andreas; Snezhko, Alexey; Aranson, Igor S

    2017-02-01

    Assemblages of microscopic colloidal particles exhibit fascinating collective motion when energized by electric or magnetic fields. The behaviors range from coherent vortical motion to phase separation and dynamic self-assembly. Although colloidal systems are relatively simple, understanding their collective response, especially under out-of-equilibrium conditions, remains elusive. We report on the emergence of flocking and global rotation in the system of rolling ferromagnetic microparticles energized by a vertical alternating magnetic field. By combing experiments and discrete particle simulations, we have identified primary physical mechanisms, leading to the emergence of large-scale collective motion: spontaneous symmetry breaking of the clockwise/counterclockwise particle rotation, collisional alignment of particle velocities, and random particle reorientations due to shape imperfections. We have also shown that hydrodynamic interactions between the particles do not have a qualitative effect on the collective dynamics. Our findings shed light on the onset of spatial and temporal coherence in a large class of active systems, both synthetic (colloids, swarms of robots, and biopolymers) and living (suspensions of bacteria, cell colonies, and bird flocks).

  2. Coordinated Behaviour in Pigeon Flocks.

    Makoto Yomosa

    Full Text Available We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns.

  3. RESISTÊNCIA ANTI-HELMÍNTICA EM REBANHOS OVINOS DA REGIÃO DA ASSOCIAÇÃO DOS MUNICÍPIOS DO ALTO IRANI (AMAI, OESTE DE SANTA CATARINA ANTHELMINTIC RESISTANCE ON SHEEP FLOCKS FROM ASSOCIATION OF THE MUNICIPALITIES OF THE ALTO IRANI REGION (AMAI, WEST OF SANTA CATARINA STATE, BRAZIL

    Ingrid Kelly Zanchet

    2007-09-01

    Full Text Available

    Para conhecer a situação da resistência anti-hel-míntica em ovinos de propriedades localizadas nos mu-nicípios da Associação dos Municípios do Alto Irani (AMAI, oeste de Santa Catarina, Brasil, foram avalia-dos nove rebanhos pelo teste de redução da OPG (ovos por grama de fezes. Este teste consiste na comparação da média da OPG de um grupo de animais quatorze dias após o tratamento com a média de um grupo controle não-medicado. Consideraram-se efetivas as drogas capazes de reduzir a OPG em 95%. Os princípios ativos utilizados foram: levamisol (7,5 mg/kg, closantel (7,5 mg/Kg, al-bendazol (10 e 5 mg/Kg, ivermectin e moxidectin (0,2 mg/Kg. Detectou-se resistência dos nematódeos gastrin-testinais a todos os grupos anti-helmínticos testados, sen-do que 100% das propriedades apresentam resistência ao ivermectin; 66,7% ao moxidectin, 44,4% ao levamisol e 75% aos benzimidazóis. Para as lactonas macrocíclicas e benzimidazóis, tanto o gênero Haemonchus sp. quanto Trichostrongylus sp. apresentaram resistência. Para o le-vamisol, a resistência está restrita a Trichostrongylus sp. Também foi detectada a presença de uma população de Haemonchus sp. resistente ao closantel e uma de Nema-todirus sp. resistente ao albendazol. Estes dados mostram a urgência de difundir medidas de controle integrado de parasitoses, visando prolongar a vida  útil dos princípios ativos ainda disponíveis para uso.

    PALAVRAS-CHAVES: Ovinos, resistência anti-helmíntica, Santa Catarina.

    In order to know the situation of the anthelmintic resistance in sheep farms in the municipalities of Asso-ciation of the municipalities of the High Irani Region - AMAI, West of Santa Catarina State, Brazil, nine flocks were submitted to the faecal egg counts reduction test (FECRT. This test consists in comparing the mean FEC of a group of sheep, 14 days after treatment with the mean FEC of a non-treated control group. Only drugs that could

  4. Natural and experimental infection of sheep with European bat lyssavirus type-1 of Danish bat origin

    Tjørnehøj, Kirsten; Fooks, A.R.; Agerholm, J.S.

    2006-01-01

    In 1998 and 2002, European bat lyssavirus type-1 (EBLV-1) was demonstrated in brain tissue of five Danish sheep suffering from micrological disorders. Four of the five sheep also had encephalic listeriosis. The animals originated from four flocks on pastures within a limited area of western Jutla...

  5. Emerging cases of chlamydial abortion in sheep and goats in Croatia and Bosnia and Herzegovina.

    Spičic, Silvio; Račić Ivana; Andrijanić, Milan; Duvnjak, Sanja; Zdelar-Tuk, Maja; Stepanić, Maja; Cvetnić, Zeljko

    2015-01-01

    In a recent lambing season (2012/2013), the seroprevalence of ovine chlamydiosis was monitored in small ruminant abortion cases in Croatia. Blood samples of 93 sheep and 69 goats were examined. In addition, 50 sheep and 61 goat samples were tested using molecular methods. Furthermore, 14 sheep blood samples, one goat blood sample and one sheep placenta sample from Bosnia and Herzegovina (BIH) were also tested as a part of inter-laboratory cooperation. Overall high seroprevalence was detected in sheep, 19.6% with the ELISA IDEXX kit and 20.5% with the ClVTEST kit. Seroprevalence in goats was 11.4%. In BIH, four sheep and one goat blood sample were seropositive for chlamydiosis. The disease causing agent, Chlamydia abortus (C. abortus) was confirmed using molecular methods in two sheep flocks in continental Croatia and in one sheep flock in BIH. In this study, C. abortus infection in sheep was identified for the first time in Croatia using species specific molecular methods. Ovine chlamydiosis is present in national sheep and goat flocks in Croatia and BIH. Thus should be subject to ongoing controls in the case of abortion. A combination of serological and molecular methods should be used for optimal laboratory diagnostics of C. abortus.

  6. Hydrodynamics and phases of flocks

    Toner, John; Tu Yuhai; Ramaswamy, Sriram

    2005-01-01

    We review the past decade's theoretical and experimental studies of flocking: the collective, coherent motion of large numbers of self-propelled 'particles' (usually, but not always, living organisms). Like equilibrium condensed matter systems, flocks exhibit distinct 'phases' which can be classified by their symmetries. Indeed, the phases that have been theoretically studied to date each have exactly the same symmetry as some equilibrium phase (e.g., ferromagnets, liquid crystals). This analogy with equilibrium phases of matter continues in that all flocks in the same phase, regardless of their constituents, have the same 'hydrodynamic'-that is, long-length scale and long-time behavior, just as, e.g., all equilibrium fluids are described by the Navier-Stokes equations. Flocks are nonetheless very different from equilibrium systems, due to the intrinsically nonequilibrium self-propulsion of the constituent 'organisms'. This difference between flocks and equilibrium systems is most dramatically manifested in the ability of the simplest phase of a flock, in which all the organisms are, on average moving in the same direction (we call this a 'ferromagnetic' flock; we also use the terms 'vector-ordered' and 'polar-ordered' for this situation) to exist even in two dimensions (i.e., creatures moving on a plane), in defiance of the well-known Mermin-Wagner theorem of equilibrium statistical mechanics, which states that a continuous symmetry (in this case, rotation invariance, or the ability of the flock to fly in any direction) can not be spontaneously broken in a two-dimensional system with only short-ranged interactions. The 'nematic' phase of flocks, in which all the creatures move preferentially, or are simply oriented preferentially, along the same axis, but with equal probability of moving in either direction, also differs dramatically from its equilibrium counterpart (in this case, nematic liquid crystals). Specifically, it shows enormous number fluctuations, which

  7. Do Welsh hill farmers dream of radioactive sheep?

    Roberts, Gwyn; Williams, Aled; Last, D.

    1993-01-01

    A low-power portable device is being used successfully in North Wales to provide precise position-logging of sheep grazing on upland hill pastures following irradiation by fallout from the Chernobyl reactor. This follows the discovery that radiation levels appear to vary significantly among sheep from the same flock, suggesting hot-spots of radiation. The design and execution of the system is described. (UK)

  8. Design of Connectivity Preserving Flocking Using Control Lyapunov Function

    Erfianto, Bayu; Bambang, Riyanto T.; Hindersah, Hilwadi; Muchtadi-Alamsyah, Intan

    2016-01-01

    This paper investigates cooperative flocking control design with connectivity preserving mechanism. During flocking, interagent distance is measured to determine communication topology of the flocks. Then, cooperative flocking motion is built based on cooperative artificial potential field with connectivity preserving mechanism to achieve the common flocking objective. The flocking control input is then obtained by deriving cooperative artificial potential field using control Lyapunov functio...

  9. Ovine Paratuberculosis: A Seroprevalence Study in Dairy Flocks Reared in the Marche Region, Italy

    Anna Rita, Attili; Victor, Ngu Ngwa; Silvia, Preziuso; Luciana, Pacifici; Anastasia, Domesi; Vincenzo, Cuteri

    2011-01-01

    In order to fulfil the seroprevalence gap on Mycobacterium avium subsp. paratuberculosis infection in ovine dairy farms of Marche region (central Italy), a stratified study was carried out on 2086 adult female sheep randomly chosen from 38 herds selected in Ancona and Macerata provinces. 73.7% flocks resulted infected by a commercial ELISA test (Pourquier, France), with a mean seroprevalence of 6.29% of sampled sheep in both provinces. A higher number of MAP seropositive ewes was recorded in the large herds' consistence than in the small and medium herds' consistence (P = 0.0269), and a greater percentage of infected sheep was obtained among female at early/late than in peak lactation stage (P = 0.0237). MAP infection was confirmed in 12.6% of infected farms by faecal culture. The true sheep-level seroprevalence was 15.1% ± 7.3%. PMID:21876850

  10. The Reproductive Performance of the Nigerian Dwarf Sheep | Orji ...

    Three of the most important parameters of reproduction in sheep, the age at first lambing, the lambing interval and the number of lambs born per ewe at each lambing, were analysed from the herdbook of the breeding flock of the University of Ibadan for the period-1968 to 1974. The means were as follows: 1. age at first ...

  11. Estimation of genetic parameters for body weights of Kurdish sheep ...

    Genetic parameters and (co)variance components were estimated by restricted maximum likelihood (REML) procedure, using animal models of kind 1, 2, 3, 4, 5 and 6, for body weight in birth, three, six, nine and 12 months of age in a Kurdish sheep flock. Direct and maternal breeding values were estimated using the best ...

  12. PRESENT AND FUTURE SITUATION OF SHEEP PRODUCTION IN ...

    autumn to produce winter lambs on hay and barley and, if the weather is mild, the same grazing is used as that for the mothers. This, in general, is the Mediter- ranean type of sheep husbandry. There are of course a whole range of situations in between: Percentage of national flock in different husbandry systems. Numbers ...

  13. Spontaneous flocking in human groups.

    Belz, Michael; Pyritz, Lennart W; Boos, Margarete

    2013-01-01

    Flocking behaviour, as a type of self-organised collective behaviour, is described as the spatial formation of groups without global control and explicit inter-individual recruitment signals. It can be observed in many animals, such as bird flocks, shoals or herds of ungulates. Spatial attraction between humans as the central component of flocking behaviour has been simulated in a number of seminal models but it has not been detected experimentally in human groups so far. The two other sub-processes of this self-organised collective movement - collision avoidance and alignment - are excluded or held constant respectively in this study. We created a computer-based, multi-agent game where human players, represented as black dots, moved on a virtual playground. The participants were deprived of social cues about each other and could neither communicate verbally nor nonverbally. They played two games: (1) Single Game, where other players were invisible, and (2) Joint Game, where each player could see players' positions in a local radius around himself/herself. We found that individuals approached their neighbours spontaneously if their positions were visible, leading to less spatial dispersion of the whole group compared to moving alone. We conclude that human groups show the basic component of flocking behaviour without being explicitly instructed or rewarded to do so. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Flocking regimes in a simple lattice model.

    Raymond, J R; Evans, M R

    2006-03-01

    We study a one-dimensional lattice flocking model incorporating all three of the flocking criteria proposed by Reynolds [Computer Graphics 21, 4 (1987)]: alignment, centering, and separation. The model generalizes that introduced by O. J. O'Loan and M. R. Evans [J. Phys. A. 32, L99 (1999)]. We motivate the dynamical rules by microscopic sampling considerations. The model exhibits various flocking regimes: the alternating flock, the homogeneous flock, and dipole structures. We investigate these regimes numerically and within a continuum mean-field theory.

  15. Influence of flock coating on bending rigidity of woven fabrics

    Ozdemir, O.; Kesimci, M. O.

    2017-10-01

    This work presents the preliminary results of our efforts that focused on the effect of the flock coating on the bending rigidity of woven fabrics. For this objective, a laboratory scale flocking unit is designed and flocked samples of controlled flock density are produced. Bending rigidity of the samples with different flock densities are measured on both flocked and unflocked sides. It is shown that the bending rigidity depends on both flock density and whether the side to be measured is flocked or not. Adhesive layer thickness on the bending rigidity is shown to be dramatic. And at higher basis weights, flock density gets less effective on bending rigidity.

  16. Local equilibrium in bird flocks

    Mora, Thierry; Walczak, Aleksandra M.; Del Castello, Lorenzo; Ginelli, Francesco; Melillo, Stefania; Parisi, Leonardo; Viale, Massimiliano; Cavagna, Andrea; Giardina, Irene

    2016-12-01

    The correlated motion of flocks is an example of global order emerging from local interactions. An essential difference with respect to analogous ferromagnetic systems is that flocks are active: animals move relative to each other, dynamically rearranging their interaction network. This non-equilibrium characteristic has been studied theoretically, but its impact on actual animal groups remains to be fully explored experimentally. Here, we introduce a novel dynamical inference technique, based on the principle of maximum entropy, which accommodates network rearrangements and overcomes the problem of slow experimental sampling rates. We use this method to infer the strength and range of alignment forces from data of starling flocks. We find that local bird alignment occurs on a much faster timescale than neighbour rearrangement. Accordingly, equilibrium inference, which assumes a fixed interaction network, gives results consistent with dynamical inference. We conclude that bird orientations are in a state of local quasi-equilibrium over the interaction length scale, providing firm ground for the applicability of statistical physics in certain active systems.

  17. An economic evaluation of preclinical testing strategies compared to the compulsory scrapie flock scheme in the control of classical scrapie.

    Lisa Boden

    Full Text Available Cost-benefit is rarely combined with nonlinear dynamic models when evaluating control options for infectious diseases. The current strategy for scrapie in Great Britain requires that all genetically susceptible livestock in affected flocks be culled (Compulsory Scrapie Flock Scheme or CSFS. However, this results in the removal of many healthy sheep, and a recently developed pre-clinical test for scrapie now offers a strategy based on disease detection. We explore the flock level cost-effectiveness of scrapie control using a deterministic transmission model and industry estimates of costs associated with genotype testing, pre-clinical tests and the value of a sheep culled. Benefit was measured in terms of the reduction in the number of infected sheep sold on, compared to a baseline strategy of doing nothing, using Incremental Cost Effectiveness analysis to compare across strategies. As market data was not available for pre-clinical testing, a threshold analysis was used to set a unit-cost giving equal costs for CSFS and multiple pre-clinical testing (MT, one test each year for three consecutive years. Assuming a 40% within-flock proportion of susceptible genotypes and a test sensitivity of 90%, a single test (ST was cheaper but less effective than either the CSFS or MT strategies (30 infected-sales-averted over the lifetime of the average epidemic. The MT strategy was slightly less effective than the CSFS and would be a dominated strategy unless preclinical testing was cheaper than the threshold price of £6.28, but may be appropriate for flocks with particularly valuable livestock. Though the ST is not currently recommended, the proportion of susceptible genotypes in the national flock is likely to continue to decrease; this may eventually make it a cost-effective alternative to the MT or CSFS.

  18. Density distributions and depth in flocks

    Lewis, J. M.; Turner, M. S.

    2017-12-01

    Recent experimental evidence suggests that interactions in flocks of birds do not involve a characteristic length scale. Bird flocks have also been revealed to have an inhomogeneous density distribution, with the density of birds near the border greater than near the centre. We introduce a strictly metric-free model for collective behaviour that incorporates a distributed motional bias, providing control of the density distribution. A simple version of this model is then able to provide a good fit to published data for the density variation across flocks of Starlings. We find that it is necessary for individuals on the edge of the flock to have an inward motional bias but that birds in the interior of the flock instead must have an outward bias. We discuss the ability of individuals to determine their depth within a flock and show how this might be achieved by relatively simple analysis of their visual environment.

  19. Statistical mechanics for natural flocks of birds

    Bialek, William; Cavagna, Andrea; Giardina, Irene; Mora, Thierry; Silvestri, Edmondo; Viale, Massimiliano; Walczak, Aleksandra M.

    2012-01-01

    Flocking is a typical example of emergent collective behavior, where interactions between individuals produce collective patterns on the large scale. Here we show how a quantitative microscopic theory for directional ordering in a flock can be derived directly from field data. We construct the minimally structured (maximum entropy) model consistent with experimental correlations in large flocks of starlings. The maximum entropy model shows that local, pairwise interactions between birds are sufficient to correctly predict the propagation of order throughout entire flocks of starlings, with no free parameters. We also find that the number of interacting neighbors is independent of flock density, confirming that interactions are ruled by topological rather than metric distance. Finally, by comparing flocks of different sizes, the model correctly accounts for the observed scale invariance of long-range correlations among the fluctuations in flight direction. PMID:22427355

  20. [Flocking hip joint endoprosthesis].

    Sherepo, K M

    1997-01-01

    The author indicates the similarity of a human tooth and an endoprosthesis in their action, which is the basis for developing a procedure of endoprosthesis and designing an endoprosthesis with dumping elements. The procedure has been developed during a long-term surgical experiment by examining the results by the following techniques: X-ray, bed testing, light and scanning electron microscope. Experimental results are convincing. For coating the prostheses, polytetrafluoroethylene velour is used in the experiment, but cauflene, the material of the same kind polytetrafluoroethylene, is employed in the clinical setting. The experiments yielded two inventions patented in the Russian Federation. This direction in their development seems to be fruitful in preventing the aseptic endoprosthetic instability that is the most common and severe complication after endoprosthesis and requires most frequently resurgery.

  1. Production and economic characteristics of sheep production on the island of Pag

    Marina Krvavica

    2012-03-01

    Full Text Available The aim of the research was to learn from a survey about the production and economic characteristics of sheep production as well as economic position and developmental orientation of sheep breeders on the island of Pag. Data on production and economic characteristics of sheep production on the island of Pag were collected from a survey and processed through relevant descriptive statistics methods. The respondents have on average 47 breeding sheep, 2 rams and 9 sheep intended for flock renewal rate (not older than one year; which means an average flock has 58 sheep. The average total income from sheep production in 2009 was 72,460.10 HRK. The average total production costs in 2009 were 13,260.10 HRK, including the costs of fodder and veterinary services. All farms achieved positive financial results of 59,199.90 HRK in average. As many as three quarters of respondents indicated profitability of sheep production as the main motivation to engage in sheep production; very few indicated that heritage and inability to do other jobs were the main motivation. Important limiting factors for future development of sheep breeding on the island of Pag in most farms are lack of potential heirs and high average age of farm holders. Regarding the effects of joining the European Union, half the breeders intend to improve their production and harmonise it with the EU requirements and standards; one quarter of them intend to keep the existing production capacity; and another quarter intend to quit with production.

  2. An index for quantifying flocking behavior.

    Quera, Vicenç; Herrando, Salvador; Beltran, Francesc S; Salas, Laura; Miñano, Meritxell

    2007-12-01

    One of the classic research topics in adaptive behavior is the collective displacement of groups of organisms such as flocks of birds, schools of fish, herds of mammals, and crowds of people. However, most agent-based simulations of group behavior do not provide a quantitative index for determining the point at which the flock emerges. An index was developed of the aggregation of moving individuals in a flock and an example was provided of how it can be used to quantify the degree to which a group of moving individuals actually forms a flock.

  3. Epidemiologic characterization of Colorado backyard bird flocks.

    Smith, Emily I; Reif, John S; Hill, Ashley E; Slota, Katharine E; Miller, Ryan S; Bjork, Kathe E; Pabilonia, Kristy L

    2012-06-01

    Backyard gallinaceous bird flocks may play an important role in the spread of infectious diseases within poultry populations as well as the transmission of zoonotic diseases to humans. An epidemiologic characterization was conducted of Colorado backyard flocks to gather information on general flock characteristics, human movement of birds, human-bird interaction, biosecurity practices, and flock health. Our results suggest that backyard poultry flocks in Colorado are small-sized flocks (68.6% of flocks had meat or egg) production for the family (86.44%) or as pet or hobby birds (42.27%). The backyard flock environment may promote bird-to-bird transmission as well as bird-to-human transmission of infectious disease. Birds are primarily housed with free access to the outside (96.85%), and many are moved from the home premises (46.06% within 1 yr). Human contact with backyard flocks is high, biosecurity practices are minimal, and bird health is negatively impacted by increased movement events. Increased knowledge of backyard bird characteristics and associated management practices can provide guidelines for the development of measures to decrease disease transmission between bird populations, decrease disease transmission from birds to humans, and increase the overall health of backyard birds.

  4. Epidemiology of Mycoplasma agalactiae and Mycoplasma mycoides cluster in flocks of northeastern Brazil

    Sandra Batista dos Santos

    2018-04-01

    Full Text Available ABSTRACT: The present study aimed to investigate contagious agalactia (CA in flocks from Pernambuco State. The study involved 225 goats and 63 ewes; 288 milk samples and 100 vaginal swabs were collected in total. The PCR assays were carried out using specific primers to Mycoplasma agalactiae and the Mycoplasma mycoides cluster. Among the goat’s milk samples,12.0% (27/225 were positive for Mycoplasma agalactiae DNA, while 5.3% (12/225 contained the Mycoplasma mycoides cluster. Of the vaginal swabs taken from goats, 15.4% (12/78 were positive for Mycoplasma agalactiae DNA and 3.8% (3/78 contained the Mycoplasma mycoides cluster. In the case of ewes, 4.3% (1/23 of the milk samples contained Mycoplasma agalactiae DNA, and 7.5% (3/40 were positive for the Mycoplasma mycoides cluster. Vaginal swabs taken from sheep´s were negative. Analysis of risk factors for mycoplasmosis, showed that goats and sheep flocks on the extensive breeding system are more likely to have mycoplasmosis than those on the intensive breeding system (odds ratio (OR 6.2; p=0.004; meat goat and sheep flocks are more likely to have infection compared to dairy flocks (OR 4.8; p=0.011; unclean animal housing increases the chances of infection (OR 5.0; p=0.031 and not performing quarantine increases the chances of mycoplasmosis (OR 4.6; p=0.042. Based on these findings we conclude that CA syndrome in the semiarid region of Pernambuco state can be associated with Mycoplasma agalactiae and Mycoplasma mycoides cluster.

  5. Investigations concerning the prevalence of Coxiella burnetii and Chlamydia abortus in sheep in correlation with management systems and abortion rate in Lower Saxony in 2004.

    Runge, Martin; Binder, Alfred; Schotte, Ulrich; Ganter, Martin

    2012-01-01

    The intracellular bacteria Coxiella (C) burnetii and Chlamydia (Chl) abortus induce abortion in sheep and also affect humans. While Chl. abortus only infrequently infects humans, C burnetii is the aetiological agent of numerous Q fever outbreaks during the last decades. There is only limited knowledge about the prevalence of both pathogens in sheep, although sheep are involved in almost all Q fever outbreaks in Germany. The aim of our study was to investigate the prevalence of both pathogens in flocks located in Lower Saxony, Germany, in correlation to the management form and abortion rate. Serum samples of 1714 sheep from 95 flocks located in Lower Saxony were investigated by ELISA. 2.7% of these samples were positive, 1.3% showed inconclusive results in the C. burnetii-ELISA. Elevated intra-flock seroprevalences were only detected in three migrating flocks. Chlamydia-specific antibodies could be detected in 15.1% serum samples of mainly shepherded and migrating flocks. In one of these flocks with a high intra-flock seroprevalence for C burnetii (27%) and Chlamydia (44.9%), C burnetii was detected in 21.6% of the placenta samples of normal births and in 12.5% of the colostrum samples by PCR. Aborted fetuses and the corresponding placentas were negative in C burnetii-PCR, but in most of them and also in many other placenta samples Chl. abortus could be detected by PCR and DNA microarray. This survey shows a low overall prevalence of C. burnetii in sheep in Lower Saxony in the year 2004. However, three migrating flocks with a high intra-flock prevalence are localized in the southern parts of Lower Saxony. Spreading of C burnetii could occur, because of the large radius of grazing of all three flocks.

  6. Milk yield and quality of Cres sheep and their crosses with Awassi and East Friesian sheep

    Boro Mioč

    2009-09-01

    Full Text Available The objective of this study was to establish the impact of crossing the indigenous Cres sheep with Awassi and, respectively, Awassi and East Friesian sheep on the milk yield and quality. For this purpose, through regular monthly milk yield recordings a total of 824individual milk samples from 139 sheep in the second lactation of the same flock were collected, of which: 46 purebred Cres sheep, CS; 33 crosses with 50 % Cres sheep and 50 % Awassi, CA; 60 crosses with 50 % Cres sheep, 25 % Awassi and 25 % East Friesian, CAEF. The obtained results show a significant (P<0.05; P<0.01 impact of the genotype and the lactation stage on the yield and chemical composition of milk, and the somatic cell count. The most milk was yielded by CAEF crosses (690 mL/ewe/day, i.e., 133.8 L per lactation and the least by CS (340 mL/ewe/day, i.e., 58.48 L per lactation. The content of total solids, fat and protein increased as lactation advanced, whereas the trend of the lactose content was opposite. The highest content of total solids, fat and protein were established in the milk of the indigenous Cres sheep. A positive correlation was established between the amount of yielded milk and the somatic cell count, whereas a negative correlation was established between the amount of milk and the content of solids, fat and proteins.

  7. Time-Dependent Variations in Structure of Sheep Wool Irradiated by Electron Beam

    Zuzana Hanzlíková

    2017-01-01

    Full Text Available Wool scoured in tap water with no special degreasing and containing a balanced humidity responding to usual laboratory conditions was irradiated by accelerated electron beam in the range of 0–350 kGy dose. Time variations of the wool structure were measured using FTIR, Raman, and EPR spectroscopy. The aim was to determine whether preexposure treatment of the wool, as well as postexposure time, affects the properties of the irradiated wool. Reactive products such as S-sulfonate, cystine monoxide, cystine dioxide, cysteic acid, disulphides, and carboxylates displayed a considerable fluctuation in quantity depending on both the absorbed dose and time. Mutual transformations of S-oxidized products into cysteic acid appeared to be faster than those in dry and degreased wool assuming that the present humidity inside the fibres is decisive as an oxygen source. EPR results indicated a longer lifetime for free radicals induced by lower doses compared with the radicals generated by higher ones. The pattern of the conformational composition of the secondary structure (α-helix, β-sheet, random, and residual conformations also showed a large variability depending on absorbed dose as well as postexposure time. The most stable secondary structure was observed in nonirradiated wool but even this showed a small but observable change after a longer time, too.

  8. A survey of antibodies to pestivirus in sheep in the Republic of Ireland

    O'Neill Ronan G

    2004-09-01

    Full Text Available Sera from 1,448 adult ewes in 91 flocks, representing all 26 counties in the Republic of Ireland, were examined for pestivirus antibodies using a commercially available ELISA which detected IgG1 antibody to border disease virus. Eighty-one sheep (5.6% in 42 flocks (46.0% were antibody-positive. Within infected flocks, the mean seroprevalence level was 11.4% with a range of 6.3% to 30.0%. The highest antibody prevalence was detected in sheep from central lowland counties of Ireland. Comparative neutralisation testing of 42 ELISA-positive sera detected geometric mean antibody titres of 136 to the NADL strain of bovine viral diarrhoea virus (BVDV, 92 to the Moredun strain of border disease virus and 21 to the 137/4 strain of border disease virus. These results suggest that BVDV may be the major ruminant pestivirus infecting sheep in Ireland. Although there are high numbers of infected flocks, many sheep within such flocks remain antibody-negative and are at risk of giving birth to lambs with congenital border disease.

  9. Lines of Evidence–Incremental Markings in Molar Enamel of Soay Sheep as Revealed by a Fluorochrome Labeling and Backscattered Electron Imaging Study

    Kierdorf, Horst; Kierdorf, Uwe; Frölich, Kai; Witzel, Carsten

    2013-01-01

    We studied the structural characteristics and periodicities of regular incremental markings in sheep enamel using fluorochrome injections for vital labeling of forming enamel and backscattered electron imaging in the scanning electron microscope. Microscopic analysis of mandibular first molars revealed the presence of incremental markings with a daily periodicity (laminations) that indicated successive positions of the forming front of interprismatic enamel. In addition to the laminations, incremental markings with a sub-daily periodicity were discernible both in interprismatic enamel and in enamel prisms. Five sub-daily increments were present between two consecutive laminations. Backscattered electron imaging revealed that each sub-daily growth increment consisted of a broader and more highly mineralized band and a narrower and less mineralized band (line). The sub-daily markings in the prisms of sheep enamel morphologically resembled the (daily) prisms cross striations seen in primate enamel. Incremental markings with a supra-daily periodicity were not observed in sheep enamel. Based on the periodicity of the incremental markings, maximum mean daily apposition rates of 17.0 µm in buccal enamel and of 13.4 µm in lingual enamel were recorded. Enamel extension rates were also high, with maximum means of 180 µm/day and 217 µm/day in upper crown areas of buccal and lingual enamel, respectively. Values in more cervical crown portions were markedly lower. Our results are in accordance with previous findings in other ungulate species. Using the incremental markings present in primate enamel as a reference could result in a misinterpretation of the incremental markings in ungulate enamel. Thus, the sub-daily growth increments in the prisms of ungulate enamel might be mistaken as prism cross striations with a daily periodicity, and the laminations misidentified as striae of Retzius with a supra-daily periodicity. This would lead to a considerable overestimation of

  10. Preliminary Results Regarding Organic Sheep Meat Consumption in Romania

    Elena Ilisiu

    2017-05-01

    Full Text Available With a national flock of  10.07 million sheep, Romania currently occupies the 3rd place in the EU (after the UK and Spain in terms of the sheep numbers. However, only 0.85% (85.419 heads are being reared in organic production systems. The development of sheep breeding in organic systems is very heavily influenced by the economic factors, but also by the consumer demand for organic products. An empirical study on consumer behavior towards sheep meat produced in organic system was developed in 2016. The aim of the study was to assess the possibility of developing sheep breeding sector in the organic system, in the terms of the consumer’s behavior towards  sheep meat obtained in organic system in order to develop strategies that will lead to sustainable development of the sector. The finding shown that 85% of consumers consider that sheep meat produced in organic farming system is more expensive compared to that produced in the conventional systems. However, 74% of respondents believe that higher prices are justified. The availability of the respondents to pay an additional price for organic sheep product is high, hovering around 77%. Current research highlights the potential production and marketing of sheep from Romania in organic system, which could have a positive impact on overall farm income and on animal welfare.

  11. Design of Connectivity Preserving Flocking Using Control Lyapunov Function

    Bayu Erfianto

    2016-01-01

    Full Text Available This paper investigates cooperative flocking control design with connectivity preserving mechanism. During flocking, interagent distance is measured to determine communication topology of the flocks. Then, cooperative flocking motion is built based on cooperative artificial potential field with connectivity preserving mechanism to achieve the common flocking objective. The flocking control input is then obtained by deriving cooperative artificial potential field using control Lyapunov function. As a result, we prove that our flocking protocol establishes group stabilization and the communication topology of multiagent flocking is always connected.

  12. EPIDEMIOLOGICAL INVESTIGATIONS OF A PESTE DES PETITS RUMINANTS (PPR OUTBREAK IN AFGHAN SHEEP IN PAKISTAN

    A. B. ZAHUR, A. ULLAH, H. IRSHAD, M. S. FAROOQ, M. HUSSAIN AND M. JAHANGIR

    2009-10-01

    Full Text Available Epidemiological and virological investigations were carried out during an outbreak of Peste des petits ruminants (PPR in Afghan (Bulkhi sheep in Pakistan. The overall morbidity, mortality and case fatality rates were 41.0, 1.2 and 3.0%, respectively. The epidemic curve was plotted and the values for basic reproductive number (R0 and herd immunity threshold (HIT for the affected flock were estimated to be 6.85 and 85.4%, respectively. The morbid material analysis by immuno-capture ELISA (Ic-ELISA and haemagglutination assay (HA revealed the presence of PPR virus. The PPR virus was isolated and identified through cytopathic effects, Ic-ELISA and transmission electron microscopy (TEM.

  13. Variation in the metabolism of radiocaesium between individual sheep

    Beresford, N.A.; Barnett, C.L.; Mayes, R.W.; MacEachern, P.J.; Crout, N.M.J.

    1998-01-01

    Considerable variability has been recorded in the radiocaesium activity concentration of muscle between individual sheep in the same flocks in upland areas that received fallout from the Chernobyl accident. In a previous paper we demonstrated that there is a propensity for certain sheep within a flock to be always amongst the most contaminated and others to be consistently the least contaminated. Here we report a study to determine the extent to which variation in the metabolism of radiocaesium by individual sheep may contribute to the observed variability within sheep flocks. The transfer coefficient and biological half-life of orally administered ionic radiocaesium in muscle were determined under controlled conditions in 22 ewes from an upland farm in an area of the UK which received comparatively high levels of Chernobyl fallout. There was considerable variation between individuals in both the transfer coefficient (0.19-0.56 day.kg -1 ; mean 0.34 day.kg -1 ) and biological half-life in muscle (5.2- 18.7 days; mean 9.8 days). Changes in liveweight during the study and feed intake together accounted for 72% of the variation in the derived transfer coefficients; liveweight change also accounted for 56% of the observed variation in biological half-life. In a subsequent study, the true absorption coefficient of radiocaesium was determined in 12 of the ewes. There was a positive correlation between transfer and true absorption coefficients (R=0.57). We conclude that differences in the metabolism of radiocaesium will contribute to the observed variability in radiocaesium activity concentrations within sheep flocks in areas which were contaminated by Chernobyl fallout. We also suggest that for growing animals, the influence of liveweight change and feed intake on radiocaesium transfer may be greater than observed here. Similarly, in dairy cattle, for which feed intake changes considerably during the course of a lactation, large temporal variation in radiocaesium

  14. Toxoplasma gondii and Neospora caninum seroprevalence in dairy sheep and goats mixed stock farming.

    Diakoua, Anastasia; Anastasia, Diakou; Papadopoulos, Elias; Elias, Papadopoulos; Panousis, Nikolaos; Nikolaos, Panousis; Karatzias, Charilaos; Charilaos, Karatzias; Giadinis, Nektarios; Nektarios, Giadinis

    2013-12-06

    Toxoplasma and Neospora infections are important causes of abortions and economic losses in animal production. Mixed stock farming of sheep and goats is a common practice in Mediterranean countries and could serve as a suitable model for the evaluation of differences between the two animal species regarding parasitic infections. In order to investigate the seroprevalence of T. gondii and N. caninum among flocks of small ruminants in Greece and to evaluate any prevalence difference between sheep and goats kept in mixed flocks, 833 sera samples (458 sheep and 375 goats) from 50 mixed flocks in different areas of the country were examined by ELISA for the detection of specific antibodies. Specific IgG against T. gondii were detected in 53.71% and 61.3% and against N. caninum in 16.8% and 6.9% of the sheep and goats, respectively. Goats had higher Toxoplasma seroprevalence than sheep (pgoats (pgoats that are kept together in mixed flocks. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Ovine Enzootic Abortion (OEA: a comparison of antibody responses in vaccinated and naturally-infected swiss sheep over a two year period

    Zimmermann Dieter R

    2007-09-01

    Full Text Available Abstract Background Prevention and control of ovine enzootic abortion (OEA can be achieved by application of a live vaccine. In this study, five sheep flocks with different vaccination and infection status were serologically tested using a competitive enzyme-linked immunosorbent assay (cELISA specific for Chlamydophila (Cp. abortus over a two-year time period. Results Sheep in Flock A with recent OEA history had high antibody values after vaccination similar to Flock C with natural Cp. abortus infections. In contrast, OEA serology negative sheep (Flock E showed individual animal-specific immunoreactions after vaccination. Antibody levels of vaccinated ewes in Flock B ranged from negative to positive two and three years after vaccination, respectively. Positive antibody values in the negative control Flock D (without OEA or vaccination are probably due to asymptomatic intestinal infections with Cp. abortus. Excretion of the attenuated strain of Cp. abortus used in the live vaccine through the eye was not observed in vaccinated animals of Flock E. Conclusion The findings of our study indicate that, using serology, no distinction can be made between vaccinated and naturally infected sheep. As a result, confirmation of a negative OEA status in vaccinated animals by serology cannot be determined.

  16. Flocking Transition in Confluent Tissues

    Paoluzzi, Matteo; Giavazzi, Fabio; Macchi, Marta; Scita, Giorgio; Cerbino, Roberto; Manning, Lisa; Marchetti, Cristina

    The emerging of collective migration in biological tissues plays a pivotal role in embryonic morphogenesis, wound healing and cancer invasion. While many aspects of single cell movements are well established, the mechanisms leading to coherent displacements of cohesive cell groups are still poorly understood. Some of us recently proposed a Self-Propelled Voronoi (SPV) model of dense tissues that combines self-propelled particle models and vertex models of confluent cell layers and exhibits a liquid-solid transition as a function of cell shape and cell motility. We now examine the role of cell polarization on collective cell dynamics by introducing an orientation mechanism that aligns cell polarization with local cell motility. The model predicts a density-independent flocking transition tuned by the strength of the aligning interaction, with both solid and liquid flocking states existing in different regions of parameter space. MP and MCM were supported by the Simons Foundation Targeted Grant in the Mathematical Modeling of Living Systems Number: 342354 and by the Syracuse Soft Matter Program.

  17. Radiocaesium in grazing sheep. A statistical analysis of variability, survey methodology and long term behaviour

    Mehli, H

    1996-05-01

    Since 1987 sheep grazing in the areas of Norway that received Chernobyl-fallout have been monitored before slaughter. These monitoring data formed the basis for development of a model describing the long term behaviour of radiocesium in unimproved pasture showing that in years with good mushroom abundance 70-80% of the radiocesium concentration in sheep is due to fungi consumption. A study of sampling strategy and variability of radiocesium concentration within flocks was also performed. 55 refs., 31 figs., 15 tabs.

  18. Radiocaesium in grazing sheep. A statistical analysis of variability, survey methodology and long term behaviour

    Mehli, H.

    1996-05-01

    Since 1987 sheep grazing in the areas of Norway that received Chernobyl-fallout have been monitored before slaughter. These monitoring data formed the basis for development of a model describing the long term behaviour of radiocesium in unimproved pasture showing that in years with good mushroom abundance 70-80% of the radiocesium concentration in sheep is due to fungi consumption. A study of sampling strategy and variability of radiocesium concentration within flocks was also performed. 55 refs., 31 figs., 15 tabs

  19. Fore-aft asymmetric flocking

    Chen, Qiu-shi; Patelli, Aurelio; Chaté, Hugues; Ma, Yu-qiang; Shi, Xia-qing

    2017-08-01

    We show that fore-aft asymmetry, a generic feature of living organisms and some active matter systems, can have a strong influence on the collective properties of even the simplest flocking models. Specifically, an arbitrarily weak asymmetry favoring front neighbors changes qualitatively the phase diagram of the Vicsek model. A region where many sharp traveling band solutions coexist is present at low noise strength, below the Toner-Tu liquid, at odds with the phase-separation scenario well describing the usual isotropic model. Inside this region, a "banded-liquid" phase with algebraic density distribution coexists with band solutions. Linear stability analysis at the hydrodynamic level suggests that these results are generic and not specific to the Vicsek model.

  20. Fluctuating nonlinear hydrodynamics of flocking

    Yadav, Sunil Kumar; Das, Shankar P.

    2018-03-01

    Starting from a microscopic model, the continuum field theoretic description of the dynamics of a system of active ingredients or "particles" is presented. The equations of motion for the respective collective densities of mass and momentum follow exactly from that of a single element in the flock. The single-particle dynamics has noise and anomalous momentum dependence in its frictional terms. The equations for the collective densities are averaged over a local equilibrium distribution to obtain the corresponding coarse grained equations of fluctuating nonlinear hydrodynamics (FNH). The latter are the equations used frequently for describing active systems on the basis of intuitive arguments. The transport coefficients which appear in the macroscopic FNH equations are determined in terms of the parameters of the microscopic dynamics.

  1. Survey on coenurosis in sheep and goats in Egypt

    Enas A. Desouky

    2011-09-01

    Full Text Available A total of 75 sheep and goats from apparently healthy and from clinically affected flocks were examined for Coenurus cerebralis cysts from different localities in Egypt. Of 25 animals examined from clinically diseased sheep and goats, 25 (100% revealed the presence of infestation with one to four coenuri in the brain. The sites of predilection were the left hemisphere (48%, followed by the right hemisphere (40% and the cerebellum (12%. There was no apparent effect of the age of sheep and goats on susceptibility to infestation with C. cerebralis. Another 50 animals from apparently healthy sheep and goat herds presented no C. cerebralis cysts. The cysts from infested sheep could infest newborn puppies experimentally, with a prepatent period of 60 days post infestation. A total of 15 immature worms that were recovered from one puppy did not reach patency until 105 days post infestation with C. cerebralis cyst scolices. Pathological changes in C. cerebralis-infested sheep brain revealed parasitic elements, demyelinated nerve tracts, hyperaemic blood vessels with round cell infiltration, encephalomalacia with round cell infiltration and palisading macrophages and giant cells, as well as focal replacement of the brain parenchyma with caseated and calcified materials. The morphological characteristics of both the larval stage from sheep and goats and adult worms of Taenia multiceps from experimentally infested dogs are described. The results conclude that C. cerebralis is one of the principal causes of nervous manifestations of coenurosis in clinically diseased sheep and goats in Egypt.

  2. Towards evenly distributed grazing patterns: including social context in sheep management strategies

    Agustina di Virgilio

    2016-06-01

    Full Text Available Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock grazing on three different paddocks (with sizes from 80 to 1000 Ha during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets, age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females used more intensively the most preferred areas and low-ranked (i.e., yearlings used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour. Discussion. Although homogenization and segregation of

  3. Towards evenly distributed grazing patterns: including social context in sheep management strategies.

    di Virgilio, Agustina; Morales, Juan Manuel

    2016-01-01

    Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals' foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals' space use patterns, our aim was to explore the potential effects of including animals' social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour). Discussion. Although homogenization and segregation of flocks by classes

  4. 9 CFR 147.21 - Flock sanitation.

    2010-01-01

    ... allow the litter to be maintained in a dry condition. Frequent stirring of the litter may be necessary... status of both the flock and introduced birds should be evaluated. (h) In rearing broiler or replacement...

  5. Boundary information inflow enhances correlation in flocking.

    Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco

    2013-04-19

    The most conspicuous trait of collective animal behavior is the emergence of highly ordered structures. Less obvious to the eye, but perhaps more profound a signature of self-organization, is the presence of long-range spatial correlations. Experimental data on starling flocks in 3D show that the exponent ruling the decay of the velocity correlation function, C(r)~1/r(γ), is extremely small, γflocks. The effect of the dynamical field is to create an information inflow from border to bulk that triggers long-range spin-wave modes, thus giving rise to an anomalously long-ranged correlation. The biological origin of this phenomenon can be either exogenous-information produced by environmental perturbations is transferred from boundary to bulk of the flock-or endogenous-the flock keeps itself in a constant state of dynamical excitation that is beneficial to correlation and collective response.

  6. Objects in contact with classical scrapie sheep act as a reservoir for scrapie transmission

    Timm eKonold

    2015-09-01

    Full Text Available Classical scrapie is an environmentally transmissible prion disease of sheep and goats. Prions can persist and remain potentially infectious in the environment for many years and thus pose a risk of infecting animals after re-stocking. In vitro studies using serial Protein Misfolding Cyclic Amplification (sPMCA have suggested that objects on a scrapie-affected sheep farm could contribute to disease transmission. This in vivo study aimed to determine the role of field furniture (water troughs, feeding troughs, fencing and other objects that sheep may rub against used by a scrapie-infected sheep flock as a vector for disease transmission to scrapie-free lambs with the prion protein genotype VRQ/VRQ, which is associated with high susceptibility to classical scrapie. When the field furniture was placed in clean accommodation sheep became infected when exposed to either a water trough (four out of five or to objects used for rubbing (four out of seven. This field furniture had been used by the scrapie-infected flock eight weeks earlier and had previously been shown to harbor scrapie prions by sPMCA. Sheep also became infected (20 out of 23 through exposure to contaminated field furniture placed within pasture not used by scrapie-infected sheep for 40 months, even though swabs from this furniture tested negative by PMCA. This infection rate decreased (1 out of 12 on the same paddock after replacement with clean field furniture. Twelve grazing sheep exposed to field furniture not in contact with scrapie-infected sheep for 18 months remained scrapie-free.The findings of this study highlight the role of field furniture used by scrapie-infected sheep to act as a reservoir for disease re-introduction although infectivity declines considerably if the field furniture has not been in contact with scrapie-infected sheep for several months. PMCA may not be as sensitive as VRQ/VRQ sheep to test for environmental contamination.

  7. Effects of the level of early productivity on the lifespan of ewes in contrasting flock environments.

    Douhard, F; Jopson, N B; Friggens, N C; Amer, P R

    2016-12-01

    Selection for high levels of prolificacy has allowed substantial improvements in the production efficiency of New Zealand (NZ) sheep farms, but the consequences on ewe lifetime performance are mostly unknown. In this study, the relationship between the level of prolificacy early in ewes' productive lives and their probability to survive later (i.e. stayability) was evaluated in two contrasting NZ flock environments. Records were obtained from 6605 ewes from four ram breeder flocks representing either a moderate (n=2) or a highly variable (n=2) nutritional environment. All ewes lambed for the first time at 2 years of age and were mated the following year. The number of lambs born during the first 2 years of productive life (NLB2-3) was used as a measure of early prolificacy. Effects of NLB2-3 on stayability to 4, 5, 6, 7 and 8 years old were analysed using logistic regression. Curvilinear effects (logit-transformed) were detected (Pewe stayability was reduced when the proportion of the litter that survived from birth to weaning (i.e. ewe rearing ability) was submaximal during the early productive life. High prolific ewes had a low rearing ability whatever the environment whereas the rearing ability of lowly prolific ewes was apparently more sensitive to the nutritional environment. The poor maternal performance of ewes with low levels of NLB2-3 led to a premature culling by breeders whereas the high early reproductive effort associated with high levels of NLB2-3 seemed to be at the cost of ewes' survival, even in the moderate flock environment. In conclusion, the flock environment influenced the level of early prolificacy beyond which ewe longevity was reduced. It is suggested that further selection for high and early prolificacy in NZ flocks is likely to impair ewes' lifetime productivity.

  8. Problems and Solution Proposals Related to Sheep and Goat Husbandry in Kastamonu Province

    Hacer Tüfekci

    2015-06-01

    Full Text Available This study was conducted by using a survey made at 80 enterprises from 63 villages with the aim of determining situations, problems and solution proposals related to the sheep and goat farms in Kastamonu province. The average age of the farmers was 49.3 years. The farmers were 8.75% of primary school graduates, 68.75% of secondary school and also 22.6% of illiterate. The enterprises have raised animals as 31.75% of state + own land and 68.75%’ of private + leased land. Also they are kept the rate of 70% Hair goat, 30% Angora goat and 55% Merino sheep, 42.5% Akkaraman sheep, and 16.25% Turkmen genotype, 7.5% Sakız sheep and 6.25% of Kıvırcık Sheep. The average flock sizes goat and sheep enterprises were 77.3 head goats and 71.7 heads sheep, respectively. Sixty percent of the breeder feed their animals on the pasture for 8-10 months and only 30% the breeders give supplementary feeding before and during mating period. The enterprises have 31.2% parturition chamber and 92.5% lamb growth areas. While all enterprises are routinely used to protective vaccines but only used disinfectant of 73.7% enterprises. The reason of sheep and goat breeders is majority contributions of income and habits. So, flock sizes are small (74.5 heads animal. In conclusion, young people by encouraging small animal farming in the province of Kastamonu, should be given to technical, economic support and educational seminars. In the future, as the sole source of income and a large flock size may lead to a development of sheep and goat breeding in Kastamonu province.

  9. Induction of photosensitivity in sheep with Erodium moschatum (L. L'Hérit

    J.C. Stroebel

    2002-07-01

    Full Text Available Erodium moschatum is an exotic weed in the southern and southwestern coastal areas of the Western Cape Province (WCP, South Africa. It has been suspected as the cause of photosensitivity in sheep. However, attempts to induce photosensitivity by dosing it to sheep have thus far been unsuccessful. During August 1999, 2 sheep suffering from severe photosensitivity were presented for clinical examination to the Western Cape Provincial Veterinary Laboratory (WCPVL. One sheep was sacrificed for autopsy. Except for skin lesions associated with photosensitivity, no icterus or other lesions were present. Histopathological examination of affected skin revealed epidermal necrosis while the liver had no microscopic lesions. It was therefore concluded that the sheep might have been suffering from primary photosensitivity. The farmfrom which the sheep came, situated in the Malmesbury district, WCP, was visited to determine the source of the photodynamic agent. The flock from which the sheep originated had been grazing in a camp where E. moschatum was growing abundantly and had been heavily grazed. Some remaining Erodium in the camp was collected, pulped and dosed over a period of 7 days to an adult sheep. Another sheep was dosed simultaneously with Erodium growing on the premises of the WCPVL. Both sheep developed mild photosensitivity, which was confirmed by histopathological examination of skin biopsies. It was concluded that E. moschatum can induce photosensitivity (probably the primary type in sheep if ingested in large quantities.

  10. Flocking transitions in confluent tissues.

    Giavazzi, Fabio; Paoluzzi, Matteo; Macchi, Marta; Bi, Dapeng; Scita, Giorgio; Manning, M Lisa; Cerbino, Roberto; Marchetti, M Cristina

    2018-04-25

    Collective cell migration in dense tissues underlies important biological processes, such as embryonic development, wound healing and cancer invasion. While many aspects of single cell movements are now well established, the mechanisms leading to displacements of cohesive cell groups are still poorly understood. To elucidate the emergence of collective migration in mechanosensitive cells, we examine a self-propelled Voronoi (SPV) model of confluent tissues with an orientational feedback that aligns a cell's polarization with its local migration velocity. While shape and motility are known to regulate a density-independent liquid-solid transition in tissues, we find that aligning interactions facilitate collective motion and promote solidification, with transitions that can be predicted by extending statistical physics tools such as effective temperature to this far-from-equilibrium system. In addition to accounting for recent experimental observations obtained with epithelial monolayers, our model predicts structural and dynamical signatures of flocking, which may serve as gateway to a more quantitative characterization of collective motility.

  11. Effective dimension in flocking mechanisms

    Baglietto, Gabriel; Albano, Ezequiel V.

    2011-01-01

    Even in its minimal representation (Vicsek Model, VM [T. Vicsek, A. Czirok, E. Ben-Jacob, I. Cohen and O. Shochet. Phys. Rev. Lett. 75, 1226 (1995).]), the widespread phenomenon of flocking raises intriguing questions to the statistical physicists. While the VM is very close to the better understood XY Model because they share many symmetry properties, a major difference arises by the fact that the former can sustain long-range order in two dimensions, while the latter can not. Aiming to contribute to the understanding of this feature, by means of extensive numerical simulations of the VM, we study the network structure of clusters showing that they can also sustain purely orientational, mean-field-like, long-range order. We identify the reason of this capability with the key concept of ''effective dimension.'' In fact, by analyzing the behavior of the average path length and the mean degree, we show that this dimension is very close to four, which coincides with the upper critical dimension of the XY Model, where orientational order is also of a mean-field nature. We expect that this methodology could be generalized to other types of dynamical systems.

  12. Research on an infectious disease transmission by flocking birds.

    Tang, Mingsheng; Mao, Xinjun; Guessoum, Zahia

    2013-01-01

    The swarm intelligence is becoming a hot topic. The flocking of birds is a natural phenomenon, which is formed and organized without central or external controls for some benefits (e.g., reduction of energy consummation). However, the flocking also has some negative effects on the human, as the infectious disease H7N9 will easily be transmited from the denser flocking birds to the human. Zombie-city model has been proposed to help analyzing and modeling the flocking birds and the artificial society. This paper focuses on the H7N9 virus transmission in the flocking birds and from the flocking birds to the human. And some interesting results have been shown: (1) only some simple rules could result in an emergence such as the flocking; (2) the minimum distance between birds could affect H7N9 virus transmission in the flocking birds and even affect the virus transmissions from the flocking birds to the human.

  13. Dynamics of Sheep Production in Brazil

    Samuel Rezende Paiva

    2013-07-01

    Full Text Available Sheep production is present on all continents and has been practiced in Brazil since the colonization. In this study, the multitemporal dynamics of sheep production in Brazil is examined using official government data (Brazilian Institute for Geography and Statistics-IBGE from 1976 to 2010. Maps of flock growth rates and growth acceleration maps by municipality were elaborated. The Southern states are seen to show a reduction in production mainly due to the wool crisis in the 1970s and 80s. The Northeast is seen to be important for meat production. More recently, centerwest and northern states have shown an increase in growth rates but this is still incipient. The maps of growth, acceleration and midpoint for sheep production showed a noticeable return to an increase in production in the South in recent years. The midpoint of production flow was in the northeast direction, which has stagnated. There was great dynamics in sheep production over the whole Brazilian territory, which affected supply chains due to the expansion of domestic and foreign markets. Areas with higher fluctuations in production are more vulnerable in terms of investment policies.

  14. Tay-Sachs disease in Jacob sheep.

    Torres, Paola A; Zeng, Bai Jin; Porter, Brian F; Alroy, Joseph; Horak, Fred; Horak, Joan; Kolodny, Edwin H

    2010-12-01

    Autopsy studies of four Jacob sheep dying within their first 6-8 months of a progressive neurodegenerative disorder suggested the presence of a neuronal storage disease. Lysosomal enzyme studies of brain and liver from an affected animal revealed diminished activity of hexosaminidase A (Hex A) measured with an artificial substrate specific for this component of β-hexosaminidase. Absence of Hex A activity was confirmed by cellulose acetate electrophoresis. Brain lipid analyses demonstrated the presence of increased concentrations of G(M2)-ganglioside and asialo-G(M2)-ganglioside. The hexa cDNA of Jacob sheep was cloned and sequenced revealing an identical number of nucleotides and exons as in human HexA and 86% homology in nucleotide sequence. A missense mutation was found in the hexa cDNA of the affected sheep caused by a single nucleotide change at the end of exon 11 resulting in skipping of exon 11. Transfection of normal sheep hexa cDNA into COS1 cells and human Hex A-deficient cells led to expression of Hex S but no increase in Hex A indicating absence of cross-species dimerization of sheep Hex α-subunit with human Hex β-subunits. Using restriction site analysis, the heterozygote frequency of this mutation in Jacob sheep was determined in three geographically separate flocks to average 14%. This large naturally occurring animal model of Tay-Sachs disease is the first to offer promise as a means for trials of gene therapy applicable to human infants. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Sheep and goat production practice in agroforestry systems of Gedio Zone, Ethiopia

    Selamawit Debele

    2015-06-01

    Full Text Available The study was conducted to describe sheep and goat production practice in three Agro-ecological Woredas of Gedio zone, southern Ethiopia. A set of semi-structured questionnaire was used to collect information from 120 sheep and goat owners based on single-visit-interviews. 32.6% of them participate in crop production, 56.5% of them involved in both animal and crop production and 5% of them involved in crop production, animal production and off farm activity. Sheep flock in the study sites were significantly different; and were 5.63, 6.97 and 3.4 in Wenago, Dilla and Kochera sites, respectively. Major feed resources were grazing (33.5%. The highest mortality rate occurred in suckling flock (16.24% lambs; 16.3% kids, young flock (9.64% lambs; 13.24% kids and breeding females (ewes 12.06% and does 14.1% in all study sites. Sheep and goat production in the studied areas was constrained by different problems; where the major ones are availability and cost of feeds, limitation of land for the expansion of production and poor extension services. Sheep and goats are very important smallholder producers due to their biological factors such as short generation interval, twinning, have short growth periods and do not require much space. DOI: http://dx.doi.org/10.3126/ije.v4i2.12658 International Journal of Environment Vol.4(2 2015: 296-307

  16. Intraepithelial and interstitial deposition of pathological prion protein in kidneys of scrapie-affected sheep.

    Ciriaco Ligios

    Full Text Available Prions have been documented in extra-neuronal and extra-lymphatic tissues of humans and various ruminants affected by Transmissible Spongiform Encephalopathy (TSE. The presence of prion infectivity detected in cervid and ovine blood tempted us to reason that kidney, the organ filtrating blood derived proteins, may accumulate disease associated PrP(Sc. We collected and screened kidneys of experimentally, naturally scrapie-affected and control sheep for renal deposition of PrP(Sc from distinct, geographically separated flocks. By performing Western blot, PET blot analysis and immunohistochemistry we found intraepithelial (cortex, medulla and papilla and occasional interstitial (papilla deposition of PrP(Sc in kidneys of scrapie-affected sheep. Interestingly, glomerula lacked detectable signals indicative of PrP(Sc. PrP(Sc was also detected in kidneys of subclinical sheep, but to significantly lower degree. Depending on the stage of the disease the incidence of PrP(Sc in kidney varied from approximately 27% (subclinical to 73.6% (clinical in naturally scrapie-affected sheep. Kidneys from flocks without scrapie outbreak were devoid of PrP(Sc. Here we demonstrate unexpectedly frequent deposition of high levels of PrP(Sc in ovine kidneys of various flocks. Renal deposition of PrP(Sc is likely to be a pre-requisite enabling prionuria, a possible co-factor of horizontal prion-transmission in sheep.

  17. An outbreak of tuberculosis in Lleyn sheep in the UK associated with clinical signs.

    van der Burgt, G M; Drummond, F; Crawshaw, T; Morris, S

    2013-01-19

    This case report describes an outbreak of Mycobacterium bovis infection a Lleyn sheep flock associated with clinical signs of illthrift. There was no known direct contact with tuberculous cattle although bovine tuberculosis (bTB) is endemic in the area. The spoligotype isolated from the diseased sheep was the local spoligotype. The repeated use of the comparative intradermal tuberculin test, and the subsequent removal of reactor animals, resulted in apparent elimination of bTB from the flock. Lesions caused by M bovis in sheep may contain very few acid-fast bacilli, and gross lesions may resemble those found in cases of Caseous Lymphadenitis. Routine meat inspection may, therefore, not always easily detect this notifiable disease.

  18. Diffusion of individual birds in starling flocks

    Cavagna, A.; Queirós, S. M. Duarte; Giardina, I.; Stefanini, F.; Viale, M.

    2013-01-01

    Flocking is a paradigmatic example of collective animal behaviour, where global order emerges out of self-organization. Each individual has a tendency to align its flight direction with those of neighbours, and such a simple form of interaction produces a state of collective motion of the group. When compared with other cases of collective ordering, a crucial feature of animal groups is that the interaction network is not fixed in time, as each individual moves and continuously changes its neighbours. The possibility to exchange neighbours strongly enhances the stability of global ordering and the way information is propagated through the group. Here, we assess the relevance of this mechanism in large flocks of starlings (Sturnus vulgaris). We find that birds move faster than Brownian walkers both with respect to the centre of mass of the flock, and with respect to each other. Moreover, this behaviour is strongly anisotropic with respect to the direction of motion of the flock. We also measure the amount of neighbours reshuffling and find that neighbours change in time exclusively as a consequence of the random fluctuations in the individual motion, so that no specific mechanism to keep one's neighbours seems to be enforced. On the contrary, our findings suggest that a more complex dynamical process occurs at the border of the flock. PMID:23407827

  19. Flocking and rendezvous in distributed robotics

    Francis, Bruce A

    2016-01-01

    This brief describes the coordinated control of groups of robots using only sensory input – and no direct external commands. Furthermore, each robot employs the same local strategy, i.e., there are no leaders, and the text also deals with decentralized control, allowing for cases in which no single robot can sense all the others. One can get intuition for the problem from the natural world, for example, flocking birds. How do they achieve and maintain their flying formation? Recognizing their importance as the most basic coordination tasks for mobile robot networks, the brief details flocking and rendezvous. They are shown to be physical illustrations of emergent behaviors with global consensus arising from local interactions. The authors extend the consideration of these fundamental ideas to describe their operation in flying robots and prompt readers to pursue further research in the field.  Flocking and Rendezvous in Distributed Robotics will provide graduate students a firm grounding in the subject, w...

  20. Flocking and invariance of velocity angles.

    Liu, Le; Huang, Lihong; Wu, Jianhong

    2016-04-01

    Motsch and Tadmor considered an extended Cucker-Smale model to investigate the flocking behavior of self-organized systems of interacting species. In this extended model, a cone of the vision was introduced so that outside the cone the influence of one agent on the other is lost and hence the corresponding influence function takes the value zero. This creates a problem to apply the Motsch-Tadmor and Cucker-Smale method to prove the flocking property of the system. Here, we examine the variation of the velocity angles between two arbitrary agents, and obtain a monotonicity property for the maximum cone of velocity angles. This monotonicity permits us to utilize existing arguments to show the flocking property of the system under consideration, when the initial velocity angles satisfy some minor technical constraints.

  1. Flocking with minimal cooperativity: the panic model.

    Pilkiewicz, Kevin R; Eaves, Joel D

    2014-01-01

    We present a two-dimensional lattice model of self-propelled spins that can change direction only upon collision with another spin. We show that even with ballistic motion and minimal cooperativity, these spins display robust flocking behavior at nearly all densities, forming long bands of stripes. The structural transition in this system is not a thermodynamic phase transition, but it can still be characterized by an order parameter, and we demonstrate that if this parameter is studied as a dynamical variable rather than a steady-state observable, we can extract a detailed picture of how the flocking mechanism varies with density.

  2. A discontinuous Galerkin method on kinetic flocking models

    Tan, Changhui

    2014-01-01

    We study kinetic representations of flocking models. They arise from agent-based models for self-organized dynamics, such as Cucker-Smale and Motsch-Tadmor models. We prove flocking behavior for the kinetic descriptions of flocking systems, which indicates a concentration in velocity variable in infinite time. We propose a discontinuous Galerkin method to treat the asymptotic $\\delta$-singularity, and construct high order positive preserving scheme to solve kinetic flocking systems.

  3. Impulsive Flocking of Dynamical Multiagent Systems with External Disturbances

    Fujun Han

    2017-01-01

    Full Text Available Flocking motion of multiagent systems is influenced by various external disturbances in complex environment. By applying disturbance observer, flocking of multiagent systems with exogenous disturbances is studied. Based on the robust features of impulsive control, a distributed impulsive control protocol is presented with disturbance observer, and flocking motion of multiagent systems is analyzed. Moreover, a sufficient condition is obtained to ensure the flocking motion of multiagent systems following a leader. Finally, simulation results show the validity of the theoretical conclusion.

  4. Some causes of the variable shape of flocks of birds.

    Charlotte K Hemelrijk

    Full Text Available Flocks of birds are highly variable in shape in all contexts (while travelling, avoiding predation, wheeling above the roost. Particularly amazing in this respect are the aerial displays of huge flocks of starlings (Sturnus vulgaris above the sleeping site at dawn. The causes of this variability are hardly known, however. Here we hypothesise that variability of shape increases when there are larger local differences in movement behaviour in the flock. We investigate this hypothesis with the help of a model of the self-organisation of travelling groups, called StarDisplay, since such a model has also increased our understanding of what causes the oblong shape of schools of fish. The flocking patterns in the model prove to resemble those of real birds, in particular of starlings and rock doves. As to shape, we measure the relative proportions of the flock in several ways, which either depend on the direction of movement or do not. We confirm that flock shape is usually more variable when local differences in movement in the flock are larger. This happens when a flock size is larger, b interacting partners are fewer, c the flock turnings are stronger, and d individuals roll into the turn. In contrast to our expectations, when variability of speed in the flock is higher, flock shape and the positions of members in the flock are more static. We explain this and indicate the adaptive value of low variability of speed and spatial restriction of interaction and develop testable hypotheses.

  5. Genetic diversity of Gallibacterium anatis isolates from different chicken flocks

    Bojesen, A.M.; Torpdahl, Mia; Christensen, H.

    2003-01-01

    of chickens from an organic, egg-producing flock and a layer parent flock. A subset of strains was also characterized by pulsed-field gel electrophoresis and biotyping. The organic flock isolates were characterized by more than 94% genetic similarity, indicating that only a single clone was apparent...

  6. Flies and Campylobacter infection of broiler flocks

    Hald, Birthe; Skovgård, Henrik; Bang, Dang Duong

    2004-01-01

    A total of 8.2% of flies caught outside a broiler house in Denmark had the potential to transmit Campylobacter jejuni to chickens, and hundreds of flies per day passed through the ventilation system into the broiler house. Our study suggests that flies may be an important source of Campylobacter ...... infection of broiler flocks in summer....

  7. Prevalence, distribution, and risk factor for sheep pox and goat pox (SPGP) in Algeria.

    Kardjadj, Moustafa

    2017-03-01

    A cross-sectional study using a tested questionnaire was carried out across Algeria between January and June 2014. Our investigation demonstrated that of the 150 flocks visited, 21 were positive for sheep pox and goat pox (SPGP) with an overall flock prevalence of 14% (95% CI 11.08-16.92%) suggesting that SPGP is endemic in Algeria. Our results showed also that the disease appears only in sheep and no case affecting goats has been reported. For the risk factor analysis, univariate analysis of variables followed by a multiple logistic regression identified steppe region (OR = 1.81, 95% CI 0.87-2.57; P = 0.037), large flocks (OR = 2. 19, 95% CI 1.02-3.36; P = 0.027), and transhumance (OR = 3.98, 95% CI 2.59-5.34; P = 0.021) as risk factors in the spread of the disease. Furthermore, our study revealed that the use of vaccination as preventive measures in the selected flocks decreased the odds for SPGP positivity by 5.78 (95% CI 2.22-9.34; P < 0.001) times compared to non vaccinated flocks. In conclusion, our findings documented an evidence of a widespread distribution and endemic establishment of the SPGP in Algerian sheep population despite the annual vaccination program. Consequently, the vaccination must cover all the Algerian sheep population to improve animal welfare and reduce economic losses associated with outbreak episodes.

  8. From particle to kinetic and hydrodynamic descriptions of flocking

    Ha, Seung-Yeal; Tadmor, Eitan

    2008-01-01

    We discuss the Cucker-Smale's (C-S) particle model for flocking, deriving precise conditions for flocking to occur when pairwise interactions are sufficiently strong long range. We then derive a Vlasov-type kinetic model for the C-S particle model and prove it exhibits time-asymptotic flocking behavior for arbitrary compactly supported initial data. Finally, we introduce a hydrodynamic description of flocking based on the C-S Vlasov-type kinetic model and prove flocking behavior \\emph{without...

  9. Factors of welfare reduction in dairy sheep and goats

    Antonio Pazzona

    2010-01-01

    Full Text Available Scientific research on factors causing the reduction of well-being in sheep and goats is rather recent, as are studies of strategies to minimize the adverse effects of environmental challenges and improper management practices on flock welfare. Sheep and goats, considered very rustic animals, are reared prevalently under extensive production systems and are widespread mainly in marginal areas. For these reasons, only few studies on the welfare of these species have been carried out in the past. More recently, the scenario has changed, due to a gradual diffusion of intensive and semi-intensive production systems, especially in dairy sheep and goat breeds, to the growing concern of consumers about the life conditions of farmed animals, and to the issuing of a number of rules and laws on the safety of animal products and well-being of farmed livestock. As a consequence, several research groups have turned their attention to the welfare of sheep and goats. Nevertheless, information on this topic is still scarce. This paper reviews major critical points regarding the endangerment of welfare in farmed sheep and goats. Climatic extremes and seasonal fluctuations in herbage amount and quality are discussed as important causes of the reduction of well-being in extensive production systems, which can impair production efficiency of grazing animals and dramatically affect the welfare and health status of sheep and goats. Space allowance and structures of sheep and goat houses are described as the main potential sources of discomfort for housed flocks, together with inadequate control of micro-environment, and inappropriate milking procedures and human-animal interactions. Recent studies on the impact of high ambient temperature, different ventilation regimes, high stocking densities, reduced airspace and poor litter management on behaviour, immune and endocrine response, and on performance of sheep and goats are discussed. The effects of inadequate milking

  10. Sheep laterality.

    Anderson, Dean M; Murray, Leigh W

    2013-01-01

    Turning preferences among 309 white-faced ewes were individually evaluated in an enclosed, artificially lit T-maze, followed by each ewe choosing either a right or left return alley to return to peers. Data recorded included time in the start box, time in the T-maze, exit arm chosen to leave the T-maze, and return alley. Right and left arms of the T-maze were chosen 65.7% and 34.3% of the time, respectively, while right and left return alleys were chosen 32.4% and 67.6%, respectively. Exit arm and return alley were not independently chosen (p laterality was not related (α =.05) to time of day the test was administered, ewe's age or genetics, most recent liveweight, or most recent shorn fleece weight. The mean time spent in the start box (21 s) was not related to exit arm (p =.947) or return alley (p =.779). Mean time (15 s) spent in the T-maze was not related to exit arm (p =.086) or return alley (p =.952). More research will be required to understand sheep turning laterality and how it can impact working facilities and research equipment.

  11. Temporal and contextual consistency of leadership in homing pigeon flocks.

    Carlos D Santos

    Full Text Available Organized flight of homing pigeons (Columba livia was previously shown to rely on simple leadership rules between flock mates, yet the stability of this social structuring over time and across different contexts remains unclear. We quantified the repeatability of leadership-based flock structures within a flight and across multiple flights conducted with the same animals. We compared two contexts of flock composition: flocks of birds of the same age and flight experience; and, flocks of birds of different ages and flight experience. All flocks displayed consistent leadership-based structures over time, showing that individuals have stable roles in the navigational decisions of the flock. However, flocks of balanced age and flight experience exhibited reduced leadership stability, indicating that these factors promote flock structuring. Our study empirically demonstrates that leadership and followership are consistent behaviours in homing pigeon flocks, but such consistency is affected by the heterogeneity of individual flight experiences and/or age. Similar evidence from other species suggests leadership as an important mechanism for coordinated motion in small groups of animals with strong social bonds.

  12. A Flocking Based algorithm for Document Clustering Analysis

    Cui, Xiaohui [ORNL; Gao, Jinzhu [ORNL; Potok, Thomas E [ORNL

    2006-01-01

    Social animals or insects in nature often exhibit a form of emergent collective behavior known as flocking. In this paper, we present a novel Flocking based approach for document clustering analysis. Our Flocking clustering algorithm uses stochastic and heuristic principles discovered from observing bird flocks or fish schools. Unlike other partition clustering algorithm such as K-means, the Flocking based algorithm does not require initial partitional seeds. The algorithm generates a clustering of a given set of data through the embedding of the high-dimensional data items on a two-dimensional grid for easy clustering result retrieval and visualization. Inspired by the self-organized behavior of bird flocks, we represent each document object with a flock boid. The simple local rules followed by each flock boid result in the entire document flock generating complex global behaviors, which eventually result in a clustering of the documents. We evaluate the efficiency of our algorithm with both a synthetic dataset and a real document collection that includes 100 news articles collected from the Internet. Our results show that the Flocking clustering algorithm achieves better performance compared to the K- means and the Ant clustering algorithm for real document clustering.

  13. Reduced flocking by birds on islands with relaxed predation.

    Beauchamp, Guy

    2004-05-22

    Adaptive hypotheses for the evolution of flocking in birds have usually focused on predation avoidance or foraging enhancement. It still remains unclear to what extent each factor has contributed to the evolution of flocking. If predation avoidance were the sole factor involved, flocking should not be prevalent when predation is relaxed. I examined flocking tendencies along with mean and maximum flock size in species living on islands where predation risk is either absent or negligible and then compared these results with matched counterparts on the mainland. The dataset consisted of 46 pairs of species from 22 different islands across the world. The tendency to flock was retained on islands in most species, but in pairs with dissimilar flocking tendencies, island species were less likely to flock. Mean and maximum flock size were smaller on islands than on the mainland. Potential confounding factors such as population density, nest predation, habitat type, food type and body mass failed to account for the results. The results suggest that predation is a significant factor in the evolution of flocking in birds. Nevertheless, predation and other factors, such as foraging enhancement, probably act together to maintain the trait in most species.

  14. Sheep production as a Senecio spp. control tool

    Paulo Mota Bandarra

    2012-10-01

    Full Text Available Since poisoning by Senecio spp. is one of the main causes of cattle death in southern Brazil, control of these plants is a priority for the local livestock production. After the pasture has been mowed, grazing by 16 sheep was efficient for controlling Senecio brasiliensis and Senecio madagascariensis populations in a 5.5-hectare area that had long been severely infested with these species. A total of 28,629 plants among S. brasiliensis (flower-of-souls, 10,122 and S.madagascariensis (fireweed, 18,507 were almost completely eliminated in a two-year period. The number of sheep was kept at 3.0 stock units/ha, but a variable number of cattle were temporarily stocked according to pasture availability. The major sanitary practice applied to the sheep was anthelmintic administration. Liver biopsies taken from sheep and cattle before and after experimental period didn't reveal any change associable with seneciosis. The performance levels of the sheep were comparable to those observed in flocks managed under traditional extensive grazing systems in southern Brazil.

  15. Flocking algorithm for autonomous flying robots.

    Virágh, Csaba; Vásárhelyi, Gábor; Tarcai, Norbert; Szörényi, Tamás; Somorjai, Gergő; Nepusz, Tamás; Vicsek, Tamás

    2014-06-01

    Animal swarms displaying a variety of typical flocking patterns would not exist without the underlying safe, optimal and stable dynamics of the individuals. The emergence of these universal patterns can be efficiently reconstructed with agent-based models. If we want to reproduce these patterns with artificial systems, such as autonomous aerial robots, agent-based models can also be used in their control algorithms. However, finding the proper algorithms and thus understanding the essential characteristics of the emergent collective behaviour requires thorough and realistic modeling of the robot and also the environment. In this paper, we first present an abstract mathematical model of an autonomous flying robot. The model takes into account several realistic features, such as time delay and locality of communication, inaccuracy of the on-board sensors and inertial effects. We present two decentralized control algorithms. One is based on a simple self-propelled flocking model of animal collective motion, the other is a collective target tracking algorithm. Both algorithms contain a viscous friction-like term, which aligns the velocities of neighbouring agents parallel to each other. We show that this term can be essential for reducing the inherent instabilities of such a noisy and delayed realistic system. We discuss simulation results on the stability of the control algorithms, and perform real experiments to show the applicability of the algorithms on a group of autonomous quadcopters. In our case, bio-inspiration works in two ways. On the one hand, the whole idea of trying to build and control a swarm of robots comes from the observation that birds tend to flock to optimize their behaviour as a group. On the other hand, by using a realistic simulation framework and studying the group behaviour of autonomous robots we can learn about the major factors influencing the flight of bird flocks.

  16. Boundary Information Inflow Enhances Correlation in Flocking

    Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco

    2013-04-01

    The most conspicuous trait of collective animal behavior is the emergence of highly ordered structures. Less obvious to the eye, but perhaps more profound a signature of self-organization, is the presence of long-range spatial correlations. Experimental data on starling flocks in 3D show that the exponent ruling the decay of the velocity correlation function, C(r)˜1/rγ, is extremely small, γ≪1. This result can neither be explained by equilibrium field theory nor by off-equilibrium theories and simulations of active systems. Here, by means of numerical simulations and theoretical calculations, we show that a dynamical field applied to the boundary of a set of Heisenberg spins on a 3D lattice gives rise to a vanishing exponent γ, as in starling flocks. The effect of the dynamical field is to create an information inflow from border to bulk that triggers long-range spin-wave modes, thus giving rise to an anomalously long-ranged correlation. The biological origin of this phenomenon can be either exogenous—information produced by environmental perturbations is transferred from boundary to bulk of the flock—or endogenous—the flock keeps itself in a constant state of dynamical excitation that is beneficial to correlation and collective response.

  17. Epidemiological characteristics and clinicopathological features of bluetongue in sheep and cattle, during the 2014 BTV serotype 4 incursion in Greece.

    Katsoulos, Panagiotis-Dimitrios; Giadinis, Nektarios D; Chaintoutis, Serafeim C; Dovas, Chrysostomos I; Kiossis, Evangelos; Tsousis, Georgios; Psychas, Vassilios; Vlemmas, Ioannis; Papadopoulos, Theologos; Papadopoulos, Orestis; Zientara, Stéphan; Karatzias, Harilaos; Boscos, Constantinos

    2016-03-01

    During 2014, an outbreak of Bluetongue virus (BTV) infections attributed to serotype 4 occurred in Greece and spread to south-eastern Europe. In the present article, the clinical and epidemiological data of 15 sheep flocks and 5 dairy cattle herds affected in Greece are described. In sheep, the most frequent clinical signs observed were fever, hyporexia, and edema of the face. A number of clinically affected sheep had chronic laminitis resulting in chronic lameness. Confirmation of suspect clinical cases was performed using BTV-specific real-time RT-PCR, and serotype 4-specific RT-PCR. The average morbidity of bluetongue in the sheep flocks was estimated to be 15.3 % (95 % C.I. 6.8-23.8 %) and the average mortality and case fatality were 4.5 % (95 % C.I. 1.5-7.6 %) and 32.0 % (95 % C.I. 18.1-42.9 %), respectively. The BTV seroprevalence and the ratio of clinical manifestations-to-infections determined in seven of these flocks, were on average 36.5 % (95 % C.I. 15.7-57.3 %) and 24.6 % (95 % C.I. 12.8-36.3 %). BTV ratio of clinical manifestations-to-infections was higher in the imported western European sheep breeds examined compared to the local ones. In dairy cattle, the average herd prevalence of viremia was 48.8 % (95 % C.I. 15.3-82.4 %) and none had signs associated with bluetongue. The results of this study indicate that the 2014 Greek BTV-4 has significant impact on the health status and the viability of sheep in affected flocks but does not cause clinical signs in cattle, despite the high prevalence of viremia.

  18. High fluoride and low calcium levels in drinking water is associated with low bone mass, reduced bone quality and fragility fractures in sheep.

    Simon, M J K; Beil, F T; Rüther, W; Busse, B; Koehne, T; Steiner, M; Pogoda, P; Ignatius, A; Amling, M; Oheim, R

    2014-07-01

    Chronic environmental fluoride exposure under calcium stress causes fragility fractures due to osteoporosis and bone quality deterioration, at least in sheep. Proof of skeletal fluorosis, presenting without increased bone density, calls for a review of fracture incidence in areas with fluoridated groundwater, including an analysis of patients with low bone mass. Understanding the skeletal effects of environmental fluoride exposure especially under calcium stress remains an unmet need of critical importance. Therefore, we studied the skeletal phenotype of sheep chronically exposed to highly fluoridated water in the Kalahari Desert, where livestock is known to present with fragility fractures. Dorper ewes from two flocks in Namibia were studied. Chemical analyses of water, blood and urine were executed for both cohorts. Skeletal phenotyping comprised micro-computer tomography (μCT), histological, histomorphometric, biomechanical, quantitative backscattered electron imaging (qBEI) and energy-dispersive X-ray (EDX) analysis. Analysis was performed in direct comparison with undecalcified human iliac crest bone biopsies of patients with fluoride-induced osteopathy. The fluoride content of water, blood and urine was significantly elevated in the Kalahari group compared to the control. Surprisingly, a significant decrease in both cortical and trabecular bones was found in sheep chronically exposed to fluoride. Furthermore, osteoid parameters and the degree and heterogeneity of mineralization were increased. The latter findings are reminiscent of those found in osteoporotic patients with treatment-induced fluorosis. Mechanical testing revealed a significant decrease in the bending strength, concurrent with the clinical observation of fragility fractures in sheep within an area of environmental fluoride exposure. Our data suggest that fluoride exposure with concomitant calcium deficit (i) may aggravate bone loss via reductions in mineralized trabecular and cortical bone

  19. Molecular characterization and phylogenetic analysis of small ruminant lentiviruses isolated from Canadian sheep and goats

    Bertoni Giuseppe

    2011-06-01

    Full Text Available Abstract Background Small Ruminant Lentiviruses (SRLV are widespread in Canadian sheep and goats and represent an important health issue in these animals. There is however no data about the genetic diversity of Caprine Arthritis Encephalitis Virus (CAEV or Maedi Visna Virus (MVV in this country. Findings We performed a molecular and phylogenetic analysis of sheep and goat lentiviruses from a small geographic area in Canada using long sequences from the gag region of 30 infected sheep and 36 infected goats originating from 14 different flocks. Pairwise DNA distance and phylogenetic analyses revealed that all SRLV sequences obtained from sheep clustered tightly with prototypical Maedi visna sequences from America. Similarly, all SRLV strains obtained from goats clustered tightly with prototypical US CAEV-Cork strain. Conclusions The data reported in this study suggests that Canadian and US SRLV strains share common origins. In addition, the molecular data failed to bring to light any evidence of past cross species transmission between sheep and goats, which is consistent with the type of farming practiced in this part of the country where single species flocks predominate and where opportunities of cross species transmissions are proportionately low.

  20. Mixed species flocking of tits (Parus spp.): a field experiment.

    Székely, T; Szép, T; Juhász, T

    1989-03-01

    We tested two general models of flocking behaviour, namely the antipredation model and foraging efficiency model on mixed-species tit flocks (Parus spp.). After food addition the size of mixed-species flocks was significantly less than in the control samples. In the presence of extra food significantly more birds were observed either in monospecific flocks or solitary, than during the control observations. In the presence of a living predator the birds foraged in larger mixed-specifies flocks than during the control observations. In addition, the social behaviour of Great Spotted Woodpecker, Middle Spotted Woodpecker and Nuthatch shifted to mixed-specific flocking. The size of monospecific flocks was independent of both treatments. The density of birds increased significantly after food addition, while in the predator presence the birds tended to leave the forest. These results support the view that both the antipredation model and foraging efficiency model seem to be valid for mixed-species flocking. However, in the case of monospecific flocks, the territory maintenance could be the most important factor.

  1. Self-Organized Fission Control for Flocking System

    Mingyong Liu

    2015-01-01

    Full Text Available This paper studies the self-organized fission control problem for flocking system. Motivated by the fission behavior of biological flocks, information coupling degree (ICD is firstly designed to represent the interaction intensity between individuals. Then, from the information transfer perspective, a “maximum-ICD” based pairwise interaction rule is proposed to realize the directional information propagation within the flock. Together with the “separation/alignment/cohesion” rules, a self-organized fission control algorithm is established that achieves the spontaneous splitting of flocking system under conflict external stimuli. Finally, numerical simulations are provided to demonstrate the effectiveness of the proposed algorithm.

  2. Research on an Infectious Disease Transmission by Flocking Birds

    Mingsheng Tang

    2013-01-01

    Full Text Available The swarm intelligence is becoming a hot topic. The flocking of birds is a natural phenomenon, which is formed and organized without central or external controls for some benefits (e.g., reduction of energy consummation. However, the flocking also has some negative effects on the human, as the infectious disease H7N9 will easily be transmited from the denser flocking birds to the human. Zombie-city model has been proposed to help analyzing and modeling the flocking birds and the artificial society. This paper focuses on the H7N9 virus transmission in the flocking birds and from the flocking birds to the human. And some interesting results have been shown: (1 only some simple rules could result in an emergence such as the flocking; (2 the minimum distance between birds could affect H7N9 virus transmission in the flocking birds and even affect the virus transmissions from the flocking birds to the human.

  3. Technological level and epidemiological aspects of sheep husbandry in Minas Gerais, southeastern Brazil

    Aurora M.G. Gouveia

    2014-09-01

    Full Text Available Epidemiological and health aspects of sheep husbandry were assessed on 213 sheep flocks in 142 municipalities from the state of Minas Gerais, southeastern Brazil. An updated questionnaire was filled out for each flock, requesting data on the farm, the flock and the farmer by the veterinarians of the State Government Agency for Animal Health (Instituto Mineiro de Agropecuária. Thirteen important variables were selected and scored to determine the technological level of the 117 farms; 0.9% of them was classified as high technological level, 45.3% as medium technological level and 53.0% as low technological level. Lamb production was the main objective of the farms and the main features were low-frequencies of individual identification of animals (16.9%, technical assistance (31.9%, use of quarantine for newly acquired animals (0.9% the separation of animals by age group (3.7% and requeste the sanitary certificate at purchasing of animals (11.7%. The main health problems reported were abortion (23.9%, keratoconjunctivitis (17.9%, contagious ecthyma (13.6%, pneumonia (10.3%, diarrhea (9.3% and caseous lymphadenitis (6.1%. Information of the epidemiological situation and the mainly health measures used in the sheep farms are important to improve the productivity and quality of the lamb.

  4. Field observations during the Bluetongue serotype 8 epidemic in 2006 II. Morbidity and mortality rate, case fatality and clinical recovery in sheep and cattle in the Netherlands

    Elbers, A.R.W.; Backx, A.; Mintiens, K.; Gerbier, G.; Staubach, C.; Hendrickx, G.; Spek, van der A.N.

    2008-01-01

    Data collected in the Netherlands during the Bluetongue serotype 8 (BTV-8) epidemic indicated that in outbreak cattle herds, predominantly dairy and nursing cows were clinically affected and not young stock, beef cattle, beef calves, or breeding animals. In outbreak sheep flocks, mainly ewes and ¿

  5. Copper intoxication in sheep

    Gazaryan, V.S.; Sogoyan, I.S.; Agabalov, G.A.; Mesropyan, V.V.

    1966-01-01

    Of 950 sheep fed hay from a vineyard sprayed regularly with copper sulfate, 143 developed clinical copper poisoning and 103 died. The Cu content of the hay was 10.23 mg%, of the liver of dead sheep 17-52 mg%, and of the blood serum of affected sheep 0.86 mg%. The symptoms and the histological findings in kidneys and liver are described.

  6. Flock-based surveillance for lowpathogenic avian influenza virus in ...

    Flock-based surveillance for lowpathogenic avian influenza virus in commercial breeders and layers, southwest Nigeria. ... African Journal of Infectious Diseases ... Background: Flock surveillance systems for avian influenza (AI) virus play a critical role in countries where vaccination is not practiced so as to establish the ...

  7. Rubin H. Flocks and Colloidal Gold Treatments for Prostate Cancer

    Henry M. Rosevear

    2011-01-01

    Full Text Available In the early 1950s, Rubin H. Flocks of the University of Iowa began to treat prostate cancer patients with colloidal gold (Au198 therapy, evolving his technique over nearly 25 years in 1515 patients. We reviewed the long-term outcomes of Flocks' prostate cancer patients as compared to those patients treated by other methods at the University of Iowa before Flocks' chairmanship. We reviewed archived patient records, Flocks' published data, and long-term survival data from the Iowa Tumor Registry to determine short- and long-term outcomes of Flocks' work with colloidal gold. We also reviewed the literature of Flocks' time to compare his outcomes against those of his contemporaries. The use of colloidal gold, either as primary or adjunctive therapy, provided short- and long-term survival benefit for the majority of Flocks' patients as compared to historical treatment options (p < 0.001. Flocks' use of colloidal gold for the treatment of locally advanced prostate cancer offered short- and long-term survival benefits compared to other contemporary treatments.

  8. Risk factors and likelihood of Campylobacter colonization in broiler flocks

    SL Kuana

    2007-09-01

    Full Text Available Campylobacter was investigated in cecal droppings, feces, and cloacal swabs of 22 flocks of 3 to 5 week-old broilers. Risk factors and the likelihood of the presence of this agent in these flocks were determined. Management practices, such as cleaning and disinfection, feeding, drinkers, and litter treatments, were assessed. Results were evaluated using Odds Ratio (OR test, and their significance was tested by Fisher's test (p<0.05. A Campylobacter prevalence of 81.8% was found in the broiler flocks (18/22, and within positive flocks, it varied between 85 and 100%. Campylobacter incidence among sample types was homogenous, being 81.8% in cecal droppings, 80.9% in feces, and 80.4% in cloacal swabs (230. Flocks fed by automatic feeding systems presented higher incidence of Campylobacter as compared to those fed by tube feeders. Litter was reused in 63.6% of the farm, and, despite the lack of statistical significance, there was higher likelihood of Campylobacter incidence when litter was reused. Foot bath was not used in 45.5% of the flocks, whereas the use of foot bath associated to deficient lime management increased the number of positive flocks, although with no statiscal significance. The evaluated parameters were not significantly associated with Campylobacter colonization in the assessed broiler flocks.

  9. Flocking dynamics and roosting behaviour of Meyer's parrot ...

    For most of the year, Meyer's parrots in the Okavango Delta do not form large feeding flocks, and groups larger than two or three are probably the result of opportunistic aggregation at favoured food items after dispersion from communal roosts. Communal roosting likely does not facilitate flocking unless the food resources ...

  10. Starling flock networks manage uncertainty in consensus at low cost.

    George F Young

    Full Text Available Flocks of starlings exhibit a remarkable ability to maintain cohesion as a group in highly uncertain environments and with limited, noisy information. Recent work demonstrated that individual starlings within large flocks respond to a fixed number of nearest neighbors, but until now it was not understood why this number is seven. We analyze robustness to uncertainty of consensus in empirical data from multiple starling flocks and show that the flock interaction networks with six or seven neighbors optimize the trade-off between group cohesion and individual effort. We can distinguish these numbers of neighbors from fewer or greater numbers using our systems-theoretic approach to measuring robustness of interaction networks as a function of the network structure, i.e., who is sensing whom. The metric quantifies the disagreement within the network due to disturbances and noise during consensus behavior and can be evaluated over a parameterized family of hypothesized sensing strategies (here the parameter is number of neighbors. We use this approach to further show that for the range of flocks studied the optimal number of neighbors does not depend on the number of birds within a flock; rather, it depends on the shape, notably the thickness, of the flock. The results suggest that robustness to uncertainty may have been a factor in the evolution of flocking for starlings. More generally, our results elucidate the role of the interaction network on uncertainty management in collective behavior, and motivate the application of our approach to other biological networks.

  11. Starling Flock Networks Manage Uncertainty in Consensus at Low Cost

    Young, George F.; Scardovi, Luca; Cavagna, Andrea; Giardina, Irene; Leonard, Naomi E.

    2013-01-01

    Flocks of starlings exhibit a remarkable ability to maintain cohesion as a group in highly uncertain environments and with limited, noisy information. Recent work demonstrated that individual starlings within large flocks respond to a fixed number of nearest neighbors, but until now it was not understood why this number is seven. We analyze robustness to uncertainty of consensus in empirical data from multiple starling flocks and show that the flock interaction networks with six or seven neighbors optimize the trade-off between group cohesion and individual effort. We can distinguish these numbers of neighbors from fewer or greater numbers using our systems-theoretic approach to measuring robustness of interaction networks as a function of the network structure, i.e., who is sensing whom. The metric quantifies the disagreement within the network due to disturbances and noise during consensus behavior and can be evaluated over a parameterized family of hypothesized sensing strategies (here the parameter is number of neighbors). We use this approach to further show that for the range of flocks studied the optimal number of neighbors does not depend on the number of birds within a flock; rather, it depends on the shape, notably the thickness, of the flock. The results suggest that robustness to uncertainty may have been a factor in the evolution of flocking for starlings. More generally, our results elucidate the role of the interaction network on uncertainty management in collective behavior, and motivate the application of our approach to other biological networks. PMID:23382667

  12. Benzimidazole resistance of sheep nematodes in Norway confirmed through controlled efficacy test

    Domke Atle V

    2012-08-01

    Full Text Available Abstract Background Resistance against benzimidazoles (BZ has recently been detected in Norwegian sheep flocks through a large scale prevalence survey based on the faecal egg count reduction test (FECRT. The use of this test in combination with bulk larval culture only gives an indication of which gastrointestinal nematodes genera that are involved and these results have to be confirmed by a controlled efficacy test (CET to get accurate information about resistant nematodes populations at species level. A CET was therefore performed with larvae from two flocks where BZ resistance was previously detected through FECRT. Results The latter test confirmed the previous results in both flocks. In flock A, the BZ resistant nematode population consisted solely of Haemonchus contortus, whereas H. contortus and Teladorsagia circumcincta comprised the resistant worm population in flock B. Conclusions Some discrepancies that have been recorded between FECRT and CET results regarding time for post-treatment coproscopical examination and a temporary suppression of faecal egg excretion are discussed.

  13. A retrospective study on salmonella infection in Danish broiler flocks

    Angen, Øystein; Skov, M. N.; Chriél, Mariann

    1996-01-01

    -year period from 1992 to 1993 in Denmark. The AM database contains information collected by the ante-mortem veterinarians, from the slaughterhouses, and from the salmonella examinations carried out at the National Veterinary Laboratory. The epidemiological unit was the individual broiler flock....... The salmonella status of the flock was determined by examining the caecal tonsils from 16 3-week-old chickens from each flock. This procedure would detect a salmonella-infected flock, with a probability above 95%, if the prevalence is above 20%. Furthermore, the structure and quality of the collected data have...... been evaluated. Fourteen variables were selected for analysis by multivariable logistic regression. An increased risk of salmonella infection in the broiler Becks was associated with the biggest hatcheries and feedmill, with an increasing number of houses on the farm, if the preceding flock...

  14. Identification and characterization of serogroup M Dichelobacter nodosus from sheep with virulent footrot.

    Dhungyel, Om; Schiller, Natalie; Whittington, Richard

    2015-04-17

    As part of an outbreak-specific footrot vaccination field trial a total of 1282 footrot lesion samples were collected from 2 sheep flocks on King Island, Tasmania. Breeding rams were shared between the two flocks, suggesting a common source of infection. All samples were tested for Dichelobacter nodosus. A total of 1047 D. nodosus isolates were obtained in pure culture (490 from 670 lesion samples from flock 1, and 557 from 612 lesion samples from flock 2) were tested by agglutination and PCR tests for the 9 common Australian serogroups A to I. After the first rounds of a specific vaccination program, a significant proportion of the isolates of D. nodosus from these flocks were found to be negative in the serogrouping tests and the prevalence of the disease remained high in both. Those isolates were tested retrospectively against New Zealand and Nepal serogroup M antisera and found to be positive. Fimbrial gene (fimA) sequences of three isolates collected over three years were identical indicating that these strains belonged to one serogroup and were most closely related to New Zealand and Nepal serogroup M sequences. More than 40% of the D. nodosus isolates from these flocks belonged to serogroup M and were virulent in tests for protease activity. The next most prevalent serogroup was A (23%). This study reports the identification and characterization of serogroup M isolates of D. nodosus from Australia, and led to routine testing for serogroup M in flocks where specific vaccination will be applied for control, treatment and eradication of the virulent footrot. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Application of probiotics and different size of sodium bicarbonate powders for feedlot sheep fattening

    Supratman, Hery; Ramdani, Diky; Kuswaryan, Sondy; Budinuryanto, Dwi Cipto; Joni, I. Made

    2018-02-01

    This paper reports the use of probiotic and sodium bicarbonate in the diet of feedlot sheep. Probiotics from Heriyaki powder can function as forge preservative and sodium bicarbonate as an artificial rumen buffer that helps to stabilize pH levels in sheep's stomach. The objectives of this formulation is to improve the rumen function, feed efficiency and reduce the risk of acidosis leading to a significant increase of average daily gain (ADG, gram/head/day) of feedlot sheep. Heriyaki probiotic liquid was prepared by fermenting beans mixed with sugarcane molasses while Heriyaki powder was obtained by mixing the Heriyaki probiotic liquid with rice hull powder and additional molasses sugarcane in anaerobic condition for 5 days. The powder was then applied for preparing whole maize silage 0.5 wt% in anaerobic condition for 7 days before feeding. Meanwhile, the feed concentrate contained acid buffer of sodium bicarbonate powder at different doses and sizes [0.35 wt% commercial size (T1), 0.18 wt% mesh -400 (T2) and 0.35 wt% mesh -400 (T3)]. The diet treatment was a total mixed ratio containing 1 kg silage and 700 g concentrate. The experiment was conducted to compare the effect of 3 different treatments (T1, T2 and T3) on dry matter intake (DMI, g/day), ADG and feed conversion ratio (FCR) of feedlot sheep for 2 months fattening, where each treatment was applied into a flock colony for 6 heads of sheep with three flock replications involving 54 heads of sheep in total for all the treatments. The results showed no difference (P>0.05) in DMI, ADG and FCR of feedlot sheep confirming the use of low-dose and finer sodium bicarbonate powder in T2 yield a targeted ADG of > 110 g but being more efficient than other treatments.

  16. Breeding objectives for Targhee sheep.

    Borg, R C; Notter, D R; Kuehn, L A; Kott, R W

    2007-11-01

    Breeding objectives were developed for Targhee sheep under rangeland production conditions. Traits considered were those for which EPD were available from the US National Sheep Improvement Program and included direct and maternal effects on 120-d weaning weight (WW and MM, respectively); yearling weight (YW); yearling fleece weight, fiber diameter, and staple length; and percent lamb crop (PLC), measured as the number of lambs born per 100 ewes lambing. A bioeconomic model was used to predict the effects of a change of 1 additive SD in EPD for each trait, holding all other traits constant at their mean, on animal performance, feed requirements, feed costs, and economic returns. Resulting economic weightings were then used to derive selection indexes. Indexes were derived separately for 3 prolificacy levels (1.41, 1.55, and 1.70 lambs/ewe lambing), 2 triplet survival levels (50 and 67%), 2 lamb pricing policies (with or without discounting of prices for heavy feeder lambs), and 3 forage cost scenarios (renting pasture, purchasing hay, or reducing flock size to accommodate increased nutrient requirements for production). Increasing PLC generally had the largest impact on profitability, although an increase in WW was equally important, with low feed costs and no discounting of prices for heavy feeder lambs. Increases in PLC were recommended at all 3 prolificacy levels, but with low triplet survival the value of increasing PLC eventually declined as the mean litter size increased to approximately 2.15 lambs/ewe lambing and above. Increasing YW (independent of WW) increased ewe maintenance costs and reduced profitability. Predicted changes in breeding values for WW and YW under index selection varied with lamb pricing policy and feed costs. With low feed costs or no discounts for heavy lambs, YW increased at a modest rate in association with increasing WW, but with high feed costs or discounting of heavy lambs, genetic trends in WW were reduced by approximately 50% to

  17. Leptospirosis in sheep and goats under tropical conditions.

    Martins, Gabriel; Lilenbaum, Walter

    2014-01-01

    Inadequate management practices and poor reproductive performance have been reported as fundamental factors on reducing the levels of productivity in livestock. Different pathogens have been reported in small ruminants' herds/flocks with reproductive failures. The aim of the present study was to review aspects of leptospirosis in small ruminants, mainly its impact on reproduction and consequently on productivity of the herds/flocks under tropical conditions. Leptospiral infection in goats and sheep is common in several countries, and those species can also act as carriers of leptospires. Severe disease is often associated to young animals and is frequently associated to incidental serovars. In contrast, subclinical infection is mainly characterized by reproductive problems, such as infertility, abortion, occurrence of stillbirths, and weak lambs/goat kids. Moreover, laboratorial tests are essential to achieve an accurate diagnosis of the infection. Microscopic agglutination test is the most common indirect test of leptospirosis, being used worldwide. In small ruminants, PCR consists on a recommendable method for diagnosing animals that carry leptospires. Control of leptospirosis in small ruminants involves measures such as the identification and treatment of the carriers and other sources of infection, quarantine in acquired animals, and systematic immunization with commercial vaccines containing the circulating serovars in the herd/flock. Productivity of small ruminant breeding can dramatically increase with adequate sanitary conditions and control of leptospirosis. Immunization of all the animals combined to the treatment of carriers may successfully control the infection and importantly reduce the economic reproductive hazards that are observed under tropical conditions.

  18. Parturition difficulties in sheep

    Grommers, F. J.; Elving, L.; Eldik, P. van

    1985-01-01

    The incidence of difficult parturition was recorded in Texel Sheep lambs (224), Milk Sheep lambs (273) and various crossbreeds (1043) in ten spring lambing seasons. at lambing time the ewes were under 24-hour observation. Difficult parturition is defined as necessity for obstetrical assistance as

  19. Flock worker's lung: chronic interstitial lung disease in the nylon flocking industry.

    Kern, D G; Crausman, R S; Durand, K T; Nayer, A; Kuhn, C

    1998-08-15

    Two young men working at a nylon flocking plant in Rhode Island developed interstitial lung disease of unknown cause. Similar clusters at the same company's Canadian plant were reported previously. To define the extent, clinicopathologic features, and potential causes of the apparent disease outbreak. Case-finding survey and retrospective cohort study. Academic occupational medicine program. All workers employed at the Rhode Island plant on or after 15 June 1990. Symptomatic employees had chest radiography, pulmonary function tests, high-resolution computed tomography, and serologic testing. Those with unexplained radiographic or pulmonary function abnormalities underwent bronchoalveolar lavage, lung biopsy, or both. The case definition of "flock worker's lung" required histologic evidence of interstitial lung disease (or lavage evidence of lung inflammation) not explained by another condition. Eight cases of flock worker's lung were identified at the Rhode Island plant. Three cases were characterized by a high proportion of eosinophils (25% to 40%) in lavage fluid. Six of the seven patients who had biopsy had histologic findings of nonspecific interstitial pneumonia, and the seventh had bronchiolitis obliterans organizing pneumonia. All seven of these patients had peribronchovascular interstitial lymphoid nodules, usually with germinal centers, and most had lymphocytic bronchiolitis and interstitial fibrosis. All improved after leaving work. Review of the Canadian tissue specimens showed many similar histologic findings. Among the 165-member study cohort, a 48-fold or greater increase was seen in the sex-adjusted incidence rate of all interstitial lung disease. Work in the nylon flocking industry poses substantial risk for a previously unrecognized occupational interstitial lung disease. Nylon fiber is the suspected cause of this condition.

  20. Cohesive motion in one-dimensional flocking

    Dossetti, V

    2012-01-01

    A one-dimensional rule-based model for flocking, which combines velocity alignment and long-range centering interactions, is presented and studied. The induced cohesion in the collective motion of the self-propelled agents leads to unique group behavior that contrasts with previous studies. Our results show that the largest cluster of particles, in the condensed states, develops a mean velocity slower than the preferred one in the absence of noise. For strong noise, the system also develops a non-vanishing mean velocity, alternating its direction of motion stochastically. This allows us to address the directional switching phenomenon. The effects of different sources of stochasticity on the system are also discussed. (paper)

  1. Revisiting the flocking transition using active spins.

    Solon, A P; Tailleur, J

    2013-08-16

    We consider an active Ising model in which spins both diffuse and align on lattice in one and two dimensions. The diffusion is biased so that plus or minus spins hop preferably to the left or to the right, which generates a flocking transition at low temperature and high density. We construct a coarse-grained description of the model that predicts this transition to be a first-order liquid-gas transition in the temperature-density ensemble, with a critical density sent to infinity. In this first-order phase transition, the magnetization is proportional to the liquid fraction and thus varies continuously throughout the phase diagram. Using microscopic simulations, we show that this theoretical prediction holds in 2D whereas the fluctuations alter the transition in 1D, preventing, for instance, any spontaneous symmetry breaking.

  2. Cucker-Smale Flocking with Bounded Cohesive and Repulsive Forces

    Qiang Song

    2013-01-01

    Full Text Available This paper proposes two Cucker-Smale-type flocking models by introducing both cohesive and repulsive forces to second-order multiagent systems. Under some mild conditions on the initial state of the flocking system, it is shown that the velocity consensus of the agents can be reached independent of the parameter which describes the decay of communication rates. In particular, the collision between any two agents can always be avoided by designing an appropriate bounded repulsive function based on the initial energy of the flock. Numerical examples are given to demonstrate the effectiveness of the theoretical analysis.

  3. Prevalence of Campylobacter jejuni in poultry breeder flocks

    Ludovico Dipineto

    2010-01-01

    Full Text Available The aim of this work is to present the preliminary results of a study about the prevalence of Campylobacter jejuni in poultry breeder flocks. It was examined three different breeder flocks of Bojano in Molise region. A total of 360 cloacal swabs and 80 enviromental swabs was collected. Of the 3 flocks studied, 6.9% tested were positive for Campylobacter spp. The most-prevalent isolated species is C. jejuni (8.2%. Only 3 of the 360 cloacal swabs samples examined were associated with C. coli. The environmental swabs resulted negative. This results confirms again that poultry is a reservoir of this germ.

  4. Prevalence of paratuberculosis in the dairy goat and dairy sheep industries in Ontario, Canada

    Bauman, Cathy A.; Jones-Bitton, Andria; Menzies, Paula

    2016-01-01

    ). Using 3-test latent class Bayesian models, true farm-level prevalence was estimated to be 83.0% [95% probability interval (PI): 62.6% to 98.1%] for dairy goats and 66.8% (95% PI: 41.6% to 91.4%) for dairy sheep. The within-farm true prevalence for dairy goats was 35.2% (95% PI: 23.0% to 49......A cross-sectional study was undertaken (October 2010 to August 2011) to estimate the prevalence of paratuberculosis in the small ruminant dairy industries in Ontario, Canada. Blood and feces were sampled from 580 goats and 397 sheep (lactating and 2 y of age or older) that were randomly selected...... from 29 randomly selected dairy goat herds and 21 convenience -selected dairy sheep flocks. Fecal samples were analyzed using bacterial culture (BD BACTEC MGIT 960) and polymerase chain reaction (Tetracore); serum samples were tested with the Prionics Parachek enzyme-linked immunosorbent assay (ELISA...

  5. Mutual relationships among body condition score, live weight, and back tissue development in meat sheep

    Martin Ptáček

    2014-01-01

    Full Text Available Body tissue development and proportion affect predisposition to optimum functioning of production attributes, health, and fertility of sheep. Therefore, the objective of this study was to determine relationships among indicators of mature ewes’ nutritional status documented by the body condition score and live weight using ultrasonic evaluation of backfat thickness and depth of musculus longissimus lumborum et thoracis. The monitoring was carried out in Suffolk sheep (n = 942 for a period of 2 years. A significant increase (P P P P in vivo. Results of the present study could serve in flock management as a tool for evaluation of the current nutritional status as well as a basic ground for further research focused on development of sheep fattiness and carcass traits evaluation.

  6. The influence of radiation on reproduction of sheep

    Stanikova, A.; Pastorova, B.; Halagan, J.; Maracek, I.; Sopkova, D.

    2006-01-01

    Qualitative and quantitative histological changes in the sexual apparatus of slovak merino ewes were studies in the anoestrous period after irradiation (2.5 Gy) and hormonal stimulation. Estrus synchronization of the sheep has been carried out by application of 20 mg chlorosuperlutine in impregnated vaginal Ageline sponges. The sheep were hormone stimulated by application of 1500 IU of Serum gonadotrophin. The animals were killed approximately 120 h after the application of the hormone. Samples from the sexual apparatus were processed by the common histological methods for examination under a light microscope and for examination under a scanning electron microscope (SEM). Despite higher number of ovulations in irradiated and hormonally stimulated sheep, the examination of viability of irradiated oocytes showed absence of pregnancy in all 20 sheep after mating. This indicated that the dose of 2.5 Gy was not harmless to the reproductive system of sheep. (authors)

  7. Acute and chronic disease associated with naturally occurring T-2 mycotoxicosis in sheep.

    Ferreras, M C; Benavides, J; García-Pariente, C; Delgado, L; Fuertes, M; Muñoz, M; García-Marín, J F; Pérez, V

    2013-02-01

    A flock of approximately 1,000 sheep were exposed intermittently to food contaminated with T-2 toxin (T-2), a potent type-A trichothecene mycotoxin produced primarily by Fusarium sporotrichioides and Fusarium poae. In the acute stage of the intoxication, affected sheep developed anorexia, decreased water consumption, ruminal atony, soft faeces and apathy. One hundred and ninety of the exposed sheep died. The main gross lesions observed in animals dying during the acute disease were rumenitis and ulcerative abomasitis, depletion of lymphocytes in lymphoid organs, necrosis of the exocrine pancreas, myocarditis and intense oedema of the skin and brain. Sheep developing the chronic stage of disease showed weight loss and reproductive inefficiency and the main pathological features observed in animals dying during this stage were gastrointestinal inflammation, myocardial fibrosis and necrotic and suppurative lesions in the oral cavity. Opportunistic infections (e.g. mycotic mastitis or parasitic pneumonia) were also identified in these animals. Increased serum concentrations of lactate dehydrogenase and creatine kinase were observed, most likely related to heart lesions. T-2 toxins were detected in all samples of the diet of these animals that were analyzed. The changes in the sheep reported here are similar to those described previously in experimental studies. Lesions observed in the present animals suggest an additional cardiotoxic effect of T-2 in sheep. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Recent studies on Dictyocaulus filaria and other lungworms of sheep and goats in India

    Dhar, D.N.

    1982-01-01

    Additional areas of the country were surveyed for lungworm infections in sheep and goats. More sheep than goats and more sheep of the private breeders in comparison to Government flocks were found infected. Infection with Dictyocaulus filaria and un-identified species of Varestrongylus and Protostrongylus were reported from sheep and goats and Muellerius spp, only from sheep. About 0.36 million lambs have been successfully immunized against D. filaria in the endemic areas with the radiation-attenuated vaccine produced at the Srinagar laboratory. It has been shown that lambs infected with D. filaria at the time of vaccination develop a poor protection following vaccination in comparison to lambs free from the infection. This has posed a problem in the field of stimulating a satisfactory protection in lambs found infected with D. filaria at the time of vaccination. In consequence, very young lambs, aged 6-10 week have been effectively protected against D. filaria by vaccination under field conditions. Goats are more succeptible hosts to D. filaria than sheep. Laboratory studies have shown that young kids, like lambs, can be effectively immunized against D. filaria by double vaccination with 50 Krad gamma irradiated larvae. (author)

  9. The treatment and eradication of sheep lice and ked with cyhalothrin--a new synthetic pyrethroid.

    Rundle, J C; Forsyth, B A

    1984-12-01

    A new synthetic pyrethroid, cyhalothrin, has been evaluated as both a sheep dip and a jetting fluid for the control of body lice (Damalinia ovis), face lice (Linognathus ovillus), foot lice (Linognathus pedalis) and the sheep ked (Melophagus ovinus). A dip wash concentration of 1.25 ppm cyhalothrin eradicated D. ovis from sheep. A jetting fluid at a concentration of 20 ppm also eradicated D. ovis. In the field cyhalothrin was evaluated at 20 ppm as a dip wash and at 50 ppm as a jetting fluid. These field trials confirmed the ability of cyhalothrin to eradicate D. ovis from short and long-woolled sheep. The sucking lice, L. ovillus and L. pedalis, were also found to be very susceptible to cyhalothrin at a dip wash concentration of 20 ppm, but it was necessary to treat the predilection sites infested by these parasites twice within a 3-week period to achieve their eradication. Sheep ked (M. ovinus) were eradicated from an infected flock of sheep after plunge dipping in cyhalothrin at 20 ppm.

  10. Economic Cost of Ovine Johne’s Disease in Clinically Affected New Zealand Flocks and Benefit-Cost of Vaccination

    Gautam, Milan; Anderson, Peter; Ridler, Anne; Wilson, Peter; Heuer, Cord

    2018-01-01

    The aims of this study were to estimate the on-fam economic cost of ovine Johne’s disease (OJD) based on collected incidence and mortality data, and the benefit-cost of OJD vaccination in typical OJD affected flocks in New Zealand after having vaccinated for a number of years. Owners of 20 sheep breeding and finishing farms known to be clinically affected by ovine Johne’s disease in New Zealand participated in the study and were monitored for up to two years. Farms were categorized as fine-wool (Merino, Half-Bred, Corriedale, n = 15), and other breeds (Romney, composite breeds, n = 5). Ovine JD was confirmed by gross- and histo-pathology in 358 ewes culled due to chronic progressive wasting. An additional 228 ewes with low body condition score (BCS), but not targeted for culling, were tested with ELISA to estimate the proportion of OJD in ewes in the lower 5% BCS of the flock. Calculations were done separately for fine-wool and other breeds. Based on the data, mortality due to OJD, its associated cost and the benefit-cost of vaccination were evaluated for a hypothetical farm with 2000 ewes by stochastic simulation. Total ewe mortality was similar in fine-wool and other breeds, but the estimated mortality due to OJD was 2.7 times as high in fine-wool (median 1.8%, interquartile range IQR 1.2–2.7%) than other breeds (median 0.69%, IQR 0.3–1.2%), but with large variation between farms. ELISA results demonstrated fine-wool sheep had a higher seroprevalence than other breeds (39%, 95% CI 18–61% vs. 9%, 95% CI 0–22%). Stochastic modelling indicated that the average annual cost of mortality due to OJD in a flock of 2000 ewes was NZD 13,100 (IQR 8900–18,600) in fine-wool and NZD 4300 (IQR 2200–7600) in other breeds. Vaccinating replacement lambs against OJD may be cost-effective in most flocks when the pre-vaccination annual ewe mortality due to OJD is >1%. To make the best-informed decision about vaccination it is therefore essential for farmers to

  11. Flock size, diet composition, and habitat characteristics of the ...

    gla- cial history (Magin 2001). Some of the plant species endemic to SMNP are stonecrop. Rosularia simiensis and tussock grass Festuca gilbertiana. SMNP is home to 22 species. Flock size, diet composition, and habitat characteristics of ...

  12. Flocking of quad-rotor UAVs with fuzzy control.

    Mao, Xiang; Zhang, Hongbin; Wang, Yanhui

    2018-03-01

    This paper investigates the flocking problem of quad-rotor UAVs. Considering the actual situations, we derived a new simplified quad-rotor UAV model which is more reasonable. Based on the model, the T-S fuzzy model of attitude dynamic equation and the corresponding T-S fuzzy feedback controller are discussed. By introducing a double-loop control construction, we adjust its attitude to realize the position control. Then a flocking algorithm is proposed to achieve the flocking of the quad-rotor UAVs. Compared with the flocking algorithm of the mass point model, we dealt with the collision problem of the quad-rotor UAVs. In order to improve the airspace utilization, a more compact configuration called quasi e-lattice is constructed to guarantee the compact flight of the quad-rotor UAVs. Finally, numerical simulations are provided to illustrate the effectiveness of the obtained theoretical results. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  13. How many dissenters does it take to disorder a flock?

    Yllanes, D.; Leoni, M.; Marchetti, M. C.

    2017-10-01

    We consider the effect of introducing a small number of non-aligning agents in a well-formed flock. To this end, we modify a minimal model of active Brownian particles with purely repulsive (excluded volume) forces to introduce an alignment interaction that will be experienced by all the particles except for a small minority of ‘dissenters’. We find that even a very small fraction of dissenters disrupts the flocking state. Strikingly, these motile dissenters are much more effective than an equal number of static obstacles in breaking up the flock. For the studied system sizes we obtain clear evidence of scale invariance at the flocking-disorder transition point and the system can be effectively described with a finite-size scaling formalism. We develop a continuum model for the system which reveals that dissenters act like annealed noise on aligners, with a noise strength that grows with the persistence of the dissenters’ dynamics.

  14. AD HOC TEAMWORK BEHAVIORS FOR INFLUENCING A FLOCK

    Katie Genter

    2016-02-01

    Full Text Available Ad hoc teamwork refers to the challenge of designing agents that can influence the behavior of a team, without prior coordination with its teammates. This paper considers influencing a flock of simple robotic agents to adopt a desired behavior within the context of ad hoc teamwork. Specifically, we examine how the ad hoc agents should behave in order to orient a flock towards a target heading as quickly as possible when given knowledge of, but no direct control over, the behavior of the flock. We introduce three algorithms which the ad hoc agents can use to influence the flock, and we examine the relative importance of coordinating the ad hoc agents versus planning farther ahead when given fixed computational resources. We present detailed experimental results for each of these algorithms, concluding that in this setting, inter-agent coordination and deeper lookahead planning are no more beneficial than short-term lookahead planning.

  15. Risk Factors Associated with Brucella Seropositivity in Sheep and Goats in Duhok Province, Iraq

    Ali. G. Alhamada

    2017-12-01

    Full Text Available Sera from 432 small ruminants (335 sheep and 97 goats from 72 farms in Duhok Province, northern Iraq, were collected to investigate risk factors associated with brucellosis seropositivity. Serum samples were tested using the Rose Bengal test (RBT and an indirect enzyme-linked immunosorbent assay (iELISA. Using parallel interpretation, RBT and iELISA results showed that 31.7% (95% confidence interval (CI: 26.1, 36.3 of sheep and 34.0% (95% CI: 24.7, 44.3 of goats had antibodies against Brucella in the study area. A random-effects multivariable logistic regression model indicated that a higher chance of being seropositive (odds ratio (OR = 1.7; 95% 1.4; 2.2 was associated with an increase in the age of animals. The odds of Brucella seropositivity in flocks where sheep and goats grazed together was 2.0 times higher (95% CI: 1.08; 3.9 compared to flocks where sheep and goats grazed separately. The odds of Brucella seropositivity in small ruminants was 2.2 higher (95% CI: 1.2; 4.3 for animals originating from farms with a history of goat abortion in the preceding 12 months. In contrast, for every 1000 Iraqi Dinars (~0.85 US Dollar spent by the farmers on control of Brucella in their flocks, the odds of Brucella seropositivity decreased significantly (OR = 0.9, p-value = 0.021. The final model also indicated significant differences in Brucella seropositivity between the different districts of Duhok Province. This study provides a contribution to the epidemiology of brucellosis in small ruminants in northern Iraq.

  16. Trypanosoma (megatrypanum) melophagium in the sheep ked, Melophagus ovinus. A scanning electron microscope (SEM) study of the parasites and the insect gut wall surfaces.

    Molyneux, D H; Selkirk, M; Lavin, D

    1978-12-01

    A description of the different stages of Trypanosoma (M.) melophagium in different regions of the gut of the sheep ked (Melophagus ovinus) as observed by the SEM is presented. The extensive pile carpet or palisade colonization of the midgut and pylorus is described. The method of attachment and the relationship of the parasites to the microvilli in the midgut and the cuticle of the pylorus and ileum observed by other methods are confirmed. The micro-structure of the surfaces themselves in the regions of the gut to which parasites attach are described. The use of the technique for the study of other similar systems is discussed.

  17. Factors affecting on longevity in Northern Khorasan Kordish sheep

    razieh saghi

    2016-04-01

    Full Text Available Introduction The longevity is normally defined as the length of its productive life in the flock, which is the amount of time an animal spends producing (1. Longevity reflects the ability of ewe to avoid being culled for low production, low fertility, illness and influences the number and cost of replacements required to maintain the flock size. The benefit of increasing longevity are increased average age of the flock, having more ewes available for sale at the end of their four parity, having more ewe lambs to sell, and higher productivity from a slightly older flock age profile (2. Sheep population of Khorasan province (10. In sheep production, longevity has an important influence on the economic returns. Reliable estimates of non genetic effects of longevity are needed to aid establishing an efficient strategy for improving ewe productivity. Thus, the objective of this study was the factors affecting on longevity in Northern Khorasan Kordish sheep. We want to determine effect of environmental and non-genetic factors on longevity. Material and Methods In order to investigate on factors affecting longevity trait in Northen Khorasan Kordish sheep, records of 7469 sheep (187 sire and 2258 dam between 1990 to 2012 that were collected by breeding station of Hossein Abad in Shirvan (This city is located in the north of Mashhad were used. Flock has been kept under village system. Breeding ewes were identified in the data set as those that lambed at 2 year of age and culled at 6 to 7 year of age duo to oldness. Ram kept until a male offspring was available for replacement. In this study longevity was defined as the age of a ewe (in day when it leaves the flock. Ewes were generally removed from the flock due to poor production, low fertility, death and illness. Ewes were identified as being removed from the flock if a lambing record was present at n year of age but not at n+1 years of age. All females were culled before reaching 7 years of age

  18. Switching hierarchical leadership mechanism in homing flight of pigeon flocks

    Chen, Duxin; Vicsek, Tamás; Liu, Xiaolu; Zhou, Tao; Zhang, Hai-Tao

    2016-06-01

    To explore the fascinating inter-individual interaction mechanism governing the abundant biological grouping behaviors, more and more efforts have been devoted to collective motion investigation in recent years. Therein, bird flocking is one of the most intensively studied behaviors. A previous study (Nagy M. et al., Nature, 464 (2010) 890.) claims the existence of a well-defined hierarchical structure in pigeon flocks, which implies that a multi-layer leadership network leads to the occurrence of highly coordinated pigeon flock movements. However, in this study, by using high-resolution GPS data of homing flight of pigeon flocks, we reveal an explicit switching hierarchical mechanism underlying the group motions of pigeons. That is, a pigeon flock has a long-term leader for smooth moving trajectories, whereas the leading tenure passes to a temporary one upon sudden turns or zigzags. Therefore, the present observation helps explore more deeply into the principle of a huge volume of bird flocking dynamics. Meanwhile, from the engineering point of view, it may shed some light onto industrial multi-robot coordination and unmanned air vehicle formation control.

  19. Outdoor flocking of quadcopter drones with decentralized model predictive control.

    Yuan, Quan; Zhan, Jingyuan; Li, Xiang

    2017-11-01

    In this paper, we present a multi-drone system featured with a decentralized model predictive control (DMPC) flocking algorithm. The drones gather localized information from neighbors and update their velocities using the DMPC flocking algorithm. In the multi-drone system, data packages are transmitted through XBee ® wireless modules in broadcast mode, yielding such an anonymous and decentralized system where all the calculations and controls are completed on an onboard minicomputer of each drone. Each drone is a double-layered agent system with the coordination layer running multi-drone flocking algorithms and the flight control layer navigating the drone, and the final formation of the flock relies on both the communication range and the desired inter-drone distance. We give both numerical simulations and field tests with a flock of five drones, showing that the DMPC flocking algorithm performs well on the presented multi-drone system in both the convergence rate and the ability of tracking a desired path. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Biodiversity of Helminths of Sheep Breed in Vojvodina (Northern Serbia

    Ivan PAVLOVIĆ

    2017-11-01

    Full Text Available Vojvodina is situated in the northern part of Serbia. The region is divided into: Bačka in the northwest, Banat in the east and Srem in the southwest. A small part of the Mačva region is also located in Vojvodina, in the Srem District. Vojvodina is abundant with numerous grasslands suitable for sheep grazing. The present study was conducted in 90 sheep flocks from the territory of Vojvodina in the period of March 2014 to January 2015, using into consideration the biodiversity and sesonal occurance and prevalence of isolated parasites. Fecal samples were examined by using qualitative and quantitative coprological methods. Infection we occurred at 81.22% of sheep. We found eggs of Nematodirus sp. (71.22%, Ostertagia sp. (69.22%, Trichostrongylus sp. (66.55%, Haemonchus sp. (64.44%, Chabertia ovina (60.11%, Dictyocaulus spp. (49.00%, Oesophagostomum sp.(36.77%, Dicrocelium dendriticum (34.66%, Marshallagia sp. (29.66%, Cooperia sp. (27.88%, Moniezia sp. (26.77%, Bunostomum sp. (22.33% and Skrjabinema sp. (13,66%.

  1. Atypical dermatophilosis of sheep in Kenya : clinical communication

    J.K. Wabacha

    2007-06-01

    Full Text Available An outbreak of an atypical form of ovine dermatophilosis affecting the lips and muzzle with a very high morbidity in weaners and hoggets in Kenya is reported. Clinical diagnosis of ovine dermatophilosis was made and confirmed by direct microscopic examination as well as isolation and identification of Dermatophilus congolensis from scab material from the affected sheep. The morbidity rate within the flock was 31.8 % (237 / 745 with 98.3 % (233 / 237 of the affected sheep being weaners and hoggets. No fatalities were recorded. The lesions, confined in the lips and the muzzle, were swelling of both the upper and lower lips, circumscribed lumps in the skin of both the upper and lower lips, oedema of the head and the submandibular area and scabs and crusts on the lips and muzzle. Within 1 week following treatment with long acting oxytetracycline (20 % at a rate of 20 mg/kg body weight, intramuscularly and a topical application of oxytetracycline spray, lumps regressed in size and were covered by dark-brown scabs. Removal of the dark-brown scabs revealed erythematous areas covered with purulent material and horny erythematous projections (papillae projecting from the surfaces. Within the 2nd week, the horny erythematous projections formed greyish scabs, which later peeled off leaving alopaecic areas around the lips. The paper highlights atypical dermatophilosis of sheep and we believe that this is the first published report of an outbreak of ovine dermatophilosis in Kenya.

  2. Identifying influential neighbors in animal flocking.

    Li Jiang

    2017-11-01

    Full Text Available Schools of fish and flocks of birds can move together in synchrony and decide on new directions of movement in a seamless way. This is possible because group members constantly share directional information with their neighbors. Although detecting the directionality of other group members is known to be important to maintain cohesion, it is not clear how many neighbors each individual can simultaneously track and pay attention to, and what the spatial distribution of these influential neighbors is. Here, we address these questions on shoals of Hemigrammus rhodostomus, a species of fish exhibiting strong schooling behavior. We adopt a data-driven analysis technique based on the study of short-term directional correlations to identify which neighbors have the strongest influence over the participation of an individual in a collective U-turn event. We find that fish mainly react to one or two neighbors at a time. Moreover, we find no correlation between the distance rank of a neighbor and its likelihood to be influential. We interpret our results in terms of fish allocating sequential and selective attention to their neighbors.

  3. Identifying influential neighbors in animal flocking.

    Jiang, Li; Giuggioli, Luca; Perna, Andrea; Escobedo, Ramón; Lecheval, Valentin; Sire, Clément; Han, Zhangang; Theraulaz, Guy

    2017-11-01

    Schools of fish and flocks of birds can move together in synchrony and decide on new directions of movement in a seamless way. This is possible because group members constantly share directional information with their neighbors. Although detecting the directionality of other group members is known to be important to maintain cohesion, it is not clear how many neighbors each individual can simultaneously track and pay attention to, and what the spatial distribution of these influential neighbors is. Here, we address these questions on shoals of Hemigrammus rhodostomus, a species of fish exhibiting strong schooling behavior. We adopt a data-driven analysis technique based on the study of short-term directional correlations to identify which neighbors have the strongest influence over the participation of an individual in a collective U-turn event. We find that fish mainly react to one or two neighbors at a time. Moreover, we find no correlation between the distance rank of a neighbor and its likelihood to be influential. We interpret our results in terms of fish allocating sequential and selective attention to their neighbors.

  4. A flocking based method for brain tractography.

    Aranda, Ramon; Rivera, Mariano; Ramirez-Manzanares, Alonso

    2014-04-01

    We propose a new method to estimate axonal fiber pathways from Multiple Intra-Voxel Diffusion Orientations. Our method uses the multiple local orientation information for leading stochastic walks of particles. These stochastic particles are modeled with mass and thus they are subject to gravitational and inertial forces. As result, we obtain smooth, filtered and compact trajectory bundles. This gravitational interaction can be seen as a flocking behavior among particles that promotes better and robust axon fiber estimations because they use collective information to move. However, the stochastic walks may generate paths with low support (outliers), generally associated to incorrect brain connections. In order to eliminate the outlier pathways, we propose a filtering procedure based on principal component analysis and spectral clustering. The performance of the proposal is evaluated on Multiple Intra-Voxel Diffusion Orientations from two realistic numeric diffusion phantoms and a physical diffusion phantom. Additionally, we qualitatively demonstrate the performance on in vivo human brain data. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Clusterflock: a flocking algorithm for isolating congruent phylogenomic datasets.

    Narechania, Apurva; Baker, Richard; DeSalle, Rob; Mathema, Barun; Kolokotronis, Sergios-Orestis; Kreiswirth, Barry; Planet, Paul J

    2016-10-24

    Collective animal behavior, such as the flocking of birds or the shoaling of fish, has inspired a class of algorithms designed to optimize distance-based clusters in various applications, including document analysis and DNA microarrays. In a flocking model, individual agents respond only to their immediate environment and move according to a few simple rules. After several iterations the agents self-organize, and clusters emerge without the need for partitional seeds. In addition to its unsupervised nature, flocking offers several computational advantages, including the potential to reduce the number of required comparisons. In the tool presented here, Clusterflock, we have implemented a flocking algorithm designed to locate groups (flocks) of orthologous gene families (OGFs) that share an evolutionary history. Pairwise distances that measure phylogenetic incongruence between OGFs guide flock formation. We tested this approach on several simulated datasets by varying the number of underlying topologies, the proportion of missing data, and evolutionary rates, and show that in datasets containing high levels of missing data and rate heterogeneity, Clusterflock outperforms other well-established clustering techniques. We also verified its utility on a known, large-scale recombination event in Staphylococcus aureus. By isolating sets of OGFs with divergent phylogenetic signals, we were able to pinpoint the recombined region without forcing a pre-determined number of groupings or defining a pre-determined incongruence threshold. Clusterflock is an open-source tool that can be used to discover horizontally transferred genes, recombined areas of chromosomes, and the phylogenetic 'core' of a genome. Although we used it here in an evolutionary context, it is generalizable to any clustering problem. Users can write extensions to calculate any distance metric on the unit interval, and can use these distances to 'flock' any type of data.

  6. Imported coenurosis in sheep

    Schweizer, G.; Grünenfelder, F.; Sydler, T.; Rademacher, N.; Braun, U.; Deplazes, P.

    2006-01-01

    Thirteen sheep from a milk producing farm in the Canton of Grisons that presented chronic coenurosis were examined and subjected to treatment trials at the veterinary hospital in Zurich. Symptoms were first observed around two months after the import of two dogs from Italy (Abruzza) of which one was infected with Taenia multiceps and Echinococcus granulosus. The most frequently observed clinical symptoms of the sheep were reduced general condition, circling, reduced menace reflex, apathy, unsteady gait and head tilt. Analyses of cerebrospinal fluid revealed an increased leucocyte count in 3 sheep and eosinophilia in 4 sheep. In 4 animals that underwent computertomography, one or more hypodense, definable lesions were found in the brain. In 2 sheep surgical treatment and in 10 animals medical treatment with either Praziquantel (n=8) or Oxfendazol (n=2) was attempted. Only one animal treated with Praziquantel needed not to be euthanized. At necropsy, one or two coenurus cysts could be found either in a side ventricle (n=2), in the cerebellum (n=3) or in the cerebrum (n=7). The locations corresponded with the clinical findings. Despite Praziquantel or Oxfendazol treatment, living protoscoleces could be found in the parasite cysts [de

  7. The use of a Psoroptes ovis serodiagnostic test for the analysis of a natural outbreak of sheep scab

    Burgess Stewart TG

    2012-01-01

    Full Text Available Abstract Background Sheep scab is a highly contagious disease of sheep caused by the ectoparasitic mite Psoroptes ovis. The disease is endemic in the UK and has significant economic impact through its effects on performance and welfare. Diagnosis of sheep scab is achieved through observation of clinical signs e.g. itching, pruritis and wool loss and ultimately through the detection of mites in skin scrapings. Early stages of infestation are often difficult to diagnose and sub-clinical animals can be a major factor in disease spread. The development of a diagnostic assay would enable farmers and veterinarians to detect disease at an early stage, reducing the risk of developing clinical disease and limiting spread. Methods Serum samples were obtained from an outbreak of sheep scab within an experimental flock (n = 480 (3 samples each from 160 sheep allowing the assessment, by ELISA of sheep scab specific antibody prior to infestation, mid-outbreak (combined with clinical assessment and post-treatment. Results Analysis of pre-infestation samples demonstrated low levels of potential false positives (3.8%. Of the 27 animals with clinical or behavioural signs of disease 25 tested positive at the mid-outbreak sampling period, however, the remaining 2 sheep tested positive at the subsequent sampling period. Clinical assessment revealed the absence of clinical or behavioural signs of disease in 132 sheep, whilst analysis of mid-outbreak samples showed that 105 of these clinically negative animals were serologically positive, representing potential sub-clinical infestations. Conclusions This study demonstrates that this ELISA test can effectively diagnose sheep scab in a natural outbreak of disease, and more importantly, highlights its ability to detect sub-clinically infested animals. This ELISA, employing a single recombinant antigen, represents a major step forward in the diagnosis of sheep scab and may prove to be critical in any future control

  8. Presence and species identity of rumen flukes in cattle and sheep in the Netherlands.

    Ploeger, H W; Ankum, L; Moll, L; van Doorn, D C K; Mitchell, G; Skuce, P J; Zadoks, R N; Holzhauer, M

    2017-08-30

    The purpose of the study was to gain knowledge about the prevalence and identity of rumen flukes (RF) in cattle and sheep in the Netherlands. Routine faecal examinations of diagnostic submissions between May 2009 and September 2014 showed a mean annual herd or flock RF prevalence of 15.8% for cattle and 8.0% for sheep. Prevalence in cattle was higher after 2012 than before, which may reflect a change in detection method as well as an increase in true prevalence. During November and December 2014, an abattoir survey was conducted to allow for scoring of rumen fluke burden and to obtain specimens for molecular species characterization. Over 8 visits to 5 abattoirs in areas deemed to pose a high risk for trematode infection, 116 cows and 41 sheep from 27 herds and 10 flocks were examined. Prevalence of RF was higher in beef cattle than in dairy cattle and higher in cattle than in sheep. Median fluke burden was >100 specimens per animal for most positive animals. Using a semi-quantitative RF density score as a gold standard, sensitivity and specificity of a modified quantitative Dorsman egg counting method were estimated at 82.6% and 83.3%, respectively. Of 14 collected adult rumen flukes, twelve (8 bovine and 4 ovine specimens) were identified as Calicophoron daubneyi. The other two, of bovine origin, were identified as Paramphistomum leydeni, which was unexpected as in other European countries all recently collected rumen flukes in both cattle and sheep were identified as C. daubneyi. The findings implicate that multiple rumen fluke species, intermediate host species and transmission cycles may play a role in rumen fluke infections in the Netherlands. Copyright © 2017. Published by Elsevier B.V.

  9. Experimental transmission of atypical scrapie to sheep

    Spiropoulos John

    2007-08-01

    Full Text Available Abstract Background Active surveillance for transmissible spongiform encephalopathies in small ruminants has been an EU regulatory requirement since 2002. A number of European countries have subsequently reported cases of atypical scrapie, similar to previously published cases from Norway, which have pathological and molecular features distinct from classical scrapie. Most cases have occurred singly in flocks, associated with genotypes considered to be more resistant to classical disease. Experimental transmissibility of such isolates has been reported in certain ovinised transgenic mice, but has not previously been reported in the natural host. Information on the transmissibility of this agent is vital to ensuring that disease control measures are effective and proportionate. Results This report presents the successful experimental transmission, in 378 days, of atypical scrapie to a recipient sheep of homologous genotype with preservation of the pathological and molecular characteristics of the donor. This isolate also transmitted to ovinised transgenic mice (Tg338 with a murine phenotype indistinguishable from that of Nor 98. Conclusion This result strengthens the opinion that these cases result from a distinct strain of scrapie agent, which is potentially transmissible in the natural host under field conditions.

  10. Emergence of the scale-invariant proportion in a flock from the metric-topological interaction.

    Niizato, Takayuki; Murakami, Hisashi; Gunji, Yukio-Pegio

    2014-05-01

    Recently, it has become possible to more precisely analyze flocking behavior. Such research has prompted a reconsideration of the notion of neighborhoods in the theoretical model. Flocking based on topological distance is one such result. In a topological flocking model, a bird does not interact with its neighbors on the basis of a fixed-size neighborhood (i.e., on the basis of metric distance), but instead interacts with its nearest seven neighbors. Cavagna et al., moreover, found a new phenomenon in flocks that can be explained by neither metric distance nor topological distance: they found that correlated domains in a flock were larger than the metric and topological distance and that these domains were proportional to the total flock size. However, the role of scale-free correlation is still unclear. In a previous study, we constructed a metric-topological interaction model on three-dimensional spaces and showed that this model exhibited scale-free correlation. In this study, we found that scale-free correlation in a two-dimensional flock was more robust than in a three-dimensional flock for the threshold parameter. Furthermore, we also found a qualitative difference in behavior from using the fluctuation coherence, which we observed on three-dimensional flocking behavior. Our study suggests that two-dimensional flocks try to maintain a balance between the flock size and flock mobility by breaking into several smaller flocks. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Clinicopathological studies on facial eczema outbreak in sheep in Southwest Turkey.

    Ozmen, Ozlem; Sahinduran, Sima; Haligur, Mehmet; Albay, Metin Koray

    2008-10-01

    After very hot summer, 22 sheep from 5 different flocks consisting of approximately 150-200 animals each were diagnosed with facial eczema in September 2005, in southwest Turkey. Photophobia, corneal opacity, severe ulcers of the facial skin, especially localized around the eyes and mouth, and 3% mortality were the most prominent clinical symptoms. GGT levels of the animals were very high and varying between 261- 328 U/l. While the activities of ALT and total bilirubin were elevated and AST was normal in affected sheep. Total bilirubin level was higher than normal. Seven of the 22 sheep were euthanatized and necropsy was performed on all of these animals. Severe icterus, hepatomegaly, enlarged gallbladder, congestion of mesenteric vessels were the common necropsy findings. Histopathological changes of the liver included necrosis of the hepatocytes, cholangiohepatitis characterized by mononuclear inflammatory cell infiltrate in the portal area and mild to severe fibrosis around bile ducts. A diagnosis of sporidesmin toxicosis was made based on the histopathology of the livers, the elevation in liver enzymes, and the development of cutaneous lesions consistent with photosensitization and high spore counts in the ruminal contents. Surviving sheep were treated with procaine penicillin + dihidrostreptomycin sulfate, multivitamin complexes and flunixin meglumine. Additionally, zinc sulphate was also given at a dose of 6 gr per 100 lt drinking water for 28 days. All treated sheep recovered. Pasture spore counts were between 96,300- 267,500 spores/g grass.

  12. Emergent behaviour of a generalized Viscek-type flocking model

    Ha, Seung-Yeal; Jeong, Eunhee; Kang, Moon-Jin

    2010-01-01

    We present a planar agent-based flocking model with a distance-dependent communication weight. We derive a sufficient condition for the asymptotic flocking in terms of the initial spatial and heading-angle diameters and a communication weight. For this, we employ differential inequalities for the spatial and phase diameters together with the Lyapunov functional approach. When the diameter of the agent's initial heading-angles is sufficiently small, we show that the diameter of the heading-angles converges to the average value of the initial heading-angles exponentially fast. As an application of flocking estimates, we also show that the Kuramoto model with a connected communication topology on the regular lattice Z d for identical oscillators exhibits a complete-phase-frequency synchronization, when coupled oscillators are initially distributed on the half circle

  13. Stability of model flocks in turbulent-like flow

    Khurana, Nidhi; Ouellette, Nicholas T

    2013-01-01

    We report numerical simulations of a simple model of flocking particles in the presence of an uncertain background environment. We consider two types of environmental perturbations: random noise applied separately to each particle, and spatiotemporally correlated ‘noise’ provided by a turbulent-like flow field. The effects of these two types of noise are very different; surprisingly, the applied flow field tends to destroy the global order of the flocking model even for vanishingly small flow amplitudes. Local order, however, is preserved in smaller sub-flocks, although their composition changes dynamically. Our results suggest that realistic perturbations must be considered in assessing the stability of models of collective animal behavior, and that random noise is not a sufficient proxy. (paper)

  14. Graphics Processing Unit Enhanced Parallel Document Flocking Clustering

    Cui, Xiaohui [ORNL; Potok, Thomas E [ORNL; ST Charles, Jesse Lee [ORNL

    2010-01-01

    Analyzing and clustering documents is a complex problem. One explored method of solving this problem borrows from nature, imitating the flocking behavior of birds. One limitation of this method of document clustering is its complexity O(n2). As the number of documents grows, it becomes increasingly difficult to generate results in a reasonable amount of time. In the last few years, the graphics processing unit (GPU) has received attention for its ability to solve highly-parallel and semi-parallel problems much faster than the traditional sequential processor. In this paper, we have conducted research to exploit this archi- tecture and apply its strengths to the flocking based document clustering problem. Using the CUDA platform from NVIDIA, we developed a doc- ument flocking implementation to be run on the NVIDIA GEFORCE GPU. Performance gains ranged from thirty-six to nearly sixty times improvement of the GPU over the CPU implementation.

  15. Reduced lentivirus susceptibility in sheep with TMEM154 mutations.

    Heaton, Michael P; Clawson, Michael L; Chitko-Mckown, Carol G; Leymaster, Kreg A; Smith, Timothy P L; Harhay, Gregory P; White, Stephen N; Herrmann-Hoesing, Lynn M; Mousel, Michelle R; Lewis, Gregory S; Kalbfleisch, Theodore S; Keen, James E; Laegreid, William W

    2012-01-01

    Visna/Maedi, or ovine progressive pneumonia (OPP) as it is known in the United States, is an incurable slow-acting disease of sheep caused by persistent lentivirus infection. This disease affects multiple tissues, including those of the respiratory and central nervous systems. Our aim was to identify ovine genetic risk factors for lentivirus infection. Sixty-nine matched pairs of infected cases and uninfected controls were identified among 736 naturally exposed sheep older than five years of age. These pairs were used in a genome-wide association study with 50,614 markers. A single SNP was identified in the ovine transmembrane protein (TMEM154) that exceeded genome-wide significance (unadjusted p-value 3×10(-9)). Sanger sequencing of the ovine TMEM154 coding region identified six missense and two frameshift deletion mutations in the predicted signal peptide and extracellular domain. Two TMEM154 haplotypes encoding glutamate (E) at position 35 were associated with infection while a third haplotype with lysine (K) at position 35 was not. Haplotypes encoding full-length E35 isoforms were analyzed together as genetic risk factors in a multi-breed, matched case-control design, with 61 pairs of 4-year-old ewes. The odds of infection for ewes with one copy of a full-length TMEM154 E35 allele were 28 times greater than the odds for those without (p-valuesheep from Nebraska, Idaho, and Iowa, the relative risk of infection was 2.85 times greater for sheep with a full-length TMEM154 E35 allele (p-valuesheep were homozygous for TMEM154 deletion mutations and remained uninfected despite a lifetime of significant exposure. Together, these findings indicate that TMEM154 may play a central role in ovine lentivirus infection and removing sheep with the most susceptible genotypes may help eradicate OPP and protect flocks from reinfection.

  16. Pythiosis in sheep from Paraná, southern Brazil

    Fábio D. Bernardo

    2015-06-01

    Full Text Available Abstract: This paper reports pythiosis in a sheep from southwestern Paraná, Brazil, confirmed by indirect ELISA (Enzime-Linked Immunosorbent Assay and immunohistochemistry, as well as it describes the macro and microscopic injuries, in order to understand the pathogenicity. A 4-year-old ewe from a flock of 30 Santa Inês sheep, raised semi-extensively with access to a weir, showed cachexia, bilateral enlargement in nasal region, a serous and bloody secretion with a fetid odor from its nose and swollen submandibular and retropharyngeal lymph nodes. Blood collection was performed trough jugular vein puncture in order to make complete blood cell count (CBC and to obtain serum for the subsequent serological examination. As the hematological counts were within the normal range for sheep, the animal was euthanized and submitted to necropsy. Indirect ELISA resulted positive for pythiosis. Necropsy revealed necrosis of the hard palate with a diameter of 3.5cm and extending up to the nasal cavity, forming a fistula. Submandibular and retropharyngeal lymph nodes were enlarged and edematous on section. Microscopic findings for submandibular and retropharyngeal lymph nodes consisted in moderate infiltration of eosinophils mainly in the subcapsular sinus, characterizing reactive eosinophilic lymphadenitis. The nasal cavity revealed rhinitis and oral cavity stomatitis with necro-eosinophilic and pronounced multifocal granulomatous infiltration and presence of hyphae. Hyphae found in palate and nasal cavity were positive for Pythium insidiosum by Grocott's method and immunohistochemistry, the last one considered to be confirmatory for the pathogen diagnostic. This report has an important epidemiological aspect, as it is the first case of pythiosis in sheep confirmed by serology in South Brazil and an alert of possible infection by the pathogen in floodplains.

  17. Prevalence and antimicrobial susceptibility of thermophilic Campylobacter in organic and conventional broiler flocks

    Heuer, Ole Eske; Pedersen, Karl; Andersen, J.S.

    2001-01-01

    Aims: To determine the flock prevalence and to estimate the within flock prevalence of Campylobacter in broiler flocks from different rearing systems, and to determine the antimicrobial susceptibility of Campylobacter isolates to selected antimicrobial substances. Methods and Results: One hundred...... and sixty broiler flocks originating from organic, conventional and extensive indoor production farms were investigated for the presence of Campylobacter at the time of slaughter. Campylobacter isolates from a subsample of positive flocks were subjected to susceptibility testing. Campylobacter spp. were...... isolated from 100% of organic broiler flocks, from 36.7% of conventional broiler flocks and from 49.2% of extensive indoor broiler flocks. Six of 62 Campylobacter isolates were resistant to one or more of the antimicrobials tested. Conclusions: These results indicate that the special characteristics...

  18. Composition and foraging behaviour of mixed-species flocks in two ...

    Enlarged flock size resulted from a general increase in flocking tendency of all species. At the species level, the Long-billed Crombec Sylvietta rufescens and the Chinspot Batis Batis molitor showed clear feeding benefits within flocks, whereas tits obtained no feeding benefit. Crombecs and batises also changed foraging ...

  19. An Outbreak of Sheep Pox in Zabajkalskij kray of Russia.

    Maksyutov, R A; Gavrilova, E V; Agafonov, A P; Taranov, O S; Glotov, A G; Miheev, V N; Shchelkunov, S N; Sergeev, A N

    2015-08-01

    In this study, we investigated recent sheep pox outbreaks that occurred in Ononsky and Borzunsky regions of Zabajkalskij kray of Russia. The outbreaks involved in 2756 animals of which 112 were infected and 3 were slaughtered. Samples of injured skin of infected sheep were analysed by electron microscopy and CaPV-specific P32 gene amplification. Following sequence analysis of entire P32 gene showed that both specimens were identical to the sequence of several sheep poxvirus isolates from China and India. The close location of China to the last decade's Russian outbreaks suggest that possible future outbreaks in Russia could occur along the border regions with countries where sheep and goat pox are not controlled. © 2013 Blackwell Verlag GmbH.

  20. Beam radiation curing of adhesives for flocking on heat-sensitive substrates

    Nablo, S.V.; Fussa, A.D.

    1979-01-01

    A process is described for curing the adhesive used to hold flock fiber material to a heat-sensitive substrate consisting of temperature-sensitive plastic, natural fibers, wood, paper, or paper-foil laminates. An electron-curable adhesive layer (acrylic, epoxy, epoxy esters, acrylic latex, or urethane) a few mils thick is applied to the substrate and a layer of texturing material is attached to the adhesive layer with fibers substantially perpendicular to the layer. The assembly of substrate and adhesively secured material is passed at a rate of about 20 to 80 meters per minute under an unscanned electron curtain beam which possesses an energy of 150 keV +- 30 percent and delivers an electron dose of 2 megarads +- 50 percent to the adhesive layer. (LL)

  1. Invited review: Current production trends, farm structures, and economics of the dairy sheep and goat sectors.

    Pulina, G; Milán, M J; Lavín, M P; Theodoridis, A; Morin, E; Capote, J; Thomas, D L; Francesconi, A H D; Caja, G

    2018-05-30

    Dairy small ruminants account for approximately 21% of all sheep and goats in the world, produce around 3.5% of the world's milk, and are mainly located in subtropical-temperate areas of Asia, Europe, and Africa. Dairy sheep are concentrated around the Mediterranean and Black Sea regions, where their dairy products are typical ingredients of the human diet. Dairy goats are concentrated in low-income, food-deficit countries of the Indian subcontinent, where their products are a key food source, but are also present in high-income, technologically developed countries. This review evaluates the status of the dairy sheep and goat sectors in the world, with special focus on the commercially and technically developed industries in France, Greece, Italy, and Spain (FGIS). Dairy small ruminants account for a minor part of the total agricultural output in France, Italy, and Spain (0.9 to 1.8%) and a larger part in Greece (8.8%). In FGIS, the dairy sheep industry is based on local breeds and crossbreeds raised under semi-intensive and intensive systems and is concentrated in a few regions in these countries. Average flock size varies from small to medium (140 to 333 ewes/farm), and milk yield from low to medium (85 to 216 L/ewe), showing substantial room for improvement. Most sheep milk is sold to industries and processed into traditional cheese types, many of which are Protected Denomination of Origin (PDO) cheeses for gourmet and export markets (e.g., Pecorino, Manchego, and Roquefort). By comparing break-even milk price among FGIS countries, we observed the following: (1) most Greek and French dairy sheep farms were unprofitable, with the exception of the intensive Chios farms of Greece; (2) milk price was aligned with cost of production in Italy; and (3) profitable farms coexisted with unprofitable farms in Spain. In FGIS, dairy goat production is based on local breeds raised under more extensive systems than sheep. Compared with sheep, average dairy goat herds are

  2. Genetic Testing for TMEM154 Mutations Associated with Lentivirus Susceptibility in Sheep

    Petrik, Dustin T.; Simpson, Barry; Kijas, James W.; Clawson, Michael L.; Chitko-McKown, Carol G.; Harhay, Gregory P.; Leymaster, Kreg A.

    2013-01-01

    In sheep, small ruminant lentiviruses cause an incurable, progressive, lymphoproliferative disease that affects millions of animals worldwide. Known as ovine progressive pneumonia virus (OPPV) in the U.S., and Visna/Maedi virus (VMV) elsewhere, these viruses reduce an animal’s health, productivity, and lifespan. Genetic variation in the ovine transmembrane protein 154 gene (TMEM154) has been previously associated with OPPV infection in U.S. sheep. Sheep with the ancestral TMEM154 haplotype encoding glutamate (E) at position 35, and either form of an N70I variant, were highly-susceptible compared to sheep homozygous for the K35 missense mutation. Our current overall aim was to characterize TMEM154 in sheep from around the world to develop an efficient genetic test for reduced susceptibility. The average frequency of TMEM154 E35 among 74 breeds was 0.51 and indicated that highly-susceptible alleles were present in most breeds around the world. Analysis of whole genome sequences from an international panel of 75 sheep revealed more than 1,300 previously unreported polymorphisms in a 62 kb region containing TMEM154 and confirmed that the most susceptible haplotypes were distributed worldwide. Novel missense mutations were discovered in the signal peptide (A13V) and the extracellular domains (E31Q, I74F, and I102T) of TMEM154. A matrix-assisted laser desorption/ionization–time-of flight mass spectrometry (MALDI-TOF MS) assay was developed to detect these and six previously reported missense and two deletion mutations in TMEM154. In blinded trials, the call rate for the eight most common coding polymorphisms was 99.4% for 499 sheep tested and 96.0% of the animals were assigned paired TMEM154 haplotypes (i.e., diplotypes). The widespread distribution of highly-susceptible TMEM154 alleles suggests that genetic testing and selection may improve the health and productivity of infected flocks. PMID:23408992

  3. Genetic testing for TMEM154 mutations associated with lentivirus susceptibility in sheep.

    Michael P Heaton

    Full Text Available In sheep, small ruminant lentiviruses cause an incurable, progressive, lymphoproliferative disease that affects millions of animals worldwide. Known as ovine progressive pneumonia virus (OPPV in the U.S., and Visna/Maedi virus (VMV elsewhere, these viruses reduce an animal's health, productivity, and lifespan. Genetic variation in the ovine transmembrane protein 154 gene (TMEM154 has been previously associated with OPPV infection in U.S. sheep. Sheep with the ancestral TMEM154 haplotype encoding glutamate (E at position 35, and either form of an N70I variant, were highly-susceptible compared to sheep homozygous for the K35 missense mutation. Our current overall aim was to characterize TMEM154 in sheep from around the world to develop an efficient genetic test for reduced susceptibility. The average frequency of TMEM154 E35 among 74 breeds was 0.51 and indicated that highly-susceptible alleles were present in most breeds around the world. Analysis of whole genome sequences from an international panel of 75 sheep revealed more than 1,300 previously unreported polymorphisms in a 62 kb region containing TMEM154 and confirmed that the most susceptible haplotypes were distributed worldwide. Novel missense mutations were discovered in the signal peptide (A13V and the extracellular domains (E31Q, I74F, and I102T of TMEM154. A matrix-assisted laser desorption/ionization-time-of flight mass spectrometry (MALDI-TOF MS assay was developed to detect these and six previously reported missense and two deletion mutations in TMEM154. In blinded trials, the call rate for the eight most common coding polymorphisms was 99.4% for 499 sheep tested and 96.0% of the animals were assigned paired TMEM154 haplotypes (i.e., diplotypes. The widespread distribution of highly-susceptible TMEM154 alleles suggests that genetic testing and selection may improve the health and productivity of infected flocks.

  4. Detection of antibodies against pestivirus in sheep with history of reproductive disorder in the State of São Paulo

    Natália Carrillo Gaeta

    2016-06-01

    Full Text Available ABSTRACT. Gaeta N.C., Rizzo H., Meira Jr E.B.S., Pituco E.M., Okuda L.H., Ribeiro C.P. & Gregory L. [Detection of antibodies against pestivirus in sheep with history of reproductive disorder in the State of São Paulo.] Detecção de anticorpos anti-pestivírus em ovinos com histórico de problema reprodutivo no Estado de São Paulo. Revista Brasileira de Medicina Veterinária, 38(2:153-156, 2016. Departamento de Clínica Médica. Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo, SP 05508-270, Brasil. E-mail: natalia.gaeta@hotmail.com Pestivirus are responsible for reproductive disorders in sheep and, although they are widely studied in other countries, Brazil lacks information on the prevalence of virus in sheep flocks. To investigate the occurrence of pestiviruses in the State of São Paulo, 268 samples of serum sheep with a history of reproductive problems from 28 properties were collected. Using virusneutralization as the diagnostic technique, it was found two (1% positive animals, with antibody titer of 20, with both females showing a history of reproductive problems, one with neonatal death and another, showing uterine secretion. Two properties studied showed reactive animals (7%. In five of these (18%, bovine co-creation was observed. There were no associations between any reagent animals and the risk factors studied. This work is one of the pioneers in the study of the prevalence of anti-pestivirus antibodies in Brazilian sheep flocks. The low frequency and low viral titer observed suggest that pestivirus are not an important agent related to the presence of reproductive disorders in sheep herds.

  5. Reduced lentivirus susceptibility in sheep with TMEM154 mutations.

    Michael P Heaton

    2012-01-01

    Full Text Available Visna/Maedi, or ovine progressive pneumonia (OPP as it is known in the United States, is an incurable slow-acting disease of sheep caused by persistent lentivirus infection. This disease affects multiple tissues, including those of the respiratory and central nervous systems. Our aim was to identify ovine genetic risk factors for lentivirus infection. Sixty-nine matched pairs of infected cases and uninfected controls were identified among 736 naturally exposed sheep older than five years of age. These pairs were used in a genome-wide association study with 50,614 markers. A single SNP was identified in the ovine transmembrane protein (TMEM154 that exceeded genome-wide significance (unadjusted p-value 3×10(-9. Sanger sequencing of the ovine TMEM154 coding region identified six missense and two frameshift deletion mutations in the predicted signal peptide and extracellular domain. Two TMEM154 haplotypes encoding glutamate (E at position 35 were associated with infection while a third haplotype with lysine (K at position 35 was not. Haplotypes encoding full-length E35 isoforms were analyzed together as genetic risk factors in a multi-breed, matched case-control design, with 61 pairs of 4-year-old ewes. The odds of infection for ewes with one copy of a full-length TMEM154 E35 allele were 28 times greater than the odds for those without (p-value<0.0001, 95% CI 5-1,100. In a combined analysis of nine cohorts with 2,705 sheep from Nebraska, Idaho, and Iowa, the relative risk of infection was 2.85 times greater for sheep with a full-length TMEM154 E35 allele (p-value<0.0001, 95% CI 2.36-3.43. Although rare, some sheep were homozygous for TMEM154 deletion mutations and remained uninfected despite a lifetime of significant exposure. Together, these findings indicate that TMEM154 may play a central role in ovine lentivirus infection and removing sheep with the most susceptible genotypes may help eradicate OPP and protect flocks from reinfection.

  6. The performance of probiotic fermented sheep milk and ice cream sheep milk in inhibiting enamel mineral loss.

    Nadelman, P; Frazão, J V; Vieira, T I; Balthazar, C F; Andrade, M M; Alexandria, A K; Cruz, A G; Fonseca-Gonçalves, A; Maia, L C

    2017-07-01

    The study aimed to evaluate the effects of two different sheep milk-based food matrices - fermented sheep milk and ice cream - with added probiotic bacteria (Lactobacillus casei 431) on dental enamel subjected to an in vitro highly cariogenic challenge. Sixty enamel blocks were selected and randomly allocated into five treatment groups (n=12): conventional fermented sheep milk (CFSM), probiotic fermented sheep milk (PFSM), conventional sheep milk ice cream (CSMIC), probiotic sheep milk ice cream (PSMIC) and control using deionized water. The blocks were subjected to highly cariogenic pH cycling and the products were applied (5min), in a blinded way, once a day to simulate a daily use for 8 consecutive days. A microhardness test was performed before and after the treatment to estimate the percentage of microhardness surface loss (% SML). Scanning electronic microscopy (SEM) was performed to confirm the mineral loss. All groups had lost microhardness after the experiment. However, CFSM and PFSM exhibited the most positive findings when compared to the control in both ice creams. Scanning electron microscopy showed less mineral loss in CFSM and PFSM compared with CSMIC, PSMIC and control after the cariogenic challenge. Overall, fermented milk decreased mineral loss from enamel subjected to a highly cariogenic challenge, regardless of the presence of probiotics in their composition, which had a higher efficacy compared to ice cream. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Modeling the flocking propensity of passerine birds in two Neotropical habitats.

    Pomara, Lars Y; Cooper, Robert J; Petit, Lisa J

    2007-08-01

    We examined the importance of mixed-species flock abundance, individual bird home range size, foraging height, and foraging patch characteristics in predicting the propensity for five Neotropical passerine bird species (Slaty Antwren, Myrmotherula schisticolor; Golden-crowned Warbler, Basileuterus culicivorus; Slate-throated Redstart, Myioborus miniatus; Wilson's Warbler, Wilsonia pusilla; and Black-and-white Warbler, Mniotilta varia) to forage within flocks, rather than solitarily. We used study plots in primary mid-elevation forest and in shade coffee fields in western Panama. We expected that all species would spend as much time as possible flocking, but that the social and environmental factors listed above would limit compatibility between flock movements and individual bird movements, explaining variability in flocking propensity both within and among species. Flocking propensity was well predicted by home range size and flock abundance together, for four of the five species. While flock abundance was uniform across plots, home range sizes varied among species and plots, so that home range size appeared to be the principle factor limiting flocking propensity. Estimates of flock abundance were still required, however, for calculating flocking propensity values. Foraging height and patch characteristics slightly improved predictive ability for the remaining species, M. miniatus. In general, individual birds tended to join flocks whenever one was available inside their home range, regardless of a flock's specific location within the home range. Flocking propensities of individual species were lower in shade coffee fields than in forests, and probably vary across landscapes with variations in habitat. This variability affects the stability and species composition of flocks, and may affect survival rates of individual species.

  8. Tracers as invisible evidence - The transfer and persistence of flock fibres during a car exchange.

    Slot, Ana; van der Weerd, Jaap; Roos, Martin; Baiker, Martin; Stoel, Reinoud D; Zuidberg, Matthijs C

    2017-06-01

    This study assessed the recovery of flock fibres used as a tracer in a car exchange scenario. Flock fibres were deposited onto a car seat (or model thereof) and their transfer and persistence was investigated after a real or simulated car exchange. The overall aim of this study was to achieve an optimal use of flock fibres as tracers, i.e. to be able to select a fit-for-purpose flock fibre, to be able to predict the amount of flock fibres to be recovered from crime related items, and to be able to use these numbers to exclude accidental uptake. The effect of a number of variables on the transfer and persistence of flock fibres was studied, including flock fibre length, car upholstery, and trousers material. Laboratory based experiments were undertaken first, followed by realistic field based experiments. The flock fibres were captured in a non-destructive manner through fluorescence photography. A Matlab algorithm enabled fast automated counting of flock fibres on the images. Results indicate that an initial rapid loss of flock fibres from garments may be expected as a result of moderate movement. Although the amount of flock fibres to be recovered is affected by the flock fibre length, the type of car upholstery, and the type of trousers materials (if frictional force is taken into consideration), large numbers of flock fibres have been recovered from all target materials throughout the transfer route. These numbers are higher than the amount of flock fibres recovered due to accidental uptake. In conclusion, flock fibres can serve as invisible evidence to reconstruct a series of events. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Speed Determines Leadership and Leadership Determines Learning during Pigeon Flocking.

    Pettit, Benjamin; Ákos, Zsuzsa; Vicsek, Tamás; Biro, Dora

    2015-12-07

    A key question in collective behavior is how individual differences structure animal groups, affect the flow of information, and give some group members greater weight in decisions. Depending on what factors contribute to leadership, despotic decisions could either improve decision accuracy or interfere with swarm intelligence. The mechanisms behind leadership are therefore important for understanding its functional significance. In this study, we compared pigeons' relative influence over flock direction to their solo flight characteristics. A pigeon's degree of leadership was predicted by its ground speeds from earlier solo flights, but not by the straightness of its previous solo route. By testing the birds individually after a series of flock flights, we found that leaders had learned straighter homing routes than followers, as we would expect if followers attended less to the landscape and more to conspecifics. We repeated the experiment from three homing sites using multiple independent flocks and found individual consistency in leadership and speed. Our results suggest that the leadership hierarchies observed in previous studies could arise from differences in the birds' typical speeds. Rather than reflecting social preferences that optimize group decisions, leadership may be an inevitable consequence of heterogeneous flight characteristics within self-organized flocks. We also found that leaders learn faster and become better navigators, even if leadership is not initially due to navigational ability. The roles that individuals fall into during collective motion might therefore have far-reaching effects on how they learn about the environment and use social information. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Production parameters for a commercial Dorper flock on extensive ...

    tion on initial records at 2 or 3 years suggested that selection in the current flock should be directed against barrenness or failure to rear at least one ... numbers in South Africa, while breeding stock have also been exported to other ..... tages over birth type as a selection criterion for increased. Table 3 Least squares means ...

  11. Maintaining genetic stability in a control flock of South African ...

    means of whole progeny and replacement groups for the measured characters ... The whole problem of the estimation of genetic change was ... that a genetic control flock is a segregating population in which ... 5,5 years, were divided into five equal groups by stratified ..... A note on tests of significance and optimal ex-.

  12. Evaluation of Copper Supplementation to Control Haemonchus contortus Infections of Sheep in Sweden

    Rydzik A

    2004-09-01

    Full Text Available A pen study was conducted to assess the effect of providing daily copper mineral supplement, or copper wire particle (COWP capsules, on established or incoming mixed nematode infections in young sheep. For lambs with established (6 week old infections, COWP resulted in 97% and 56% reduction of the adult and early L4 stages of H. contortus, respectively, compared with controls (p Teladorsagia circumcincta infections in the COWP lambs compared with controls (p H. contortus infections, but lack of parasites during the grazing season prevented an adequate assessment from being made. These results indicate that there is little, if any, benefit from a parasite control standpoint in recommending copper therapy, specifically to control parasites in Swedish sheep flocks.

  13. Constraints to Hamari sheep farming under range conditions in Darfur and Kordofan Regions of Western Sudan.

    Tirab, Ahmed Berima; Chimonyo, Michael

    2016-08-01

    The study was conducted to identify the major production constraints of Hamari sheep in Darfur and Kordofan Regions of Western Sudan. A structured questionnaire was administered to 128 farmers in Darfur and Kordofan. Feed shortages, prevalence of diseases and parasites, and predation were more severe in Darfur than Kordofan (P Darfur Region (P Darfur region ranked diseases, parasites and predation higher than those practising semi-nomadic and sedentary system in Kordofan region (P Darfur Region than those practising semi-nomadic system in Kordofan Region (P < 0.05). It can be concluded that the severity of challenges facing Hamari sheep producers vary with flock size, region and production system used.

  14. Fatal pneumonia of bighorn sheep following association with domestic sheep.

    Foreyt, W J; Jessup, D A

    1982-04-01

    During 1979-1980 acute fibrinopurulent bronchopneumonia resulted in high mortality or total loss of herds of bighorn sheep (Ovis canadensis) in California and Washington. Contact with domestic sheep occurred shortly before the onset of disease in each case. Circumstantial evidence indicated that the apparently healthy domestic sheep transmitted pathogenic bacteria to the bighorns, resulting in mortality. Pasteurella multocida and Corynebacterium pyogenes were isolated from pulmonary tissue of dead bighorns. The presence of domestic sheep may have been an important stress which initiated or compounded the disease.

  15. Impact of Mycobacterium avium subspecies paratuberculosis on profit efficiency in semi-extensive dairy sheep and goat farms of Apulia, southern Italy.

    Sardaro, Ruggiero; Pieragostini, Elisa; Rubino, Giuseppe; Petazzi, Ferruccio

    2017-01-01

    A recent study on paratubercolosis in semi-extensive dairy sheep and goat farms in Apulia revealed a flock positivity of 60.5% and a seroprevalence of 3.0% for sheep and 14.5% for goat, with peaks of 50%. In such a context, providing detailed economic information is crucial for the implementation of a suitable control plan. In this paper we investigated the impact of Mycobacterium avium subspecies paratuberculosis (MAP) on profit efficiency of the Apulian dairy sheep and goat farms. Empirical results through a stochastic frontier model showed that the uninfected farms had a mean level of profit efficiency of 84%, which dropped to 64% in the presence of paratubercolosis as it negatively affected the productivity of feeding, veterinary and labour factors. Structural, managerial and production aspects were involved in the greater inefficiency of the infected farms compared to the uninfected ones: lower experience and schooling of farmers, no access to credit, fewer family members (women in particular) participating in the farming activities, high density of animals per hectare, small flocks, high number of goats in mixed flocks, no confinement practices for young and purchased animals and no pasture rotation. Hence, targeted interventions on these factors by decision makers can ensure effectiveness and efficiency to veterinary and economic action plans. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Organic Turkey Flocks: A Reservoir of Streptococcus gallolyticus subspecies gallolyticus.

    Jochen Schulz

    Full Text Available Streptococcus gallolyticus subspecies gallolyticus (S. gallolyticus can colonise the gastrointestinal tract of humans and animals and is known to cause similar infections in both humans and animals. Data about the spread or prevalence in farm animals are missing. In this study, Trypton Soya Agar was modified to a selective medium enabling the isolation and quantification of S. gallolyticus from faecal samples. The bacterium was observed in 82 out of 91 faecal samples obtained from 18 different organic turkey flocks. The prevalence of shedding birds was estimated by the number of positive fresh droppings and reached up to 100% on most farms. Furthermore, for the first time S. gallolyticus was quantified in faeces from poultry flocks. The median of colony forming units (CFU per gramme faeces was 3.6 x 10(5 CFU/g. Typing of one isolate from each positive faecal sample by multilocus sequence typing delivered 24 sequence types (STs. Most of the isolates belonged to the clonal complex CC58. The same STs of this complex were detected in up to six different flocks. Partly, these flocks were located in various regions and stocked with varying breeding lines. Regarding the biochemical profiles of the same STs from different farms, the results did not contradict a spread of specific STs in the organic turkey production. Moreover, checking the pubMLST database revealed that STs found in this study were also found in other animal species and in humans. The high detection rate and the number of S. gallolyticus in turkey faeces indicate that this bacterium probably belongs to the common microbiota of the gastrointestinal tract of turkeys from organic flocks. Furthermore, the findings of this study support the suggestion of a possible interspecies transmission.

  17. Cyclic and Coherent States in Flocks with Topological Distance

    Bhattacherjee, Biplab; Bhattacharya, Kunal; Manna, Subhrangshu

    2014-01-01

    A simple model of the two dimensional collective motion of a group of mobile agents have been studied. Like birds, these agents travel in open free space where each of them interacts with the first n neighbors determined by the topological distance with a free boundary condition. Using the same prescription for interactions used in the Vicsek model with scalar noise it has been observed that the flock, in absence of the noise, arrives at a number of interesting stationary states. One of the two most prominent states is the `single sink state' where the entire flock travels along the same direction maintaining perfect cohesion and coherence. The other state is the `cyclic state' where every individual agent executes a uniform circular motion, and the correlation among the agents guarantees that the entire flock executes a pulsating dynamics i.e., expands and contracts periodically between a minimum and a maximum size of the flock. We have studied another limiting situation when refreshing rate of the interaction zone is the fastest. In this case the entire flock gets fragmented into smaller clusters of different sizes. On introduction of scalar noise a crossover is observed when the agents cross over from a ballistic motion to a diffusive motion. Expectedly the crossover time is dependent on the strength of the noise η and diverges as η → 0. An even more simpler version of this model has been studied by suppressing the translational degrees of freedom of the agents but retaining their angular motion. Here agents are the spins, placed at the sites of a square lattice with periodic boundary condition. Every spin interacts with its n = 2, 3 or 4 nearest neighbors. In the stationary state the entire spin pattern moves as a whole when interactions are anisotropic with n = 2 and 3; but it is completely frozen when the interaction is isotropic with n=4$. These spin configu

  18. Cyclic and Coherent States in Flocks with Topological Distance

    Biplab eBhattacherjee

    2014-01-01

    Full Text Available A simple model of the two dimensional collective motion of a group of mobile agents have been studied. Like birds, these agents travel in open free space where each of them interacts with the first $n$ neighbors determined by the topological distance with a free boundary condition. Using the same prescription for interactions used in the Vicsek model with scalar noise it has been observed that the flock, in absence of the noise, arrives at a number of interesting stationary states. One of the two most prominent states is the `single sink state' where the entire flock travels along the same direction maintaining perfect cohesion and coherence. The other state is the `cyclic state' where every individual agent executes a uniform circular motion, and the correlation among the agents guarantees that the entire flock executes a pulsating dynamics i.e., expands and contracts periodically between a minimum and a maximum size of the flock. We have studied another limiting situation when refreshing rate of the interaction zone is the fastest. In this case the entire flock gets fragmented into smaller clusters of different sizes. On introduction of scalar noise a crossover is observed when the agents cross over from a ballistic motion to a diffusive motion. Expectedly the crossover time is dependent on the strength of the noise $eta$ and diverges as $eta to 0$. An even more simpler version of this model has been studied by suppressing the translational degrees of freedom of the agents but retaining their angular motion. Here agents are the spins, placed at the sites of a square lattice with periodic boundary condition. Every spin interacts with its $n$ = 2, 3 or 4 nearest neighbors. In the stationary state the entire spin pattern moves as a whole when interactions are anisotropic with $n$ = 2 and 3; but it is completely frozen when the interaction is isotropic with $n=4$. These spin configu

  19. Lighting during grow-out and Salmonella in broiler flocks

    Bailey Richard H

    2010-06-01

    Full Text Available Abstract Background Lighting is used during conventional broiler grow-out to modify bird behaviour to reach the goals of production and improve bird welfare. The protocols for lighting intensity vary. In a field study, we evaluated if the lighting practices impact the burden of Salmonella in broiler flocks. Methods Conventional grow-out flocks reared in the states of Alabama, Mississippi and Texas, USA in 2003 to 2006 were sampled 1 week before harvest (n = 58 and upon arrival for processing (n = 56 by collecting feathered carcass rinsate, crop and one cecum from each of 30 birds, and during processing by collecting rinsate of 30 carcasses at pre-chilling (n = 56 and post-chilling points (n = 54. Litter samples and drag swabs of litter were collected from the grow-out houses after bird harvest (n = 56. Lighting practices for these flocks were obtained with a questionnaire completed by the growers. Associations between the lighting practices and the burden of Salmonella in the flocks were tested while accounting for variation between the grow-out farms, their production complexes and companies. Results Longer relative duration of reduced lights during the grow-out period was associated with reduced detection of Salmonella on the exterior of birds 1 week before harvest and on the broiler carcasses at the post-chilling point of processing. In addition, starting reduced lights for ≥18 hours per day later in the grow-out period was associated with decreased detection of Salmonella on the exterior of broilers arriving for processing and in the post-harvest drag swabs of litter from the grow-out house. Conclusions The results of this field study show that lighting practices implemented during broiler rearing can impact the burden of Salmonella in the flock. The underlying mechanisms are likely to be interactive.

  20. SHEEP TEMPORAL BONE

    Kesavan

    2016-03-01

    Full Text Available INTRODUCTION Human temporal bones are difficult to procure now a days due to various ethical issues. Sheep temporal bone is a good alternative due to morphological similarities, easy to procure and less cost. Many middle ear exercises can be done easily and handling of instruments is done in the procedures like myringoplasty, tympanoplasty, stapedotomy, facial nerve dissection and some middle ear implants. This is useful for resident training programme.

  1. Composition of Mix Species Foraging Flocks of Birds in Riverstan of Montane Region, Sri Lanka

    W.G.D.D.M. Shermila

    2013-04-01

    Full Text Available Montane zone mixed-species bird flock system is distinct from that of low-land wet zone of SriLanka, although some species are present in both systems. The present study identified the mixed speciesflocks of birds in Riverstan at Knuckles Region, Sri Lanka. Monthly transect counts and opportunisticobservations were made between January and May, 2012. A total of 78 flocks and 27 bird species wereencountered at Riverstan during the study period. The flock size varied between 2 to 13 species and 4 to58 individuals. The mean number of species per flock was 6.03 ± 2.25 and the mean number ofindividuals in a flock was 18.41±9.87. The flock size was positively correlated with the number of speciespresent (r = 0.756, P <0.05. Grey-headed Canary Flycatcher was the most abundant species (mean2.68±1.02 birds per flocks while Sri Lanka White-eye was the most frequent species (mean 5.69±3.92birds per flocks. Grey-headed Canary Flycatcher and Sri Lanka Scimitar-babbler were the nuclear speciesin Riverstan. The leading species were Sri Lanka white-eye and Sri Lanka Yellow-eared Bulbul. Differentbird species used different heights within flocks.Keywords: Mixed-species flock, Nuclear species, Abundance, Foraging flocks

  2. Gaucher disease in sheep.

    Karageorgos, Litsa; Lancaster, Malcolm J; Nimmo, Judith S; Hopwood, John J

    2011-02-01

    Gaucher disease, an autosomal recessive lysosomal storage disorder caused by mutations in the β-glucocerebrosidase gene, was recently discovered in sheep on a "Southdown" sheep stud in Victoria, Australia. Clinical signs include neuropathy, thickened leathery skin, and ichthyosis, with lambs unable to stand from birth. Affected lambs were found to be deficient in glucocerebrosidase activity, and mutational analysis found them to be homozygous for the missense mutations c.1142G>A (p.C381Y) and c.1400C>T (p.P467L). In addition, four silent mutations were detected (c.777C>A [p.Y259Y], c1203A>G [p.Q401Q], c.1335T>C [p.I445I], c.1464C>G [p.L488L]). The human equivalent [C342Y] to the C381Y mutation leads to an acute neuronopathic phenotype in patients. Identification of an acute neuronopathic form of Gaucher disease in sheep provides a large animal model that will enable studies of pathology and evaluation of therapies to treat this common lysosomal storage disorder.

  3. Monitoring the on-farm welfare of sheep and goats

    Agostino Sevi

    2010-01-01

    Full Text Available Schemes for on-farm welfare assessment in sheep and goats are not yet available. Factors responsible for this lack of availability are discussed in the first part of this review. Requisites for reliable methods of welfare assessment to be used in sheep and goat farms are discussed, taking into account the peculiarities of the small ruminant production systems in terms of flock management and farm location. Some housing parameters related to structures, design and micro-environment are reviewed and could be included in schemes of welfare assessment on farm. Human-animal interaction, health status of the animals in terms of body condition scoring, skin and hair conditions, lameness and injuries, and management practices in relation to cleanliness, animal handling and moving, milking procedures and abnormal behaviours, are proposed as potential animal-based indicators. When available, validity, reliability and feasibility of the proposed parameters are discussed. The voluntary adhesion to welfare standards in Sardinia and the application of a scientifically validated protocol in Basilicata are reported as examples of practical experiences.

  4. Semi-flocking algorithm for motion control of mobile sensors in large-scale surveillance systems.

    Semnani, Samaneh Hosseini; Basir, Otman A

    2015-01-01

    The ability of sensors to self-organize is an important asset in surveillance sensor networks. Self-organize implies self-control at the sensor level and coordination at the network level. Biologically inspired approaches have recently gained significant attention as a tool to address the issue of sensor control and coordination in sensor networks. These approaches are exemplified by the two well-known algorithms, namely, the Flocking algorithm and the Anti-Flocking algorithm. Generally speaking, although these two biologically inspired algorithms have demonstrated promising performance, they expose deficiencies when it comes to their ability to maintain simultaneous robust dynamic area coverage and target coverage. These two coverage performance objectives are inherently conflicting. This paper presents Semi-Flocking, a biologically inspired algorithm that benefits from key characteristics of both the Flocking and Anti-Flocking algorithms. The Semi-Flocking algorithm approaches the problem by assigning a small flock of sensors to each target, while at the same time leaving some sensors free to explore the environment. This allows the algorithm to strike balance between robust area coverage and target coverage. Such balance is facilitated via flock-sensor coordination. The performance of the proposed Semi-Flocking algorithm is examined and compared with other two flocking-based algorithms once using randomly moving targets and once using a standard walking pedestrian dataset. The results of both experiments show that the Semi-Flocking algorithm outperforms both the Flocking algorithm and the Anti-Flocking algorithm with respect to the area of coverage and the target coverage objectives. Furthermore, the results show that the proposed algorithm demonstrates shorter target detection time and fewer undetected targets than the other two flocking-based algorithms.

  5. Factors affecting reproduction in Merino ewes of the Tygerhoek flock

    ouderdomsgroepe ... paarmassa teen 'n skerper helling toe te neem as by enkelinge. S.-Afr. Tydskr. Veek. 1986, 16: 36 - 42. Keywords: ..... growth and reproductive performance in young sheep given differential nutrition from 9 to 18 months of age.

  6. Fatal Pasteurella haemolytica pneumonia in bighorn sheep after direct contact with clinically normal domestic sheep.

    Foreyt, W J

    1989-03-01

    Six Rocky Mountain bighorn sheep were raised in captivity from birth (n = 5) or taken from the wild as a lamb (n = 1). After the bighorn sheep were in captivity for over a year, 6 clinically normal domestic sheep were placed on the 2 ha of pasture on which the bighorn sheep were kept. Nasal swab specimens were obtained from all sheep at the time the domestic sheep were introduced. Pasteurella haemolytica was isolated from swab specimens obtained from 4 of 6 domestic sheep, but not from specimens obtained from the bighorn sheep. All 6 bighorn sheep died of acute hemorrhagic pneumonia after exposure to domestic sheep. Death in the bighorn sheep occurred on days 4, 27, 27, 29, 36, or 71 after initial exposure to domestic sheep. Pasteurella haemolytica was isolated from respiratory tract tissue specimens of all bighorn sheep at the time of death. None of the domestic sheep were clinically ill during the study. At the end of the study, 3 of 6 domestic sheep were euthanatized, and at necropsy, P haemolytica was isolated from 2 of them. The most common serotypes in bighorn and domestic sheep were P haemolytica T-3 and A-2. Other serotypes isolated included P haemolytica A-1, A-9, and A-11 in bighorn sheep and A-1 in domestic sheep. On the basis of results of this study and of other reports, domestic sheep and bighorn sheep should not be managed in proximity to each other because of the potential fatal consequences in bighorn sheep.

  7. Transcriptome-based phylogeny of endemic Lake Baikal amphipod species flock: fast speciation accompanied by frequent episodes of positive selection.

    Naumenko, Sergey A; Logacheva, Maria D; Popova, Nina V; Klepikova, Anna V; Penin, Aleksey A; Bazykin, Georgii A; Etingova, Anna E; Mugue, Nikolai S; Kondrashov, Alexey S; Yampolsky, Lev Y

    2017-01-01

    Endemic species flocks inhabiting ancient lakes, oceanic islands and other long-lived isolated habitats are often interpreted as adaptive radiations. Yet molecular evidence for directional selection during species flocks radiation is scarce. Using partial transcriptomes of 64 species of Lake Baikal (Siberia, Russia) endemic amphipods and two nonendemic outgroups, we report a revised phylogeny of this species flock and analyse evidence for positive selection within the endemic lineages. We confirm two independent invasions of amphipods into Baikal and demonstrate that several morphological features of Baikal amphipods, such as body armour and reduction in appendages and sensory organs, evolved in several lineages in parallel. Radiation of Baikal amphipods has been characterized by short phylogenetic branches and frequent episodes of positive selection which tended to be more frequent in the early phase of the second invasion of amphipods into Baikal when the most intensive diversification occurred. Notably, signatures of positive selection are frequent in genes encoding mitochondrial membrane proteins with electron transfer chain and ATP synthesis functionality. In particular, subunits of both the membrane and substrate-level ATP synthases show evidence of positive selection in the plankton species Macrohectopus branickii, possibly indicating adaptation to active plankton lifestyle and to survival under conditions of low temperature and high hydrostatic pressures known to affect membranes functioning. Other functional categories represented among genes likely to be under positive selection include Ca-binding muscle-related proteins, possibly indicating adaptation to Ca-deficient low mineralization Baikal waters. © 2016 John Wiley & Sons Ltd.

  8. A study on sheep farming practices in relation to future production strategies in Bensa district of Southern Ethiopia.

    Kenfo, Hizkel; Mekasha, Yoseph; Tadesse, Yosef

    2018-04-01

    The study was carried out in Bensa district of Sidama zone, Southern Ethiopia. Agro-ecologically, the study sites were classified into highland and mid-altitude. The objective of the study was to identify sheep farming practices in relation to future production strategies in the study area. A total of 128 households from four kebeles (lower administrative structure) were selected purposively based on sheep population and production potential and accessibility. Data was collected through semi-structured questionnaire, focus group discussions, and key informants. The result showed that most of the household heads were male (92.75%) and mixed crop-livestock system was the dominant production system. Among the livestock species, sheep accounted for the largest proportion across the two agro ecologies and the average sheep flock size/household was 4.6 ± 0.33 and 22 4.3 ± 0.213 in highland and in mid-altitude, respectively. The primary reason of keeping sheep was for cash income and saving across the two agro ecologies. The major feed resources for sheep during the wet and dry seasons were natural pasture and crop residues respectively across the two agro ecologies. Feed shortages, disease, parasite prevalence, and market were the major sheep production constraints in highland while feed shortage, genotype, disease, parasite prevalence, and market in mid-altitude. It can be concluded that for enhancing future production from sheep in the area, emphasis is to be given on feed availability, disease management, breeding policy, and marketing strategies.

  9. [Suppression of cycling activity in sheep using parenteral progestagen treatment].

    Janett, F; Camponovo, L; Lanker, U; Hässig, M; Thun, R

    2004-03-01

    The objective of this study was to evaluate the effect of two synthetic progestagen preparations Chlormadinone acetate (CAP, Chronosyn, Veterinaria AG Zürich) and Medroxyprogesterone acetate (MPA, Nadigest, G Streuli & Co. Uznach) on cycling activity and fertility in sheep. A flock of 28 non pregnant white alpine sheep was randomly divided into three groups, A (n = 10), B (n = 9) and C (n = 9). During a period of 4 weeks the cycling activity was confirmed by blood progesterone analysis. Thereafter, the animals of group A were treated with 50 mg CAP, those of group B with 140 mg MPA and those of group C with physiological saline solution. All injections were given intramuscularly. Suppression of endogenous progesterone secretion lasted from 28 to 49 days (mean = 39 days) in group A and from 42 to 70 days (mean = 50 days) in group B. The synchronization effect of both preparations was unsatisfactory as the occurrence of first estrus was distributed over a period of 3 weeks in group A and 4 weeks in group B. These findings could also be confirmed by the lambing period which lasted 52 days in group A and 36 days in group B. Control animals lambed within 9 days due to the synchronizing effect of the ram. The first fertile estrus was observed 36 days (group A) and 45 days (group B) after the treatment. In group A all 10 animals and in groups B and C 8 of 9 ewes each became pregnant. Parenteral progestagen application with CAP and MPA is a simple, safe and reversible method of estrus suppression in the sheep. The minimal suppressive duration of 4 (CAP) and 5 weeks (MPA) is not sufficient when a period of 3 months (alpine pasture period) is desired.

  10. Behaviour of confined sheep fed with different concentrate sources

    A.H.H. Minervino

    2014-08-01

    Full Text Available In this study we examined the effects of different feed concentrates on sheep behaviour. Our hypothesis was that citric pulp would stimulate rumination and be capable of replacing other concentrates traditionally used for feeding in confinement, to reduce the risk of urolithiasis. Ten adult Santa Inês sheep were distributed in a Latin square with five different diets, one control diet with 80% hay and 20% commercial feed and four diets containing 30% coast-cross hay and 70% of the following concentrates: pelleted citrus pulp, citrus pulp meal, cornmeal or wheat bran. After 21d of adaptation to each one of the five diets, the sheep were visually monitored for 24 h at 3 min intervals to record the time spent ruminating, time spent eating and time spent resting; the animals' positions (standing or lying down were also noted. Daytime was considered to be from 06:00h to 18:00h. The data were evaluated using ANOVA, with Tukey post-hoc test or throughout Two-sample T test for circadian and position assessment. Citrus pulp diets resulted in time spent ruminating similar to the control diet (601, 590 and 669 min, respectively, but greater (P<0.05 than the cornmeal group (421min, which showed that citrus pulp generated effective rumination. The estimated saliva production in the control diet (26L was greater than in the other groups, and was greater in the citrus pulp groups (24L/d than cornmeal (21L/d. Feeding with cornmeal led to shorter time spent eating and time spent ruminating than all other diets. The sheep had higher time spent resting at night when fed concentrates (P<0.05. For all diets, about 90% of the time spent ruminating occurred with the animals lying down. Pelleted citrus pulp, citrus pulp meal and to a lesser degree wheat bran, led to adequate time spent ruminating. The use of citrus pulp can act as a preventive management measure to reduce the incidence of urolithiasis in sheep flocks.

  11. Breeding Practices in Sheep Farming

    M.A. Shejal

    2009-02-01

    Full Text Available The sheep is an important economic livestock species, contributing greatly to the Indian economy, especially in arid, semi arid and mountain areas. The current population in world is 1110.78 millions, around 44.85 millions (1987 sheeps in India (ICAR., 2002. Sheeps are mostly reared for meat and wool. The average annual wool production per sheep is between 3.5 to 5.5 kg of fine quality wool in Australia, New Zealand and U.S.S.R., where as in India except Magra sheep which annually yield more than 2 kg wool having staple length 5.8 cm, the average of rest of the wool produced is less than 1.0 kg per sheep of inferior quality (Banerjee G.C., 1998. Therefore many farmers in southern India adapted sheep rearing for meat production than for wool production. For yielding more production from sheep farming one should have sound knowledge of general information related to the reproduction and different breeding practices. [Vet. World 2009; 2(1.000: 43-44

  12. A real-time PCR approach to identify anthelmintic-resistant nematodes in sheep farms.

    Milhes, M; Guillerm, M; Robin, M; Eichstadt, M; Roy, C; Grisez, C; Prévot, F; Liénard, E; Bouhsira, E; Franc, M; Jacquiet, P

    2017-03-01

    Resistance to fenbendazole, ivermectin, and moxidectin was explored by a fecal egg count reduction test in four meat sheep flocks in southwestern France where anthelmintic resistance was suspected. The FECR test results of the present study confirmed the presence of benzimidazole resistance in three out of the four farms and the presence of ivermectin resistance in one flock. In addition, a suspicion of moxidectin resistance was shown in this latter farm. Both conventional morphological and molecular identifications were performed on larval cultures before and after the treatment in the studied farms. A high positive correlation was found between the number of larvae counted under binocular microscope and the number of larvae estimated by the qPCR analysis (R 2  = 0.88) and a high Cohen's Kappa value (0.91) in the detection of strongylid larvae in larval cultures. According to qPCR results, Trichostrongylus species demonstrated high levels of BZ resistance and Teladorsagia circumcincta was involved in the IVM resistance in one farm. The molecular procedures used in this study have the potential to be beneficial for anthelmintic resistance surveillance in sheep industry.

  13. Bloat in sheep (Ovis aries).

    Colvin, H W; Backus, R C

    1988-01-01

    1. Most of the field studies on bloat are conducted with cattle and most of the laboratory experiments seeking to explain the various parameters associated with bloat are done with sheep. 2. Based on grazing behaviour, it would be expected that sheep might bloat more severely than cattle because they selectively choose to eat leaves over stems and chew what they ingest more frequently than cattle. Furthermore, sheep appear to select legumes over grasses because the legumes can be eaten more rapidly. However, because they are selective, sheep eat more slowly than cattle. Despite a higher bloat expectation, bloating in sheep is reported to be less of a problem than in cattle. 3. Although frothing of rumen ingesta was described earlier in cattle as the cause of acute legume bloat, experiments with frothy bloat in sheep preceded those in cattle. 4. Anti-frothing agents were used in sheep before cattle to treat acute legume bloat. 5. Experiments devoted to the study of eructation in ruminants were carried out on sheep, then cattle. 6. Convincing evidence that rumen motility does not cease during acute legume bloat was gathered using sheep. 7. Although the transected tracheal technique for the determination of the volume of eructated gas was developed with cattle, the pathway of eructated gas was confirmed with sheep. 8. All the current evidence accumulated from experiments with sheep supports the hypothesis that death due to legume bloat is caused by acute neural, respiratory, and cardiovascular insult resulting from the effect of the distended rumen on thoracic viscera, diaphragm, intercostal muscles, and the abdominal vena cava. 9. Experiments with sheep and cattle being fed scabrous and nonscabrous diets similar in chemical composition show that sheep are more resistant than cattle to the increase in intrarumen pressure, decline in rumen contraction amplitude, and decrease in rumen contraction frequency caused by nonscabrous diets. 10. The sequence of events in the

  14. Assessment of flukicide efficacy against Fasciola hepatica in sheep in Sweden in the absence of a standardised test.

    Novobilský, Adam; Amaya Solis, Natalia; Skarin, Moa; Höglund, Johan

    2016-12-01

    Anthelmintic resistance (AR) to Fasciola hepatica is emerging worldwide. Recently, AR to the adulticide compound albendazole (ABZ) was shown in Argentina and Spain. In Sweden, ABZ treatment failure against F. hepatica was first reported in sheep in 2012. The present study tested the efficacy of ABZ and triclabendazole (TCBZ) in sheep naturally infected with F. hepatica using a combination of three different diagnostic methods: faecal egg counts (FEC), coproantigen ELISA (cELISA) and Fasciola egg hatch test (FEHT). Two deworming trials, in November 2014 and January 2015, were performed on two sheep farms (farms A and B) in south-western Sweden. Except ABZ in November, treatment with ABZ or TCBZ achieved sufficient efficacy (97-100%) against adult F. hepatica on farm A. In contrast, ABZ treatment failed in the sheep flock on farm B, despite low initial faecal egg output. On farm B, ABZ efficacy based on FEC was 67% (95% CI: 35-84) and four of eight ewes tested were coproantigen-positive 21 days post-treatment. Ovicidal activity of ABZ against Fasciola eggs in isolates from both farms and one additional bovine isolate were tested by FEHT to exclude the presence of juvenile flukes and other factors such as dosing failure and poor quality of drug product. Irrespective of drug trial, data from FEHT showed significantly lower ovicidal activity of ABZ for the ovine farm B isolate than for the isolate from farm A. This confirms that the low efficacy of ABZ in sheep flock B was associated with ABZ resistance. Overall, the usefulness of three complementary methods for detection of ABZ resistance in the field was demonstrated. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Campylobacter spp. contamination of chicken carcasses during processing in relation to flock colonisation.

    Allen, V M; Bull, S A; Corry, J E L; Domingue, G; Jørgensen, F; Frost, J A; Whyte, R; Gonzalez, A; Elviss, N; Humphrey, T J

    2007-01-01

    The presence and numbers of campylobacters on chicken carcasses from 26 slaughter groups, originating from 22 single-house flocks and processed in four UK plants, were studied in relation to the level of flock colonisation determined by examining the caecal contents of at least ten birds per group. The prevalence of campylobacters on carcasses from five campylobacter-negative flocks processed just after other negative flocks was low (8.0 log(10) cfu) than carcasses originating from low prevalence flocks (average of 2.3 log(10) cfu; range: defeathering and evisceration areas but not in the chillers. This was the case even when campylobacters were not isolated from the target flock. Campylobacters on carcasses from two partly colonised flocks were either the same subtype, as determined by speciation, Multi-Locus Sequence Typing (MLST) and flaA Restricted Fragment Length Polymorphism (RFLP) typing, as those in the fully colonised flocks processed previously, although not necessarily the most prevalent ones; or were the same subtypes as those found in the caeca of the flock itself. The prevalences of the different campylobacter subtypes found on carcasses from two fully colonised flocks did not closely reflect those found in the caeca. MLST combined with flaA RFLP provided a good method for ascertaining the relatedness of strains isolated from carcasses and caecal contents. This study showed that carcass contamination is related to the within-flock prevalence of campylobacter colonisation, but that contamination from previously processed flocks was also significant, especially on carcasses from low prevalence flocks. Forced dry air cooling of carcasses reduced contamination levels.

  16. Flock sizes and sex ratios of canvasbacks in Chesapeake Bay and North Carolina

    Haramis, G.M.; Derleth, E.L.; Link, W.A.

    1994-01-01

    Knowledge of the distribution, size, and sex ratios of flocks of wintering canvasbacks (Aythya valisineria) is fundamental to understanding the species' winter ecology and providing guidelines for management. Consequently, in winter 1986-87, we conducted 4 monthly aerial photographic surveys to investigate temporal changes in distribution, size, and sex ratios of canvasback flocks in traditional wintering areas of Chesapeake Bay and coastal North Carolina. Surveys yielded 35mm imagery of 194,664 canvasbacks in 842 flocks. Models revealed monthly patterns of flock size in North Carolina and Virginia, but no pattern of change in Maryland. A stepwise analysis of flock size and sex ratio fit a common positive slope (increasing proportion male) for all state-month datasets, except for North Carolina in February where the slope was larger (P lt 0.001). State and month effects on intercepts were significant (P lt 0.001) and confirmed a previously identified latitudinal gradient in sex ratio in the survey region. There was no relationship between flock purity (% canvasbacks vs. other species) and flock size except in North Carolina in January, February, and March when flock purity was related to flock size. Contrasting characteristics in North Carolina with regard to flock size (larger flocks) and flock purity suggested that proximate factors were reinforcing flocking behavior and possibly species fidelity there. Of possible factors, the need to locate foraging sites within this large, open-water environment was hypothesized to be of primary importance. Comparison of January 1981 and 1987 sex ratios indicated no change in Maryland, but lower (P lt 0.05) canvasback sex ratios (proportion male) in Virginia and North Carolina.

  17. Anomalous behaviour of mutual information in finite flocks

    Barnett, L.; Brown, J.; Bossomaier, T.

    2017-11-01

    The existing consensus is that flocks are poised at criticality, entailing long correlation lengths and a maximal value of Shannon mutual information in the large-system limit. We show, by contrast, that for finite flocks which do not truly break ergodicity in the long-observation-time limit, mutual information may not only fail to peak at criticality —as observed for other critical systems— but also diverge as noise tends to zero. This result carries implications for other finite-size, out-of-equilibrium systems, where observation times may vary widely compared to time scales of internal system dynamics; thus it may not be assumed that mutual information locates the phase transition.

  18. Flocking at a distance in active granular matter

    Soni, Harsh; Kumar, Nitin; Ramaswamy, Sriram; Sood, Ajay

    2014-03-01

    Flocking, the self-organised motion of vast numbers of living creatures in a single direction, relies on organisms sensing each other's presence, orientation and direction of movement. We have attempted to emulate these properties in experiments of fore-aft asymmetric particles energised by a vertically vibrated horizontal surface, and validate and extend our results using computer simulations and a simple hydrodynamic theory. In these studies the asymmetric rods communicate their orientation and directed motion over several rod lengths through a medium of spherical beads. This results in a phase transition from an isotropic state to a coherently moving flock at exceptionally low rod concentrations, an observation reinforced by large-scale numerical simulations. Our findings include a phase diagram in the plane of rod and bead concentrations, power-law spatial correlations upon approaching the phase boundary, and insights into the underlying mechanisms.

  19. Flocking particles in a non-Newtonian shear thickening fluid

    Mucha, Piotr B.; Peszek, Jan; Pokorný, Milan

    2018-06-01

    We prove the existence of strong solutions to the Cucker–Smale flocking model coupled with an incompressible viscous non-Newtonian fluid with the stress tensor of a power–law structure for . The fluid part of the system admits strong solutions while the solutions to the CS part are weak. The coupling is performed through a drag force on a periodic spatial domain . Additionally, we construct a Lyapunov functional determining the large time behavior of solutions to the system.

  20. Relevance of metric-free interactions in flocking phenomena.

    Ginelli, Francesco; Chaté, Hugues

    2010-10-15

    We show that the collective properties of self-propelled particles aligning with their topological (Voronoi) neighbors are qualitatively different from those of usual models where metric interaction ranges are used. This relevance of metric-free interactions, shown in a minimal setting, indicate that realistic models for the cohesive motion of cells, bird flocks, and fish schools may have to incorporate them, as suggested by recent observations.

  1. Flocking-based Document Clustering on the Graphics Processing Unit

    Cui, Xiaohui [ORNL; Potok, Thomas E [ORNL; Patton, Robert M [ORNL; ST Charles, Jesse Lee [ORNL

    2008-01-01

    Abstract?Analyzing and grouping documents by content is a complex problem. One explored method of solving this problem borrows from nature, imitating the flocking behavior of birds. Each bird represents a single document and flies toward other documents that are similar to it. One limitation of this method of document clustering is its complexity O(n2). As the number of documents grows, it becomes increasingly difficult to receive results in a reasonable amount of time. However, flocking behavior, along with most naturally inspired algorithms such as ant colony optimization and particle swarm optimization, are highly parallel and have found increased performance on expensive cluster computers. In the last few years, the graphics processing unit (GPU) has received attention for its ability to solve highly-parallel and semi-parallel problems much faster than the traditional sequential processor. Some applications see a huge increase in performance on this new platform. The cost of these high-performance devices is also marginal when compared with the price of cluster machines. In this paper, we have conducted research to exploit this architecture and apply its strengths to the document flocking problem. Our results highlight the potential benefit the GPU brings to all naturally inspired algorithms. Using the CUDA platform from NIVIDA? we developed a document flocking implementation to be run on the NIVIDA?GEFORCE 8800. Additionally, we developed a similar but sequential implementation of the same algorithm to be run on a desktop CPU. We tested the performance of each on groups of news articles ranging in size from 200 to 3000 documents. The results of these tests were very significant. Performance gains ranged from three to nearly five times improvement of the GPU over the CPU implementation. This dramatic improvement in runtime makes the GPU a potentially revolutionary platform for document clustering algorithms.

  2. Kinetic theory of flocking: derivation of hydrodynamic equations.

    Ihle, Thomas

    2011-03-01

    It is shown how to explicitly coarse-grain the microscopic dynamics of the rule-based Vicsek model for self-propelled agents. The hydrodynamic equations are derived by means of an Enskog-type kinetic theory. Expressions for all transport coefficients are given. The transition from a disordered to a flocking state, which at large particle speeds appears to be a fluctuation-induced first-order phase transition, is studied numerically and analytically.

  3. Uncertainty Quantification in Control Problems for Flocking Models

    Giacomo Albi

    2015-01-01

    Full Text Available The optimal control of flocking models with random inputs is investigated from a numerical point of view. The effect of uncertainty in the interaction parameters is studied for a Cucker-Smale type model using a generalized polynomial chaos (gPC approach. Numerical evidence of threshold effects in the alignment dynamic due to the random parameters is given. The use of a selective model predictive control permits steering of the system towards the desired state even in unstable regimes.

  4. Spontaneous fluctuations in a zero-noise model of flocking

    Chakraborty, Abhijit; Bhattacharya, Kunal

    2016-11-01

    Investigations into the complex structure and dynamics of collectively moving groups of living organisms have provided valuable insights. Understanding the emergent features, especially, the origin of fluctuations, appears to be challenging in the current scheme of models. It has been argued that flocks are poised at criticality. We present a two-dimensional self-propelled particle model where neighbourhoods and forces are defined through topology-based rules. The attractive forces are modeled in order to maintain cohesion in the flock in open-boundary conditions. We find that fluctuations occur spontaneously in the absence of any external noise. For certain values of the parameters the flock shows a high degree of order as well as scale-free decay of spatial correlations in velocity and speed. We characterize the dynamical behaviour of the system using the Lyapunov spectrum. Largest exponents being positive but small in magnitude suggest that the apparent high susceptibility may result from the system operating near the borderline of order and chaos.

  5. Hydrodynamic Equations for Flocking Models without Velocity Alignment

    Peruani, Fernando

    2017-10-01

    The spontaneous emergence of collective motion patterns is usually associated with the presence of a velocity alignment mechanism that mediates the interactions among the moving individuals. Despite of this widespread view, it has been shown recently that several flocking behaviors can emerge in the absence of velocity alignment and as a result of short-range, position-based, attractive forces that act inside a vision cone. Here, we derive the corresponding hydrodynamic equations of a microscopic position-based flocking model, reviewing and extending previous reported results. In particular, we show that three distinct macroscopic collective behaviors can be observed: i) the coarsening of aggregates with no orientational order, ii) the emergence of static, elongated nematic bands, and iii) the formation of moving, locally polar structures, which we call worms. The derived hydrodynamic equations indicate that active particles interacting via position-based interactions belong to a distinct class of active systems fundamentally different from other active systems, including velocity-alignment-based flocking systems.

  6. Characteristics of Smallholder Sheep Production at Selected ...

    The household owners of sheep seldom fed forage to their sheep (17.86%), while 25% of commercial sheep farmers fed forage. The common diseases in the area were diarrhea, pneumonia and mange. The constraints to sheep production in the area included automobile accidents, seasonal lack of feed, diseases, theft and ...

  7. An estimate of seasonality and intensity of infection with gastrointestinal nematodes in sheep and goats . in West Java

    Beriajaya

    1998-12-01

    Full Text Available Tracer Inoodle tbin-tail sheep and Kacang goats were used to measure the seasonal changes in gastrointestinal nematodes parasitism i ~'und[, .xillapek .Fodd~ 'ofis in West Java . Each 3 months for 12 months worm-free male sheep (5 and goats (5 about 5 months of age were ~ $Jri~tgldI o% ef- farmer, and managed as part of their flock for 2 months . Animals were then returned to the laboratory and maintained on "`~^taaan-ftwAiet in elevated slatted pens for 3 weeks prior to slaughter. In all trials sheep had higher faecal egg counts than goats . Egg counts were significantly lower during the late dry-early wet season due mainly to lower burdens of Oesophagostomum spp. than at other times of the year. The predominant genera recovered from faecal larval cultures were Haemonchus and Trichostrongylus . At post mortem more than 94 percent of animals were infected with Trichostrongylus colubriformis, T. axei, Haemonchus contortus, Oesophagostomum columbianwn and Strongyloides papillosus . Other species found, in descending order of occurrence, were Cooperia curticei, Trichuris ovis, Bunostornum trigonocephalum, Oesophagostomumn asperum, Capillaria bovis and Gaigena pachycelis. It was concluded that intensity of exposure of both sheep and goats to H contortus, T. axei and C. curticei was similar throughout the year, but that availability of infectioe larvae of T. colubriformis was higher during the dry than the wet season and vise versa for O. columbianum . Sheep had higher burdens of T. Colubrzformis than goats but similar numbers of other species.

  8. Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

    Qiu, Huaxin; Duan, Haibin

    2017-11-01

    Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  9. EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2014. Scientific Opinion on the scrapie situation in the EU after 10 years of monitoring and control in sheep and goats

    Hald, Tine; Baggesen, Dorte Lau

    of breeding programmes for resistance to CS (BP-CS) in the dissemination of resistance into the general sheep population has been assessed for those countries for which the CS trend analysis has been performed. CS in sheep was reported in 17 MSs (average prevalence: 8.7 cases/10 000 tests), with heterogeneous...... the failure to improve the disease situation in the remaining seven MSs. At a national level, a reduction in CS seems to be linked to better-achieving BP-CSs. Control options applied to CS in sheep and goats indicate that a CS eradication policy that relies solely on the detection of infected flocks by post...... in sheep and goats are formulated....

  10. ANTIPARASITICAL PROTECTION IN SHEEP FARMS

    DOINA ARDELEANU

    2008-10-01

    Full Text Available Through our researches were carried out at ICDCOC- Palas, Constantza, we proposed ourselves to establish the poly-parasitism structure on sheep, as well as elaborating efficientical methods for anti-parasitical prophylaxis and fighting in sheep populations and pasture sourfaces, in order to ensuring anti-parasitical protection in sheep exploitations The copro-parasitological examinations was carried ovoscopicaly (flotation - by Willis and Mc. Master methods; sediment – by polyvalent method and larvoscopicaly – by Baermann method. The parasitological examination of coprological smears which were harvested on sheep showed the presence of polyparasitism phenomenon with protozoans (coccidiae: Eimeria spp. and helmints (cestodae: Moniesia expansa; gastro-intestinal nemathodes: Trichostrongylus spp., Nematodirus spp., Strongyloides papillosus and pulmonary nemathodes: Müellerius capillaris, Protostrongylus rufescens, Dictyocaulus filaria. Also, we proposed ourselves to study the paresites and their intermediary stages on pastures which were exploited with sheep, comparatively with mowed pastures. In the ansamble of research activities a special place is occupied by testing differents methods, in order to prevention and fighting of parasitical infestations on sheep and pasture in sheep farms.

  11. Selection signatures in worldwide sheep populations.

    Fariello, Maria-Ines; Servin, Bertrand; Tosser-Klopp, Gwenola; Rupp, Rachel; Moreno, Carole; San Cristobal, Magali; Boitard, Simon; Drögemüller, Cord; The International Sheep Genomics Consortium, ISGC

    2014-01-01

    The diversity of populations in domestic species offers great opportunities to study genome response to selection. The recently published Sheep HapMap dataset is a great example of characterization of the world wide genetic diversity in sheep. In this study, we re-analyzed the Sheep HapMap dataset to identify selection signatures in worldwide sheep populations. Compared to previous analyses, we made use of statistical methods that (i) take account of the hierarchical structure of sheep popula...

  12. Selection Signatures in Worldwide Sheep Populations

    Fariello, Maria-Ines; Servin, Bertrand; Tosser-Klopp, Gwenola; Rupp, Rachel; Moreno, Carole; Cristobal, Magali San; Boitard, Simon

    2014-01-01

    The diversity of populations in domestic species offers great opportunities to study genome response to selection. The recently published Sheep HapMap dataset is a great example of characterization of the world wide genetic diversity in sheep. In this study, we re-analyzed the Sheep HapMap dataset to identify selection signatures in worldwide sheep populations. Compared to previous analyses, we made use of statistical methods that (i) take account of the hierarchical structure of sheep popula...

  13. Flocking of the Motsch-Tadmor Model with a Cut-Off Interaction Function

    Jin, Chunyin

    2018-04-01

    In this paper, we study the flocking behavior of the Motsch-Tadmor model with a cut-off interaction function. Our analysis shows that connectedness is important for flocking of this kind of model. Fortunately, we get a sufficient condition imposed only on the model parameters and initial data to guarantee the connectedness of the neighbor graph associated with the system. Then we present a theoretical analysis for flocking, and show that the system achieves consensus at an exponential rate.

  14. Prevalence and risk factors for Salmonella spp. colonization in broiler flocks in Shiraz, southern Iran

    Maryam Ansari-Lari

    2014-04-01

    Full Text Available Salmonella spp. are important food borne pathogens worldwide that frequently infect poultry flocks. This cross-sectional study was conducted to determine the prevalence of Salmonella spp. colonization in broiler flocks in Shiraz (southern Iran and to find the possible association of infection status with some potential risk factors including vaccination program and use of antibiotics. During October 2009 to April 2010, a total of 40 broiler flocks were selected in slaughterhouse and 20 cloacae contents were collected from each flock. Every five cloacae contents were pooled and investigated for Salmonella spp. using appropriate culture methods. The flock was considered positive if any of the pooled samples turned positive in culture. Statistical analysis was performed using multiple logistic regression. Nine out of 40 flocks (22.50%, 95% CI: 9-36 were positive for Salmonella spp. colonization. Nearly 75.00% of flock owners reported that they used antibiotics during production period, more frequently fluoroquinolones, combination of trimethoprim-sulfonamides (TMP/SU and tetracycline. Nearly 60.00% of the flocks which had used TMP/SU were positive for Salmonella spp. compared with 10.00% of the flocks which did not use this antibiotic (p = 0.006. Increasing flock age was associated with a decreased chance of Salmonella spp. detection (p = 0.003. In flocks which received infectious bronchitis vaccine, 36.00% were positive for Salmonella spp. whereas this was 15.00% for flocks which did not receive this vaccine (p = 0.08. Careful monitoring of antibiotics use and further studies to determine the most appropriate vaccination program in the field is recommended.

  15. Effect of climate and farm environment on Campylobacter spp. colonisation in Norwegian broiler flocks

    Jonsson, Malin E.; Chriél, Mariann; Norström, Madelaine

    2012-01-01

    of Campylobacter spp. in Norwegian broiler flocks and factors related to the climate and the farm environment. Data from 18,488 broiler flocks from 623 different farms during 2002–2007 were included in the study. A logistic regression analysis was conducted where Campylobacter spp. status of a broiler flock...... at the time of slaughter was defined as the dependent variable and farm was modelled as a random effect. The following factors were found to increase the probability for a broiler flock to test positive for Campylobacter spp.: daily mean temperature above 6°C during the rearing period, private water supply...

  16. Role of batch depletion of broiler houses on the occurrence of Campylobacter spp. in chicken flocks

    Hald, Birthe; Rattenborg, Erik; Madsen, Mogens

    2001-01-01

    Aims: The effect of batch depletion of broiler houses for campylobacter occurrence in broiler flocks was estimated in 10 flocks, each comprising a separate female and male batch. Methods and Results: The chicks were sampled first bq; cloacal swabs in the broiler houses before the start...... that batch depletion of broiler houses increased the prevalence of Campylobacter spp.-infected broilers in the flocks, that the introduction occurred a hen catching the first batch, and that campylobacter spreads through the entire flock within a week. Significance and Impact of the Study: The results from...

  17. Risk factors for Campylobacter spp. infection in Senegalese broiler-chicken flocks.

    Cardinale, E; Tall, F; Guèye, E F; Cisse, M; Salvat, G

    2004-06-10

    Our objective was to identify the risk factors for Campylobacter infection in Senegalese broiler flocks. Seventy broiler farms were studied around Dakar from January 2000 to December 2001 around Dakar. A questionnaire was administered to the farmers, and samples of fresh droppings were taken to assess the flocks' Campylobacter status. About 63% of the flocks were infected by Campylobacter spp.; Campylobacter jejuni was the most-prevalent species (P hatchery to the farm as feed plates (rather than specifically designed feed plates). Alternatively, thorough cleaning and disinfection of poultry-house surroundings and manure disposal outside the farm were associated with decreased flock risk.

  18. Sarcocystis arieticanis (Apicomplexa: Sarcocystidae) infecting the heart muscles of the domestic sheep, Ovis aries (Artiodactyla: Bovidae), from K. S. A. on the basis of light and electron microscopic data.

    Al Quraishy, Saleh; Morsy, Kareem; Bashtar, Abdel-Rahman; Ghaffar, Fathy Abdel; Mehlhorn, Heinz

    2014-10-01

    In the present study, the heteroxenous life cycle of Sarcocystis species from three strains of the slaughtered sheep at Al-Azizia and Al-Saada abattoirs in Riyadh city, K.S.A., was studied. Muscle samples of the oesophagus, diaphragm, tongue, skeletal and heart muscles were examined. Varied natural infection rates in the muscles of the examined sheep strains were recorded as 83% in Niemy, 81.5% in Najdy and 90% in Sawakny sheep. Muscles of the diaphragm showed the highest infection level above all organs except Najdy sheep in which oesophagus has the highest rate. Also, the heart was the lowest infected organ (40% Niemy, 44% Najdy and 53% Sawakny). Microscopic sarcocysts of Sarcocystis arieticanis are easily identified in sections through the heart muscles of the domestic sheep Ovis aries (Artiodactyla: Bovidae). Cysts measured 38.5-64.4 μm (averaged 42.66 μm) in width and 62.4-173.6 μm (averaged 82.14 μm) in length. The validity of this species was confirmed by means of ultrastructural characteristics of the primary cyst wall (0.1-0.27 μm thick) which revealed the presence of irregularly shaped crowded and hairy-like projections underlined by a thin layer of ground substance. This layer consisted mainly of fine, dense homogenous granules enclosing the developing metrocytes and merozoites that usually contain nearly all the structures of the apical complex and fill the interior cavity of the cyst. Several septa derived from the ground substance divided the cyst into compartments. The merozoites were banana-shaped and measured 12-16 μm in length with centrally or posteriorly located nuclei. Experimental infection of carnivores by feeding heavily infected sheep muscles revealed that the dog, Canis familiaris, is the only final host of the present Sarcocystis species. Gamogony, sporogonic stages and characteristics of sporulated oocysts were also investigated.

  19. Protein turnover in sheep

    Buttery, P.J.

    1981-01-01

    Considerable advances have been made in the knowledge of the mechanisms and control of synthesis and degradation of proteins in animal tissues during the last decade. Most of the work on the measurement of synthetic and degradative rates of the mixed protein fraction from tissues has been conducted in the rat. There have, unfortunately, been few publications describing results of protein turnover studies with ruminants. Consideration is given here to the techniques used to measure protein turnover, and some of the results obtained, particularly with sheep, are summarized. No attempt has been made to discuss directly the situation in parasitized animals; rather the aim is to provide background information which complements other work dealing with the effects of parasites on the nitrogen metabolism of ruminants. (author)

  20. Field evaluation of the efficacy and safety of a deltamethrin pour on formulation (Butox® 7.5 mg/ml pour on) for the control of Culicoides midges in sheep

    Weiher, Wiebke

    2014-01-01

    Culicoides spp. (Diptera: Ceratopogonidae) are the main vectors of Bluetongue and Schmallenberg virus disease, which are infectious diseases of ruminants. Recently, both viral diseases occurred for the first time in Germany and caused substantial suffering and large economic losses, primarily in sheep flocks. None of the currently available insecticides is registered to control infestations with Culicoides midges in ruminants. This study aimed to assess the safety and efficacy of a pour on fo...

  1. Detection of Coxiella burnetii in Aborted Fetuses of Cattle and Sheep Using Polymerase Chain Reaction Assay in Mashhad City, Iran

    Zeinab Abiri

    2016-02-01

    Full Text Available Background: Coxiella burnetii is an important intracellular pathogen that ruminants can act as primary reservoirs. Reservoirs may excrete the bacterium into the placenta, vaginal mucus and feces. Objectives: The aim of this study was to detect C. burnetii in aborted samples from ruminant flocks in Mashhad city, northeast of Iran, using the polymerase chain reaction (PCR assay. Materials and Methods: A total number of 154 fetal tissue samples of cattle, sheep and goat were subjected to nested PCR assay. Results: Sixteen (17.3% out of 92 samples from sheep and 15 (25% from 60 cattle fetuses were positive. Conclusions: The results of this study indicate the presence of C. burnetii in aborted ruminants and these can be the potential reservoirs of C. burnetii in the mentioned area.

  2. Genetic Diversity of Sheep Breeds from Albania, Greece, and Italy Assessed by Mitochondrial DNA and Nuclear Polymorphisms (SNPs

    Lorraine Pariset

    2011-01-01

    Full Text Available We employed mtDNA and nuclear SNPs to investigate the genetic diversity of sheep breeds of three countries of the Mediterranean basin: Albania, Greece, and Italy. In total, 154 unique mtDNA haplotypes were detected by means of D-loop sequence analysis. The major nucleotide diversity was observed in Albania. We identified haplogroups, A, B, and C in Albanian and Greek samples, while Italian individuals clustered in groups A and B. In general, the data show a pattern reflecting old migrations that occurred in postneolithic and historical times. PCA analysis on SNP data differentiated breeds with good correspondence to geographical locations. This could reflect geographical isolation, selection operated by local sheep farmers, and different flock management and breed admixture that occurred in the last centuries.

  3. Corrosion resistance of tank material for flock storage in the Fukushima Daiichi Nuclear Power Plant

    Sano, Yuichi; Anbai, Hiromu; Takeuchi, Masayuki; Ogino, Hideki; Koizumi, Kenji

    2014-01-01

    The installation of the storage tank made of SS400 is under planning in the Fukushima Daiichi nuclear power plant for the flock which was generated in the coagulation process for radioactive contaminated water. The flock contains the seawater and has a possibility to make a crevice and local corrosion on the surface of the tank. Air agitation will be applied in the storage tank to prevent the accumulation of the flock and hydrogen generated by radiolysis, which will increase the diffusion of oxygen and the corrosion of SS400. In addition, the effect of radiation from the flock on the corrosion should be considered. In this study, we investigated the corrosion behavior of SS400 in the flock under the aeration-agitation condition with γ-ray irradiation. Based on the flock storage condition announced by Tokyo Electric Power Company (TEPCO), immersion tests were performed with SS400 coupons under several conditions and corrosion rates were estimated by the weight loss of the coupons. After the immersion tests, the surfaces of the coupons were observed by microscopy for evaluating the local corrosion. To evaluate corrosion mechanism in detail, electrochemical tests were also carried out. In all of these tests, the non-radioactive flock as a surrogate and artificial seawater were used. Corrosion rates of SS400 increased significantly with aeration flow rates in the seawater with/without the flock, but this tendency was weaker in the seawater with the flock, especially under the condition where coupons were buried in the flock. The electrochemical tests indicated the suppression of the cathodic reaction, i.e. dissolved oxygen reduction, in the seawater with the flock. The effect of γ-ray irradiation on the corrosion rates was not remarkable under the assumed dose rate. Microscopic analysis of the immersed coupons showed no severe corrosion including local corrosion occurred. The corrosion rate could be decreased effectively by suppressing the dissolved oxygen reduction

  4. Prevalence and antimicrobial resistance among Escherichia coli and Salmonella in Ontario smallholder chicken flocks.

    Lebert, L; Martz, S-L; Janecko, N; Deckert, A E; Agunos, A; Reid, A; Rubin, J E; Reid-Smith, R J; McEwen, S A

    2018-02-01

    Surveillance is an important component of an overall strategy to address antimicrobial resistant bacteria in food animals and the food chain. The poultry market has many points of entry into the Canadian food chain, and some production practices are underrepresented in terms of surveillance. For example, pathogen carriage and antimicrobial resistance surveillance data are limited in smallholder chicken flocks raised for slaughter at provincially inspected abattoirs. In Canada, antimicrobial resistance in Escherichia coli and Salmonella isolated from commercial broiler chicken flocks, slaughtered at federally inspected abattoirs, is monitored by the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS). The objective of this study was to establish baseline information of antimicrobial resistance presence in E. coli and Salmonella isolated from smallholder flocks in Ontario, utilizing CIPARS collection and isolation methodologies, and to compare findings with CIPARS federally inspected abattoir data from Ontario, Canada. Five chickens per flock were sampled from 205 smallholder flocks. Of 1,025 samples, the E. coli prevalence was 99% (1,022/1,025), and 47% (483/1,022) of positive E. coli isolates were resistant to one or more of the 14 antimicrobials. Furthermore, as compared to results reported for the CIPARS commercial flocks, E. coli isolates from smallholder flocks had significantly lower resistance prevalence to six of 14 individual antimicrobials. Recovery of E. coli did not differ between federally inspected and provincially inspected flocks. Salmonella prevalence at the bird level in smallholder flocks was 0.3% (3/1,025), significantly lower (p ≪ 0.0001, 95% CI 0.080%-0.86%) than federally inspected commercial flocks. The overall differences found between the commercial and smallholder flocks may be explained by differences in poultry husbandry practices and hatchery sources. © 2017 Her Majesty the Queen in Right of Canada

  5. Identification and phylogenetic analysis of a sheep pox virus isolated from the Ningxia Hui Autonomous Region of China.

    Zhu, X L; Yang, F; Li, H X; Dou, Y X; Meng, X L; Li, H; Luo, X N; Cai, X P

    2013-05-14

    An outbreak of sheep pox was investigated in the Ningxia Hui Autonomous Region in China. Through immunofluorescence testing, isolated viruses, polymerase chain reaction identification, and electron microscopic examination, the isolated strain was identified as a sheep pox virus. The virus was identified through sequence and phylogenetic analysis of the P32 gene, open reading frame (ORF) 095, and ORF 103 genes. This study is the first to use the ORF 095 and ORF 103 genes as candidate genes for the analysis of sheep pox. The results showed that the ORF 095 and ORF 103 genes could be used for the genotyping of the sheep pox virus.

  6. Collective motion with anticipation: flocking, spinning, and swarming.

    Morin, Alexandre; Caussin, Jean-Baptiste; Eloy, Christophe; Bartolo, Denis

    2015-01-01

    We investigate the collective dynamics of self-propelled particles able to probe and anticipate the orientation of their neighbors. We show that a simple anticipation strategy hinders the emergence of homogeneous flocking patterns. Yet anticipation promotes two other forms of self-organization: collective spinning and swarming. In the spinning phase, all particles follow synchronous circular orbits, while in the swarming phase, the population condensates into a single compact swarm that cruises coherently without requiring any cohesive interactions. We quantitatively characterize and rationalize these phases of polar active matter and discuss potential applications to the design of swarming robots.

  7. 78 FR 25943 - Changes to Scrapie Flock Certification Program

    2013-05-03

    ... Health Programs, VS, APHIS, 4700 River Road Unit 39, Riverdale, MD 20737-1231; (301) 851-3497... systems of sheep and goats. It belongs to a group of diseases called transmissible spongiform... voluntary program within the broader NSEP. Producers who elect to join the SFCP agree to follow a set of...

  8. Morphometric, densitometric and mechanical properties of mandibular deciduous teeth in 5-month-old Polish Merino sheep.

    Tatara, Marcin R; Szabelska, Anna; Krupski, Witold; Tymczyna, Barbara; Luszczewska-Sierakowska, Iwona; Bieniaś, Jarosław; Ostapiuk, Monika

    2014-02-19

    Caries, enamel hypoplasia, molar incisor hipomineralization, amylogenesis imperfecta, dentine dysplasia, hypophosphatasia and other dental disorders lead to tooth mineralization disturbances and structural abnormalities, decreasing masticatory organ functions. Dental disorders in sheep can lead to premature slaughter before they have attained final stage of their reproductive life and induce economic loss due to high flock replacement costs. Growth rate, health status and meat quality of sheep depends on tooth properties and quality determining in large extent efficiency of the masticatory apparatus and initial food break up. Considering lack of basic anatomical and physiological data on teeth properties in sheep, the aim of the study was to evaluate morphometric, densitometric and mechanical traits of deciduous mandibular incisor, canine and the second premolar obtained at the slaughter age of 5 months of life. The obtained results have shown the highest values of weight, total tooth volume, enamel volume and dentine volume in second premolar. Morphometric and mechanical parameters of incisors reached the highest values in first incisor and decreased gradually in second and third incisor, and in canine. Densitometric measurements have not revealed significant differences of the volumetric tooth mineral density in hard dental tissues between the investigated teeth. In conclusion, proposed methodological approach is noninvasive since the deciduous teeth undergo physiological replacement with permanent teeth. Deciduous teeth can be easy collected for analyses from large animal population and may reflect mineral status and metabolism resulting from postnatal growth and development of the whole flock. In individual cases, evaluation of properties of deciduous teeth may serve for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory system functions.

  9. Leadership of Winter Mixed-Species Flocks by Tufted Titmice (Baeolophus bicolor: Are Titmice Passive Nuclear Species?

    Thomas A. Contreras

    2011-01-01

    Full Text Available The tufted titmouse (Baeolophus bicolor, TUTI is a nuclear species in winter foraging flocks whose antipredator calls are used to manage predation risk by diverse heterospecifics. We hypothesized that satellite species in mixed flocks follow TUTI (not vice versa, thereby defining the role of TUTI as a “passive” nuclear species. We followed 20 winter mixed-species flocks in North-Central Florida and assessed angular-angular correlations between overall flock, TUTI, and satellite species movement directions. We observed significant correlations between overall flock movement directions and those of TUTI, confirming our central prediction. Within flocks, however, fine-scale movement directions of satellite species were often more highly correlated with those of other satellites than with TUTI movements. We conclude that TUTI are passive nuclear species whose movements define flock paths, but within flocks, TUTI movements may have less influence on satellite movements than do other factors.

  10. Mobile Sensing of Pedestrian Flocks in Indoor Environments using WiFi Signals

    Kjærgaard, Mikkel Baun; Wirz, Martin; Roggen, Daniel

    2012-01-01

    a cohesive whole - specifically flocks - with clustering approaches operating on three different feature sets derived from WiFi signals which are comparatively analysed. Automatic detection of flocks has several important applications, including social and psychological sensing and emergency research studies...

  11. 9 CFR 146.23 - Terminology and classification; flocks and products.

    2010-01-01

    ... layers through routine serological surveillance of each participating commercial table-egg layer flock. A... SERVICE, DEPARTMENT OF AGRICULTURE LIVESTOCK IMPROVEMENT NATIONAL POULTRY IMPROVEMENT PLAN FOR COMMERCIAL POULTRY Special Provisions for Commercial Table-Egg Layer Flocks § 146.23 Terminology and classification...

  12. A model for an economically optimal replacement of a breeder flock.

    Yassin, Hurria; Velthuis, Annet G J; Giesen, Gerard W J; Oude Lansink, Alfons G J M

    2012-12-01

    A deterministic model is developed to support the tactical and operational replacement decisions at broiler breeder farms. The marginal net revenue approach is applied to determine the optimal replacement age of a flock. The objective function of the model maximizes the annual gross margin over the flock's production cycle. To calculate the gross margin, future egg production, fertility, or hatchability of the eggs, revenues and variable costs of a flock were estimated. For tactical decisions, the optimal laying length is the age at which the average gross margin of an average flock is maximal. For operational decisions, a flock should be replaced when the marginal gross margin of a replaceable flock is less than the average gross margin of an average flock. To demonstrate the model, a broiler breeder flock from a Dutch breeder farm was used. A sensitivity analysis showed that the optimal replacement decision, for both tactical and operational management, is sensitive to the decrease in the weekly egg production after the peak and the prices of feed and hatching eggs. The effect of the decrease in weekly fertility after the peak on the replacement decision is related to the payment system for hatching eggs.

  13. Who Is Spreading Avian Influenza in the Moving Duck Flock Farming Network of Indonesia?

    Joerg Henning

    Full Text Available Duck populations are considered to be a reservoir of Highly pathogenic avian influenza (HPAI virus H5N1 in some agricultural production systems, as they are able to shed the virus for several days without clinical signs. Countries endemically affected with HPAI in Asia are characterised by production systems where ducks are fed on post-harvest spilled rice. During this scavenging process it is common for ducks to come into contact with other duck flocks or wild birds, thereby providing opportunities for virus spread. Effective risk management for HPAI has been significantly compromised by a limited understanding of management of moving duck flocks in these countries, despite of a small number of recent investigations. Here, for the first time, we described the management of moving duck flocks and the structure of the moving duck flock network in quantitative terms so that factors influencing the risk of HPAIV transmission can be identified. By following moving duck flock farmers over a period of 6 months in Java, Indonesia, we were able to describe the movement of flocks and to characterise the network of various types of actors associated with the production system. We used these data to estimate the basic reproductive number for HPAI virus spread. Our results suggest that focussing HPAI prevention measures on duck flocks alone will not be sufficient. Instead, the role of transporters of moving duck flocks, hatcheries and rice paddy owners, in the spread of the HPAI virus needs to be recognised.

  14. Footpad dermatitis in Dutch broiler flocks: Prevalence and factors of influence

    Jong, de I.C.; Harn, van J.; Gunnink, H.; Hindle, V.A.; Lourens, A.

    2012-01-01

    In some European countries, footpad dermatitis (FPD) is measured as an indicator of broiler welfare. Prevalence and seasonal variation of FPD was determined within broiler flocks (fast-growing breeds) in the Netherlands. Samples were taken from 386 Dutch flocks at 8 slaughterhouses during a period

  15. Foraging intention affects whether willow tits call to attract members of mixed-species flocks.

    Suzuki, Toshitaka N; Kutsukake, Nobuyuki

    2017-06-01

    Understanding how individual behaviour influences the spatial and temporal distribution of other species is necessary to resolve the complex structure of species assemblages. Mixed-species bird flocks provide an ideal opportunity to investigate this issue, because members of the flocks are involved in a variety of behavioural interactions between species. Willow tits ( Poecile montanus ) often produce loud calls when visiting a new foraging patch to recruit other members of mixed-species flocks. The costs and benefits of flocking would differ with individual foraging behaviours (i.e. immediate consumption or caching); thus, willow tits may adjust the production of loud calls according to their foraging intention. In this study, we investigated the link between foraging decisions and calling behaviour in willow tits and tested its influence on the temporal cohesion with members of mixed-species flocks. Observations at experimental foraging patches showed that willow tits produced more calls when they consumed food items compared with when they cached them. Playback experiments revealed that these calls attracted flock members and helped to maintain their presence at foraging patches. Thus, willow tits adjusted calling behaviour according to their foraging intention, thereby coordinating the associations with members of mixed-species flocks. Our findings demonstrate the influence of individual decision-making on temporal cohesion with other species and highlight the importance of interspecific communication in mixed-species flocking dynamics.

  16. 9 CFR 145.63 - Terminology and classification; flocks and products.

    2010-01-01

    ... Terminology and classification; flocks and products. Participating flocks, and the eggs and baby poultry... examination monitoring program of hatcher debris or eggs for ostriches, emus, rheas, or cassowaries acceptable... made that can be traced to a source in that State, that uses a bacteriological examination monitoring...

  17. Reduction of campylobacter infections in broiler flocks by application of hygiene measures

    Giessen, A.W. van de; Tilburg, J.J.H.C.; Ritmeester, W.S.; Plas, J. van der

    1998-01-01

    Transmission routes of Campylobacter spp. in broilers and possibilities for prevention of infections were studied on two Dutch broiler farms. The occurrence of Campylobacter spp. was studied in successive broiler flocks, in the environment of the farms and in some of the parent flocks involved.

  18. Stakeholder Perceptions of Welfare Issues and Indicators for Extensively Managed Sheep in Australia.

    Doughty, Amanda K; Coleman, Grahame J; Hinch, Geoff N; Doyle, Rebecca E

    2017-03-23

    An online survey was designed to form the basis of a framework for the welfare assessment of extensively managed sheep in Australia. The survey focused on welfare compromise and useful welfare indicators. A total of 952 people completed the survey in its entirety, representing four stakeholder groups: Public (53.6%), Producer (27.4%), Scientist (9.9%), and Service provider (9.1%). Animal welfare was considered to be important by all participating groups in this survey (average score of 3.78/4). Respondents felt the welfare of grazing sheep was generally adequate but improvement was desired (2.98/5), with female members of the public rating sheep welfare significantly worse than other respondents ( p risk to welfare (3.87/5), followed by heat stress (3.79), lameness (3.57) and husbandry practices (3.37). Key indicators recognised by all respondents were those associated with pain and fear (3.98/5), nutrition (4.23), mortality/management (4.27), food on offer (4.41) and number of illness/injures in a flock (4.33). There were gender and stakeholder differences in the perceived importance of both welfare issues and indicators with women and the public consistently rating issues (all p indicators (all p < 0.05) to be of greater significance than other respondents. These results highlight the importance of including all stakeholders and an even balance of genders when developing a welfare framework that can address both practical and societal concerns.

  19. Production trials involving use of the FAMACHA© system for haemonchosis in sheep : preliminary results

    J.A. Van Wyk

    2008-09-01

    Full Text Available In three trials conducted on two separate farms the production of sheep treated for naturally acquired haemonchosis using the FAMACHA© system of targeted selective treatment (TST (i.e. to treat only those animals unable to manage unaided in the face of heavy Haemonchus challenge was compared to that of suppressively drenched sheep in the same flock. As expected by the research team who developed and evaluated the FAMACHA© system, TST did result in some loss in production. However, despite high levels of worm challenge in two of the trials and the fact that the comparison was with suppressive drenching which is not sustainable, the total effect was relatively small in relation to the important advantage of using the TST as regards reduced selection for anthelmintic resistance (AR. Concerning the sustainability of worm control, it is concluded that the development of drug resistance to anthelmintics leaves sheep and goat farmers in South Africa no choice but to use methods of TST such as FAMACHA©. The FAMACHA© system can also be a useful clinical aid for early on-farm detection of AR by farmers; the degree of improvement in the colour of the ocular mucous membrane from pale to red in individually drenched anaemic animals over a period of 7-14 days can give a good indication of the efficacy of the compound(s used.

  20. Economic values for production traits for different sheep breeds in Kosovo

    Hysen Bytyqi

    2015-10-01

    Full Text Available Generally, all traits of economic importance should be included in the breeding goal of livestock breeding programmes. The main aim of this study was to examine economic values for a combination of dairy and meat traits of the dual purpose Bardhoka (BAR, Balusha (BAL, Sharri (SHA and Kosova (KOS sheep breeds in Kosovo. The underlying herd model is based on a deterministic approach considering a sheep flock with milk production, lamb fattening and replacement stock. In order to examine the economic impact for different sheep breeds, the production traits considered were milk (milk yield and fattening (daily gain. For each lactation cycle among the breeds the main revenues resulted from selling milk (€ 61.82/46.03/26.37/27.22 and fattened lambs (€ 34.06/39.88/35.42/33.92 for BAR/BAL/ SHA/KOS, respectively. For BAR and BAL the economic value per average ewe place and year was € 37.7 for both breeds, while for SHA and KOS it was € 35.1 and € 32.5, respectively. For lamb fattening, daily gain was found to have the highest economic value at € 7.00 for BAL, SHA and KOS, while for BAR it was € 6.67. The relative economic values for milk yield and daily gain for BAR, BAL, SHA and KOS were 84.96:15.04, 84.42:15.58, 83.45:16.55, and 82.36:17.64, respectively.

  1. Identification of Natural Infections in Sheep/Goats with HoBi-like Pestiviruses in China.

    Shi, H; Kan, Y; Yao, L; Leng, C; Tang, Q; Ji, J; Sun, S

    2016-10-01

    The natural infections of HoBi-like pestiviruses in cattle have been reported in South America, Europe and Asia. In China, although the detections of HoBi-like pestivirus have been reported, the epidemiological investigation was limited. From January 2014 to October 2015, several flocks of sheep/goats in Henan province in central China suffered respiratory diseases which were recovered slowly after antibiotics treatment. To test whether it is the HoBi-like pestivirus caused this symptom, 49 serum samples and 22 nasal swabs were then collected for analysis by serology and RT-PCR. Serological result revealed that prevalence of pestivirus in small ruminants was 12.2% (6/49) in central China. Sequence analysis of partial 5'-UTR nucleotides of pestivirus-positive samples suggested that HoBi-like pestivirus might have circulated in sheep/goats of China for a period and have evolved into new genotype clusters. It is apparent that the study provides the molecular evidence of natural infections in goat/sheep species with HoBi-like pestiviruses in China. © 2016 Blackwell Verlag GmbH.

  2. A Distributed Flocking Approach for Information Stream Clustering Analysis

    Cui, Xiaohui [ORNL; Potok, Thomas E [ORNL

    2006-01-01

    Intelligence analysts are currently overwhelmed with the amount of information streams generated everyday. There is a lack of comprehensive tool that can real-time analyze the information streams. Document clustering analysis plays an important role in improving the accuracy of information retrieval. However, most clustering technologies can only be applied for analyzing the static document collection because they normally require a large amount of computation resource and long time to get accurate result. It is very difficult to cluster a dynamic changed text information streams on an individual computer. Our early research has resulted in a dynamic reactive flock clustering algorithm which can continually refine the clustering result and quickly react to the change of document contents. This character makes the algorithm suitable for cluster analyzing dynamic changed document information, such as text information stream. Because of the decentralized character of this algorithm, a distributed approach is a very natural way to increase the clustering speed of the algorithm. In this paper, we present a distributed multi-agent flocking approach for the text information stream clustering and discuss the decentralized architectures and communication schemes for load balance and status information synchronization in this approach.

  3. Assortative flocking in crossbills and implications for ecological speciation.

    Smith, Julie W; Sjoberg, Stephanie M; Mueller, Matthew C; Benkman, Craig W

    2012-10-22

    How reproductive isolation is related to divergent natural selection is a central question in speciation. Here, we focus on several ecologically specialized taxa or 'call types' of red crossbills (Loxia curvirostra complex), one of the few groups of birds providing much evidence for ecological speciation. Call types differ in bill sizes and feeding capabilities, and also differ in vocalizations, such that contact calls provide information on crossbill phenotype. We found that two call types of red crossbills were more likely to approach playbacks of their own call type than those of heterotypics, and that their propensity to approach heterotypics decreased with increasing divergence in bill size. Although call similarity also decreased with increasing divergence in bill size, comparisons of responses to familiar versus unfamiliar call types indicate that the decrease in the propensity to approach heterotypics with increasing divergence in bill size was a learned response, and not a by-product of calls diverging pleiotropically as bill size diverged. Because crossbills choose mates while in flocks, assortative flocking could lead indirectly to assortative mating as a by-product. These patterns of association therefore provide a mechanism by which increasing divergent selection can lead to increasing reproductive isolation.

  4. Spatially balanced topological interaction grants optimal cohesion in flocking models.

    Camperi, Marcelo; Cavagna, Andrea; Giardina, Irene; Parisi, Giorgio; Silvestri, Edmondo

    2012-12-06

    Models of self-propelled particles (SPPs) are an indispensable tool to investigate collective animal behaviour. Originally, SPP models were proposed with metric interactions, where each individual coordinates with neighbours within a fixed metric radius. However, recent experiments on bird flocks indicate that interactions are topological: each individual interacts with a fixed number of neighbours, irrespective of their distance. It has been argued that topological interactions are more robust than metric ones against external perturbations, a significant evolutionary advantage for systems under constant predatory pressure. Here, we test this hypothesis by comparing the stability of metric versus topological SPP models in three dimensions. We show that topological models are more stable than metric ones. We also show that a significantly better stability is achieved when neighbours are selected according to a spatially balanced topological rule, namely when interacting neighbours are evenly distributed in angle around the focal individual. Finally, we find that the minimal number of interacting neighbours needed to achieve fully stable cohesion in a spatially balanced model is compatible with the value observed in field experiments on starling flocks.

  5. 2D Hand Tracking Based on Flocking with Obstacle Avoidance

    Zihong Chen

    2014-02-01

    Full Text Available Hand gesture-based interaction provides a natural and powerful means for human-computer interaction. It is also a good interface for human-robot interaction. However, most of the existing proposals are likely to fail when they meet some skin-coloured objects, especially the face region. In this paper, we present a novel hand tracking method which can track the features of the hand based on the obstacle avoidance flocking behaviour model to overcome skin-coloured distractions. It allows features to be split into two groups under severe distractions and merge later. The experiment results show that our method can track the hand in a cluttered background or when passing the face, while the Flocking of Features (FoF and the Mean Shift Embedded Particle Filter (MSEPF methods may fail. These results suggest that our method has better performance in comparison with the previous methods. It may therefore be helpful to promote the use of the hand gesture-based human-robot interaction method.

  6. Risk factors associated with Salmonella enterica serovar typhimurium infection in Danish broiler flocks

    Skov, M. N.; Angen, Øystein; Chriel, M.

    1999-01-01

    A retrospective longitudinal study was conducted to identify risk factors associated with Salmonella enterica serovar typhimurium (S. typhimurium) infection in Danish broiler flocks. The data included all broiler flocks slaughtered in 1995, and the epidemiological unit was the individual broiler...... flock. The S. typhimurium status was determined by microbiological examination of 60 fresh fecal samples. This procedure should detect an infected flock with a probability above 95%, if the prevalence is above 5%, and given that the sensitivity of the test is 100%. Nineteen variables were selected...... for analysis. Five factors and an interaction term were found significant by multivariate logistic regression analysis. An increased risk for S, typhimurium infection was associated with two parent flocks, one confirmed infected and one suspected of being infected with S. typhimurium, with two...

  7. Reductive Effect of Fly Screens on the Campylobacter Prevalence of Broiler Flocks in Summer

    Hald, B.; Sommer, Helle Mølgaard; Skovgård, H. S.

    Flies act as vectors in the introduction of Campylobacter from the environment to broiler flocks. We conducted a case-control study to evaluate the effect of fly screens on the prevalence of Campylobacter in broiler flocks. Cases were 52 broiler flocks reared in 20 houses on 11 farms between June...... and November 2006, where houses were equipped with fly screens made of glass fibre mesh. The controls consisted of 70 broiler flocks reared in 25 matched houses on 13 farms without screens. Other bio-security and management routines were strictly as before the study. All broiler houses were ventilated through...... wall inlets and roof outlets. The broiler flocks were sampled at days 21, 28, and 35 and at slaughter (on day 35 to 42). Samples were tested for Campylobacter by PCR. Campylobacter prevalence data were analyzed using SAS (SAS Institute). In fly screened houses, the Campylobacter prevalence was 15.4% (8...

  8. Genetic parameters for fitness and neonatal behavior traits in sheep.

    Matheson, S M; Bünger, L; Dwyer, C M

    2012-11-01

    Poor neonatal survival constrains productivity and good welfare. The heritability of survival in sheep is very low, suggesting that genetic progress will be slow. Previously we have shown that a difficult birth and low neonatal lamb vigor are important predictors of future survival. In this study we investigated the heritability of these traits, and their relationship to production traits, as an alternative indirect route to improve lamb survival. Neonatal lamb data from 11,092 animals were collected over 2 years from 290 commercial sheep flocks, using previously developed methods to rapidly assess three traits (birth assistance, lamb vigor, sucking ability) on farm. Heritabilities for neonatal traits were moderate: birth assistance (mean ± standard error; 0.26 ± 0.03), lamb vigor (0.40 ± 0.04) and sucking ability (0.32 ± 0.03). Genetic correlations between neonatal traits were moderate to high, and positive. Heritabilities for production traits were also moderate: 8-week weight (0.27 ± 0.06), 20-week weight (0.39 ± 0.07), ultrasound muscle depth (0.37 ± 0.06). Genetic and phenotypic correlations between the neonatal traits and production traits were not significantly different from zero. However, lambs that were scored as of poor vigor at birth were less likely to be recorded at 8 or 20 weeks, indicating that they may have died. The data demonstrate that the neonatal survival traits of birth assistance, lamb vigor and sucking assistance are moderately heritable when treated as a lamb trait, indicating that selection to target these lamb traits would successfully, and efficiently, improve survival without influencing productivity.

  9. REPRODUCTIVE SEASONALITY OF SHEEP IN MEXICO

    Jaime Arroyo

    2011-07-01

    Full Text Available In order to discuss and analyze the available information concerning the seasonal breeding behavior of sheep in Mexico, this review was conducted. We analyzed the neuroendocrine basis that modulate the annual reproductive cycle in sheep and then discussed the degree of reproductive seasonality in Creole sheep wool, breeds originating in high latitudes and hair sheep, mainly in Pelibuey ewes. The Creole sheep wool show continuous annual reproductive activity and short seasonal anestrous. The females of northern origin, express seasonal reproductive activity, similar to that observed in individuals geographically located at latitudes above 35º. Pelibuey sheep show variable annual reproductive behavior with reduced anestrus or lack thereof.  It is suggested that the neuroendocrine mechanisms regulating seasonal anestrus in ewes, are active in the sheep of northern origin that live in Mexico, in a manner contrary is not activated in Creole and hair sheep.

  10. The Prevalence of Sheep Traumatic Myiasis in Three Counties from the West Side of Romania and Bacteria Isolated from the Insects Maggots

    Daniela Marina Mot

    2013-10-01

    Full Text Available Myiasis represents an infestation of animals and humans caused by the maggots of certain fly species of Diptera order, Insecta class, which feed on the hosts' living or dead tissues or body fluids. In sheep, myiasis is a major animal welfare issue developing serious pain, suffering and in untreated cases may result in tissue injuries, reproduction and productivity losses and even death. There are two most important fly species which cause traumatic cutaneous myiasis of sheep in Europe: Wohlfahrtia magnifica (Sarcophagidae implicated in etiology of wound myiasis in southern and eastern Europe and Lucilia sericata (Calliphoridae, implicated in etiology of sheep strike, mainly in the middle latitudes of Europe continent. A few farmers from Timiş, Arad and Caraş-Severin counties were been asked to response to a questionnaire on the prevalence of traumatic myiasis which evolved in their sheep flock in April-September period of year 2012. From a total number of 2206 sheep taken into study were been discovered 1658 healthy sheep (75.16% and 548 sheep with myiasis (24.84%. From identified lesions with myiasis were been collected insects maggots from all three stages of development and were been prepared in Microbiology laboratory in the view to obtain data on the culturable bacteria isolated under aerobic conditions. Bacteria detected from maggots samples were: Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Micrococcus luteus and Escherichia coli. The myasis insects maggots in sheep infestation can acquire many bacteria from their host or from their surroundings, all these can, together another bacteria, complicate the lesions and without treatment may lead to animals death.

  11. Effect of body condition score at mating on the reproductive performance of Kivircik sheep under an extensive production system.

    Yilmaz, Murat; Altin, Tufan; Karaca, Orhan; Cemal, Ibrahim; Bardakcioglu, Husnu Erbay; Yilmaz, Onur; Taskin, Turgay

    2011-12-01

    The aim of this study was to determine the effects of the body condition score (BCS) of ewes before and during the mating season on their reproductive performance under an extensive production system. In this study, 240 Kivircik sheep from the flocks of two breeders were used for over a 2-year period. The flocks were fed under extensive conditions on natural pastures throughout the year. The ewes were synchronized in two different periods, one of which was 45 days before the other. Before the introduction of rams to the ewes, the ewes were weighed after measuring their BCS. Detailed records were kept for every flock in each year. We found significant effects of BCS on pregnancy rate, lambing rate (P < 0.05) and fecundity (P < 0.05). The BCS for the highest pregnancy, lambing rate, and fecundity was determined between 2.01 and 3.00, while the lowest rates for these traits were ≤ 1.50. The highest rates of the pregnancy rate, lambing rate, and fecundity and gestation productivity were 75.9%, 70.9%, 1.11 and 3.34 kg, respectively.

  12. Reproduction and adaptation characteristics in D’man sheep

    A. Lahlou-Kassi

    1988-10-01

    Full Text Available D’man breed (D is found in the oasis of the subsaharian regions of Morocco and reared usually in sedentary type of management with small flocks (< 10 ewes. Preliminary field surveys showed that D is early maturing, prolific and aseasonal. Hence, a multidisciplinary research programme on D was started in 1974. This paper reports the findings of these studies and describes the approach used to (1 characterize and evaluate the performances of D in field and station, (2 study the physiological mechanism involved in its peculiar reproduction and production, (3 study the genetic basis of reproduction parameters, and (4 evaluate use of D in crossbreeding schemes to improve the productivity of other Moroccoan breeds. Results show that D is one of the rare breeds that is simultaneously early maturing, highly prolific and completely aseasonal. However, studies on water turnover and nitrogen recycling show that D is not well adapted to hot climate and poor nutrition. Its reproduction parameters are relatively independent of photoperiod and related to a low sensitivity to negative oestrogen feedback. D male is characterized by high libido and can be used for synchronizing oestruses through the »ram effect». Crossbreeding experiments with non-prolific sheep confirm the heritability of reproductive parameters. However, the genetic basis for these is not yet well known.

  13. Carry-over of thermophilic Campylobacter spp. between sequential and adjacent poultry flocks.

    Alter, Thomas; Weber, Rita Margarete; Hamedy, Ahmad; Glünder, Gerhard

    2011-01-10

    Nineteen flocks of four poultry species were monitored at a veterinary field station to investigate the distribution and spread of Campylobacter genotypes between sequential and adjacent flocks. Caecal and liver samples were obtained at frequent intervals from birds of all flocks and examined for Campylobacter. Amplified fragment length polymorphism (AFLP) analysis was performed to genotype Campylobacter isolates. Of the 1643 caecal and liver samples investigated, 452 (27.5%) caecal samples and 11 (0.7%) liver samples contained Campylobacter. Of the caecal isolates 76.3% were identified as Campylobacter jejuni and 23.7% were identified as Campylobacter coli. Poultry flocks were largely colonized by more than one AFLP type and an intense exchange of Campylobacter genotypes between different poultry flocks occurred. These findings indicate that multiple genotypes can constitute the Campylobacter population within single poultry flocks, hinting to different sources of exposure and/or genetic drifts within the Campylobacter population. Nevertheless, in most flocks single Campylobacter genotypes predominated. Some strains superseded others resulting in colonization by successive Campylobacter genotypes during the observation period. In conclusion, the data demonstrate that the large genetic diversity of Campylobacter must be considered in epidemiological evaluations and microbial risk assessments of Campylobacter in poultry. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Flocking at a distance in active granular matter.

    Kumar, Nitin; Soni, Harsh; Ramaswamy, Sriram; Sood, A K

    2014-09-03

    The self-organized motion of vast numbers of creatures in a single direction is a spectacular example of emergent order. Here, we recreate this phenomenon using actuated nonliving components. We report here that millimetre-sized tapered rods, rendered motile by contact with an underlying vibrated surface and interacting through a medium of spherical beads, undergo a phase transition to a state of spontaneous alignment of velocities and orientations above a threshold bead area fraction. Guided by a detailed simulation model, we construct an analytical theory of this flocking transition, with two ingredients: a moving rod drags beads; neighbouring rods reorient in the resulting flow like a weathercock in the wind. Theory and experiment agree on the structure of our phase diagram in the plane of rod and bead concentrations and power-law spatial correlations near the phase boundary. Our discovery suggests possible new mechanisms for the collective transport of particulate or cellular matter.

  15. Flocking of multiple mobile robots based on backstepping.

    Dong, Wenjie

    2011-04-01

    This paper considers the flocking of multiple nonholonomic wheeled mobile robots. Distributed controllers are proposed with the aid of backstepping techniques, results from graph theory, and singular perturbation theory. The proposed controllers can make the states of a group of robots converge to a desired geometric pattern whose centroid moves along a desired trajectory under the condition that the desired trajectory is available to a portion of the group of robots. Since communication delay is inevitable in distributed control, its effect on the performance of the closed-loop systems is analyzed. It is shown that the proposed controllers work well if communication delays are constant. To show effectiveness of the proposed controllers, simulation results are included.

  16. Estimation of the sensitivity of various environmental sampling methods for detection of Salmonella in duck flocks.

    Arnold, Mark E; Mueller-Doblies, Doris; Gosling, Rebecca J; Martelli, Francesca; Davies, Robert H

    2015-01-01

    Reports of Salmonella in ducks in the UK currently rely upon voluntary submissions from the industry, and as there is no harmonized statutory monitoring and control programme, it is difficult to compare data from different years in order to evaluate any trends in Salmonella prevalence in relation to sampling methodology. Therefore, the aim of this project was to assess the sensitivity of a selection of environmental sampling methods, including the sampling of faeces, dust and water troughs or bowls for the detection of Salmonella in duck flocks, and a range of sampling methods were applied to 67 duck flocks. Bayesian methods in the absence of a gold standard were used to provide estimates of the sensitivity of each of the sampling methods relative to the within-flock prevalence. There was a large influence of the within-flock prevalence on the sensitivity of all sample types, with sensitivity reducing as the within-flock prevalence reduced. Boot swabs (individual and pool of four), swabs of faecally contaminated areas and whole house hand-held fabric swabs showed the overall highest sensitivity for low-prevalence flocks and are recommended for use to detect Salmonella in duck flocks. The sample type with the highest proportion positive was a pool of four hair nets used as boot swabs, but this was not the most sensitive sample for low-prevalence flocks. All the environmental sampling types (faeces swabs, litter pinches, drag swabs, water trough samples and dust) had higher sensitivity than individual faeces sampling. None of the methods consistently identified all the positive flocks, and at least 10 samples would be required for even the most sensitive method (pool of four boot swabs) to detect a 5% prevalence. The sampling of dust had a low sensitivity and is not recommended for ducks.

  17. Cost structure and profitability of Assaf dairy sheep farms in Spain.

    Milán, M J; Frendi, F; González-González, R; Caja, G

    2014-01-01

    Twenty dairy sheep farms of Assaf breed, located in the Spanish autonomous community of Castilla y León and included in a group receiving technical support, were used to study their production cost structure and to assess their economic profitability during 2009. On average, farms had 89.2±38.0 ha (own, 38%), 592±63 ewes, yielded 185.9±21.1×10(3) L/yr (i.e., 316±15 L/ewe), and were attended by 2.3±0.2 annual working units (family, 72%). Total annual income was €194.4±23.0×10(3)/yr (€1.0=$1.3) from milk (78.6%), lamb (13.2%), culled ewes (0.5%), and other sales (0.8%, wool and manure), and completed with the European Union sheep subsidy (6.9%). Total costs were €185.9±19.0×10(3)/yr to attend to feeding (61.6%), labor (18.2%), equipment maintenance and depreciation (7.6%), finances (3.0%), animal health (2.5%), energy, water and milking supplies (2.2%), milk recording (0.5%), and other costs (4.4%; assurances, shearing, association fees, and so on). Mean dairy sheep farm profit was €8.5±5.8×10(3)/yr (€7.4±8.3/ewe) on average, and varied between -€40.6 and €81.1/ewe among farms. Only 60% of farms were able to pay all costs, the rest had negative balances. Nevertheless, net margin was €31.0±6.5×10(3)/yr on average, varying between €0.6 and €108.4×10(3)/yr among farms. In this case, without including the opportunity costs, all farms had positive balances. Total annual cost (TAC; €/ewe) and total annual income (TAI; €/ewe) depended on milk yield (MY; L/ewe) and were TAC=161.6 + 0.502 MY (R(2)=0.50), and TAI=78.13 + 0.790 MY (R(2)=0.88), respectively, with the break-even point being 291 L/ewe. Conversely, farm TAC (€/yr) and farm TAI (€/yr) were also predicted as a function of the number of ewes (NOE) per flock, as TAC=18,401 + 282.8 NOE (R(2)=0.89) and TAI=330.9 NOE (R(2)=0.98), with the break-even point being 383 ewes/flock. Finally, according to the increasing trend expected for agricultural commodity prices, it was

  18. Mastitis in sheep--The last 10 years and the future of research.

    Gelasakis, A I; Mavrogianni, V S; Petridis, I G; Vasileiou, N G C; Fthenakis, G C

    2015-12-14

    Bacterial mastitis is a significant welfare and financial problem in sheep flocks. This paper reviews the recently published literature, including publications that highlight the significance and virulence factors of the causal agents, especially Staphylococcus aureus and Mannheimia haemolytica, the primary causes of the disease. Research has also contributed to the understanding of risk factors, including genetic susceptibility of animals to infections, supporting future strategies for sustainable disease control. Pathogenetic mechanisms, including the role of the local defenses in the teat, have also been described and can assist formulation of strategies that induce local immune responses in the teat of ewes. Further to well-established diagnostic techniques, i.e., bacteriological tests and somatic cell counting, advanced methodologies, e.g., proteomics technologies, will likely contribute to more rapid and accurate diagnostics, in turn enhancing mastitis control efforts. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Early structural changes in sheep lung following thoracic irradiation

    Guerry-Force, M.L.; Perkett, E.A.; Brigham, K.L.; Meyrick, B.

    1988-01-01

    Using a large animal model of radiation lung injury--the sheep exposed to bilateral thoracic irradiation--we have recently shown the development of sustained pulmonary hypertension during the first 4 weeks following radiation. This is the period prior to the onset of pneumonitis and pulmonary fibrosis. In the present study, we have examined biopsy and autopsy lung tissue from these same sheep and assessed the sequential changes in lung morphology. Six unanesthetized sheep received bilateral thoracic irradiation (a total of 15 Gy); control sheep were sham irradiated. Lung biopsy tissue was taken prior to and at weekly or biweekly intervals during the 4 weeks immediately following radiation. The lungs were also removed at autopsy for light and electron microscopic examination. Our results show early (Week 1) interstitial and progressive intraalveolar edema accompanied by endothelial and epithelial injury. A gradual increase in number of interstitial mononuclear cells was evident from Week 1, both in the lung tissue and in perivascular cuffs. The number of peripheral lung interstitial mononuclear cells was twice baseline from Week 3 and included accumulation of lymphocytes, fibroblasts, and intravascular macrophages. The increased numbers of mononuclear cells paralleled the development of chronic pulmonary hypertension, perhaps suggesting their involvement in the pathogenesis of this disease. Alternatively, it may be that increased mononuclear cell number represents a stage of lung repair

  20. Novel Textile Scaffolds Generated by Flock Technology for Tissue Engineering of Bone and Cartilage.

    Walther, Anja; Hoyer, Birgit; Springer, Armin; Mrozik, Birgit; Hanke, Thomas; Cherif, Chokri; Pompe, Wolfgang; Gelinsky, Michael

    2012-03-22

    Textile scaffolds can be found in a variety of application areas in regenerative medicine and tissue engineering. In the present study we used electrostatic flocking-a well-known textile technology-to produce scaffolds for tissue engineering of bone. Flock scaffolds stand out due to their unique structure: parallel arranged fibers that are aligned perpendicularly to a substrate, resulting in mechanically stable structures with a high porosity. In compression tests we demonstrated good mechanical properties of such scaffolds and in cell culture experiments we showed that flock scaffolds allow attachment and proliferation of human mesenchymal stem cells and support their osteogenic differentiation. These matrices represent promising scaffolds for tissue engineering.

  1. From phase to microphase separation in flocking models: the essential role of nonequilibrium fluctuations.

    Solon, Alexandre P; Chaté, Hugues; Tailleur, Julien

    2015-02-13

    We show that the flocking transition in the Vicsek model is best understood as a liquid-gas transition, rather than an order-disorder one. The full phase separation observed in flocking models with Z(2) rotational symmetry is, however, replaced by a microphase separation leading to a smectic arrangement of traveling ordered bands. Remarkably, continuous deterministic descriptions do not account for this difference, which is only recovered at the fluctuating hydrodynamics level. Scalar and vectorial order parameters indeed produce different types of number fluctuations, which we show to be essential in selecting the inhomogeneous patterns. This highlights an unexpected role of fluctuations in the selection of flock shapes.

  2. Time-asymptotic interactions of two ensembles of Cucker-Smale flocking particles

    Ha, Seung-Yeal; Ko, Dongnam; Zhang, Xiongtao; Zhang, Yinglong

    2017-07-01

    We study the time-asymptotic interactions of two ensembles of Cucker-Smale flocking particles. For this, we use a coupled hydrodynamic Cucker-Smale system and discuss two frameworks, leading to mono-cluster and bi-cluster flockings asymptotically depending on initial configurations, coupling strengths, and the far-field decay property of communication weights. Under the proposed two frameworks, we show that mono-cluster and bi-cluster flockings emerge asymptotically exponentially fast and algebraically slow, respectively. Our asymptotic analysis uses the Lyapunov functional approach and a Lagrangian formulation of the coupled system.

  3. Analysis of factors important for the occurrence of Campylobacter in Danish broiler flocks

    Sommer, Helle Mølgaard; Heuer, Ole Eske; Sørensen, Anna Irene Vedel

    2013-01-01

    a multivariate analysis including all 43 variables. A multivariate analysis was conducted using a generalized linear model, and the correlations between the houses from the same farms were accounted for by adding a variance structure to the model. The procedures for analyses included backward elimination...... of positive flocks/total number of flocks delivered over the 2-year period).The following factors were found to be significantly associated with the occurrence of Campylobacter in the broiler flocks: old broiler houses, late introduction of whole wheat in the feed, relatively high broiler age at slaughter...

  4. Resistance delaying strategies on UK sheep farms: A cost benefit analysis.

    Learmount, Jane; Glover, Mike J; Taylor, Mike A

    2018-04-30

    UK guidelines for the sustainable control of parasites in sheep (SCOPS) were formulated with the primary aim of delaying development of anthelmintic resistance (AR) on UK sheep farms. Promoting their use requires the engagement and commitment of stakeholders. An important driver for behavioural change in sheep farmers is evidence of economic benefits. A recent evaluation of SCOPS guidance in practice demonstrated a significant reduction in anthelmintic use, suggesting economic benefits through a direct reduction in product and labour costs. However, in order to maintain production, a range of alternative control strategies are advised, resulting in additional costs to farmers and so a full cost benefit analysis of best practice management was undertaken. We allocated financial values to the management recommendations described in the SCOPS technical manual. Benefits were calculated using data for production variables and anthelmintic use measured during studies to evaluate the effect of SCOPS recommendations on 16 UK sheep farms and from other published work. As SCOPS control is not prescriptive and a range of different diagnostics are available, best and worst case scenarios were presented, comparing the cheapest methods (e.g. egg counts without larval culture) and management situations (e.g closed flocks not requiring quarantine treatments) with the most laborious and expensive. Simulations were run for farms with a small, medium or large flock (300; 1000; 1900 ewes) as well as comparing scenarios with and without potential production benefits from using effective wormers. Analysis demonstrated a moderate cost for all farms under both scenarios when production benefits were not included. A cost benefit was demonstrated for medium and large farms when production benefits were included and the benefit could be perceived as significant in the case of the large farms for the best case scenario (>£5000 per annum). Despite a significant potential reduction in

  5. Fatal pneumonia following inoculation of healthy bighorn sheep with Pasteurella haemolytica from healthy domestic sheep.

    Foreyt, W J; Snipes, K P; Kasten, R W

    1994-04-01

    In a series of three experiments, isolates of Pasteurella haemolytica biotype A, serotype 2, ribotype reference WSU-1, from healthy domestic sheep, were inoculated intratracheally into eight bighorn sheep (Ovis canadensis canadensis) and seven domestic sheep with doses of bacteria ranging from 5.3 x 10(8) to 8.6 x 10(11) colony forming units. Seven of eight inoculated bighorn sheep died from acute pneumonia within 48 hr of inoculation, whereas all seven domestic sheep inoculated with comparable or greater doses of bacteria remained healthy. One contact control bighorn sheep also died 6 days after its penmates received P. haemolytica. Three other noncontact control bighorn sheep remained healthy during the experiments. Pasteurella haemolytica biotype A, serotype 2, ribotype reference WSU-1 in the inocula was recovered from one or more tissues from all bighorns that died; whereas, it was not detected in any bighorn sheep before inoculation. Three different ribotypes of P. haemolytica A2 were recovered from bighorn sheep; however, only the ribotype reference WSU-1 in the domestic sheep-origin inoculum was recovered from all dead bighorn sheep, and was not recovered from bighorn sheep that survived the experiments. Thus, a relatively nonpathogenic and common isolate of P. haemolytica from healthy domestic sheep was lethal in bighorn sheep under experimental conditions.

  6. Genetic variability of six French meat sheep breeds in relation to their genetic management.

    Huby, Marie; Griffon, Laurent; Moureaux, Sophie; De Rochambeau, Hubert; Danchin-Burge, Coralie; Verrier, Etienne

    2003-01-01

    Some demographic parameters, the genetic structure and the evolution of the genetic variability of six French meat sheep breeds were analysed in relation with their management. Four of these breeds are submitted to more or less intense selection: the Berrichon du Cher (BCH), Blanc du Massif Central (BMC), Charollais (CHA) and Limousin (LIM); the other two breeds are under conservation: the Roussin de La Hague (RLH) and Solognot (SOL). Genealogical data of the recorded animals born from 1970 to 2000 and of their known ancestors were used. The most balanced contributions of the different flocks to the sire-daughter path was found in the SOL. In the BCH, a single flock provided 43% of the sire-AI sire path, whereas the contributions of the flocks were more balanced in the BMC and LIM (the only other breeds where AI is used to a substantial amount). The distribution of the expected genetic contribution of the founder animals was found to be unbalanced, especially in the BCH and LIM. The effective numbers of ancestors (founders or not) for the ewes born from 1996 to 2000 were equal to 35 (BCH), 144 (BMC), 112 (CHA), 69 (LIM), 40 (RLH) and 49 (SOL). Inbreeding was not analysed in the BMC, due to incomplete pedigree information. From 1980 on, the rates of inbreeding, in percentage points per year, were +0.112 (BCH), +0.045 (CHA), +0.036 (LIM), +0.098 (RLH) and +0.062 (SOL). The implications of the observed trends on genetic variability are discussed in relation to the genetic management of each breed. The need for a larger selection basis in the BCH, the efficiency of the rules applied in the SOL to preserve the genetic variability and the need for a more collective organisation in the CHA and RLH are outlined.

  7. Genetic variability of six French meat sheep breeds in relation to their genetic management

    Coralie Danchin-Burge

    2003-11-01

    Full Text Available Abstract Some demographic parameters, the genetic structure and the evolution of the genetic variability of six French meat sheep breeds were analysed in relation with their management. Four of these breeds are submitted to more or less intense selection: the Berrichon du Cher (BCH, Blanc du Massif Central (BMC, Charollais (CHA and Limousin (LIM; the other two breeds are under conservation: the Roussin de La Hague (RLH and Solognot (SOL. Genealogical data of the recorded animals born from 1970 to 2000 and of their known ancestors were used. The most balanced contributions of the different flocks to the sire-daughter path was found in the SOL. In the BCH, a single flock provided 43% of the sire-AI sire path, whereas the contributions of the flocks were more balanced in the BMC and LIM (the only other breeds where AI is used to a substantial amount. The distribution of the expected genetic contribution of the founder animals was found to be unbalanced, especially in the BCH and LIM. The effective numbers of ancestors (founders or not for the ewes born from 1996 to 2000 were equal to 35 (BCH, 144 (BMC, 112 (CHA, 69 (LIM, 40 (RLH and 49 (SOL. Inbreeding was not analysed in the BMC, due to incomplete pedigree information. From 1980 on, the rates of inbreeding, in percentage points per year, were +0.112 (BCH, +0.045 (CHA, +0.036 (LIM, +0.098 (RLH and +0.062 (SOL. The implications of the observed trends on genetic variability are discussed in relation to the genetic management of each breed. The need for a larger selection basis in the BCH, the efficiency of the rules applied in the SOL to preserve the genetic variability and the need for a more collective organisation in the CHA and RLH are outlined.

  8. Genetic correlations among and between wool, growth and reproduction traits in Merino sheep.

    Safari, E; Fogarty, N M; Gilmour, A R; Atkins, K D; Mortimer, S I; Swan, A A; Brien, F D; Greeff, J C; van der Werf, J H J

    2007-04-01

    Data from seven research resource flocks across Australia were combined to provide accurate estimates of genetic correlations among production traits in Merino sheep. The flocks represented contemporary Australian Merino fine, medium and broad wool strains over the past 30 years. Over 110,000 records were available for analysis for each of the major wool traits, and 50,000 records for reproduction and growth traits with over 2700 sires and 25,000 dams. Individual models developed from the single trait analyses were extended to the various combinations of two-trait models to obtain genetic correlations among six wool traits [clean fleece weight (CFW), greasy fleece weight, fibre diameter (FD), yield, coefficient of variation of fibre diameter and standard deviation of fibre diameter], four growth traits [birth weight, weaning weight, yearling weight (YWT), and hogget weight] and four reproduction traits [fertility, litter size, lambs born per ewe joined, lambs weaned per ewe joined (LW/EJ)]. This study has provided for the first time a comprehensive matrix of genetic correlations among these 14 wool, growth and reproduction traits. The large size of the data set has also provided estimates with very low standard errors. A moderate positive genetic correlation was observed between CFW and FD (0.29 +/- 0.02). YWT was positively correlated with CFW (0.23 +/- 0.04), FD (0.17 +/- 0.04) and LWEJ (0.58 +/- 0.06), while LW/EJ was negatively correlated with CFW (-0.26 +/- 0.05) and positively correlated with FD (0.06 +/- 0.04) and LS (0.68 +/- 0.04). These genetic correlations, together with the estimates of heritability and other parameters provide the basis for more accurate prediction of outcomes in complex sheep-breeding programmes designed to improve several traits.

  9. Preliminary bluetongue Transmission with the sheep ked Melophagus ovinus (L.).

    Luedke, A J; Jochim, M M; Bowne, J G

    1965-09-01

    Five experiments indicated that the sheep ked MELOPHAGUS OVINUS (L.), can transmit bluetongue virus (BTV) in sheep. It was not determined whether these were mechanical or biological transmissions, although the results suggested mechanical transmission. Sheep keds were manually transferred from a BTV-host sheep to 18 susceptible test sheep. Of these, 10 were positive (5 with mild reactions), 6 questionable, and 2 negative for BTV. Three of the mildly reacting sheep and 3 of the questionable sheep had highly intensified reactions on challenge inoculation. Five of the positive sheep were immune on challenge inoculation. Blood from 2 positive reactors was subpassaged into susceptible sheep, which reacted with typical disease signs.

  10. Preliminary Bluetongue Transmissions with the Sheep Ked Melophagus Ovinus (L.)*

    Luedke, A. J.; Jochim, M. M.; Bowne, J. G.

    1965-01-01

    Five experiments indicated that the sheep ked MELOPHAGUS OVINUS (L.), can transmit bluetongue virus (BTV) in sheep. It was not determined whether these were mechanical or biological transmissions, although the results suggested mechanical transmission. Sheep keds were manually transferred from a BTV-host sheep to 18 susceptible test sheep. Of these, 10 were positive (5 with mild reactions), 6 questionable, and 2 negative for BTV. Three of the mildly reacting sheep and 3 of the questionable sheep had highly intensified reactions on challenge inoculation. Five of the positive sheep were immune on challenge inoculation. Blood from 2 positive reactors was subpassaged into susceptible sheep, which reacted with typical disease signs. PMID:4221988

  11. Molecular detection of Theileria spp. and Babesia spp. in sheep and ixodid ticks from the northeast of Iran.

    Razmi, Gholamreza; Pourhosseini, Moslem; Yaghfouri, Saeed; Rashidi, Ahmad; Seidabadi, Mohsen

    2013-02-01

    Theilerioses and babesioses are important diseases in Iranian sheep. The present study was undertaken to identify and classify/specify Theileria spp. and Babesia spp. in sheep and vector ticks. Investigation was carried out from 2009 to 2011 in the Khorasan Razavi Province, Iran. In total, 302 sheep originating from 60 different flocks were clinically examined and their blood collected. In addition, from the same flocks, ixodid ticks were sampled. Stained blood smears were microscopically examined for the presence of Theileria and Babesia organisms, and a semi-nested PCR was used for subsequent molecular specification. From the ticks, salivary glands and uterus were isolated and subsequently analyzed by semi-nested PCR. Piroplasm organisms were observed in 29% of the blood smears with low parasitemia, whereas 65% of the blood samples yielded positive PCR findings. The presence of Theileria ovis (55.6%), Theileria lestoquardi, and mixed infection with Theileria spp. and Babesia ovis were detected by semi-nested PCR in 0.3%, 5.6%, and 0.99%, respectively. In total, 429 ixodid ticks were collected from different areas of the province. The most prevalent ticks were Rhipicephalus turanicus (n = 376; 87.6% of the total), followed by Hyalomma marginatum turanicum (n = 30; 7.0%), Dermacentor raskemensis (n = 12; 2.8%), Hyalomma anatolicum anatolicum (n = 7; 1.6%), Dermacentor marginatus (n = 2; 0.5%), Rhipicephalus bursa (n = 1; 0.2%), and Haemaphysalis sp. (n = 1; 0.2%). Of the positive R. turanicus samples, 5 (5.7%) were infected with T. ovis and 2 (2.9%) with T. lestoquardi. Neither Babesia ovis nor Babesia motasi infection was detected in salivary glands or uterine samples of the ticks. The results also suggest that R. turanicus could be the vector responsible for transmission of the 2 Theileria species.

  12. Retraction and expansion of flock mobility in central asia: costs and ...

    Retraction and expansion of flock mobility in central asia: costs and consequences. Carol Kerven, Ilya Ilych Alimaev, Roy Behnke, Grant Davidson, Leen Franchois, Nurlan Malmakov, Erik Mathijs, Aidos Smailov, Sayat Temirbekov, Iain Wright ...

  13. 9 CFR 145.33 - Terminology and classification; flocks and products.

    2010-01-01

    ... POULTRY Special Provisions for Multiplier Meat-Type Chicken Breeding Flocks and Products § 145.33... demonstrate pullorum or typhoid infection; (vii) All poultry, including exhibition, exotic, and game birds...

  14. Micro-flock patterns and macro-clusters in chiral active Brownian disks

    Levis, Demian; Liebchen, Benno

    2018-02-01

    Chiral active particles (or self-propelled circle swimmers) feature a rich collective behavior, comprising rotating macro-clusters and micro-flock patterns which consist of phase-synchronized rotating clusters with a characteristic self-limited size. These patterns emerge from the competition of alignment interactions and rotations suggesting that they might occur generically in many chiral active matter systems. However, although excluded volume interactions occur naturally among typical circle swimmers, it is not yet clear if macro-clusters and micro-flock patterns survive their presence. The present work shows that both types of pattern do survive but feature strongly enhance fluctuations regarding the size and shape of the individual clusters. Despite these fluctuations, we find that the average micro-flock size still follows the same characteristic scaling law as in the absence of excluded volume interactions, i.e. micro-flock sizes scale linearly with the single-swimmer radius.

  15. Occurrence of quinolone- and beta-lactam-resistant Escherichia coli in danish broiler flocks

    Bortolaia, Valeria; Guardabassi, Luca; Bisgaard, Magne

    An increased concern for the possible transfer of resistant bacteria or mobile resistance elements from food animals to humans has resulted in rigorous legislation preventing i.e. practical use of fluoroquinolones in the Danish broiler industry (Olesen et al., 2004; Petersen et al., 2006...... and nalidixic acid resistances were detected in all flocks. The numbers of E. coli resistant to these drugs were higher in plates from parent flocks than in those from offspring flocks. A broiler parent flock without any history of quinolone usage tested positive for ciprofloxacin-resistant E. coli, although...... and mutations responsible for these types of resistance. References DANMAP 2005. 2006. Use of antimicrobial agents and occurrence of antimicrobial resistance in bacteria from food animals, foods and humans in Denmark. Danish Veterinary Laboratory, Copenhagen, Denmark, ISSN 1600-2032. Olesen, I., H. Hasman...

  16. Fixed-Wing UAVs Flock Control through Cohesion and Repulsion Behaviours Combined with a Leadership

    Cezary Kownacki

    2016-02-01

    Full Text Available The aim of this paper is to present a novel approach to swarm control of small fixed-wing UAVs, which combines only two flocking behaviours with a leadership feature. In the presented approach, two fundamental rules of Reynolds flocking are applied, i.e., cohesion and repulsion, as the base of a decentralized control of self-organization of the flock. These rules are combined with a leadership feature, which is responsible for a global behaviour of guidance, as in the case of animals. Such a bio-inspired combination allows the achievement of a coherent collective flight of a flock of fixed-wing UAVs without applying formal behaviours of migration and alignment. This highly simplifies an implementation of the algorithm. The presented results include both numerical simulations and experimental flights, which validate the hardware implementation of the approach.

  17. Domestic sheep show average Coxiella burnetii seropositivity generations after a sheep-associated human Q fever outbreak and lack detectable shedding by placental, vaginal, and fecal routes

    Oliveira, Ryan D.; Mousel, Michelle R.; Pabilonia, Kristy L.; Highland, Margaret A.; Taylor, J. Bret; Knowles, Donald P.

    2017-01-01

    Coxiella burnetii is a globally distributed zoonotic bacterial pathogen that causes abortions in ruminant livestock. In humans, an influenza-like illness results with the potential for hospitalization, chronic infection, abortion, and fatal endocarditis. Ruminant livestock, particularly small ruminants, are hypothesized to be the primary transmission source to humans. A recent Netherlands outbreak from 2007–2010 traced to dairy goats resulted in over 4,100 human cases with estimated costs of more than 300 million euros. Smaller human Q fever outbreaks of small ruminant origin have occurred in the United States, and characterizing shedding is important to understand the risk of future outbreaks. In this study, we assessed bacterial shedding and seroprevalence in 100 sheep from an Idaho location associated with a 1984 human Q fever outbreak. We observed 5% seropositivity, which was not significantly different from the national average of 2.7% for the U.S. (P>0.05). Furthermore, C. burnetii was not detected by quantitative PCR from placentas, vaginal swabs, or fecal samples. Specifically, a three-target quantitative PCR of placenta identified 0.0% shedding (exact 95% confidence interval: 0.0%-2.9%). While presence of seropositive individuals demonstrates some historical C. burnetii exposure, the placental sample confidence interval suggests 2016 shedding events were rare or absent. The location maintained the flock with little or no depopulation in 1984 and without C. burnetii vaccination during or since 1984. It is not clear how a zero-shedding rate was achieved in these sheep beyond natural immunity, and more work is required to discover and assess possible factors that may contribute towards achieving zero-shedding status. We provide the first U.S. sheep placental C. burnetii shedding update in over 60 years and demonstrate potential for C. burnetii shedding to reach undetectable levels after an outbreak event even in the absence of targeted interventions, such

  18. Domestic sheep show average Coxiella burnetii seropositivity generations after a sheep-associated human Q fever outbreak and lack detectable shedding by placental, vaginal, and fecal routes.

    Ryan D Oliveira

    Full Text Available Coxiella burnetii is a globally distributed zoonotic bacterial pathogen that causes abortions in ruminant livestock. In humans, an influenza-like illness results with the potential for hospitalization, chronic infection, abortion, and fatal endocarditis. Ruminant livestock, particularly small ruminants, are hypothesized to be the primary transmission source to humans. A recent Netherlands outbreak from 2007-2010 traced to dairy goats resulted in over 4,100 human cases with estimated costs of more than 300 million euros. Smaller human Q fever outbreaks of small ruminant origin have occurred in the United States, and characterizing shedding is important to understand the risk of future outbreaks. In this study, we assessed bacterial shedding and seroprevalence in 100 sheep from an Idaho location associated with a 1984 human Q fever outbreak. We observed 5% seropositivity, which was not significantly different from the national average of 2.7% for the U.S. (P>0.05. Furthermore, C. burnetii was not detected by quantitative PCR from placentas, vaginal swabs, or fecal samples. Specifically, a three-target quantitative PCR of placenta identified 0.0% shedding (exact 95% confidence interval: 0.0%-2.9%. While presence of seropositive individuals demonstrates some historical C. burnetii exposure, the placental sample confidence interval suggests 2016 shedding events were rare or absent. The location maintained the flock with little or no depopulation in 1984 and without C. burnetii vaccination during or since 1984. It is not clear how a zero-shedding rate was achieved in these sheep beyond natural immunity, and more work is required to discover and assess possible factors that may contribute towards achieving zero-shedding status. We provide the first U.S. sheep placental C. burnetii shedding update in over 60 years and demonstrate potential for C. burnetii shedding to reach undetectable levels after an outbreak event even in the absence of targeted

  19. Conium maculatum (poison hemlock) toxicosis in a flock of range turkeys.

    Frank, A A; Reed, W M

    1987-01-01

    Five 20-week-old tom turkeys from a flock of range turkeys were presented for examination; the flock had a history of salivation, tremors, paralysis, and increased mortality. Necropsy revealed numerous seeds identified as seeds from Conium maculatum (poison hemlock) within the crop, proventriculus, and gizzard. Histopathologic alterations were limited to catarrhal enteritis. Clinical signs of Conium maculatum toxicosis abated after the turkeys were removed from their range, which was infested with poison hemlock.

  20. Nitrogen emissions from broilers measured by mass balance over eighteen consecutive flocks.

    Coufal, C D; Chavez, C; Niemeyer, P R; Carey, J B

    2006-03-01

    Emission of nitrogen in the form of ammonia from poultry rearing facilities has been an important topic for the poultry industry because of concerns regarding the effects of ammonia on the environment. Sound scientific data is needed to accurately estimate air emissions from poultry operations. Many factors, such as season of the year, ambient temperature and humidity, bird health, and management practices can influence ammonia volatilization from broiler rearing facilities. Precise results are often difficult to attain from commercial facilities, particularly over long periods of time. Therefore, an experiment was conducted to determine nitrogen loss from broilers in a research facility under conditions simulating commercial production for 18 consecutive flocks. Broilers were reared to 40 to 42 d of age and fed diets obtained from a commercial broiler integrator. New rice hulls were used for litter for the first flock, and the same litter was recycled for all subsequent flocks with caked litter removed between flocks. All birds, feeds, and litter materials entering and leaving the facility were quantified, sampled, and analyzed for total nitrogen content. Nitrogen loss was calculated by the mass balance method in which loss was equal to the difference between the nitrogen inputs and the nitrogen outputs. Nitrogen partitioning as a percentage of inputs averaged 15.29, 6.84, 55.52, 1.27, and 21.08% for litter, caked litter, broiler carcasses, mortalities, and nitrogen loss, respectively, over all eighteen flocks. During the production of 18 flocks of broilers on the same recycled litter, the average nitrogen emission rate was calculated to range from 4.13 to 19.74 g of N/ kg of marketed broiler (grams of nitrogen per kilogram) and averaged 11.07 g of N/kg. Nitrogen loss was significantly (P broiler grow-out facilities varies significantly on a flock-to-flock basis.

  1. An Improved Fast Flocking Algorithm with Obstacle Avoidance for Multiagent Dynamic Systems

    Jialiang Wang

    2014-01-01

    Full Text Available Flocking behavior is a common phenomenon in nature, such as flocks of birds and groups of fish. In order to make the agents effectively avoid obstacles and fast form flocking towards the direction of destination point, this paper proposes a fast multiagent obstacle avoidance (FMOA algorithm. FMOA is illustrated based on the status of whether the flocking has formed. If flocking has not formed, agents should avoid the obstacles toward the direction of target. If otherwise, these agents have reached the state of lattice and then these agents only need to avoid the obstacles and ignore the direction of target. The experimental results show that the proposed FMOA algorithm has better performance in terms of flocking path length. Furthermore, the proposed FMOA algorithm is applied to the formation flying of quad-rotor helicopters. Compared with other technologies to perform the localization of quad-rotor helicopter, this paper innovatively constructs a smart environment by deploying some wireless sensor network (WSN nodes using the proposed localization algorithm. Finally, the proposed FMOA algorithm is used to conduct the formation flying of these quad-rotor helicopters in the smart environment.

  2. To flock or fight: neurochemical signatures of divergent life histories in sparrows.

    Goodson, James L; Wilson, Leah C; Schrock, Sara E

    2012-06-26

    Many bird species exhibit dramatic seasonal switches between territoriality and flocking, but whereas neuroendocrine mechanisms of territorial aggression have been extensively studied, those of seasonal flocking are unknown. We collected brains in spring and winter from male field sparrows (Spizella pusilla), which seasonally flock, and male song sparrows (Melospiza melodia), which are territorial year-round in much of their range. Spring collections were preceded by field-based assessments of aggression. Tissue series were immunofluorescently multilabeled for vasotocin, mesotocin (MT), corticotropin-releasing hormone (CRH), vasoactive intestinal polypeptide, tyrosine hydroxylase, and aromatase, and labeling densities were measured in many socially relevant brain areas. Extensive seasonal differences are shared by both species. Many measures correlate significantly with both individual and species differences in aggression, likely reflecting evolved mechanisms that differentiate the less aggressive field sparrow from the more aggressive song sparrow. Winter-specific species differences include a substantial increase of MT and CRH immunoreactivity in the dorsal lateral septum (LS) and medial amygdala of field sparrows but not song sparrows. These species differences likely relate to flocking rather than the suppression of winter aggression in field sparrows, because similar winter differences were found for two other emberizids that are not territorial in winter--dark-eyed juncos (Junco hyemalis), which seasonally flock, and eastern towhees (Pipilo erythropthalmus), which do not flock. MT signaling in the dorsal LS is also associated with year-round species differences in grouping in estrildid finches, suggesting that common mechanisms are targeted during the evolution of different life histories.

  3. Foraging efficiency of a predator flock for randomly moving prey: A simulation study

    Lee, Sang-Hee; Kwon, Ohsung

    2016-03-01

    Flocking behavior of animals is highly advantageous for taking food resources. The degree of the advantage is related to the ability of flock members to detect their prey and the mobility of prey individuals. In this study, to explore the relation, we constructed a model to simulate a predator flock and its randomly moving prey. The predator members have the prey detection ability, which was characterized as sensing distance, R, and a sensing angle, θ. The mobility of the prey individuals was characterized as the maximum traveling distance of an iteration time step, L. The relative flock foraging efficiency, ɛ, was defined as ɛ = 1 - (Td/Tup). Tup and Td represent the spent time for the flock to eat all prey individuals and to uptake the last remaining 10% prey, respectively. Simulation results showed that ɛ increased, maximized, and decreased with the increase of R, regardless of L. As the number of prey, N, increased, the tendency of the increasing and decreasing was diluted. The result was briefly discussed in relation to the flock foraging behavior and the development of the model toward applications for real ecosystems.

  4. Demography of Dall's sheep in northwestern Alaska

    Kleckner, Christopher; Udevitz, Mark S.; Adams, Layne G.; Shults, Brad S.

    2003-01-01

    Dall’s sheep in northwestern Alaska declined in the early 1990s following the severe 1989-90 and 1990-91 winters. In the Baird Mountains of Noatak National Preserve, estimates of adult sheep declined by 50% from 800 in 1989 to under 400 in 1991. Population counts remained low throughout 1991 to 1996, reaching a minimum of 244 adult sheep in 1996. Few lambs were observed during annual midsummer aerial surveys in 1991 to 1994. We suspect that these declines resulted from a combination of poorer nutritional condition and increased vulnerability of sheep to predation resulting from severe winter conditions.As a result of these declines, both subsistence and sport hunting seasons were closed by emergency order in 1991, resulting in substantial management controversy. The affected publics, although willing to accept the closures, questioned the validity of the sheep survey data and strongly emphasized their interest in restoring harvests as soon as populations increased sufficiently. In 1995 the Northwest Arctic Regional Advisory Council, the local advisory committee for the Federal Subsistence Board, passed a motion supporting efforts to initiate research on sheep populations in the region to better understand the factors limiting sheep populations and to evaluate sheep survey methodologies.Currently estimates of Dall’s sheep population size and composition in the western Brooks Range are based on intensive fixed-wing aerial surveys conducted annually since 1986 in areas including the Baird Mountains. The annual variation in recent Baird Mountains aerial counts cannot be explained with reasonable assumptions about reproduction and survival, suggesting that there is some variability in the proportion of the population observed each year or that a substantial number of sheep move during the survey. Prior to our research, no attempt had been made to estimate visibility bias or precision for these surveys.Our understanding of Dall’s sheep population biology comes

  5. Selection signatures in worldwide sheep populations.

    Fariello, Maria-Ines; Servin, Bertrand; Tosser-Klopp, Gwenola; Rupp, Rachel; Moreno, Carole; San Cristobal, Magali; Boitard, Simon

    2014-01-01

    The diversity of populations in domestic species offers great opportunities to study genome response to selection. The recently published Sheep HapMap dataset is a great example of characterization of the world wide genetic diversity in sheep. In this study, we re-analyzed the Sheep HapMap dataset to identify selection signatures in worldwide sheep populations. Compared to previous analyses, we made use of statistical methods that (i) take account of the hierarchical structure of sheep populations, (ii) make use of linkage disequilibrium information and (iii) focus specifically on either recent or older selection signatures. We show that this allows pinpointing several new selection signatures in the sheep genome and distinguishing those related to modern breeding objectives and to earlier post-domestication constraints. The newly identified regions, together with the ones previously identified, reveal the extensive genome response to selection on morphology, color and adaptation to new environments.

  6. ORGANIC PRODUCTION OF SHEEP MILK

    Juan Carlos Ángeles Hernández

    2014-04-01

    Full Text Available Organic production systems are based on natural processes, leveraging local resources and decreasing in soil degradation. Effectiveness of milk production of organic systems vs. conventional production systems is a subject open to debate. There are various studies in which there is a positive effect of organic systems in relation to the welfare and animal health, product quality and environmental impact. However, some authors report lower milk yields production and increased susceptibility to environmental conditions compared with those obtained in conventional systems. The lower milk yields in organic systems in Dairy sheep's production, are related to the limited nutritional value, low genetic potential, and the changing environmental conditions. These systems are mainly a production method for a specific market with premium quality products and high standards in their production processes. Thus, a company organic Dairy sheep production should be considered viable when present a positive global sustainability level, that is socially beneficial, economically viable and environmentally responsible.

  7. Meat quality of goat and sheep sausages

    Teixeira, A.; Pereira, Etelvina; Rodrigues, Sandra

    2012-01-01

    The main objective of this work was to contribute to the characterization of a new product, based on goat and sheep meat with a strategy, which gives value-added to meat from culled goats and sheep, which have a very low commercial price. Carcasses from animals weighing more than the body weight allowed by PDO label specifications were used to produce fresh sausages. Sheep and goats sausages were produced in a traditional industry, in Northeast Portugal. The following character...

  8. Giant fluctuations and structural effects in a flocking epithelium

    Giavazzi, Fabio; Malinverno, Chiara; Corallino, Salvatore; Ginelli, Francesco; Scita, Giorgio; Cerbino, Roberto

    2017-09-01

    Epithelial cells cultured in a monolayer are very motile in isolation but reach a near-jammed state when mitotic division increases their number above a critical threshold. We have recently shown that a monolayer can be reawakened by over-expression of a single protein, RAB5A, a master regulator of endocytosis. This reawakening of motility was explained in terms of a flocking transition that promotes the emergence of a large-scale collective migratory pattern. Here we focus on the impact of this reawakening on the structural properties of the monolayer. We find that the unjammed monolayer is characterised by a fluidisation at the single cell level, and by enhanced non-equilibrium large-scale number fluctuations at a larger length scale. Also, with the help of numerical simulations, we trace back the origin of these fluctuations to the self-propelled active nature of the constituents, and to the existence of a local alignment mechanism, leading to the spontaneous breaking of the orientational symmetry.

  9. Giant fluctuations and structural effects in a flocking epithelium

    Giavazzi, Fabio; Cerbino, Roberto; Malinverno, Chiara; Corallino, Salvatore; Scita, Giorgio; Ginelli, Francesco

    2017-01-01

    Epithelial cells cultured in a monolayer are very motile in isolation but reach a near-jammed state when mitotic division increases their number above a critical threshold. We have recently shown that a monolayer can be reawakened by over-expression of a single protein, RAB5A, a master regulator of endocytosis. This reawakening of motility was explained in terms of a flocking transition that promotes the emergence of a large-scale collective migratory pattern. Here we focus on the impact of this reawakening on the structural properties of the monolayer. We find that the unjammed monolayer is characterised by a fluidisation at the single cell level, and by enhanced non-equilibrium large-scale number fluctuations at a larger length scale. Also, with the help of numerical simulations, we trace back the origin of these fluctuations to the self-propelled active nature of the constituents, and to the existence of a local alignment mechanism, leading to the spontaneous breaking of the orientational symmetry. (paper)

  10. Critical thresholds in flocking hydrodynamics with non-local alignment.

    Tadmor, Eitan; Tan, Changhui

    2014-11-13

    We study the large-time behaviour of Eulerian systems augmented with non-local alignment. Such systems arise as hydrodynamic descriptions of agent-based models for self-organized dynamics, e.g. Cucker & Smale (2007 IEEE Trans. Autom. Control 52, 852-862. (doi:10.1109/TAC.2007.895842)) and Motsch & Tadmor (2011 J. Stat. Phys. 144, 923-947. (doi:10.1007/s10955-011-0285-9)) models. We prove that, in analogy with the agent-based models, the presence of non-local alignment enforces strong solutions to self-organize into a macroscopic flock. This then raises the question of existence of such strong solutions. We address this question in one- and two-dimensional set-ups, proving global regularity for subcritical initial data. Indeed, we show that there exist critical thresholds in the phase space of the initial configuration which dictate the global regularity versus a finite-time blow-up. In particular, we explore the regularity of non-local alignment in the presence of vacuum. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  11. The International Sheep and Wool Handbook

    Antonello Cannas

    2011-02-01

    Full Text Available This revised book is an expanded and updated version of the Australian Sheep and Wool Handbook published in 1991 and focuses on the sheep wool and meat industry. The book is divided in 5 sections, each including several chapters written by well-known and qualified researchers and industry representatives from many countries. The first section on Major sheep and wool industries, in my opinion, is particularly interesting because it explores the sheep and wool industries of leading countries (e.g. Australia, South Africa and New Zealand and continents (Europe and South America, and those of emerging countries (e.g. China.....

  12. Influence of sustained deworming pressure on the anthelmintic resistance status in strongyles of sheep under field conditions.

    Vijayasarathi, M K; Sreekumar, C; Venkataramanan, R; Raman, M

    2016-10-01

    Anthelmintic resistance (AR) status in Madras Red sheep from selected field flocks of a government funded scheme, covered by regular, sustained anthelmintic treatment for more than 10 years was determined. Parameters such as fecal egg count reduction test (FECRT), larval paralysis assay (LPA), and allele-specific-PCR (AS-PCR) were used to test the efficacy of fenbendazole, tetramisole, and ivermectin at recommended doses, in two seasons. Sheep belonging to non-beneficiary farmers were used as controls. Mean FECRT values of beneficiary group during winter and summer seasons were 77.77 and 76.04, 93.65 and 92.12, and 95.37 and 98.06 %, respectively, for fenbendazole, tetramisole, and ivermectin. In the non-beneficiary groups, the corresponding values were 74.82 and 81.09 %, 96.05 and 97.40 %, and 97.26 and 98.23 %, respectively. The results revealed resistance to fenbendazole, suspect resistance to tetramisole and susceptibility to ivermectin in beneficiary flock. In non-beneficiary flock, while resistance was noticed against fenbendazole, both tetramisole and ivermectin were effective. FECR values were found to be significantly different between beneficiary and non-beneficiary groups against tetramisole. The results of LPA confirmed this finding, as 50 % of the Haemonchus contortus larvae were paralyzed at the concentration of 0.0156 μg/ml in the beneficiary group, while those of non-beneficiary groups required lower concentrations of 0.0078 μg/ml. AS-PCR revealed the predominance of heterozygous susceptible population of H. contortus in the beneficiary group. In this study, resistance to fenbendazole was confirmed in both the beneficiary and non-beneficiary groups and this could be attributed to frequent use of benzimidazoles as seen from the deworming records. Emergence of tetramisole resistance was detected in the beneficiary group, where the drug was used continuously for 4 years. Ivermectin was found to be effective in all the flocks. It is

  13. A Case–Control Study on the Origin of Atypical Scrapie in Sheep, France

    Morignat, Eric; Ducrot, Christian; Calavas, Didier

    2009-01-01

    A matched case–control study (95 cases and 220 controls) was designed to study risk factors for atypical scrapie in sheep in France. We analyzed contacts with animals from other flocks, lambing and feeding practices, and exposure to toxic substances. Data on the prnp genotype were collected for some case and control animals and included in a complementary analysis. Sheep dairy farms had a higher risk for scrapie (odds ratio [OR] 15.1, 95% confidence interval [CI] 3.3–69.7). Lower risk was associated with organic farms (OR 0.15, 95% CI 0.02–1.26), feeding corn silage (OR 0.16, 95% CI 0.05–0.53), and feeding vitamin and mineral supplements (OR 0.6, 95% CI 0.32–1.14). Genetic effects were quantitatively important but only marginally changed estimates of other variables. We did not find any risk factor associated with an infectious origin of scrapie. Atypical scrapie could be a spontaneous disease influenced by genetic and metabolic factors. PMID:19402956

  14. Case report of a pustular dermatitis outbreak in sheep: Clinical and food safety considerations

    Mariana Roccaro

    2018-04-01

    Full Text Available The objective of this report is to describe an outbreak of pustular dermatitis in a flock of about 200 sheep, its clinical evolution and food safety implications. The onset of the symptoms was sudden and the lesions spread very quickly from ewe to ewe, so that in about 3 days almost all of the lactating sheep were stricken. Pustules from 5 different animals, six milk samples, two cheese samples, teat cup samples from the milking machine and farmer’s hands were analysed. A pure culture of Staphylococcus aureus, producing staphylococcal enterotoxin (SE C, was isolated from pustules. Milk and cheese showed a contamination by coagulase positive staphylococci <15 and 30 colony forming units respectively and the absence of SE. Farmer’s hands and teat cups samples resulted negative for coagulase positive staphylococci. Therapy with daily topical medicaments was prescribed and a prophylactic intervention was suggested by the administration of an autovaccine. The low level of milk and cheese contamination and the absence of SE in cheese supported the decision to not advise the farmer to recall cheese produced with milk from affected animals.

  15. Detection of pregnancy in sheep using an ELISA for pregnancy-specific protein B.

    Milisits-Németh, Tímea; Balogh, Orsolya Gabriella; Egerszegi, István; Kern, László; Sasser, R Garth; Gábor, György

    2018-06-01

    The early detection of pregnancy and the determination of fetal numbers have economic benefits in sheep production because of the seasonal breeding patterns where missing a breeding opportunity means the loss of one productive year. The purpose of this study was to evaluate the efficacy of the B6-HRP ELISA for ovine pregnancy-specific protein B (oPSPB) measurement in the detection of pregnancy and estimation of fetal numbers in different sheep breeds. BioPRYN® ELISA assay kit was used for the detection of pregnancy in the experimental animals. Ninety-three ewes of three breeds (British Milksheep - BM, Lacaune - L and Transylvanian Racka - TR), each from three farms in Hungary, were included in the study. BM and L ewes were artificially inseminated (AI). Thirty-five days after AI, all ewes were examined by transabdominal ultrasound. The TR flock was mated naturally over a six-week period. At the end of the mating period, the ewes were similarly examined by ultrasound. Blood samples were taken from all pregnant ewes twice (35 and 65 days after AI), and serum samples were assayed by the BioPRYN test. It can be concluded that the detection of serum PSPB by ELISA is a much easier, safer, less expensive and highly accurate method for the detection of ovine pregnancy. Although some breed-related differences were detectable at 35 and 65 days post breeding, no differences in oPSPB levels were found in pregnant ewes carrying different numbers of fetuses.

  16. Effect of climate and farm environment on Campylobacter spp. colonisation in Norwegian broiler flocks.

    Jonsson, Malin E; Chriél, Mariann; Norström, Madelaine; Hofshagen, Merete

    2012-11-01

    Campylobacteriosis is the most frequently reported zoonosis in the EU. A recent report states that between 50% and 80% of the human campylobacteriosis cases could be attributed to broiler as a reservoir. The current study was conducted to investigate associations between the presence of Campylobacter spp. in Norwegian broiler flocks and factors related to the climate and the farm environment. Data from 18,488 broiler flocks from 623 different farms during 2002-2007 were included in the study. A logistic regression analysis was conducted where Campylobacter spp. status of a broiler flock at the time of slaughter was defined as the dependent variable and farm was modelled as a random effect. The following factors were found to increase the probability for a broiler flock to test positive for Campylobacter spp.: daily mean temperature above 6°C during the rearing period, private water supply, presence of other livestock farms within a distance of 2 km, presence of other broiler farms within a distance of 4 km with flocks positive for Campylobacter spp. within 30 days prior to slaughter, heavy rainfall 11-30 days prior to slaughter, region and year. Daily mean temperature below 0°C reduced the probability. The study emphasises the importance of the farm environment and the climate for the occurrence of Campylobacter spp. in broiler flocks. The farm environment is probably a part of the Campylobacter spp. pathway into and between broiler flocks where farmyard run-off and humans or flies entering the houses might constitute vehicles transporting the organism. Fly activity is temperature-driven and flies might be a part of the explanation of the increased risk for Campylobacter spp. related to increased temperature demonstrated in the study. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Decay of interspecific avian flock networks along a disturbance gradient in Amazonia

    Mokross, Karl; Ryder, Thomas B.; Côrtes, Marina Corrêa; Wolfe, Jared D.; Stouffer, Philip C

    2014-01-01

    Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks. PMID:24335983

  18. Quinolone- and ß-lactam-resistance in Escherichia coli from Danish and Italian broiler flocks

    Bortolaia, Valeria; Guardabassi, Luca; Bisgaard, Magne

    /ml), ampicillin (32 µg/ml), cefotaxime (2 µg/ml) or ceftiofur (8 µg/ml). The ß-glucuronidase test was performed for verification of presumptive E. coli. The same methods were used to analyse sock samples collected from six Italian broiler flocks. PCR with primers for the CTX-M-type ESBLs was performed...... usage and none of the flocks was positive for cephalosporin-resistant E. coli. In Italy, resistance to ciprofloxacin was detected in all flocks and resistances to ceftiofur and cefotaxime were detected in five flocks. Primers specific for the CTX-M-type ESBLs generated PCR amplicons from isolates from...

  19. Feather-pecking and injurious pecking in organic laying hens in 107 flocks from eight European countries

    Bestman, M.; Verwer, Cynthia; Brenninkmeyer, Christine

    2017-01-01

    Feather-pecking and cannibalism may reduce the potential of organic husbandry to enhance the welfare of laying hens. We report risk factors for these issues based on a large survey of 107 commercial flocks in eight European countries. Information was collected regarding housing, management...... and flock characteristics (age, genotype). Near the end of lay, 50 hens per flock were assessed for plumage condition and wounds. Potential influencing factors were screened and submitted to a multivariate model. The majority of the flocks (81%) consisted of brown genotypes and were found in six countries...

  20. Does mixed-species flocking influence how birds respond to a gradient of land-use intensity?

    Mammides, Christos; Chen, Jin; Goodale, Uromi Manage; Kotagama, Sarath Wimalabandara; Sidhu, Swati; Goodale, Eben

    2015-07-22

    Conservation biology is increasingly concerned with preserving interactions among species such as mutualisms in landscapes facing anthropogenic change. We investigated how one kind of mutualism, mixed-species bird flocks, influences the way in which birds respond to different habitat types of varying land-use intensity. We use data from a well-replicated, large-scale study in Sri Lanka and the Western Ghats of India, in which flocks were observed inside forest reserves, in 'buffer zones' of degraded forest or timber plantations, and in areas of intensive agriculture. We find flocks affected the responses of birds in three ways: (i) species with high propensity to flock were more sensitive to land use; (ii) different flock types, dominated by different flock leaders, varied in their sensitivity to land use and because following species have distinct preferences for leaders, this can have a cascading effect on followers' habitat selection; and (iii) those forest-interior species that remain outside of forests were found more inside flocks than would be expected by chance, as they may use flocks more in suboptimal habitat. We conclude that designing policies to protect flocks and their leading species may be an effective way to conserve multiple bird species in mixed forest and agricultural landscapes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  1. Generalised linear mixed models analysis of risk factors for contamination of Danish broiler flocks with Salmonella typhimurium

    Chriél, Mariann; Stryhn, H.; Dauphin, G.

    1999-01-01

    are the broiler flocks (about 4000 flocks) which are clustered within producers. Broiler flocks with ST-infected parent stocks show increased risk of salmonella infection, and also the hatchery affects the salmonella status significantly. Among the rearing factors, only the use of medicine as well as the time......We present a retrospective observational study of risk factors associated with the occurrence of Salmonella typhimurium (ST) in Danish broiler flocks. The study is based on recordings from 1994 in the ante-mortem database maintained by the Danish Poultry Council. The epidemiological units...

  2. The rate of spread of sheep scab within small groups of Merino and Dorper sheep : short communication

    T. Meintjies

    2002-07-01

    Full Text Available A single Merino sheep, artificially infested with the sheep scab mite, Psoroptes ovis, and a similarly infested Dorper sheep were placed with 9 uninfested Merino or 9 uninfested Dorper sheep respectively during winter and the rate of spread of infestation on the uninfested sheep observed. The same procedure was repeated in summer. It took 14 and 8 weeks respectively in winter before all sheep in the 2 groups displayed lesions of sheep scab, whereas in summer it took 10 and 12 weeks before all sheep had lesions.

  3. Pneumonia in bighorn sheep: Risk and resilience

    Cassirer, E. Frances; Manlove, Kezia R.; Almberg, Emily S.; Kamath, Pauline; Cox, Mike; Wolff, Peregrine L.; Roug, Annette; Shannon, Justin M.; Robinson, Rusty; Harris, Richard B.; Gonzales, Ben J.; Plowright, Raina K.; Hudson, Peter J.; Cross, Paul C.; Dobson, Andrew; Besser, Thomas E.

    2018-01-01

    Infectious disease was an important driver of historic declines and extirpations of bighorn sheep (Ovis canadensis) in North America and continues to impede population restoration and management. Domestic sheep have long been linked to pneumonia outbreaks in bighorn sheep and this association has now been confirmed in 13 captive commingling experiments. However, ecological and etiological complexities still hinder our understanding and control of the disease. We provide an overview of the current state of knowledge about the biology and management of respiratory disease in bighorn sheep and propose strategies for moving forward. Epizootic pneumonia in bighorn sheep is polymicrobial. Mycoplasma ovipneumoniae, a bacterium host-specific to Caprinae and commonly carried by healthy domestic sheep and goats appears to be a necessary primary agent. All-age epizootics following introduction of M. ovipneumoniae along with other pathogens into bighorn sheep populations are usually severe (median mortality 47%) but fatality rates vary widely, from 15 – 100%. Disease severity may be influenced by the strain of M. ovipneumoniae, by secondary bacterial and viral pathogens, and by factors affecting transmission and host immunity. Once introduced, M. ovipneumoniae can persist in bighorn sheep populations for decades. Carrier dams transmit the pathogen to their susceptible lambs, triggering fatal pneumonia outbreaks in nursery groups, which limits recruitment and slows or prevents population recovery. The result is that demographic costs of pathogen persistence often outweigh the impacts of the initial invasion and die-off. There is currently no effective vaccine or antibiotic for domestic or wild sheep and to date, no management actions have been successful in reducing morbidity, mortality, or disease spread once pathogen invasion has occurred. Molecular-based strain typing suggests that spillover of M. ovipneumoniae into bighorn sheep populations from domestic small ruminants

  4. Evaluation of milk cathelicidin for detection of dairy sheep mastitis.

    Addis, M F; Tedde, V; Dore, S; Pisanu, S; Puggioni, G M G; Roggio, A M; Pagnozzi, D; Lollai, S; Cannas, E A; Uzzau, S

    2016-08-01

    Mastitis due to intramammary infections is one of the most detrimental diseases in dairy sheep farming, representing a major cause of reduced milk productions and quality losses. In particular, subclinical mastitis presents significant detection and control problems, and the availability of tools enabling its timely, sensitive, and specific detection is therefore crucial. We have previously demonstrated that cathelicidins, small proteins implicated in the innate immune defense of the host, are specifically released in milk of mastitic animals by both epithelial cells and neutrophils. Here, we describe the development of an ELISA for milk cathelicidin and assess its value against somatic cell counts (SCC) and bacteriological culture for detection of ewe mastitis. Evaluation of the cathelicidin ELISA was carried out on 705 half-udder milk samples from 3 sheep flocks enrolled in a project for improvement of mammary health. Cathelicidin was detected in 35.3% of milk samples (249/705), and its amount increased with rising SCC values. The cathelicidin-negative (n=456) and cathelicidin-positive (n=249) sample groups showed a clear separation in relation to SCC, with median values of 149,500 and 3,300,000 cells/mL, respectively. Upon bacteriological culture, 20.6% (145/705) of the milk samples showed microbial growth, with coagulase-negative staphylococci being by far the most frequent finding. A significant proportion of all bacteriologically positive milk samples were positive for cathelicidin (110/145, 75.9%). Given the lack of a reliable gold standard for defining the true disease status, sensitivity (Se) and specificity (Sp) of the cathelicidin ELISA were assessed by latent class analysis against 2 SCC thresholds and against bacteriological culture results. At an SCC threshold of 500,000 cells/mL, Se and Sp were 92.3 and 92.3% for cathelicidin ELISA, 89.0 and 94.9% for SCC, and 39.4 and 93.6% for bacteriological culture, respectively. At an SCC threshold of 1

  5. Electrostatic flocking of chitosan fibres leads to highly porous, elastic and fully biodegradable anisotropic scaffolds.

    Gossla, Elke; Tonndorf, Robert; Bernhardt, Anne; Kirsten, Martin; Hund, Rolf-Dieter; Aibibu, Dilibar; Cherif, Chokri; Gelinsky, Michael

    2016-10-15

    Electrostatic flocking - a common textile technology which has been applied in industry for decades - is based on the deposition of short polymer fibres in a parallel aligned fashion on flat or curved substrates, covered with a layer of a suitable adhesive. Due to their highly anisotropic properties the resulting velvet-like structures can be utilised as scaffolds for tissue engineering applications in which the space between the fibres can be defined as pores. In the present study we have developed a fully resorbable compression elastic flock scaffold from a single material system based on chitosan. The fibres and the resulting scaffolds were analysed concerning their structural and mechanical properties and the biocompatibility was tested in vitro. The tensile strength and Young's modulus of the chitosan fibres were analysed as a function of the applied sterilisation technique (ethanol, supercritical carbon dioxide, γ-irradiation and autoclaving). All sterilisation methods decreased the Young's modulus (from 14GPa to 6-12GPa). The tensile strength was decreased after all treatments - except after the autoclaving of chitosan fibres submerged in water. Compressive strength of the highly porous flock scaffolds was 18±6kPa with a elastic modulus in the range of 50-100kPa. The flocked scaffolds did not show any cytotoxic effect during indirect or direct culture of human mesenchymal stem cells or the sarcoma osteogenic cell line Saos-2. Furthermore cell adhesion and proliferation of both cell types could be observed. This is the first demonstration of a fully biodegradable scaffold manufactured by electrostatic flocking. Most tissues possess anisotropic fibrous structures. In contrast, most of the commonly used scaffolds have an isotropic morphology. By utilising the textile technology of electrostatic flocking, highly porous and clearly anisotropic scaffolds can be manufactured. Flocking leads to parallel aligned short fibres, glued on the surface of a substrate

  6. Effect of production system and flock age on eggshell and egg internal quality measurements.

    Samiullah, Sami; Omar, Amal Saleh; Roberts, Juliet; Chousalkar, Kapil

    2017-01-01

    Egg quality was measured in eggs from different flocks that were reared together and then allocated to different production systems. Eggs were processed for measurements of eggshell and egg internal quality variables, scoring of ultrastructural mammillary layer features, completeness of cuticle cover, and protoporphyrin IX (PP IX) quantification. There was a significant main effect (P egg weight, and egg internal quality and significant effects of flock age on most measurements. The mammillary layer ultrastructural variables showed no clear relationship with production system and flock age. However, there was a significant interaction between production system and flock age for mammillary cap, early and late fusions. Cuticle cover ([Formula: see text]), was significantly higher in barn eggs (19.20), followed by free range (17.57), and cage eggs (15.99). Completeness of cuticle cover was significantly higher in eggs from the 44 week old flock than for 64 week and 73 week old flocks. For eggshells with cuticle intact, there was a significant main effect of both production system and flock age, and significant interaction between the two, for shell reflectivity, L*a*b* values and amount of PP IX. For PP IX, when this difference was calculated for the cuticle alone, there were no statistically significant differences. In 1 g of shell with and without cuticle, there was more PP IX in cage eggs (9.49 × 10 -8 , 7.90 × 10 -8  mM) followed by free range (8.24 × 10 -8 , 6.90 × 10 -8  mM), and barn eggs (8.64 × 10 -8 , 7.28 × 10 -8  mM). Similar trends were recorded for the amount of PP IX in 1 g of cuticle, but the difference was not statistically significant. The amount of PP IX decreased significantly with increasing flock age. Comparing the cage and barn production systems at 68 week of flock age, there was no difference for the amount of PP IX in shell with or without cuticle, or in the cuticle alone. Eggs from the cage production system were darker in color

  7. Effects of intramammary infection on whey proteinograms of sheep during lactation

    Vânia F. Lemos

    2015-03-01

    Full Text Available The study aimed to identify potential biomarkers of mammary gland infection in Santa Inês sheep. Commercial flocks of sheep provided the same hygiene, sanitary, and nutritional management under semi-intensive production systems were monitored during the lactation stage-and assessed 15, 30, 60, and 90 days after delivery (through the end of lactation and weaning. The California Mastitis Test (CMT was performed on the mammary glands. Milk was collected for bacterial examination and protein analysis. Bacterial culture and biochemical characterization of the samples were performed. Forty-two milk samples from healthy glands (negative CMT and bacterial testing and 43 milk samples from infected glands (positive CMT and bacterial testing taken at the predefined time points were assessed. A rennin solution was used to obtain the whey. The proteins analysis was performed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, which allowed for the quantification of nine whey proteins produced in healthy glands: serum albumin, lactoferrin, IgA, IgG heavy-chain (IgG HC, IgG light-chain (IgG LC, total IgG (IgG HC + IgG LC, α-lactalbumin, β-lactoglobulin, protein with MW 15.000 Da, protein with MW 29.000 Da and eleven whey proteins secreted by infected glands, including haptoglobin and α-1-acid glycoprotein. A comparison of whey proteins between healthy and infected glands showed increases (P<0.05 in the secreted and total contents of all proteins, except for IgG LC and α-lactoalbumin. The most significant changes were observed in α-1-acid glycoprotein, lactoferrin and haptoglobin, which showed three-, five-, and seven-fold increases in secretion, respectively. This study showed that haptoglobin, α-1-acid glycoprotein, lactoferrin, albumin, and the IgA and IgG immunoglobulins may serve as potential biomarkers for mammary gland infection in sheep.

  8. Presence of SNPs in GDF9 mRNA of Iranian Afshari Sheep

    Talat Saiedi

    2012-01-01

    Full Text Available Background: Multiple births occur frequently in some Iranian sheep breeds, while infertilityscarcely occurs. Mutation detection in major fecundity genes has been explored in most of Iraniansheep flocks over the last decade. However, previously reported single nucleotide polymorphisms(SNPs for bone morphogenetic protein receptor-(BMPR-1B and growth differentiation factor GDF9( known to affect fertility have not been detected. This study was conducted to assess whetherany significant mutations in GDF9 were extracted from slaughtered ewe ovaries of Iranian Afsharisheep breed.Materials and Methods: Ovaries defined as poor, fair, and excellent quality based on externalvisual appearance of follicles were used for histology and RNA extraction processes. High qualityRNAs underwent reverse transcriptase-polymerase chain reaction (RT-PCR from GDF9 mRNA,and the products sequenced.Results: No streak ovaries, which are considered indicators of infertility due to homozygocity forsome mutations in GDF9 and BMP15, were found. Sequencing results from GDF9 cDNA showedthat G2 (C471T, G3 (G477A, and G4 (G721A mutations were observed from 1, 4, and 1 out of12 ewes, respectively. Though all 3 mutations were previously reported, this is the first report ontheir presence in Iranian breeds. The first and second mutations do not alter the amino acids, whileG4 is a non-conservative mutation leading to E241K in the prohormone.Conclusion: As the G4 mutation was observed only in ovaries defined superficially as top quality,it could be considered as one of reasons for higher ovulation rate in some sheep. Furthermore sincemultiple mutations were observed in some cases, it might be possible that combinations of minormutations in GDF9 and BMP15 interact to affect fecundity in some Iranian sheep breeds.

  9. A short-term divergent selection for resistance to Teladorsagia circumcincta in Romanov sheep using natural or artificial challenge

    Cortet Jacques

    2004-03-01

    Full Text Available Abstract This experiment was conducted to assess the efficiency of selection on the basis of response to artificial challenges in order to breed sheep resistant to natural infection. A short-term divergent selection process was designed to estimate the genetic parameters of these two traits. Two flocks, including 100 Romanov ram lambs each, were challenged in 1990 when they were 6 months old. One flock received three artificial infections with 20 000 third-stage Teladorsagia circumcincta larvae, at intervals of 7 weeks. Faecal egg counts (FEC were performed on Days 22, 25 and 28 post infection (p.i. and the animals were drenched on Day 28 p.i. The other flock was grazed for 5 months on a pasture contaminated with the same species. Faecal samples were taken from the lambs at similar ages. About 5 rams with the lowest FEC and 5 with the highest FEC were selected in each flock and mated with unselected ewes. Their offspring (200 animals were challenged in 1992, half in the same way as their sires, and the other half by the other method. Because of a drought in the summer of 1990, it was necessary to repeat part of the experiment, and in 1992 the 5 and 8 rams with the lowest and highest FEC, respectively, were selected from the offspring challenged on the pasture in 1992 and were mated with unselected ewes. Their progeny (about 80 animals were challenged in 1994, half by natural infection, half by artificial infection. The mean FEC of the flock increased from the first to the third artificial infection. The natural infection was highly variable in different years, reflecting the difficulty of assessing resistance using this mode of challenge. Genetic parameters were estimated using animal models and REML solutions. The repeatabilities of the FEC following artificial and natural infection were 0.49 and 0.70 respectively within a period of one week, and 0.22 and 0.41 respectively for periods separated by intervals of 7 weeks; the heritabilities of the

  10. Dairy sheep production research at the University of Wisconsin-Madison, USA - a review.

    Thomas, David L; Berger, Yves M; McKusick, Brett C; Mikolayunas, Claire M

    2014-01-01

    Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased

  11. Dairy sheep production research at the University of Wisconsin-Madison, USA – a review

    2014-01-01

    Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased

  12. Production and Reproduction Efficiency in Turcana and Ratca Sheep Breeds

    Maria Sauer

    2017-05-01

    Full Text Available Aim of the current comparative study was to evaluate the production and reproduction efficiency in indigenous Turcana and endangered Ratca sheep breeds. Milk yield for the two breeds was on average 68.23±2.33 kg for Ratca ewes and 76.81±2.99 kg in Turcana, respectively, differences between two breeds were significant (p≤0.01. Conception rates were of 97.7±0.87% in Ratca and of 94.8±0.65% in Turcana ewes, respectively, differences were significant between the two flocks (p≤0.05, with the Ratca ewes achieving better fertility rates, compared to their counterparts, the Turcana breed. For prolificacy, the Turcana ewes outperformed significantly (p≤0.01 the Ratca, with an average litter size of 124.2±1.86% and 110.1±1.44%, respectively. Lambs survival and adult ewe culling rates were not affected by the breed factor (p>0.05. Adult ewes body weight when put to ram was significantly (p≤0.05 influenced by the breed, with Turcana ewes having on average 53.8±2.89 kg, compared to 48.0±3.22 kg for the Ratca ewes. The average farm yearly incomes were estimated to be of 150.32 EUR for Ratca ewe-unit and of 144.97 EUR for the Turcana ewe-unit. Although the Turcana outperformed the Ratca ewes, the annual revenue was higher for the Ratca, due to the state conservation subsidy for rare and endangered breeds.

  13. Decision-making in pigeon flocks: a democratic view of leadership.

    Jorge, Paulo E; Marques, Paulo A M

    2012-07-15

    When travelling in groups, animals frequently have to make decisions on the direction of travel. These decisions can be based on consensus, when all individuals take part in the decision (i.e. democratic decision; social information), or leadership, when one member or a minority of members make the decision (i.e. despotic decision; personal information). Here we investigated whether decision-making on the navigation of small flocks is based on democratic or despotic decisions. Using individual and flock releases as the experimental approach, we compared the homing performances of homing pigeons that fly singly and in groups of three. Our findings show that although small groups were either governed (i.e. when individuals in the flock had age differences) or not (i.e. when individuals in the flock had the same age) by leaders, with concern to decision-making they were all ruled by democratic decisions. Moreover, the individual homing performances were not associated with leadership. Because true leaders did not assume right away the front position in the flock, we suggest that as in human groups, starting from a central position is more effective as it allows leaders to not only transmit their own information but also to average the tendencies of the other group members. Together, the results highlight the importance of democratic decisions in group decision-making.

  14. The confusion effect when attacking simulated three-dimensional starling flocks.

    Hogan, Benedict G; Hildenbrandt, Hanno; Scott-Samuel, Nicholas E; Cuthill, Innes C; Hemelrijk, Charlotte K

    2017-01-01

    The confusion effect describes the phenomenon of decreasing predator attack success with increasing prey group size. However, there is a paucity of research into the influence of this effect in coherent groups, such as flocks of European starlings ( Sturnus vulgaris ). Here, for the first time, we use a computer game style experiment to investigate the confusion effect in three dimensions. To date, computerized studies on the confusion effect have used two-dimensional simulations with simplistic prey movement and dynamics. Our experiment is the first investigation of the effects of flock size and density on the ability of a (human) predator to track and capture a target starling in a realistically simulated three-dimensional flock of starlings. In line with the predictions of the confusion effect, modelled starlings appear to be safer from predation in larger and denser flocks. This finding lends credence to previous suggestions that starling flocks have anti-predator benefits and, more generally, it suggests that active increases in density in animal groups in response to predation may increase the effectiveness of the confusion effect.

  15. Functional Traits, Flocking Propensity, and Perceived Predation Risk in an Amazonian Understory Bird Community.

    Martínez, Ari E; Gomez, Juan P; Ponciano, José Miguel; Robinson, Scott K

    2016-05-01

    Within a community, different species might share similar predation risks, and, thus, the ability of species to signal and interpret heterospecific threat information may determine species' associations. We combined observational, experimental, and phylogenetic approaches to determine the extent to which evolutionary history and functional traits determined flocking propensity and perceived predation risk (response to heterospecific alarm calls) in a lowland Amazonian bird community. We predicted that small birds that feed myopically and out in the open would have higher flocking propensities and account for a higher proportion of positive responses to alarms. Using generalized linear models and the incorporation of phylogeny on data from 56 species, our results suggest that phylogenetic relationships alongside body size, foraging height, vegetation density, and response to alarm calls influence flocking propensity. Conversely, phylogenetic relationships did not influence response to heterospecific alarm calls. Among functional traits, however, foraging strategy, foraging density, and flocking propensity partially explained responses to alarm calls. Our results suggest that flocking propensity and perceived predation risk are positively related and that functional ecological traits and evolutionary history may explain certain species' associations.

  16. An Assessment of Omani Native Sheep Fiber Production and Quality Characteristics

    Osman Mahgoub

    2010-01-01

    Full Text Available Wool production and quality measurements were carried out on 100 Omani native female sheep (body weight 38.6 ± 5.5 kg; age 993 ± 488 d. Sheep were kept in partially shaded pens and fed ad libitum Rhodes grass hay (crude protein 8.83% plus a daily amount of 200 g general ruminant concentrate (crude protein 16.5% DM. Animals were shorn once a year and samples were taken from the left mid-side site to determine fleece and fiber characteristics. The scanning electron microscope (SEM was used to study the fine appearance of the wool fibers. A skin sample was used to study the histological arrangement and number of secondary and primary follicles. The greasy fleece weight (GFW in Omani sheep ranged between 0.50- 2.65 kg (mean 1.12 ± 0.43 kg and the GFW expressed as a percentage of BW ranged between 1.0-7.6 with a mean of 2.9 ± 1.16. Clean wool yield in Omani sheep fleece ranged between 57.1 and 88.4% with a mean of 76.4 ± 7.6. Omani sheep fleece contained various staple shapes and had a mean staple length of 22.9 ± 1.16 cm, 4.3 ± 0.8 crimps per staple; and a mean fiber diameter of 46 ± 12 µm. Electron microscopy revealed three types of fibers; wrap-around, angled type and polygonal and elongated scales. This study indicated a wide variation in the wool characteristics of Omani native sheep fleece, which suggested that selection may be employed to improve wool production and quality in these sheep.

  17. Paratuberculose em caprinos e ovinos no Brasil Paratuberculosis in goats and sheep in Brazil

    Diego M. Oliveira

    2010-01-01

    caprinos e ovinos no Brasil, determinar medidas de controle e avaliar a possibilidade de transmissão para humanos.This paper reports paratuberculosis in sheep and goats for the first time in Brazil. On Farm 1 in a flock of 33 goats and 13 sheep, one adult female goat presented progressive weight loss during about one year, and soft feces during one month before death. All the animals from the flock were submitted to the comparative tuberculin test. One sheep was positive to the avian tuberculin (2.2% and in two the results were inconclusive. On Farm 2, in a flock of 200 sheep and 80 goats, one adult ewe presented progressive weight loss during about one year, and soft feces during 20 days before death. All sheep older than four months of age and 23 goats were submitted to tuberculin test with avian tuberculin; 47 (25.4% sheep were positive, 115 (61.5% had inconclusive results, and 25 (13.4% were negative. No positive tuberculin test were observed in the goats, but in 11 (47.8% the test was inconclusive and in 12 (52.2% was negative. At necropsy both affected animals had enlarged mesenteric lymph nodes. In the affected sheep, the gut wall was thickened and corrugated, mainly in the ileum and ileocecal valve. Histologically, granulomas with mainly foamy macrophages were observed in the lamina propria and submucosa of the gut, in mesenteric lymph nodes, and in the goat also in the liver. One tuberculin positive sheep and one tuberculin negative goat from Farm 1 were euthanized and necropsied. A mild thickened of the intestinal wall was observed grossly in both animals. Inflammatory infiltrate with mainly lymphocytes was observed on the submucosa and lamina propria of the gut. In the four cases acid-alcohol positive rods, positive for Mycobacterium spp. on immunohistochemical examination were observed in macrophages and lymphocytes. New studies are necessary to know the prevalence and economical impact of paratuberculosis in goats and sheep in Brazil, to determine control

  18. Haemophilus somnus (Histophilus somni) in bighorn sheep

    2006-01-01

    Abstract Respiratory disease and poor lamb recruitment have been identified as limiting factors for bighorn-sheep populations. Haemophilus somnus (recently reclassified as Histophilus somni) is associated with respiratory disease in American bison, domestic sheep, and cattle. It is also harbored in their reproductive tracts and has been associated with reproductive failure in domestic sheep and cattle. Therefore, reproductive tract and lung samples from bighorn sheep were evaluated for the presence of this organism. Organisms identified as H. somnus were isolated from 6 of 62 vaginal but none of 12 preputial swab samples. Antigen specific to H. somnus was detected by immunohistochemical study in 4 of 12 formalin-fixed lung tissue samples of bighorn sheep that died with evidence of pneumonia. Notably, H. somnus was found in alveolar debris in areas of inflammation. The 6 vaginal isolates and 2 H. somnus isolates previously cultured from pneumonic lungs of bighorn sheep were compared with 3 representative isolates from domestic sheep and 2 from cattle. The profiles of major outer membrane proteins and antigens for all of the isolates were predominantly similar, although differences that may be associated with the host–parasite relationship and virulence were detected. The DNA restriction fragment length profiles of the bighorn-sheep isolates had similarities not shared with the other isolates, suggesting distinct phylogenetic lines. All of the isolates had similar antimicrobial profiles, but the isolates from the bighorn sheep produced less pigment than those from the domestic livestock, and growth of the former was not enhanced by CO2. Wildlife biologists and diagnosticians should be aware of the potential of these organisms to cause disease in bighorn sheep and of growth characteristics that may hinder laboratory detection. PMID:16548330

  19. Haemophilus somnus (Histophilus somni) in bighorn sheep.

    Ward, Alton C S; Weiser, Glen C; Anderson, Bruce C; Cummings, Patrick J; Arnold, Karen F; Corbeil, Lynette B

    2006-01-01

    Respiratory disease and poor lamb recruitment have been identified as limiting factors for bighorn-sheep populations. Haemophilus somnus (recently reclassified as Histophilus somni) is associated with respiratory disease in American bison, domestic sheep, and cattle. It is also harbored in their reproductive tracts and has been associated with reproductive failure in domestic sheep and cattle. Therefore, reproductive tract and lung samples from bighorn sheep were evaluated for the presence of this organism. Organisms identified as H. somnus were isolated from 6 of 62 vaginal but none of 12 preputial swab samples. Antigen specific to H. somnus was detected by immunohistochemical study in 4 of 12 formalin-fixed lung tissue samples of bighorn sheep that died with evidence of pneumonia. Notably, H. somnus was found in alveolar debris in areas of inflammation. The 6 vaginal isolates and 2 H. somnus isolates previously cultured from pneumonic lungs of bighorn sheep were compared with 3 representative isolates from domestic sheep and 2 from cattle. The profiles of major outer membrane proteins and antigens for all of the isolates were predominantly similar, although differences that may be associated with the host-parasite relationship and virulence were detected. The DNA restriction fragment length profiles of the bighorn-sheep isolates had similarities not shared with the other isolates, suggesting distinct phylogenetic lines. All of the isolates had similar antimicrobial profiles, but the isolates from the bighorn sheep produced less pigment than those from the domestic livestock, and growth of the former was not enhanced by CO2. Wildlife biologists and diagnosticians should be aware of the potential of these organisms to cause disease in bighorn sheep and of growth characteristics that may hinder laboratory detection.

  20. Pitiose em ovinos nos estados de Pernambuco e Bahia Pythiosis in sheep from Pernambuco and Bahia States, Brazil

    Manuel V. Carrera

    2013-04-01

    wetlands. The disease is characterized mainly by granulomatous lesions in the hosts. The purpose of this study was to report the occurrence of pythiosis in sheep in the states of Pernambuco (PE and Bahia (BA, Northeastern Brazil, as well as to evaluate the efficacy of an immunotherapic against ovine pythiosis. Blood samples were collected from 53 sheep, 49 from flocks in counties located in PE and four from BA. Seven sheep showed clinical signs of ovine pythiosis; one of them was submitted to euthanasia and its head and submandibular lymph node was collected and sent for histopathologic and mycological analyses. Other six sheep were treated with an immunotherapic. During the treatment the animals were kept in the Sheep Industry Sector facilities at Univasf/Petrolina-PE. ELISA, fungal culture and polymerase chain reaction (PCR methods were used to confirm the diagnosis of clinical ovine pythiosis in the sheep flock. At microscopic examination of the material collected from the nasal cavity of a sheep euthanized was observed a focally extensive area of necrosis with presence of diffuse infiltration of intact and degenerated neutrophils bordering the cartilage. Only one sheep showed clinical cure, indicating efficiency in the pythiosis treatment of 16.7% (1/6. Ovine pythiosis has been increasing in several municipalities of PE and BA. In this context, the immunotherapy may be an alternative to be searched. Therefore, further studies are needed to investigate the effect of immunotherapy on ovine pythiosis.

  1. Flocking in Multi-Agent Systems with Multiple Virtual Leaders Based Only on Position Measurements

    Su Housheng

    2012-01-01

    Most existing flocking algorithms assume one single virtual leader and rely on information on both relative positions and relative velocities among neighboring agents. In this paper, the problem of controlling a flock of mobile autonomous agents to follow multiple virtual leaders is investigated by using only position information in the sense that agents with the same virtual leader asymptotically attain the same velocity and track the corresponding virtual leader based on only position measurements. A flocking algorithm is proposed under which every agent asymptotically attains its desired velocity, collision between agents can be avoided, and the final tight formation minimizes all agents' global potentials. A simulation example is presented to verify and illustrate the theoretical results. (general)

  2. Modeling and Flocking Consensus Analysis for Large-Scale UAV Swarms

    Li Bing

    2013-01-01

    Full Text Available Recently, distributed coordination control of the unmanned aerial vehicle (UAV swarms has been a particularly active topic in intelligent system field. In this paper, through understanding the emergent mechanism of the complex system, further research on the flocking and the dynamic characteristic of UAV swarms will be given. Firstly, this paper analyzes the current researches and existent problems of UAV swarms. Afterwards, by the theory of stochastic process and supplemented variables, a differential-integral model is established, converting the system model into Volterra integral equation. The existence and uniqueness of the solution of the system are discussed. Then the flocking control law is given based on artificial potential with system consensus. At last, we analyze the stability of the proposed flocking control algorithm based on the Lyapunov approach and prove that the system in a limited time can converge to the consensus direction of the velocity. Simulation results are provided to verify the conclusion.

  3. Flocking Control of Multiple Mobile Agents with the Rules of Avoiding Collision

    Hongtao Zhou

    2015-01-01

    Full Text Available This paper investigates the flocking and the coordinative control problems of multiple mobile agents with the rules of avoiding collision. We propose a set of control laws using hysteresis in adding new links and applying new potential function to guarantee that the fragmentation of the network can be avoided, under which all agents approach a common velocity vector, and asymptotically converge to a fixed value of interagent distances and collisions between agents can be avoided throughout the motion. Furthermore, we extend the flocking algorithm to solve the flocking situation of the group with a virtual leader agent. The laws can make all agents asymptotically approach the virtual leader and collisions can be avoided between agents in the motion evolution. Finally, some numerical simulations are showed to illustrate the theoretical results.

  4. Flocking multiple microparticles with automatically controlled optical tweezers: solutions and experiments.

    Chen, Haoyao; Wang, Can; Lou, Yunjiang

    2013-06-01

    This paper presents an efficient approach to achieve microparticles flocking with robotics and optical tweezers technologies. All particles trapped by optical tweezers can be automatically moved toward a predefined region without collision. The main contribution of this paper lies in the proposal of several solutions to the flocking manipulation of microparticles in microenvironments. First, a simple flocking controller is proposed to generate the desired positions and velocities for particles' movement. Second, a velocity saturation method is implemented to prevent the desired velocities from exceeding a safe limit. Third, a two-layer control architecture is proposed for the motion control of optical tweezers. This architecture can help make many robotic manipulations achievable under microenvironments. The proposed approach with these solutions can be applied to many bioapplications especially in cell engineering and biomedicine. Experiments on yeast cells with a robot-tweezers system are finally performed to verify the effectiveness of the proposed approach.

  5. Distance Constrained Based Adaptive Flocking Control for Multiagent Networks with Time Delay

    Qing Zhang

    2015-01-01

    Full Text Available The flocking control of multiagent system is a new type of decentralized control method, which has aroused great attention. The paper includes a detailed research in terms of distance constrained based adaptive flocking control for multiagent system with time delay. Firstly, the program on the adaptive flocking with time delay of multiagent is proposed. Secondly, a kind of adaptive controllers and updating laws are presented. According to the Lyapunov stability theory, it is proved that the distance between agents can be larger than a constant during the motion evolution. What is more, velocities of each agent come to the same asymptotically. Finally, the analytical results can be verified by a numerical example.

  6. A Distributed Agent Implementation of Multiple Species Flocking Model for Document Partitioning Clustering

    Cui, Xiaohui [ORNL; Potok, Thomas E [ORNL

    2006-01-01

    The Flocking model, first proposed by Craig Reynolds, is one of the first bio-inspired computational collective behavior models that has many popular applications, such as animation. Our early research has resulted in a flock clustering algorithm that can achieve better performance than the Kmeans or the Ant clustering algorithms for data clustering. This algorithm generates a clustering of a given set of data through the embedding of the highdimensional data items on a two-dimensional grid for efficient clustering result retrieval and visualization. In this paper, we propose a bio-inspired clustering model, the Multiple Species Flocking clustering model (MSF), and present a distributed multi-agent MSF approach for document clustering.

  7. Prevalence and risk factors for Listeria monocytogenes in broiler flocks in Shiraz, southern Iran.

    Hosseinzadeh, Saeid; Shekarforoush, Seyed Shahram; Ansari-Lari, Maryam; EsalatPanah-Fard Jahromi, Mehdi; Berizi, Enayat; Abdollahi, Mostafa

    2012-06-01

    Listeria monocytogenes has been identified as an important foodborne pathogen in recent years. In humans, it most commonly affects pregnant women, neonates, children, elderly people, and persons with a suppressed immune system. It could contaminate both raw and cooked meat and poultry products. Studies regarding prevalence and risk factors of L. monocytogenes in broilers flocks are limited. Therefore, the present study was conducted to determine the prevalence and risk factors for L. monocytogenes in poultry flocks in Shiraz, southern Iran. During August to September 2009, in total, 100 broiler flocks were selected at slaughter, and 21 specimens were collected from cloacal samples from each flock. Polymerase chain reaction (PCR) was performed on the samples enriched in buffered Listeria enrichment broth (BLEB), using specific primers. Furthermore, enriched samples in BLEB and/or BLEB treated with 5% KOH were subcultured on Palcam medium. Data about farm and flocks were collected using a structured questionnaire. The prevalence of L. monocytogenes was 7% (95% CI, 2-12%) and 1% using PCR and culture, respectively. Results showed that using antibiotics during rearing period was dramatically reduced the rate of isolation (odds ratio [OR]=0.07, p=0.03), whereas house capacity of more than 10,000 birds (OR=24.03, p=0.04) and number of houses (OR=2, p=0.02) significantly increased the prevalence. The correlation between poor management of large poultry flocks and increasing the risk of contamination was more likely due to the recontamination of cooked poultry/undercooking or cross-contamination of other ready-to-eat foods.

  8. Herd immunity to Newcastle disease virus in broiler flocks in Israel.

    Wiseman, Anat; Berman, Elyakum M

    2017-08-01

    Due to the ongoing need to protect poultry from virulent Newcastle disease virus, all commercial poultry flocks in Israel are vaccinated according to a defined programme using a combination of live and inactivated vaccines. The vaccination protocol for broilers during the years of the study comprised a live vaccine administered by spray on the day of hatching, inactivated vaccine by subcutaneous injection at 10-12 days of age, and another live vaccine given by aerosol at 17-21 days of age. A cross-sectional study was designed in order to examine the influence of herd immunity on the risk of Newcastle disease outbreak in broiler flocks. The study was based on the extensive field data kept in the Poultry Health Laboratories database. The results of serology tests employing haemagglutination inhibition for Newcastle disease virus were analysed and crossed with the list of flocks that had been diagnosed with ND in the years 2007-2014. At the peak of induced immunization (fifth week of growth), 87.5% of the tested flocks had achieved herd immunity (≥85% of birds in the flock with an HI titre ≥4). Based on a logistic regression model, the odds ratio for ND in flocks without herd immunity was 3.7 (95% CI 1.8-7.3, P-value < 0.001). The higher the percentage of birds with low HI titres the higher the risk of ND outbreak. Under field conditions, herd immunity is an important indicator for the risk of ND outbreak.

  9. Broiler health status has a major negative impact on broiler flock contamination with Campylobacter spp. in Lithuania

    Legaudaite-Lydekaitiene, Viktorija; Serniene, Loreta; Vismantaite, Vaida

    2017-01-01

    analysed using the statistical package SPSS. Study revealed that 59.3% of the examined broiler flocks were contaminated with Campylobacter spp. Statistical analysis revealed that broiler flock contamination with Campylobacter was abattoir- and farm-dependent. Among a number of risk factors (e.g. the number...

  10. The role of litter beetles as potential reservoir for Salmonella enterica and thermophilic Campylobacter spp. between broiler flocks

    Skov, M.N.; Spencer, A.G.; Hald, Birthe

    2004-01-01

    broiler flocks in all) as well as beetles collected during both rotations of production and in the empty period (after cleaning and disinfection) between these flocks were monitored for the presence of salmonella. Examinations for the presence of campylobacter in the same sample materials were also...

  11. Comparison of copper heptonate with copper oxide wire particles as copper supplements for sheep on pasture of high molybdenum content.

    Judson, G J; Babidge, P J

    2002-10-01

    To assess the effectiveness of intramuscular injection of copper heptonate (CuHep) and an oral dose of copper oxide wire particles (COWP) in preventing Cu inadequacy in adult and young sheep on pasture of high Mo content. Field experiments with flocks of mature Merino wethers and crossbred weaners. Adult wethers were given 25 or 37.5 mg Cu as CuHep, 2.5 g COWP or no Cu treatment. The weaners were given 12.5 or 25 mg Cu as CuHep, 1.25 g COWP or no Cu treatment. At intervals over the next 12 (adults) or 8 (weaners) months the sheep were weighed and samples of blood and liver were collected for trace element assay. Wool samples collected from the adults at the end of the experiment were assessed for physical characteristics. The higher dosage of CuHep raised liver Cu above control group values for at least 9 months in adults and 3 months in weaners. The lower dosage of CuHep was similarly effective for 3 months in adults but was without effect in weaners. In adults the response to COWP matched that to the higher dosage of CuHep; in weaners it was greater, lasting at least 5 months. No changes indicative of Cu deficiency, apart from a depressed body weight in adults, were seen. In sheep on pasture of high Mo content a single intramuscular injection of CuHep providing 37.5 mg Cu to adults or 25 mg Cu to weaners will raise liver Cu reserves for at least 9 and 3 months respectively and may be an acceptable alternative to COWP for preventing seasonal Cu deficiency in sheep in southern Australia.

  12. Genetic distinctiveness of the Herdwick sheep breed and two other locally adapted hill breeds of the UK.

    Bowles, Dianna; Carson, Amanda; Isaac, Peter

    2014-01-01

    There is considerable interest in locally adapted breeds of livestock as reservoirs of genetic diversity that may provide important fitness traits for future use in agriculture. In marginal areas, these animals contribute to food security and extract value from land unsuitable for other systems of farming. In England, close to 50% of the national sheep flock is farmed on grassland designated as disadvantaged areas for agricultural production. Many of these areas are in the uplands, where some native breeds of sheep continue to be commercially farmed only in highly localised geographical regions to which they are adapted. This study focuses on three of these breeds, selected for their adaptation to near identical environments and their geographical concentration in regions close to one another. Our objective has been to use retrotyping, microsatellites and single nucleotide polymorphisms to explore the origins of the breeds and whether, despite their similar adaptations and proximity, they are genetically distinctive. We find the three breeds each have a surprisingly different pattern of retrovirus insertions into their genomes compared with one another and with other UK breeds. Uniquely, there is a high incidence of the R0 retrotype in the Herdwick population, characteristic of a primitive genome found previously in very few breeds worldwide and none in the UK mainland. The Herdwick and Rough Fells carry two rare retroviral insertion events, common only in Texels, suggesting sheep populations in the northern uplands have a historical association with the original pin-tail sheep of Texel Island. Microsatellite data and analyses of SNPs associated with RXFP2 (horn traits) and PRLR (reproductive performance traits) also distinguished the three breeds. Significantly, an SNP linked to TMEM154, a locus controlling susceptibility to infection by Maedi-Visna, indicated that all three native hill breeds have a lower than average risk of infection to the lentivirus.

  13. Genetic distinctiveness of the Herdwick sheep breed and two other locally adapted hill breeds of the UK.

    Dianna Bowles

    Full Text Available There is considerable interest in locally adapted breeds of livestock as reservoirs of genetic diversity that may provide important fitness traits for future use in agriculture. In marginal areas, these animals contribute to food security and extract value from land unsuitable for other systems of farming. In England, close to 50% of the national sheep flock is farmed on grassland designated as disadvantaged areas for agricultural production. Many of these areas are in the uplands, where some native breeds of sheep continue to be commercially farmed only in highly localised geographical regions to which they are adapted. This study focuses on three of these breeds, selected for their adaptation to near identical environments and their geographical concentration in regions close to one another. Our objective has been to use retrotyping, microsatellites and single nucleotide polymorphisms to explore the origins of the breeds and whether, despite their similar adaptations and proximity, they are genetically distinctive. We find the three breeds each have a surprisingly different pattern of retrovirus insertions into their genomes compared with one another and with other UK breeds. Uniquely, there is a high incidence of the R0 retrotype in the Herdwick population, characteristic of a primitive genome found previously in very few breeds worldwide and none in the UK mainland. The Herdwick and Rough Fells carry two rare retroviral insertion events, common only in Texels, suggesting sheep populations in the northern uplands have a historical association with the original pin-tail sheep of Texel Island. Microsatellite data and analyses of SNPs associated with RXFP2 (horn traits and PRLR (reproductive performance traits also distinguished the three breeds. Significantly, an SNP linked to TMEM154, a locus controlling susceptibility to infection by Maedi-Visna, indicated that all three native hill breeds have a lower than average risk of infection to the

  14. Chronic interstitial lung disease in nylon flocking industry workers--Rhode Island, 1992-1996.

    1997-09-26

    Interstitial lung disease (ILD) occurs infrequently; some cases are attributed to sarcoidosis, pulmonary hemorrhage syndromes, connective tissue diseases, hypersensitivity pneumonitis, drugs, radiation, and mineral dusts (e.g., silica or asbestos). However, most cases of ILD are of uncertain classification or etiology. This report describes preliminary findings of the investigation in Rhode Island of an outbreak of ILD among workers involved in the manufacture of finely cut nylon (flock) and flocked fabric (used for upholstery, clothing, and automobiles); the findings provide evidence of a newly recognized occupational illness.

  15. Stable Flocking of Multiple Agents Based on Molecular Potential Field and Distributed Receding Horizon Control

    Zhang Yun-Peng; Duan Hai-Bin; Zhang Xiang-Yin

    2011-01-01

    A novel distributed control scheme to generate stable flocking motion for a group of agents is proposed. In this control scheme, a molecular potential field model is applied as the potential field function because of its smoothness and unique shape. The approach of distributed receding horizon control is adopted to drive each agent to find its optimal control input to lower its potential at every step. Experimental results show that this proposed control scheme can ensure that all agents eventually converge to a stable flocking formation with a common velocity and the collisions can also be avoided at the same time. (general)

  16. Scrapie-specific pathology of sheep lymphoid tissues.

    Gillian McGovern

    Full Text Available Transmissible spongiform encephalopathies (TSEs or prion diseases often result in accumulation of disease-associated PrP (PrP(d in the lymphoreticular system (LRS, specifically in association with follicular dendritic cells (FDCs and tingible body macrophages (TBMs of secondary follicles. We studied the effects of sheep scrapie on lymphoid tissue in tonsils and lymph nodes by light and electron microscopy. FDCs of sheep were grouped according to morphology as immature, mature or regressing. Scrapie was associated with FDC dendrite hypertrophy and electron dense deposit or vesicles. PrP(d was located using immunogold labelling at the plasmalemma of FDC dendrites and, infrequently, mature B cells. Abnormal electron dense deposits surrounding FDC dendrites were identified as immunoglobulins suggesting that excess immune complexes are retained and are indicative of an FDC dysfunction. Within scrapie-affected lymph nodes, macrophages outside the follicle and a proportion of germinal centre TBMs accumulated PrP(d within endosomes and lysosomes. In addition, TBMs showed PrP(d in association with the cell membrane, non-coated pits and vesicles, and also with discrete, large and random endoplasmic reticulum networks, which co-localised with ubiquitin. These observations suggest that PrP(d is internalised via the caveolin-mediated pathway, and causes an abnormal disease-related alteration in endoplasmic reticulum structure. In contrast to current dogma, this study shows that sheep scrapie is associated with cytopathology of germinal centres, which we attribute to abnormal antigen complex trapping by FDCs and abnormal endocytic events in TBMs. The nature of the sub-cellular changes in FDCs and TBMs differs from those of scrapie infected neurones and glial cells suggesting that different PrP(d/cell membrane interactions occur in different cell types.

  17. Chronic copper poisoning and changes in the central nervous system of sheep

    Howell, J McM; Blakemore, W F; Gopinath, C; Hall, G A; Parker, J H

    1974-01-01

    Experiments were performed to determine the changes in the brain by both light and electron microscopy at various stages during the production of chronic copper poisoning in sheep. Results indicate that in brain tissue the volume of astrocytic nuclei was significantly greater than that of controls. The swollen astrocytes contained an excess of glycogen, mitochondria, and endoplasmic reticulum.

  18. Aspects Regarding the Coprological Pollution Level in Some Sheep Helminthiasis

    Octavian Negrea

    2013-10-01

    Full Text Available The investigations on the incidence and intensity of parasitism in some endoparasytes in sheep  performed on 376 animals (260 sheep and 116 young adult sheep Turcana breed, Gilău area, Cluj County, indicated an increased incidence in trihostrongilidys  of 72.7% in young  sheep and 65.0% in adult sheep. The incidence of monesya had different values ​​depending on age group, 45.5% at young sheep and 10.0% in  adult sheep. The data obtained regarding the prevalence of hepatobiliary trematodsys of sheep in the study, indicates similar values ​​for the two categories, 27.2% young sheep and 30.0% for adult sheep. Instead the extensivity of  lung strongilatosys showed notable differences between the two groups of animals, 18.1% at young sheep and 35.0% in adult sheep. The cop microscopic pollution degree with trihostrongily eggs in correlation with age group, indicated a dominance of low infestation (50% young sheep and 61.5% adult sheep. In exchange, the data obtained on parasitism intensity with cestode oncospheres expresses a dominance of medium infestation (60.0% in young sheep and the low (10.0% in adult sheep. The intensity level of Hepatobiliary trematodosys parasitism in the young sheep showed a dominance of small and medium infestations (37.5% and in adult sheep are dominant only at low infestations (45.4%. The larvae strongilatosys  parasitism intensity in the lung detected similar values ​​in the two age groups (50.0% in young sheep and 17.2% in adult sheep.

  19. Caracterização epidemiológica e fatores de risco associados à infecção por Brucella ovis em ovinos deslanados do semiárido paraibano Epidemiological characterization and risk factors associated with Brucella ovis infection in sheep in the Brazilian semiarid

    Fabrine A. Santos

    2013-04-01

    Full Text Available Este trabalho teve como objetivo determinar a prevalência de rebanhos ovinos positivos (focos e de animais soropositivos para Brucella ovis na mesorregião do Sertão, Estado da Paraíba, Nordeste do Brasil, bem como identificar fatores de risco. Foram colhidas amostras de sangue de 1.134 animais procedentes de 103 rebanhos em 17 municípios. Para o diagnóstico sorológico da infecção por B. ovis foi utilizado o teste de imunodifusão em gel de ágar (IDGA. Um rebanho foi considerado positivo quando apresentou pelo menos um animal soropositivo. Das 103 propriedades utilizadas 21 (20,39% apresentaram pelo menos um animal soropositivo e dos 1.134 animais, 59 (5,20% foram soropositivos. Realizar higiene nas instalações com periodicidade anual (odds ratio = 7,13; IC 95% = 1,56-32,47; p=0,011 e aquisição de animais (odds ratio = 6,06; IC 95% = 1,39-26,48; p=0,017 foram identificados como fatores de risco. Com base na análise de fatores de risco, recomenda-se a realização de diagnóstico da infecção por B. ovis previamente à aquisição de animais e realização periódica de higienização das instalações.The aim of this investigation was to determine the seroprevalence of Brucella ovis in sheep flocks and individual sheep in the Sertão mesorregion, Paraíba state, Northeastern Brazil, as well as to identify risk factors. Blood samples were collected from 1,134 sheep from 103 flocks in 17 counties. For the serological diagnosis of B. ovis infection the agar gel immunodiffusion test (AGID was carried out. A flock was considered positive when there was at least one seropositive animal. Of the 103 flocks used, 21 (20.39% presented at least one seropositive sheep, and of the 1,134 sheep examined 59 (5.20% seropositive animals were diagnosed. Cleaning of facilities (odds ratio = 7.13; 95% CI=1.56-32.47; p=0.011 and purchase of animals (odds ratio = 6.06; 95% CI=1.39-26.48; p=0.017 were identified as risk factors. Based on the risk factor

  20. Biosecurity Assessment and Seroprevalence of Respiratory Diseases in Backyard Poultry Flocks Located Close to and Far from Commercial Premises.

    Derksen, T; Lampron, R; Hauck, R; Pitesky, M; Gallardo, R A

    2018-03-01

    Raising backyard chickens is an ever-growing hobby in the United States. These flocks can be a substrate for respiratory disease amplification and transmission to commercial facilities. Five hundred fifty-four chickens from 41 backyard flocks were sampled in this study. ELISA kits were used to detect antibodies against avian influenza (AI), infectious laryngotracheitis (ILT), Newcastle disease (ND), infectious bronchitis (IB), Ornithobacterium rhinotracheale (ORT), Mycoplasma gallisepticum (MG), and Mycoplasma synoviae (MS). All visited flock owners answered a biosecurity questionnaire that assessed biosecurity measures. The questionnaire revealed that backyard poultry owners lack simple biosecurity measures such as use of dedicated shoes, their chicken sources are unreliable, and few of them benefit from veterinary oversight. Only one flock had a clear vaccination history against ND and IB. ORT, ND, IB, MS, MG, and ILT were the most seroprevalent in backyard poultry flocks with 97% (41/42), 77.5% (31/40), 75% (30/40), 73% (31/42), 69% (29/42), and 45% (19/42), respectively. The vaccinated flock was not considered in these calculations. When examining the distance between backyard flocks and the nearest commercial poultry facility, ND and MG were significantly more likely to be found in backyard flocks close to (4 miles) commercial poultry. Birds purchased directly from National Poultry Improvement Plan hatcheries showed a reduced ND, MG, and MS antibody prevalence. Wearing dedicated shoes decreased MS antibody-positive birds. Finally, history of wild bird contact had a clear effect on an increased seroprevalence of NDV and MG. Serological results suggest that backyard poultry flocks have the potential to serve as a reservoir or amplifier for poultry respiratory diseases. The information generated in this project should direct extension efforts toward emphasizing the importance of small flock biosecurity and chick acquisition sources.

  1. Defining the breeding goal for a sheep breed including production and functional traits using market data.

    Theodoridis, A; Ragkos, A; Rose, G; Roustemis, D; Arsenos, G

    2017-11-16

    In this study, the economic values for production and functional traits of dairy sheep are estimated through the application of a profit function model using farm-level technical and economic data. The traits incorporated in the model were milk production, prolificacy, fertility, milking speed, longevity and mastitis occurrence. The economic values for these traits were derived as the approximate partial derivative of the specified profit function. A sensitivity analysis was also conducted in order to examine how potential changes in input and output prices would affect the breeding goal. The estimated economic values of the traits revealed their economic impact on the definition of the breeding goal for the specified production system. Milk production and fertility had the highest economic values (€40.30 and €20.28 per standard genetic deviation (SDa)), while, mastitis only had a low negative value of -0.57 €/SDa. Therefore, breeding for clinical mastitis will have a minor impact on farm profitability because it affects a small proportion of the flock and has low additive variance. The production traits, which include milk production, prolificacy and milking speed, contributed most to the breeding goal (70.0%), but functional traits still had a considerable share (30.0%). The results of this study highlight the importance of the knowledge of economic values of traits in the design of a breeding program. It is also suggested that the production and functional traits under consideration can be categorized as those which can be efficiently treated through genetic improvement (e.g. milk production and fertility) while others would be better dealt with through managerial interventions (e.g. mastitis occurrence). Also, sub-clinical mastitis that affects a higher proportion of flocks could have a higher contribution to breeding goals.

  2. Focal symmetrical encephalomalacia in sheep Encefalomalacia focal simétrica em ovino

    Luciano A. Pimentel

    2010-05-01

    Full Text Available Focal symmetrical encephalomalacia (FSE is the most prominent lesion seen in the chronic form of enterotoxemia by Clostridium perfringens type D. This paper reports FSE in sheep in Brazil. Six deaths occurred within a seven days period in a flock of 70, four to 30-month-old Santa Inês sheep in the state of Paraíba in the Brazilian semiarid. The flock was grazing a paddock of irrigated sprouting Cynodon dactylon (Tifton grass, and supplemented, ad libitum, with a concentrate of soybean, corn and wheat. Nervous signs included blindness and recumbence. A 19 month-old sheep was examined clinically and necropsied after a clinical course of three days. Gross lesions were herniation of the cerebellar vermis and multifocal, bilateral, symmetric brownish areas in the internal capsule, thalamus and cerebellar peduncles. Histologic lesions were multifocal, bilateral malacia with some neutrophils, swelling of blood vessels endothelium, perivascular edema, and hemorrhages. The flock was vaccinated, before the outbreak, with only one dose of Clostridium perfringens type D vaccine. Two factors are suggested to be important for the occurrence of the disease: insufficient immunity due to the incorrect vaccination; and high nutritional levels by the supplementation with highly fermentable carbohydrates.Encefalomalacia focal simétrica (EFS é a lesão mais proeminente vista nas formas subaguda ou crônica da enterotoxemia por Clostridium perfringens tipo D. Este trabalho relata EFS em ovinos no semiárido do estado da Paraíba. Seis ovinos morreram, em um período de sete dias, dentro de um rebanho de 70 animais, da raça Santa Inês, entre 4-30 meses de idade, que pastavam em piquete de Cynodon dactylon (capim Tifton, que estava rebrotando. Os ovinos eram suplementados com um concentrado de soja, trigo e milho. Os sinais nervosos incluíam cegueira e decúbito lateral. Um ovino de 19 meses de idade foi examinado clinicamente e necropsiado, depois de um curso

  3. Frozen yogurt from sheep milk

    Elisangela de Abreu

    Full Text Available ABSTRACT The aim of this work was to develop frozen yogurt formulations from powdered yogurt of sheep milk, through an experimental design of 2², with a triplicate at the central point. The variables studied were emulsifier/stabilizer (0.50%, 0.75%, and 1.00% and powder for cream (2.75%, 3.00% and 3.25%. The parameters evaluated were sensory characteristics, texture, and microbiological counts. The results showed that the formulations had counts of S. aureus and fecal coliforms at 45 °C, lactic acid bacteria and Salmonella sp within the limits established by legislation. Instrumental analysis of texture-related parameters (firmness, cohesiveness, adhesiveness, and consistency of the formulations with different concentrations of emulsifier/stabilizer and cream powder showed no significant differences (p > 0.05. In sensory analysis, Formulations 3 and 4 with lower concentrations of emulsifier/stabilizer scored the highest values, thus indicating good acceptability.

  4. Vancomycin-resistant enterococci (VRE) in broiler flocks 5 years after the avoparcin ban

    Heuer, Ole Eske; Pedersen, Karl; Andersen, J.S.

    2002-01-01

    The glycopeptide growth promoter avoparcin was banned from animal production in Denmark in 1995. In this study, we investigated the occurrence of vancomycin-resistant enterococci (VRE) in broiler flocks in the absence of the selective pressure exerted by the use of avoparcin. One hundred sixty...

  5. Detecting Pedestrian Flocks by Fusion of Multi-Modal Sensors in Mobile Phones

    Kjærgaard, Mikkel Baun; Wirz, Martin; Roggen, Daniel

    2012-01-01

    derived from multiple sensor modalities of modern smartphones. Automatic detection of flocks has several important applications, including evacuation management and socially aware computing. The novelty of this paper is, firstly, to use data fusion techniques to combine several sensor modalities (WiFi...

  6. Flock Size and System of Turkey Management by Farmers in Zuru ...

    The study examined flock size and system of management by Turkey producers in Zuru Emirate of Kebbi State, Nigeria. Proportionate random sampling technique was used to select one hundred and eighty seven (187) Turkey producers from four Local Government Areas of the Emirate. Primary data were collected using ...

  7. 9 CFR 145.83 - Terminology and classification; flocks and products.

    2010-01-01

    ... manufacturing process; (B) Mash feed may contain animal protein if the finished feed is treated with a salmonella control product approved by the U.S. Food and Drug Administration. (C) All feed is stored and transported in such a manner as to prevent possible contamination. (iii) The flock is maintained in compliance...

  8. Identification and phylogenetic diversity of parvovirus circulating in commercial chicken and turkey flocks in Croatia.

    Bidin, M; Lojkić, I; Bidin, Z; Tiljar, M; Majnarić, D

    2011-12-01

    Phylogenetic diversity of parvovirus detected in commercial chicken and turkey flocks is described. Nine chicken and six turkey flocks from Croatian farms were tested for parvovirus presence. Intestinal samples from one turkey and seven chicken flocks were found positive, and were sequenced. Natural parvovirus infection was more frequently detected in chickens than in turkeys examined in this study. Sequence analysis of 400 nucleotide fragments of the nonstructural gene (NS) showed that our sequences had more similarity with chicken parvovirus (ChPV) (92.3%-99.7%) than turkey parvovirus (TuPV) (89.5%-98.9%) strains. Phylogenetic analysis grouped our sequences in two clades. Also, the higher prevalence of ChPV than TuPV in tested flocks was defined. The necropsy findings suggested a malabsorption syndrome followed by a preascitic condition. Further research of parvovirus infection, pathogenesis, and the possibility of its association with poult enteritis and mortality syndrome (PEMS) and runting and stunting syndrome (RSS) is needed to clarify its significance as an agent of enteric disease.

  9. Winter body mass and over-ocean flocking as components of danger management by Pacific dunlins

    Ydenberg, R.C.; Dekker, D.; Kaiser, G.; Shepherd, P.C.F.; Ogden, L.E.; Rickards, K.; Lank, D.B.

    2010-01-01

    Background: We compared records of the body mass and roosting behavior of Pacific dunlins (Calidris alpina pacifica) wintering on the Fraser River estuary in southwest British Columbia between the 1970s and the 1990s. 'Over-ocean flocking' is a relatively safe but energetically-expensive alternative

  10. A model for an economically optimal replacement of a breeder flock

    Yassin, H.; Velthuis, A.G.J.; Giesen, G.W.J.; Oude Lansink, A.G.J.M.

    2012-01-01

    A deterministic model is developed to support the tactical and operational replacement decisions at broiler breeder farms. The marginal net revenue approach is applied to determine the optimal replacement age of a flock. The objective function of the model maximizes the annual gross margin over the

  11. 9 CFR 145.23 - Terminology and classification; flocks and products.

    2010-01-01

    ... house, between 15-20 days prior to the flock being moved to laying quarters. (5) Started poultry shall... being moved to laying quarters. (5) Started poultry shall be delivered to and from the farm premises in... qualification is being sought and (a) infected wild birds, (b) contaminated feed or waste, or (c) birds...

  12. Risk factors for Campylobacter colonization in Danish broiler flocks, 2010 to 2011

    Sandberg, M; Sørensen, L L; Steenberg, B

    2015-01-01

    in the Danish Broiler Production ( KIK: ) database. House- and flock-specific data collected in the surveys were supplemented with information obtained from the KIK database. Data obtained from the two studies were analyzed separately by logistic regression analysis. In both models, the dependent variable...

  13. Birds, magnets, soap, and sandblasting: surprising connections in the theory of incompressible flocks

    Toner, John

    In this talk I'll describe the hydrodynamic theory of the motion of incompressible flocks: that is, collections of self-propelled entities (birds\\x9D) that are packed so tightly together that their density cannot change as they move. In two dimensions, this problem can be mapped onto an equilibrium magnet with a peculiar constraint. This problem, in turn, can be shown to be equivalent to a 2d smectic (soap\\x9D), with the flow lines of the flock playing the role of the smectic layers. Finally, this smectic problem can be mapped onto the 1+1 dimensional KPZ equation, which describes the growth or corrosion (sandblasting\\x9D) of a one dimensional interface. The scaling properties of this last system, which have been known exactly for a long time, can thereby be used to determine those of incompressible 2d flocks. One important implication of the resulting scaling laws is that such flocks can exhibit long-ranged order in two dimensions, unlike their equilibrium counterparts.

  14. Fluctuation-driven flocking movement in three dimensions and scale-free correlation.

    Niizato, Takayuki; Gunji, Yukio-Pegio

    2012-01-01

    Recent advances in the study of flocking behavior have permitted more sophisticated analyses than previously possible. The concepts of "topological distances" and "scale-free correlations" are important developments that have contributed to this improvement. These concepts require us to reconsider the notion of a neighborhood when applied to theoretical models. Previous work has assumed that individuals interact with neighbors within a certain radius (called the "metric distance"). However, other work has shown that, assuming topological interactions, starlings interact on average with the six or seven nearest neighbors within a flock. Accounting for this observation, we previously proposed a metric-topological interaction model in two dimensions. The goal of our model was to unite these two interaction components, the metric distance and the topological distance, into one rule. In our previous study, we demonstrated that the metric-topological interaction model could explain a real bird flocking phenomenon called scale-free correlation, which was first reported by Cavagna et al. In this study, we extended our model to three dimensions while also accounting for variations in speed. This three-dimensional metric-topological interaction model displayed scale-free correlation for velocity and orientation. Finally, we introduced an additional new feature of the model, namely, that a flock can store and release its fluctuations.

  15. On the duality between interaction responses and mutual positions in flocking and schooling.

    Perna, Andrea; Grégoire, Guillaume; Mann, Richard P

    2014-01-01

    Recent research in animal behaviour has contributed to determine how alignment, turning responses, and changes of speed mediate flocking and schooling interactions in different animal species. Here, we propose a complementary approach to the analysis of flocking phenomena, based on the idea that animals occupy preferential, anysotropic positions with respect to their neighbours, and devote a large amount of their interaction responses to maintaining their mutual positions. We test our approach by deriving the apparent alignment and attraction responses from simulated trajectories of animals moving side by side, or one in front of the other. We show that the anisotropic positioning of individuals, in combination with noise, is sufficient to reproduce several aspects of the movement responses observed in real animal groups. This anisotropy at the level of interactions should be considered explicitly in future models of flocking and schooling. By making a distinction between interaction responses involved in maintaining a preferred flock configuration, and interaction responses directed at changing it, our work provides a frame to discriminate movement interactions that signal directional conflict from interactions underlying consensual group motion.

  16. Fluctuation-driven flocking movement in three dimensions and scale-free correlation.

    Takayuki Niizato

    Full Text Available Recent advances in the study of flocking behavior have permitted more sophisticated analyses than previously possible. The concepts of "topological distances" and "scale-free correlations" are important developments that have contributed to this improvement. These concepts require us to reconsider the notion of a neighborhood when applied to theoretical models. Previous work has assumed that individuals interact with neighbors within a certain radius (called the "metric distance". However, other work has shown that, assuming topological interactions, starlings interact on average with the six or seven nearest neighbors within a flock. Accounting for this observation, we previously proposed a metric-topological interaction model in two dimensions. The goal of our model was to unite these two interaction components, the metric distance and the topological distance, into one rule. In our previous study, we demonstrated that the metric-topological interaction model could explain a real bird flocking phenomenon called scale-free correlation, which was first reported by Cavagna et al. In this study, we extended our model to three dimensions while also accounting for variations in speed. This three-dimensional metric-topological interaction model displayed scale-free correlation for velocity and orientation. Finally, we introduced an additional new feature of the model, namely, that a flock can store and release its fluctuations.

  17. Birds of a Feather Don't Always Flock Together : User Problems in ...

    Birds of a Feather Don't Always Flock Together : User Problems in Identifying ... for Advanced Learners and Oxford Advanced Learner's Dictionary) revealed a lack ... This paper is based on 14 of these phrasemes, which appear in one or more of ... Five strategies are presented to help learners with their dictionary searches.

  18. Diseases of whooping cranes seen during annual migration of the Rocky Mountain flock

    Snyder, S. Bret; Richard, Michael J.; Drewien, Roderick C.; Thomas, Nancy J.; Thilsted, John P.; Junge, Randall E.

    1991-01-01

    Diagnosis and treatment of ill whooping cranes of the Rocky Mountain flock was provided by a zoological facility. Cases of avian cholera, lead poisoning and avian tuberculosis were encountered. The zoo efforts were an adjunct to the U.S. Fish and Wildlife Service, Whooping Crane Recovery Plan.

  19. Pre-harvest surveillance of Campylobacter and Salmonella in Danish broiler flocks: a 2-year study

    Wedderkopp, A.; Gradel, K.O.; Jorgensen, J.C.

    2001-01-01

    was observed. For each flock, the presence of Campylobacter and Salmonella was recorded in order to estimate the possible correlation between colonisation with the two pathogens. In conclusion, no significant effects on intensive cleaning and disinfection procedures on Campylobacter occurrence could...

  20. Schmallenberg virus experimental infection of sheep

    Wernike, Kerstin; Hoffmann, Bernd; Bréard, Emmanuel

    2013-01-01

    production and diarrhoea for a few days. However, the knowledge about clinical signs and pathogenesis in adult sheep is limited.In the present study, adult sheep of European domestic breeds were inoculated with SBV either as cell culture grown virus or as virus with no history of passage in cell cultures...... 3–5 days by real-time RT-PCR. In total, 13 out of 30 inoculated sheep became RNAemic, with the highest viral load in animals inoculated with virus from low cell culture passaged or the animal passaged material. Contact animals remained negative throughout the study. One RNAemic sheep showed...... results in subclinical infection, transient RNAemia and a specific antibody response. Maintenance of viral RNA in the lymphoreticular system is observed for an extended period....

  1. Selective breeding for scrapie resistance in sheep

    Cristina Santos Sotomaior

    2012-11-01

    Full Text Available It is well known that the susceptibility of sheep to scrapie is determined by the host’s prion protein gene (PRNP. PRNP polymorphisms at codons 136 (alanine, A/valine, V, 154 (histidine, H/arginine, R and 171 (glutamine, Q/histidine, H/arginine, R are the main determinants of sheep susceptibility/resistance to classical scrapie. There are four major variants of the wild-type ARQ allele: VRQ, AHQ, ARH and ARR. Breeding programs have been developed in the European Union and the USA to increase the frequency of the resistant ARR allele while decreasing the frequency of the susceptible VRQ allele in sheep populations. In Brazil, little PRNP genotyping data are available for sheep, and thus far, no controlled breeding scheme for scrapie has been implemented. This review will focus on important epidemiological aspects of scrapie and the use of genetic resistance as a tool in breeding programs to control the disease.

  2. ELECTRICAL PROPERTIES OF COW AND SHEEP'S BONES

    Sawsan Ahmed Elhouri Ahmed; Mubarak Dirar Abdallah2

    2017-01-01

    In this work five samples of (cow and sheep's bones) were prepared to powders in a period of crashing (10 up to 50 sec); weight = 56.73mg To find values of: Refractive index Energy gap And Electrical Conductivity

  3. 1988 sheep monitoring programme January - December 1988

    Colgan, P.A.; Scully, B.J.

    1989-06-01

    This report summarises the work undertaken by the Board during 1988 and includes the results of in vivo farm measurements, slaughterhouse monitoring and butcher's shops surveys relating to sheep and sheepmeat

  4. 1989 sheep monitoring programme January - December 1989

    Colgan, P.A.; Scully, B.J.

    1990-06-01

    This report details the work undertaken by the Board during 1989 and includes the results of on-farm measurements, slaughterhouse monitoring and butchers' shops surveys relating to sheep and sheepmeat (author)

  5. Sheep monitoring programme January - September 1988

    Colgan, P.A.; Scully, B.J.

    1989-02-01

    This report summarises the work undertaken by the Board during the first nine months of 1988, and includes the results of in vivo farm measurements, slaughterhouse monitoring and butchers' shops surveys relating to sheep and sheepmeat.(author)

  6. Footrot and interdigital dermatitis in sheep: farmer satisfaction with current management, their ideal management and sources used to adopt new strategies.

    Wassink, G J; George, T R N; Kaler, J; Green, L E

    2010-08-01

    The aims of this research were to identify management practices that sheep farmers currently use to treat and prevent footrot in sheep and whether they consider that these are successful management tools and to find out how sheep farmers would ideally like to manage footrot in their flock. Over 90% of lameness in sheep in the UK is caused by Dichelobacter nodosus, which presents clinically as interdigital dermatitis (ID) alone or with separation of hoof horn (FR). A questionnaire was sent to 265 farmers to investigate their current management and their satisfaction with current management of the spectrum of clinical presentations of footrot. Farmers were also asked their ideal management of footrot and their interest in, and sources of information for, change. Approximately 160 farmers responded. Farmers satisfied with current management reported a prevalence of lameness 5%. These farmers practised routine foot trimming, footbathing and vaccination against footrot. Whilst 89% of farmers said they were satisfied with their management of FR over 34% were interested in changing management. Farmers identified veterinarians as the most influential source for new information. Farmers reported that ideally they would control FR by culling/isolating lame sheep, sourcing replacements from non-lame parents, trimming feet less, using antibacterial treatments less and using vaccination more. Footbathing was a commonly used management that was linked with dissatisfaction and that also was listed highly as an ideal management. Consequently, some of the ideal managements are in agreement with our understanding of disease control (culling and isolation, sourcing healthy replacements) but others are in contrast with our current knowledge of management and farmers self-reporting of satisfaction of management of footrot (less use of antibacterial treatment, more footbathing and vaccination). One explanation for this is the theory of cognitive dissonance where belief follows behaviour

  7. Sudanese live sheep and mutton exports competitiveness

    Babiker Idris Babiker

    2011-01-01

    Full Text Available The livestock sector of Sudan provides livelihood for about 17% of the population. Sudanese livestock products meet the domestic demand for meat in addition to a substantial excess for export amounting to about 22% of total country exports. It contributes about 19% of GDP. Sheep marketing in Sudan is characterised by traditional operations and is informally organised, although, recently there are great efforts by the formal livestock authorities to organise some secondary and terminal livestock markets. These markets are deficient in basic infrastructures and systematic marketing research. The system as a whole is faced by various complex obstacles and constraints, which decrease the contribution of livestock in general, and sheep in particular, to the national economy, and suppress the optimum exploitation of this resource. These obstacles are represented in the lack of transportation networks that connect the production and consumption centres to break the seasonality of supply that creates shortages and high prices at the consumption centres. This paper employs the policy analysis matrix (PAM technique to examine the Sudanese live sheep and mutton competitiveness in the international market. The results indicated that the market price was greater than the border price implying a positive incentive as an implicit subsidy to the live sheep exporter. The mutton exporters were found subsidised as well. The international value added (IVA indicted a positive foreign exchange earnings or savings. Exported live sheep and mutton coefficient of competitiveness (CIC implied that sheep and mutton exports are profitable and internationally competitive.

  8. Electronics

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  9. Determinants of sheep prices in the highlands of northeastern Ethiopia: implication for sheep value chain development.

    Kassa, Beneberu Teferra; Haile, Anteneh Girma; Essa, John Abdu

    2011-12-01

    In order to assess and identify the determinants of sheep price and price variation across time, a time series data were collected from four selected markets in North Shewa, Northeastern Ethiopia on weekly market day basis for a period of 2 years. Data on animal characteristics and purpose of buying were collected on a weekly basis from randomly selected 15-25 animals, and a total of 7,976 transactions were recorded. A general linear model technique was used to identify factors influencing sheep price, and the results showed that sheep price (liveweight sheep price per kilogram taken as a dependent variable) is affected by animal characteristics such as weight, sex, age, condition, season, and color. Most of the markets' purpose for which the animal was purchased did not affect significantly the price per kilogram. This may be due to the similarity of the markets in terms of buyer's purpose. The results suggest that there will be benefit from coordinated fattening, breeding, and marketing programs to take the highest advantage from the preferred animals' characteristics and selected festival markets. Finally, the study recommends for a coordinated action to enhance the benefit generated for all participant actors in the sheep value chain through raising sheep productivity, improving the capacity of sheep producers and agribusiness entrepreneurs to access and use latest knowledge and technologies; and strengthening linkages among actors in the sheep value chain.

  10. PRNP genetic variability and molecular typing of natural goat scrapie isolates in a high number of infected flocks.

    Fragkiadaki, Eirini G; Vaccari, Gabriele; Ekateriniadou, Loukia V; Agrimi, Umberto; Giadinis, Nektarios D; Chiappini, Barbara; Esposito, Elena; Conte, Michela; Nonno, Romolo

    2011-09-30

    One hundred and four scrapie positive and 77 negative goats from 34 Greek mixed flocks were analysed by prion protein gene sequencing and 17 caprine scrapie isolates from 11 flocks were submitted to molecular isolate typing. For the first time, the protective S146 variant was reported in Greece, while the protective K222 variant was detected in negative but also in five scrapie positive goats from heavily infected flocks. By immunoblotting six isolates, including two goat flockmates carrying the K222 variant, showed molecular features slightly different from all other Greek and Italian isolates co-analysed, possibly suggesting the presence of different scrapie strains in Greece.

  11. PRNP genetic variability and molecular typing of natural goat scrapie isolates in a high number of infected flocks

    Fragkiadaki Eirini G

    2011-09-01

    Full Text Available Abstract One hundred and four scrapie positive and 77 negative goats from 34 Greek mixed flocks were analysed by prion protein gene sequencing and 17 caprine scrapie isolates from 11 flocks were submitted to molecular isolate typing. For the first time, the protective S146 variant was reported in Greece, while the protective K222 variant was detected in negative but also in five scrapie positive goats from heavily infected flocks. By immunoblotting six isolates, including two goat flockmates carrying the K222 variant, showed molecular features slightly different from all other Greek and Italian isolates co-analysed, possibly suggesting the presence of different scrapie strains in Greece.

  12. Molecular study and nucleotide sequencing of Chlamydia abortus isolated from aborted sheep fetuses ewes of Alborz province

    amirreza ebadi

    2015-02-01

    Full Text Available Chlamydia is an obligate intracellular and gram negative coccobacilli and one of the most important causes of abortion in ruminants especially in ewes. This investigation was performed with the purpose of molecular study and sequencing of Chlamydia abortus isolated from aborted sheep fetuses of Alborz Province. In this study, DNA extraction was performed on 100 samples from aborted fetuses of 32 sheep flocks from different areas of Alborz province. Then using specific primers of gene IGS-Sr- RNA, polymerase chain reaction was conducted and 10 samples were selected randomly from the positive cases were sent to Macrogene company in Korea for sequencing. In this study, 37 samples from a total of 100 aborted fetuses were positive for Chlamydia abortus. After sequencing, more than 99 percent of the positive samples were similar with sequences in gene bank. The sequencing results indicated that the samples were very similar to isolates LN554882/1, AF051935/1 and CR848038/1 of the gene bank and were in the same cluster. Also, this investigation indicated that Chlamydia abortus is one of the main reasons of ewe abortion in Alborz province.

  13. Preliminary investigation on the relationship of Raman spectra of sheep meat with shear force and cooking loss.

    Schmidt, Heinar; Scheier, Rico; Hopkins, David L

    2013-01-01

    A prototype handheld Raman system was used as a rapid non-invasive optical device to measure raw sheep meat to estimate cooked meat tenderness and cooking loss. Raman measurements were conducted on m. longissimus thoracis et lumborum samples from two sheep flocks from two different origins which had been aged for five days at 3-4°C before deep freezing and further analysis. The Raman data of 140 samples were correlated with shear force and cooking loss data using PLS regression. Both sample origins could be discriminated and separate correlation models yielded better correlations than the joint correlation model. For shear force, R(2)=0.79 and R(2)=0.86 were obtained for the two sites. Results for cooking loss were comparable: separate models yielded R(2)=0.79 and R(2)=0.83 for the two sites. The results show the potential usefulness of Raman spectra which can be recorded during meat processing for the prediction of quality traits such as tenderness and cooking loss. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Coagulation of sheep intestinal and prefemoral lymph.

    Hanley, C A; Johnston, M G; Nelson, W

    1988-06-01

    We have determined the most suitable method for the automated analysis of the clotting parameters in sheep intestinal and prefemoral lymph as defined by the Activated Partial Thromboplastin Times (APTT; measure of intrinsic coagulation pathway) and the Prothrombin Times (PT; measure of extrinsic coagulation pathway). As opposed to optical density systems, the use of a Fibro-System Fibrometer was found to provide the most consistent assessment of coagulation with the endpoint being the time to fibrin strand formation. We measured APTT in sheep intestinal and prefemoral lymph of 59.78 +/- 7.69 seconds and 51.03 +/- 10.49 seconds respectively. These values were more prolonged than those obtained from sheep blood plasma but only in the case of intestinal lymph were the differences significant (p less than 0.025). Human blood APTT values were significantly less than both sheep blood (p less than 0.05) and sheep intestinal (p less than 0.001) and prefemoral lymph (p less than 0.01). PT values were found to be 21.56 +/- 1.14 seconds in intestinal and 22.00 +/- 1.88 seconds in prefemoral lymph. These values were also significantly greater than those obtained from sheep blood (both p less than 0.001). Human blood PTs were significantly less than both sheep blood (p less than 0.001) and intestinal and prefemoral lymph (both p less than 0.001). Measurement of APTT and PT values in intestinal lymph and PT determinations in prefemoral lymph were not affected by storage in the refrigerator or freezer. There was some indication that APTT values in prefemoral samples were susceptible to storage artifacts; however, the differences in coagulation times were not significant.

  15. Prevalence and characterization of Campylobacter jejuni isolated from pasture flock poultry.

    Hanning, Irene; Biswas, Debabrata; Herrera, Paul; Roesler, Mary; Ricke, Steven C

    2010-09-01

    The growing interest in organic and natural foods warrants a greater need for information on the food safety of these products. In this study, samples were taken from 2 pasture flock farms (N = 178; feed, water, drag swabs, and insect traps), pasture flock retail carcasses (N = 48) and 1 pasture flock processing facility (N = 16) over a period of 8 mo. A total of 105 Campylobacter isolates were obtained from 53 (30%), 36 (75%), and 16 (100%) samples from the farms, retail carcasses, and processing facility, respectively. Of the 105 isolates collected, 65 were C. jejuni, 31 were C. coli, and 9 were other Campylobacter spp. Using PCR, the C. jejuni isolates were further analyzed for virulence genes involved in colonization and survival (flaA, flaC, cadF, dnaJ, racR, cbrR), invasion (virB11, ciaB, pldA), protection against harsh conditions (sodB, htrA, clpA), toxin production (cdtA, cdtB, cdtC), siderophore transport (ceuE), and ganglioside mimicry (wlaN). In addition, the short variable region of the flaA locus (flaA SVR) was sequenced to determine the genetic diversity of the C. jejuni isolates. The flaA SVR diversity indices increased along the farm to carcass continuum. PCR-based analysis indicated a low prevalence of 5 genes involved in colonization (dnaJ, ciaB, pldA, racR, virB11). The results of this survey indicate that the prevalence of Campylobacter on organic retail carcasses is similar to prevalence reports of Campylobacter on conventional retail carcasses. However, the genetic diversity of the flaA SVR genotypes increased along the farm to carcass continuum that contrasted with conventional poultry studies. Campylobacter jejuni is a leading cause of foodborne illness with poultry and poultry products being leading sources of infection. Free-range and pasture flock chickens are becoming more popular; however, there is an inherent biosecurity risk that can increase the prevalence of foodborne pathogens in these flocks. This study aimed to determine sources

  16. Skeletal dysplasia with craniofacial deformity and disproportionate dwarfism in hair sheep of northeastern Brazil.

    Dantas, F P M; Medeiros, G X; Figueiredo, A P M; Thompson, K; Riet-Correa, F

    2014-01-01

    This paper reports a newly described form of skeletal dysplasia affecting Brazilian hair sheep of the Cabugi breed. This breed is characterized by having a short head and in some cases the animals are smaller and more compact than sheep of similar breeds. Lambs born with craniofacial abnormalities and dwarfism that die at 2-6 months of age are frequent in this breed. In a flock of 68 ewes and three rams of the Cabugi breed, 134 lambs were born over a 4-year period. Of these, 14 (10.4%) had marked cranial abnormalities and dwarfism and died or were humanely destroyed, 43 (32%) had a normal face and 77 (57.5%) had the short face characteristic of the breed. Dwarf lambs were much smaller than normal, with short legs, a domed head with retruded muzzle and protruded mandible, sternal deformities and exophthalmic eyes situated more laterally in the face than normal. Microscopical examination of long bones of the limbs, bones of the base of the skull and vertebrae showed no lesions. Bones from four affected lambs and one control lamb were macerated for morphometric examination. Although the length of the spinal cord was similar, there was disproportionate shortening of the appendicular bones, particularly the distal segments. Thus the disease was defined as a skeletal dysplasia characterized by craniofacial deformity and disproportionate dwarfism. It is suggested that the disease is inherited as an incomplete dominant trait. The shortened face, which is a feature of the Cabugi breed, may represent the heterozygous state and the more severe, often lethal, dwarfism may occur in homozygotes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Profitability of a dairy sheep genetic improvement program using artificial insemination.

    Valergakis, G E; Gelasakis, A I; Oikonomou, G; Arsenos, G; Fortomaris, P; Banos, G

    2010-10-01

    This simulation study investigated the farm-level economic benefits of a genetic improvement scheme using artificial insemination (AI) with fresh ram semen in dairy sheep of the Chios breed in Greece. Data were collected from 67 farms associated with the Chios Sheep Breeders' Cooperative 'Macedonia', describing the percentage of ewes that would be artificially inseminated in the flock, pregnancy rate, annual ram costs that could be saved using AI rather than natural mating, expected improvement in milk production, annual costs of semen and feed, milk price and number of years of AI usage. The study considered 77 760 possible scenarios in a 3 × 4 × 4 × 3 × 3 × 3 × 4 × 15 factorial arrangement. Analysis of variance was used to investigate the effect of each factor on farm profitability. All factors considered were statistically significant (P profitability and farmers should become aware that using AI is a long-term investment. Semen price, pregnancy rate and improvement in milk production also had substantial effects. The price of milk and feed had a considerably lower effect on profitability, as did the annual cost of maintaining rams that would be replaced by AI. A positive annual and cumulative return was achieved in the model within the first 6 years. The cost of semen was estimated at 8€ to 10€ per dose for the first 5 years. Where the annual improvement in milk production was 1% of annual phenotypic mean (e.g. 3.0 kg) profitability of the scheme was improved greatly.

  18. Participatory disease surveillance (PDS) of sheep and goats ...

    Keywords: Afar,Goat, Participatory disease surveillance, Sheep, PPR, Sheep and goat ... the region favors the pastoral livestock production system. ..... yellow color on carcass, in ... Foroda/Surota/ Bronchopnemonia fever, coughing, nostrils.

  19. truncatula pasture bY sheeP

    The amounts of amino acids derived by sheep on ... Keywords: Intake, digestion, Medicago truncatula, grazing, sheep ... low productivity based on studies of intake and digestion ... salivary content of extrusa was measured by tritiated water.

  20. 9 CFR 147.6 - Procedure for determining the status of flocks reacting to tests for Mycoplasma gallisepticum...

    2010-01-01

    ... (SPD) test shall be conducted. Provided, that for egg-type and meat-type chicken and waterfowl, exhibition poultry, and game bird flocks, if more than 50 percent of the samples are positive for either...

  1. Flocking dynamics and mean-field limit in the Cucker-Smale-type model with topological interactions

    Haskovec, Jan

    2013-01-01

    separating them. This makes the model scale-free and is motivated by recent extensive observations of starling flocks, suggesting that the interaction ruling animal collective behavior depends on topological rather than the metric distance. We study

  2. 9 CFR 54.8 - Requirements for flock plans and post-exposure management and monitoring plans.

    2010-01-01

    ... HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR... identification the owner of the flock may choose to maintain; (2) Sex, year of birth, breed, and when possible to...

  3. A positive role of multiplicative noise on the emergence of flocking in a stochastic Cucker-Smale system

    Sun, Yongzheng, E-mail: yzsung@gmail.com [School of Science, China University of Mining and Technology, Xuzhou 221008 (China); Lin, Wei, E-mail: wlin@fudan.edu.cn [School of Mathematical Sciences, LMNS, and Shanghai Key Laboratory of Data Science, Fudan University, Shanghai 200433 (China)

    2015-08-15

    In this article, we investigate the flocking of a stochastic Cucker-Smale system with multiplicative measurement noise. We show that there is a noise strength, below which the flocking occurs and the convergence time is a decreasing function of noise strength. Specifically, we find a power-law relationship between the convergence time and the density of group. We also investigate the influence of control parameter and an optimal value is found that minimizes the convergence time.

  4. A positive role of multiplicative noise on the emergence of flocking in a stochastic Cucker-Smale system

    Sun, Yongzheng; Lin, Wei

    2015-01-01

    In this article, we investigate the flocking of a stochastic Cucker-Smale system with multiplicative measurement noise. We show that there is a noise strength, below which the flocking occurs and the convergence time is a decreasing function of noise strength. Specifically, we find a power-law relationship between the convergence time and the density of group. We also investigate the influence of control parameter and an optimal value is found that minimizes the convergence time

  5. A positive role of multiplicative noise on the emergence of flocking in a stochastic Cucker-Smale system.

    Sun, Yongzheng; Lin, Wei

    2015-08-01

    In this article, we investigate the flocking of a stochastic Cucker-Smale system with multiplicative measurement noise. We show that there is a noise strength, below which the flocking occurs and the convergence time is a decreasing function of noise strength. Specifically, we find a power-law relationship between the convergence time and the density of group. We also investigate the influence of control parameter and an optimal value is found that minimizes the convergence time.

  6. Bartonella melophagi in Melophagus ovinus (sheep ked) collected from sheep in northern Oromia, Ethiopia.

    Kumsa, Bersissa; Parola, Philippe; Raoult, Didier; Socolovschi, Cristina

    2014-01-01

    Melophagus ovinus (sheep ked) is one of the most common ectoparasites that contributes to enormous economic losses in the productivity of sheep in many countries. The present study was conducted from January 2012 to July 2013 on M. ovinus collected from sheep at three sites in Ethiopia. Of the sheep studied, 65.7% (88/134) were infested with M. ovinus. The prevalence of M. ovinus was 76% (76/100), 47% (8/17) and 23.5% (4/17) at the Kimbibit, Chacha and Shano sites, respectively. An overall number of 229 M. ovinus specimens (138 females, 86 males and five pupae) and 554 M. ovinus specimens (272 females, 282 males) were collected from young and adult sheep, respectively. Bartonella DNA was detected in 89% (694/783) of M. ovinus using a quantitative Bartonella genus-specific PCR assay targeting the 16S/23S rRNA intergenic spacer region. The sequencing of the PCR products of fragments of the gltA and rpoB genes showed 99.6-100% and 100% homology, respectively, with B. melophagi. Statistically significant variation was not noted in the overall prevalence of Bartonella DNA between female and male M. ovinus. All of the sheep infested with M. ovinus 100% (88/88) harbored at least one M. ovinus specimen that contained Bartonella DNA. This study highlights that B. melophagi in M. ovinus from sheep in highlands in Ethiopia possibly has certain zoonotic importance. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Prevalence and risk factors for Salmonella spp. and Campylobacter spp. caecal colonization in broiler chicken and turkey flocks slaughtered in Quebec, Canada.

    Arsenault, Julie; Letellier, Ann; Quessy, Sylvain; Normand, Valérie; Boulianne, Martine

    2007-10-16

    We conducted an observational study to estimate prevalence and risk factors for Salmonella spp. and Campylobacter spp. caecal colonization in poultry. Eighty-one broiler chicken and 59 turkey flocks selected among flocks slaughtered in the province of Quebec, Canada, were included in the study. Flock status was evaluated by culturing pooled caecal contents from about 30 birds per flock. Exposure to potential risk factors was evaluated with a questionnaire. Odds ratios were computed using multivariable logistic regression. The prevalence of Salmonella-positive flocks was 50% (95% CI: 37, 64) for chickens and 54% (95% CI: 39, 70) for turkeys, respectively. Odds of Salmonella colonization were 2.6 times greater for chicken flocks which failed to lock the chicken house permanently. In turkeys, odds of Salmonella colonization were 4.8-7.7 times greater for flocks which failed to be raised by hatchery. The prevalence of Campylobacter-positive flocks was 35% (95% CI: 22, 49) for chickens and 46% (95% CI: 30, 62) for turkeys. Odds of colonization were 4.1 times higher for chicken flocks raised on farms with professional rodent control and 5.2 times higher for flocks with manure heap >200m from the poultry house, and also increased with the number of birds raised per year on the farm and with the age at slaughter. For turkeys, odds of Campylobacter flock colonization were 3.2 times greater in flocks having a manure heap at flocks drinking unchlorinated water.

  8. Survival of bighorn sheep (Ovis canadensis) commingled with domestic sheep (Ovis aries) in the absence of Mycoplasma ovipneumoniae.

    Besser, Thomas E; Cassirer, E Frances; Yamada, Catherine; Potter, Kathleen A; Herndon, Caroline; Foreyt, William J; Knowles, Donald P; Srikumaran, Subramaniam

    2012-01-01

    To test the hypothesis that Mycoplasma ovipneumoniae is an important agent of the bighorn sheep (Ovis canadensis) pneumonia that has previously inevitably followed experimental commingling with domestic sheep (Ovis aries), we commingled M. ovipneumoniae-free domestic and bighorn sheep (n=4 each). One bighorn sheep died with acute pneumonia 90 days after commingling, but the other three remained healthy for >100 days. This unprecedented survival rate is significantly different (P=0.002) from that of previous bighorn-domestic sheep contact studies but similar to (P>0.05) bighorn sheep survival following commingling with other ungulates. The absence of epizootic respiratory disease in this experiment supports the hypothesized role of M. ovipneumoniae as a key pathogen of epizootic pneumonia in bighorn sheep commingled with domestic sheep.

  9. Patterns of faecal nematode egg shedding after treatment of sheep with a long-acting formulation of moxidectin.

    Crilly, James Patrick; Jennings, Amy; Sargison, Neil

    2015-09-15

    Much of the current information on the effects of long-acting anthelmintics on nematode populations derives either from research farms or mathematical models. A survey was performed with the aim of establishing how moxidectin is currently being used on sheep farms in the south-east of Scotland. A study was undertaken on a subsection of the surveyed farms to examine the effects of long-acting moxidectin treatments in both spring and autumn on faecal nematode egg output. The survey showed that whole flock treatments of injectable 2% moxidectin were used to control sheep scab on 21% of farms. Injectable 2% moxidectin and oral moxidectin were used to control the periparturient rise in faecal nematode egg shedding by ewes on 13% and 55% of farms respectively. The effects of injectable 2% moxidectin treatment on faecal nematode egg shedding post-treatment in both the autumn and spring were investigated by faecal nematode egg counts at the time of treatment and at 2-weekly interval thereafter on eight and six farms in the autumn and spring, respectively. Faecal egg shedding recommenced at 8 weeks (autumn) and 4 weeks (spring) post-treatment. Counts increased to a peak and then declined. The mean (95% confidence interval) peak counts post-treatment were 2.8 (0.6, 5.1), 3.6 (1.7, 5.5) and 53.5 (25.1, 82.0) eggs per gram (EPG) for autumn-treated ewes, autumn-treated lambs and spring-treated ewes respectively. The spring treated sheep showed a statistically significantly earlier return to faecal egg shedding (p=0.0125, p=0.0342) compared to both other groups, statistically significantly higher peak in egg counts than the autumn treated sheep (pegg counts (p=0.0148). There was no statistically significant difference in the timing of the peak FECs between autumn and spring (p=0.211). The FECs of all groups of sheep treated with an injectable long-acting formulation of moxidectin became positive earlier than would be expected from the period of persistence given on the datasheet

  10. Comparison of bacteriological culture and PCR for detection of bacteria in ovine milk--sheep are not small cows.

    Zadoks, Ruth N; Tassi, Riccardo; Martin, Elena; Holopainen, Jani; McCallum, Sarah; Gibbons, James; Ballingall, Keith T

    2014-10-01

    Mastitis, inflammation of the mammary gland, is an important cause of disease, mortality, and production losses in dairy and meat sheep. Mastitis is commonly caused by intramammary infection with bacteria, which can be detected by bacterial culture or PCR. PathoProof (Thermo Fisher Scientific Ltd., Vantaa, Finland) is a commercially available real-time PCR system for the detection of bovine mastitis pathogens. Sheep differ from cattle in the bacterial species or bacterial strains that cause mastitis, as well as in the composition of their milk. The aim of this study was to evaluate whether the PathoProof system was suitable for detection of mastitis pathogens in sheep milk. Milk samples were collected aseptically from 219 udder halves of 113 clinically healthy ewes in a single flock. Aliquots were used for bacteriological culture and real-time PCR-based detection of bacteria. For species identified by culture, the diagnosis was confirmed by species-specific conventional PCR or by sequencing of a housekeeping gene. The majority of samples were negative by culture (74.4% of 219 samples) and real-time PCR (82.3% of 192 samples). Agreement was observed for 138 of 192 samples. Thirty-four samples were positive by culture only, mostly due to presence of species that are not covered by primers in the PCR system (e.g., Mannheimia spp.). Two samples were positive for Streptococcus uberis by culture but not by PCR directly from the milk samples. This was not due to inability of the PCR primers to amplify ovine Streptococcus uberis, as diluted DNA extracts from the same samples and DNA extracts from the bacterial isolates were positive by real-time PCR. For samples containing Staphylococcus spp., 11 samples were positive by culture and PCR, 9 by culture only, and 20 by PCR only. Samples that were negative by either method had lower bacterial load than samples that were positive for both methods, whereas no clear relation with species identity was observed. This study provides

  11. Evidence that certain clones of Campylobacter jejuni persist during successive broiler flock rotations

    Petersen, L.; Wedderkopp, A.

    2001-01-01

    selected. Twelve broiler houses located on 10 farms were included in the study. The C,jejuni isolates collected from the selected houses during the surveillance were typed using fla typing and macrorestriction profiling (MRP), and a subset of the isolates, representing each of the identified clones...... (7 of 13) had fla type 1/1, but MRPs distinguished between isolates from different houses, and fla type 1/1 clones belonged to different serotypes, Seven houses carried persistent clones that covered an interval of at least four broiler flock rotations, or at least one half year. The dominant fla...... with recurrent Campylobacter problems. The MRPs of clones belonging to fla type 1/1 serotype O:2 isolated from persistently infected flocks shared a high percentage of bands compared to the remaining isolates, indicating that some clones that have the ability to cause persistent infections in broiler farms...

  12. Novel Textile Scaffolds Generated by Flock Technology for Tissue Engineering of Bone and Cartilage

    Walther, Anja; Hoyer, Birgit; Springer, Armin; Mrozik, Birgit; Hanke, Thomas; Cherif, Chokri; Pompe, Wolfgang; Gelinsky, Michael

    2012-01-01

    Textile scaffolds can be found in a variety of application areas in regenerative medicine and tissue engineering. In the present study we used electrostatic flocking—a well-known textile technology—to produce scaffolds for tissue engineering of bone. Flock scaffolds stand out due to their unique structure: parallel arranged fibers that are aligned perpendicularly to a substrate, resulting in mechanically stable structures with a high porosity. In compression tests we demonstrated good mechanical properties of such scaffolds and in cell culture experiments we showed that flock scaffolds allow attachment and proliferation of human mesenchymal stem cells and support their osteogenic differentiation. These matrices represent promising scaffolds for tissue engineering. PMID:28817062

  13. Bidirectional sorting of flocking particles in the presence of asymmetric barriers.

    Drocco, Jeffrey A; Olson Reichhardt, C J; Reichhardt, C

    2012-05-01

    We demonstrate numerically bidirectional sorting of flocking particles interacting with an array of V-shaped asymmetric barriers. Each particle aligns with the average swimming direction of its neighbors according to the Vicsek model and experiences additional steric interactions as well as repulsion from the fixed barriers. We show that particles preferentially localize to one side of the barrier array over time and that the direction of this rectification can be reversed by adjusting the particle-particle exclusion radius or the noise term in the equations of motion. These results provide a conceptual basis for isolation and sorting of single-cell and multicellular organisms that move collectively according to flocking-type interaction rules.

  14. Time-asymptotic interaction of flocking particles and an incompressible viscous fluid

    Bae, Hyeong-Ohk; Choi, Young-Pil; Ha, Seung-Yeal; Kang, Moon-Jin

    2012-01-01

    We present a new coupled kinetic-fluid model for the interactions between Cucker–Smale (C–S) flocking particles and incompressible fluid on the periodic spatial domain T d . Our coupled system consists of the kinetic C–S equation and the incompressible Navier–Stokes equations, and these two systems are coupled through the drag force. For the proposed model, we provide a global existence of weak solutions and a priori time-asymptotic exponential flocking estimates for any smooth flow, when the kinematic viscosity of the fluid is sufficiently large. The velocity of individual C–S particles and fluid velocity tend to the averaged time-dependent particle velocities exponentially fast

  15. Flocking of Second-Order Multiagent Systems With Connectivity Preservation Based on Algebraic Connectivity Estimation.

    Fang, Hao; Wei, Yue; Chen, Jie; Xin, Bin

    2017-04-01

    The problem of flocking of second-order multiagent systems with connectivity preservation is investigated in this paper. First, for estimating the algebraic connectivity as well as the corresponding eigenvector, a new decentralized inverse power iteration scheme is formulated. Then, based on the estimation of the algebraic connectivity, a set of distributed gradient-based flocking control protocols is built with a new class of generalized hybrid potential fields which could guarantee collision avoidance, desired distance stabilization, and the connectivity of the underlying communication network simultaneously. What is important is that the proposed control scheme allows the existing edges to be broken without violation of connectivity constraints, and thus yields more flexibility of motions and reduces the communication cost for the multiagent system. In the end, nontrivial comparative simulations and experimental results are performed to demonstrate the effectiveness of the theoretical results and highlight the advantages of the proposed estimation scheme and control algorithm.

  16. Novel Textile Scaffolds Generated by Flock Technology for Tissue Engineering of Bone and Cartilage

    Thomas Hanke

    2012-03-01

    Full Text Available Textile scaffolds can be found in a variety of application areas in regenerative medicine and tissue engineering. In the present study we used electrostatic flocking—a well-known textile technology—to produce scaffolds for tissue engineering of bone. Flock scaffolds stand out due to their unique structure: parallel arranged fibers that are aligned perpendicularly to a substrate, resulting in mechanically stable structures with a high porosity. In compression tests we demonstrated good mechanical properties of such scaffolds and in cell culture experiments we showed that flock scaffolds allow attachment and proliferation of human mesenchymal stem cells and support their osteogenic differentiation. These matrices represent promising scaffolds for tissue engineering.

  17. Collective Behavior of Chiral Active Matter: Pattern Formation and Enhanced Flocking

    Liebchen, Benno; Levis, Demian

    2017-08-01

    We generalize the Vicsek model to describe the collective behavior of polar circle swimmers with local alignment interactions. While the phase transition leading to collective motion in 2D (flocking) occurs at the same interaction to noise ratio as for linear swimmers, as we show, circular motion enhances the polarization in the ordered phase (enhanced flocking) and induces secondary instabilities leading to structure formation. Slow rotations promote macroscopic droplets with late time sizes proportional to the system size (indicating phase separation) whereas fast rotations generate patterns consisting of phase synchronized microflocks with a controllable characteristic size proportional to the average single-particle swimming radius. Our results defy the viewpoint that monofrequent rotations form a vapid extension of the Vicsek model and establish a generic route to pattern formation in chiral active matter with possible applications for understanding and designing rotating microflocks.

  18. Quantized flocking control for second-order multiple agents with obstacle avoidance

    Chunguang Li

    2016-01-01

    Full Text Available A quantized flocking control for a group of second-order multiple agents with obstacle avoidance is proposed to address the problem of the exchange of information needed for quantification. With a reasonable assumption, a logarithmic or uniform quantizer is used for the exchange of relative position and velocity information between adjacent agents and the virtual leader, moving at a steady speed along a straight line, and a distributed flocking algorithm with obstacle avoidance capability is designed based on the quantitative information. The Lyapunov stability criterion of nonsmooth systems and the invariance principle are used to prove the stability of these systems. The simulations and experiments are presented to demonstrate the feasibility and effectiveness of the proposed approach.

  19. Evaluation of sampling methods for the detection of Salmonella in broiler flocks

    Skov, Marianne N.; Carstensen, B.; Tornoe, N.

    1999-01-01

    The present study compares four different sampling methods potentially applicable to detection of Salmonella in broiler flocks, based on collection of faecal samples (i) by hand, 300 fresh faecal samples (ii) absorbed on five sheets of paper (iii) absorbed on five pairs of socks (elastic cotton...... horizontal or vertical) were found in the investigation. The results showed that the sock method (five pairs of socks) had a sensitivity comparable with the hand collection method (60 pools of five faecal samples); the paper collection method was inferior, as was the use of only one pair of socks, Estimation...... tubes pulled over the boots and termed 'socks') and (iv) by using only one pair of socks. Twenty-three broiler flocks were included in the investigation and 18 of these were found to be positive by at least one method. Seven serotypes of Salmonella with different patterns of transmission (mainly...

  20. Pinning control of complex networked systems synchronization, consensus and flocking of networked systems via pinning

    Su, Housheng

    2013-01-01

    Synchronization, consensus and flocking are ubiquitous requirements in networked systems. Pinning Control of Complex Networked Systems investigates these requirements by using the pinning control strategy, which aims to control the whole dynamical network with huge numbers of nodes by imposing controllers for only a fraction of the nodes. As the direct control of every node in a dynamical network with huge numbers of nodes might be impossible or unnecessary, it’s then very important to use the pinning control strategy for the synchronization of complex dynamical networks. The research on pinning control strategy in consensus and flocking of multi-agent systems can not only help us to better understand the mechanisms of natural collective phenomena, but also benefit applications in mobile sensor/robot networks. This book offers a valuable resource for researchers and engineers working in the fields of control theory and control engineering.   Housheng Su is an Associate Professor at the Department of Contro...

  1. Erysipelas in a free-range layer flock with conjunctival oedema as an unusual clinical sign.

    Schmitt, Ferdinand; Schade, Benjamin; Böhm, Brigitte; Shimoji, Yoshihiro; Pfahler, Corinna

    2014-01-01

    Erysipelas was diagnosed in a free-range laying flock with a high mortality of up to 7% per day and a severe decrease in egg production to 45%. The disease had a short course and unusual clinical features for erysipelas, including swollen, lacrimating and encrusted eyes. Bacteriologically, trapped poultry red mites and affected animals were culture-positive for Erysipelothrix rhusiopathiae. Isolates from layers and mites were both serotype 1b. Histopathology revealed disseminated intravasal coagulopathy in conjunctival small vessels as the cause of the oedema of the eye adnexes. After treatment with penicillin, mortality and egg production returned to normal levels. Although erysipelas in laying hens is rarely reported, it can develop as an emerging disease in alternative rearing systems and should always be considered if mortality increases in an older flock, especially with a high infestation of poultry red mites.

  2. Estimation of genetic diversity between three Saudi sheep breeds ...

    Estimation of genetic diversity between three Saudi sheep breeds using DNA markers. AAG Adam, NB Hamza, MAW Salim, KS Khalil. Abstract. The genetic variation of Najdi, Harri and Awassi breeds of Saudi sheep prevailing in Raniah province of Makka district were assessed and compared to Sudanese Desert sheep ...

  3. Prevalence of Brucella antibodies in sheep and springbok ...

    It was concluded that sheep and springbok on the eleven farms had not been exposed to Brucella melitensis and B. abortus infections and that on previously positive farms the infection had been eliminated in sheep and had not spread to springbok. Key words: springbok, sheep, Brucella melitensis, Brucella abortus, ...

  4. Integrating agroforestry and sheep feed in Mali | IDRC - International ...

    The challenge. Sheep herding plays a significant role in the livelihoods of rural households in Mali and other semi-arid countries of West Africa. Although sheep herding could improve the incomes of rural women, its potential is not being realized because a lack of feed reduces the meat production of sheep. Agroforestry ...

  5. Breeding strategies to make sheep farms resilient to uncertainty

    Rose, I.J.

    2014-01-01

    The sheep industry in Western Australian has had many challenges over the last 20 years which have caused sheep numbers to decline. This decline is because sheep farms are not resilient to uncertain pasture growth and commodity prices. One way to improve resilience and profitability of farming

  6. Gastrolobium spp. poisoning in sheep: A case report

    This report describes the history and investigation of a suspected plant poisoning event in Western Australia where fifteen sheep died. One of the poisoned sheep was necropsied and gross and microscopic pathology of the poisoned sheep is described. Monofluoroacetate was detected in rumen contents ...

  7. Forage selection and performance of sheep grazing dry annual range.

    Ridder, de N.; Benjamin, R.W.; Keulen, van H.

    1986-01-01

    During 114 days of grazing, sheep grazing a dry annual pasture in Israel selected the fine fraction available with a higher nutritive value. As this fraction became depleted and feed quality dropped, organic matter intake dropped from 1.73 to 0.75 kg/sheep/d. Sheep lost weight, body condition and

  8. 9 CFR 93.435 - Sheep and goats.

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Sheep and goats. 93.435 Section 93.435... CONVEYANCE AND SHIPPING CONTAINERS Ruminants Additional General Provisions § 93.435 Sheep and goats. (a) Except as provided in paragraph (b) of this section, all sheep and goats imported into the United States...

  9. Spontaneous poisoning by Prosopis juliflora (Leguminosae) in sheep

    The aim of this paper is to describe the first report of clinical, epidemiological and pathological aspects of spontaneous poisoning by Prosopis juliflora in sheep. Of a total of 500 sheep at risk, two adult male sheep were affected; one died spontaneously and the other animal was examined, euthaniz...

  10. Grasses grazed by springbok and sheep | R. | African Journal of ...

    Grazing habits were determined by analysis of rumina from slaughtered springbok and sheep where springbok grazed together with Merino sheep in False Upper Karoo and together with Dorper sheep in Kalahari Thornveld. Results show that in both veld types, grass constituted about 39 percent of the dry mass intake of ...

  11. Winter body mass and over-ocean flocking as components of danger management by Pacific dunlins

    Ogden Lesley

    2010-01-01

    Full Text Available Abstract Background We compared records of the body mass and roosting behavior of Pacific dunlins (Calidris alpina pacifica wintering on the Fraser River estuary in southwest British Columbia between the 1970s and the 1990s. 'Over-ocean flocking' is a relatively safe but energetically-expensive alternative to roosting during the high tide period. Fat stores offer protection against starvation, but are a liability in escape performance, and increase flight costs. Peregrine falcons (Falco peregrinus were scarce on the Fraser River estuary in the 1970s, but their numbers have since recovered, and they prey heavily on dunlins. The increase has altered the balance between predation and starvation risks for dunlins, and thus how dunlins regulate roosting behavior and body mass to manage the danger. We therefore predicted an increase in the frequency of over-ocean flocking as well as a decrease in the amount of fat carried by dunlins over these decades. Results Historical observations indicate that over-ocean flocking of dunlins was rare prior to the mid-1990s and became common thereafter. Residual body masses of dunlins were higher in the 1970s, with the greatest difference between the decades coinciding with peak peregrine abundance in October, and shrinking over the course of winter as falcon seasonal abundance declines. Whole-body fat content of dunlins was lower in the 1990s, and accounted for most of the change in body mass. Conclusions Pacific dunlins appear to manage danger in a complex manner that involves adjustments both in fat reserves and roosting behavior. We discuss reasons why over-ocean flocking has apparently become more common on the Fraser estuary than at other dunlin wintering sites.

  12. Novel Textile Scaffolds Generated by Flock Technology for Tissue Engineering of Bone and Cartilage

    Walther, Anja; Hoyer, Birgit; Springer, Armin; Mrozik, Birgit; Hanke, Thomas; Cherif, Chokri; Pompe, Wolfgang; Gelinsky, Michael

    2012-01-01

    Textile scaffolds can be found in a variety of application areas in regenerative medicine and tissue engineering. In the present study we used electrostatic flocking—a well-known textile technology—to produce scaffolds for tissue engineering of bone. Flock scaffolds stand out due to their unique structure: parallel arranged fibers that are aligned perpendicularly to a substrate, resulting in mechanically stable structures with a high porosity. In compression tests we demonstrated good mechani...

  13. Winter body mass and over-ocean flocking as components of danger management by Pacific dunlins.

    Ydenberg, Ronald C; Dekker, Dick; Kaiser, Gary; Shepherd, Philippa C F; Ogden, Lesley Evans; Rickards, Karen; Lank, David B

    2010-01-21

    We compared records of the body mass and roosting behavior of Pacific dunlins (Calidris alpina pacifica) wintering on the Fraser River estuary in southwest British Columbia between the 1970s and the 1990s. 'Over-ocean flocking' is a relatively safe but energetically-expensive alternative to roosting during the high tide period. Fat stores offer protection against starvation, but are a liability in escape performance, and increase flight costs. Peregrine falcons (Falco peregrinus) were scarce on the Fraser River estuary in the 1970s, but their numbers have since recovered, and they prey heavily on dunlins. The increase has altered the balance between predation and starvation risks for dunlins, and thus how dunlins regulate roosting behavior and body mass to manage the danger. We therefore predicted an increase in the frequency of over-ocean flocking as well as a decrease in the amount of fat carried by dunlins over these decades. Historical observations indicate that over-ocean flocking of dunlins was rare prior to the mid-1990s and became common thereafter. Residual body masses of dunlins were higher in the 1970s, with the greatest difference between the decades coinciding with peak peregrine abundance in October, and shrinking over the course of winter as falcon seasonal abundance declines. Whole-body fat content of dunlins was lower in the 1990s, and accounted for most of the change in body mass. Pacific dunlins appear to manage danger in a complex manner that involves adjustments both in fat reserves and roosting behavior. We discuss reasons why over-ocean flocking has apparently become more common on the Fraser estuary than at other dunlin wintering sites.

  14. SEROMONITORING OF AVIAN INFLUENZA H9 SUBTYPE IN BREEDERS AND COMMERCIAL LAYER FLOCKS

    M. Numan, M. Siddique and M. S. Yousaf1

    2005-07-01

    Full Text Available A serological survey for detection of antibodies against avian influenza virus (AIV subtype H9 in vaccinated layer flocks was carried out. Serum samples were divided into age groups A, B, C, D (commercial layers and E, F, G, H (layer breeders. Haemagglutination inhibition (HI test was performed to determine serum antibodies against AIV-H9 subtype. Geometric mean titer (GMT values were calculated. Results showed the level of protection of vaccinated birds was satisfactory.

  15. The physics of flocking: Correlation as a compass from experiments to theory

    Cavagna, Andrea; Giardina, Irene; Grigera, Tomás S.

    2018-01-01

    Collective behavior in biological systems is a complex topic, to say the least. It runs wildly across scales in both space and time, involving taxonomically vastly different organisms, from bacteria and cell clusters, to insect swarms and up to vertebrate groups. It entails concepts as diverse as coordination, emergence, interaction, information, cooperation, decision-making, and synchronization. Amid this jumble, however, we cannot help noting many similarities between collective behavior in biological systems and collective behavior in statistical physics, even though none of these organisms remotely looks like an Ising spin. Such similarities, though somewhat qualitative, are startling, and regard mostly the emergence of global dynamical patterns qualitatively different from individual behavior, and the development of system-level order from local interactions. It is therefore tempting to describe collective behavior in biology within the conceptual framework of statistical physics, in the hope to extend to this new fascinating field at least part of the great predictive power of theoretical physics. In this review we propose that the conceptual cornerstone of this ambitious program be that of correlation. To illustrate this idea we address the case of collective behavior in bird flocks. Two key threads emerge, as two sides of one single story: the presence of scale-free correlations and the dynamical mechanism of information transfer. We discuss first static correlations in starling flocks, in particular the experimental finding of their scale-free nature, the formulation of models that account for this fact using maximum entropy, and the relation of scale-free correlations to information transfer. This is followed by a dynamic treatment of information propagation (propagation of turns across a flock), starting with a discussion of experimental results and following with possible theoretical explanations of those, which require the addition of behavioral

  16. EFFECT OF INBREEDING ON PRE-WEANING GROWTH TRAITS IN THALLI SHEEP

    A. HUSSAIN, P. AKHTAR, S. ALI, M. YOUNAS1 AND M. SHAFIQ2

    2006-07-01

    Full Text Available Pedigree records of 17250 Thalli sheep with 17030 lambings maintained at the Livestock Experiment Station, Rakh Ghulaman, Distt. Bhakkar, Pakistan during the period from 1975 to 2004 were utilized in the present study. Average values for birth weight, weights at 60 and 90 days of age, weaning weight and pre-weaning average daily gain were 4.11 ± 0.82, 11.58 ± 3.57, 14.92 ± 4.56, 18.95 ± 4.56 and 0.12 ± 0.04 kg, respectively. Coefficients of inbreeding ranged from 10.15 to 37.50 percent for 295 animals, being 1.70 percent of the flock. Inbreeding significantly (P<0.01 affected birth and 60 days weight. Birth weight and 60 days weight decreased by 0.051 and 0.048 kg for each 1 percent increase in the level of inbreeding. However, inbreeding had non significant effect on weight at 90 days of age, weaning weight and pre-weaning average daily gain. The regression values for these traits were 0.010, 0.083 and 0.105, respectively. It was concluded that inbreeding showed deleterious effects only in early stages of life but as the lambs grew older the effect of inbreeding on pre-weaning traits diminished.

  17. Isolation of Campylobacter from Brazilian broiler flocks using different culturing procedures.

    Vaz, C S L; Voss-Rech, D; Pozza, J S; Coldebella, A; Silva, V S

    2014-11-01

    Conventional culturing methods enable the detection of Campylobacter in broiler flocks. However, laboratory culture of Campylobacter is laborious because of its fastidious behavior and the presence of competing nontarget bacteria. This study evaluated different protocols to isolate Campylobacter from broiler litter, feces, and cloacal and drag swabs. Samples taken from commercial Brazilian broiler flocks were directly streaked onto Preston agar (PA), Campy-Line agar (CLA), and modified charcoal cefoperazone deoxycholate agar (mCCDA) and also enriched in blood-free Bolton broth (bfBB) for 24 and 48 h followed by plating onto the different selective media. Higher numbers of Campylobacter-positive cloacal and drag swab samples were observed using either direct plating or enrichment for 24 h before plating onto PA, compared with enrichment for 48 h (P media. Together, these data showed that direct plating onto PA and onto either CLA or mCCDA as the second selective agar enabled the reliable isolation of thermophilic Campylobacter species from broiler samples. Finally, Campylobacter was detected in all broiler flocks sampled. ©2014 Poultry Science Association Inc.

  18. A Q-Learning Approach to Flocking With UAVs in a Stochastic Environment.

    Hung, Shao-Ming; Givigi, Sidney N

    2017-01-01

    In the past two decades, unmanned aerial vehicles (UAVs) have demonstrated their efficacy in supporting both military and civilian applications, where tasks can be dull, dirty, dangerous, or simply too costly with conventional methods. Many of the applications contain tasks that can be executed in parallel, hence the natural progression is to deploy multiple UAVs working together as a force multiplier. However, to do so requires autonomous coordination among the UAVs, similar to swarming behaviors seen in animals and insects. This paper looks at flocking with small fixed-wing UAVs in the context of a model-free reinforcement learning problem. In particular, Peng's Q(λ) with a variable learning rate is employed by the followers to learn a control policy that facilitates flocking in a leader-follower topology. The problem is structured as a Markov decision process, where the agents are modeled as small fixed-wing UAVs that experience stochasticity due to disturbances such as winds and control noises, as well as weight and balance issues. Learned policies are compared to ones solved using stochastic optimal control (i.e., dynamic programming) by evaluating the average cost incurred during flight according to a cost function. Simulation results demonstrate the feasibility of the proposed learning approach at enabling agents to learn how to flock in a leader-follower topology, while operating in a nonstationary stochastic environment.

  19. Viral Agents Associated with Poult Enteritis in Croatian Commercial Turkey Flocks

    Ivana Lojkić

    2010-01-01

    Full Text Available From 2003 to 2006, samples of intestinal content and spleens from 10-day-old to 6-week-old fattening turkeys showing clinical signs of enteritis were analyzed by specific PCR and RT-PCRs for detection of haemorrhagic enteritis virus (HEV, avian reovirus (ARV, turkey astrovirus-2 (TastV-2, and turkey coronavirus (TCV. A total of 23 flocks from 6 farms were included in the study. Specific sequence for HEV hexon gene was present in 6 samples from turkeys younger than and in one turkey at 6 weeks of age. A product of TastV-2 capsid gene was detected in 17/23 intestinal content samples. A 626-bp band of sigma A (S2 encoding gene segment from avian reovirus was present in three samples, all from the same farm. Sequence analysis of 450 bp fragment of avian reovirus sigma A encoding gene sequence showed that our strain had the identity of 91.3% with the strains 138, 2408, 1733, 919, T6, and Os161. No TCV specific PCR band was found in any sample. Four flocks were positive simultaneously for HEV and TastV-2, and three flocks on TastV-2 and ARV. Severity of poult enteritis described in our study is caused by immunosuppressive TastV-2 in combination with HEV or ARV.

  20. Prevalence of gastrointestinal nematode infections in goat flocks on semi-arid rangelands of northeastern Mexico.

    Olivas-Salazar, Raquel; Estrada-Angulo, Alfredo; Mellado, Miguel; Aguilar-Caballero, Armando Jacinto; Castro-Pérez, Beatriz Isabel; Gutiérrez-Blanco, Eduardo; Ruiz-Zárate, Fernando

    2018-04-01

    The objective of this study was to determine the prevalence of gastrointestinal nematode (GIN) infection in goat flocks on semi-arid rangelands of northeastern Mexico (25° N, 350-400 mm annual precipitation). The study included 668 pluriparous goats from 18 herds in five municipalities of Coahuila and Nuevo Leon, Mexico. Five genetic groups were considered (predominance of Boer, Nubian, Alpine, Saanen, and Toggenburg). Fecal samples were taken from the rectum of each animal to determine the number of eggs per gram (EPG) of GIN. The prevalence of flocks with GIN infections was 88.9%. Similar results were observed for the number of goats infected in the flocks. The Alpine breed presented the highest prevalence and highest EPG loads of GIN, whereas Boer and Nubian were the genetic groups with the lowest (P arid zones of Mexico was found a high prevalence of infections with gastrointestinal nematodes. The municipality and the breed of the animals were factors that showed influence on this prevalence and the level of infection of the goats.

  1. Ranging Behaviour of Commercial Free-Range Broiler Chickens 1: Factors Related to Flock Variability.

    Taylor, Peta S; Hemsworth, Paul H; Groves, Peter J; Gebhardt-Henrich, Sabine G; Rault, Jean-Loup

    2017-07-20

    Little is known about the ranging behaviour of chickens. Understanding ranging behaviour is required to improve management and shed and range design to ensure optimal ranging opportunities. Using Radio Frequency Identification technology, we tracked 300 individual broiler chickens in each of four mixed sex ROSS 308 flocks on one commercial farm across two seasons. Ranging behaviour was tracked from the first day of range access (21 days of age) until 35 days of age in winter and 44 days of age in summer. Range use was higher than previously reported from scan sampling studies. More chickens accessed the range in summer (81%) than winter (32%; p range use was greater in summer flocks (4.4 ± 0.1 visits for a total of 26.3 ± 0.8 min/day) than winter flocks (3.2 ± 0.2 visits for a total of 7.9 ± 1.0 min/day). Seasonal differences were only marginally explained by weather conditions and may reflect the reduction in range exposure between seasons (number of days, hours per day, and time of day). Specific times of the day ( p ranging and external factors that may explain ranging preferences.

  2. The Study of Cooperative Obstacle Avoidance Method for MWSN Based on Flocking Control

    Zuo Chen

    2014-01-01

    Full Text Available Compared with the space fixed feature of traditional wireless sensor network (WSN, mobile WSN has better robustness and adaptability in unknown environment, so that it is always applied in the research of target tracking. In order to reach the target, the nodes group should find a self-adaptive method to avoid the obstacles together in their moving directions. Previous methods, which were based on flocking control model, realized the strategy of obstacle avoidance by means of potential field. However, these may sometimes lead the nodes group to fall into a restricted area like a trap and never get out of it. Based on traditional flocking control model, this paper introduced a new cooperative obstacle avoidance model combined with improved SA obstacle avoidance algorithm. It defined the tangent line of the intersection of node’s velocity line and the edge of obstacle as the steering direction. Furthermore, the cooperative obstacle avoidance model was also improved in avoiding complex obstacles. When nodes group encounters mobile obstacles, nodes will predict movement path based on the spatial location and velocity of obstacle. And when nodes group enters concave obstacles, nodes will temporarily ignore the gravity of the target and search path along the edge of the concave obstacles. Simulation results showed that cooperative obstacle avoidance model has significant improvement on average speed and time efficiency in avoiding obstacle compared with the traditional flocking control model. It is more suitable for obstacle avoidance in complex environment.

  3. Entangled time in flocking: Multi-time-scale interaction reveals emergence of inherent noise.

    Niizato, Takayuki; Murakami, Hisashi

    2018-01-01

    Collective behaviors that seem highly ordered and result in collective alignment, such as schooling by fish and flocking by birds, arise from seamless shuffling (such as super-diffusion) and bustling inside groups (such as Lévy walks). However, such noisy behavior inside groups appears to preclude the collective behavior: intuitively, we expect that noisy behavior would lead to the group being destabilized and broken into small sub groups, and high alignment seems to preclude shuffling of neighbors. Although statistical modeling approaches with extrinsic noise, such as the maximum entropy approach, have provided some reasonable descriptions, they ignore the cognitive perspective of the individuals. In this paper, we try to explain how the group tendency, that is, high alignment, and highly noisy individual behavior can coexist in a single framework. The key aspect of our approach is multi-time-scale interaction emerging from the existence of an interaction radius that reflects short-term and long-term predictions. This multi-time-scale interaction is a natural extension of the attraction and alignment concept in many flocking models. When we apply this method in a two-dimensional model, various flocking behaviors, such as swarming, milling, and schooling, emerge. The approach also explains the appearance of super-diffusion, the Lévy walk in groups, and local equilibria. At the end of this paper, we discuss future developments, including extending our model to three dimensions.

  4. The study of cooperative obstacle avoidance method for MWSN based on flocking control.

    Chen, Zuo; Ding, Lei; Chen, Kai; Li, Renfa

    2014-01-01

    Compared with the space fixed feature of traditional wireless sensor network (WSN), mobile WSN has better robustness and adaptability in unknown environment, so that it is always applied in the research of target tracking. In order to reach the target, the nodes group should find a self-adaptive method to avoid the obstacles together in their moving directions. Previous methods, which were based on flocking control model, realized the strategy of obstacle avoidance by means of potential field. However, these may sometimes lead the nodes group to fall into a restricted area like a trap and never get out of it. Based on traditional flocking control model, this paper introduced a new cooperative obstacle avoidance model combined with improved SA obstacle avoidance algorithm. It defined the tangent line of the intersection of node's velocity line and the edge of obstacle as the steering direction. Furthermore, the cooperative obstacle avoidance model was also improved in avoiding complex obstacles. When nodes group encounters mobile obstacles, nodes will predict movement path based on the spatial location and velocity of obstacle. And when nodes group enters concave obstacles, nodes will temporarily ignore the gravity of the target and search path along the edge of the concave obstacles. Simulation results showed that cooperative obstacle avoidance model has significant improvement on average speed and time efficiency in avoiding obstacle compared with the traditional flocking control model. It is more suitable for obstacle avoidance in complex environment.

  5. Flocking small smart machines: An experiment in cooperative, multi-machine control

    Klarer, P.R.

    1998-03-01

    The intent and purpose of this work was to investigate and demonstrate cooperative behavior among a group of mobile robot machines. The specific goal of this work was to build a small swarm of identical machines and control them in such a way as to show a coordinated movement of the group in a flocking manner, similar to that observed in nature. Control of the swarm's individual members and its overall configuration is available to the human user via a graphic man-machine interface running on a base station control computer. Any robot may be designated as the nominal leader through the interface tool, which then may be commanded to proceed to a particular geographic destination. The remainder of the flock follows the leader by maintaining their relative positions in formation, as specified by the human controller through the interface. The formation's configuration can be altered manually through an interactive graphic-based tool. An alternative mode of control allows for teleoperation of one robot, with the flock following along as described above

  6. Smothering in UK free-range flocks. Part 1: incidence, location, timing and management.

    Barrett, J; Rayner, A C; Gill, R; Willings, T H; Bright, A

    2014-07-05

    Smothering in poultry is an economic and welfare-related concern. This study presents the first results from a questionnaire addressing the incidence, location, timing and management of smothering of free-range farm managers from two commercial egg companies (representing 35 per cent of the UK free-range egg supply). Overall, nearly 60 per cent of farm mangers experienced smothering in their last flock, with an average of 25.5 birds lost per incidence, although per cent mortality due to smothering was low (x̄=1.6 per cent). The majority of farm managers also reported that over 50 per cent of all their flocks placed had been affected by smothering. The location and timing of smothering (excluding smothering in nest boxes) tended to be unpredictable and varied between farms. Blocking off corners/nest boxes and walking birds more frequently were identified as popular smothering reduction measures, although there was a wide variety of reduction measures reported overall. The motivation to implement reduction measures was related to a farm manager's previous experience of smothering. To our knowledge, this is the first study to provide a representative industry estimate on the incidence, location, timing and management of smothering. The results suggest that smothering is a common problem, unpredictable between flocks with no clear, effective reduction strategies. A follow-up study will investigate the correlations among smothering, disease and other welfare problems and may shed further light on management solutions. British Veterinary Association.

  7. Sexual transmission of Toxoplasma gondii in sheep.

    Lopes, Welber Daniel Zanetti; Rodriguez, Joana D'Ark; Souza, Fernando A; dos Santos, Thais Rabelo; dos Santos, Ricardo Silva; Rosanese, Walter Matheus; Lopes, Werik Renato Zanetti; Sakamoto, Cláudio Alessandro; da Costa, Alvimar José

    2013-07-01

    Male sheep of reproductive age were distributed into three groups: GI, a sheep inoculated (oral) with 2.0×10(5) oocysts of the P strain of Toxoplasma gondii; GII, a sheep infected (subcutaneous) with 1.0×10(6) tachyzoites of the RH strain of T. gondii; and GIII, a sheep kept as a control (not infected). After the inoculation of the males, 12 breeding ewes, which were not pregnant and which were serologically negative for reproductive diseases (particularly toxoplasmosis), were distributed into three groups, synchronized, and subsequently exposed to natural mating with previously inoculated males. The distribution was as follows: five ewes that underwent natural mating with the GI male, five ewes that were exposed to natural mating with the GII male, and two ewes that were mated with the non-infected male (control). Serum samples of all the ewes were collected on days -30, -14, -7, -1, and 0 (days before natural mating) and on days 1, 3, 5, 7, 11, 14, and weekly until birth; the presence of serum antibodies against T. gondii was assessed by IFAT. Using a bioassay and PCR, T. gondii was isolated from the semen of the infected reproducing sheep before mating. Following natural mating, 5 of the 12 females displayed antibodies specific for T. gondii; of these animals, two of the ewes underwent natural mating with the male inoculated with oocysts (GI) and three with the male infected with tachyzoites (GII). One of the females that displayed antibodies specific to this coccidian and that underwent natural mating with the GII sheep had a macerated fetus on the 70th day following coverage. Using a bioassay after the birth, it was possible to isolate T. gondii from samples of the "pool" of tissues from the five females that seroconverted after natural mating and from their respective lambs. Using PCR, the DNA of T. gondii was isolated from the "pool" of tissues from one and two females exposed to natural mating with the reproductive males infected with the oocysts and

  8. Experimental poisoning by cassava wastewater in sheep

    Valdir C. Silva

    Full Text Available ABSTRACT: The processing of Manihot esculenta (cassava tubers yield different by-products, including cassava wastewater, which is the liquid pressed out of the tuber after it has been mechanically crushed. Cyanide poisoning after ingestion of cassava wastewater has been reported in ruminants and pigs in Northeastern Brazil. With the aim of studying its toxicity, cassava wastewater was administered orally to six sheep at doses of 0.99, 0.75, 0.70, 0.63, and 0.5 mg of hydrocyanic acid kg-1 body weight, which corresponded to 14.2, 10.6, 9.8, 8.89, and 7.1 mL of wastewater kg-1. On the second day, the sheep received a volume of wastewater which corresponded to 0.46, 0.34, 0.31, 0.28, and 0.23 mg of HCN kg-1. A sheep used as control received 9.9 mL of water kg-1 BW. Sheep that received from 0.75 to 0.99 mg kg-1 of HCN on the first day exhibited severe clinical signs of poisoning, and the sheep that received 0.63 and 0.5 mg kg-1 exhibited mild clinical signs. All sheep were successfully treated with sodium thiosulfate. On the second day, only the sheep that received 0.46 mg kg-1 and 0.34 mg kg-1 exhibited mild clinical signs and recovered spontaneously. The concentration of HCN in the wastewater was 71.69±2.19 μg mL-1 immediately after production, 30.56±2.45 μg mL-1 after 24 hours, and 24.25±1.28 μg mL-1 after 48 hours. The picric acid paper test was strongly positive 5 minutes after production; moderately positive 24 hours after production, and negative 48 hours after production. We conclude that cassava wastewater is highly toxic to sheep if ingested immediately after production, but rapidly loses toxicity in 24-48 hours.

  9. 9 CFR 79.2 - Identification of sheep and goats in interstate commerce.

    2010-01-01

    ..., DEPARTMENT OF AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS... identified to its flock of origin and, for an animal born after January 1, 2002, to its flock of birth, by... without identification to flock of birth until June 1, 2003, and animals that cannot be identified to...

  10. Production parameters for Dohne Merino sheep under an ...

    accelerated lambing system, and to examine the effects of environmental variables on reproduction and growth traits of individual lambs and on lamb ..... Factors affecting reproduction in Merino ewes of the Tygerhoek flock. S. Afr. J. Anim. Sci.

  11. PRNP genetic variability and molecular typing of natural goat scrapie isolates in a high number of infected flocks

    Fragkiadaki Eirini G; Vaccari Gabriele; Ekateriniadou Loukia V; Agrimi Umberto; Giadinis Nektarios D; Chiappini Barbara; Esposito Elena; Conte Michela; Nonno Romolo

    2011-01-01

    Abstract One hundred and four scrapie positive and 77 negative goats from 34 Greek mixed flocks were analysed by prion protein gene sequencing and 17 caprine scrapie isolates from 11 flocks were submitted to molecular isolate typing. For the first time, the protective S146 variant was reported in Greece, while the protective K222 variant was detected in negative but also in five scrapie positive goats from heavily infected flocks. By immunoblotting six isolates, including two goat flockmates ...

  12. Drug use and antimicrobial resistance among Escherichia coli and Enterococcus spp. isolates from chicken and turkey flocks slaughtered in Quebec, Canada

    Boulianne, Martine; Arsenault, Julie; Daignault, Danielle; Archambault, Marie; Letellier, Ann; Dutil, Lucie

    2016-01-01

    An observational study was conducted of chicken and turkey flocks slaughtered at federal processing plants in the province of Quebec, Canada. The objectives were to estimate prevalence of drug use at hatchery and on farm and to identify antimicrobial resistance (AMR) in cecal Escherichia coli and Enterococcus spp. isolates and factors associated with AMR. Eighty-two chicken flocks and 59 turkey flocks were sampled. At the hatchery, the most used antimicrobial was ceftiofur in chickens (76% of...

  13. Drug use and antimicrobial resistance among Escherichia coli and Enterococcus spp. isolates from chicken and turkey flocks slaughtered in Quebec, Canada.

    Boulianne, Martine; Arsenault, Julie; Daignault, Danielle; Archambault, Marie; Letellier, Ann; Dutil, Lucie

    2016-01-01

    An observational study was conducted of chicken and turkey flocks slaughtered at federal processing plants in the province of Quebec, Canada. The objectives were to estimate prevalence of drug use at hatchery and on farm and to identify antimicrobial resistance (AMR) in cecal Escherichia coli and Enterococcus spp. isolates and factors associated with AMR. Eighty-two chicken flocks and 59 turkey flocks were sampled. At the hatchery, the most used antimicrobial was ceftiofur in chickens (76% of flocks) and spectinomycin in turkeys (42% of flocks). Virginiamycin was the antimicrobial most frequently added to the feed in both chicken and turkey flocks. At least 1 E. coli isolate resistant to third-generation cephalosporins was present in all chicken flocks and in a third of turkey flocks. Resistance to tetracycline, streptomycin, and sulfisoxazole was detected in > 90% of flocks for E. coli isolates. Antimicrobial resistance (AMR) was observed to bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, and tetracycline in both chicken and turkey flocks for Enterococcus spp. isolates. No resistance to vancomycin was observed. The use of ceftiofur at hatchery was significantly associated with the proportion of ceftiofur-resistant E. coli isolates in chicken flocks. In turkey flocks, ceftiofur resistance was more frequent when turkeys were placed on litter previously used by chickens. Associations between drug use and resistance were observed with tetracycline (turkey) in E. coli isolates and with bacitracin (chicken and turkey), gentamicin (turkey), and tylosin (chicken) in Enterococcus spp. isolates. Further studies are needed to provide producers and veterinarians with alternative management practices and tools in order to reduce the use of antimicrobial feed additives in poultry.

  14. Detection, identification, and differentiation of sheep pox virus and goat pox virus from clinical cases in Giza Governorate, Egypt.

    Mahmoud, M A; Khafagi, M H

    2016-12-01

    To isolate, identify, and differentiate Capripoxviruses (CaPV) (sheep pox virus and goat pox virus) infections by egg inoculation, transmission electron microscopy (TEM), and 30 kDa RNA polymerase subunit gene-based polymerase chain reaction (PCR) (RPO30) in clinically affected animals in Hawamdia township of Giza Governorate, Egypt. A total of 37 scab samples were collected from clinically suspected field cases of sheep pox and goat pox. These samples were collected during (2014-2015) during different outbreaks of sheep pox and goat pox from Hawamdia township of Giza Governorate, Egypt. The samples were subjected to egg inoculation, TEM, and (RPO30) gene-based PCR. By using the egg inoculation: Previously prepared 37 scab samples (n=23 sheep and n=14 goats) were inoculated on the chorioallantoic membrane of specific pathogen free (SPF) embryonated chicken eggs (12 days old age). In the presence of the suitable percentage of humidity and candling, the inoculated eggs were incubated at 37°C. By using the TEM: Samples showed positive pock lesions on the chorioallantoic membranes, were fixed in glutaraldehyde, then processed and sectioned for TEM. Using the (RPO30) gene-based PCR assay, 30 of positive samples after egg inoculation (n=19 sheep and n=11 goats) were screened. Using the egg inoculation, a characteristic pock lesions for poxviruses were seen in 30/37 (n=19 sheep and n=11 goats) (81.08%). Using the TEM, examination of the positive samples after egg inoculation revealed positive result in 23/30 (n=15 sheep and n=8 goats) (76.66%). The positive results represented by the presence of negatively stained oval-shape virus particles. Using the (RPO30) gene-based PCR assay, out of 30 total of positive samples after egg inoculation (n=19 sheep and n=11 goats) were screened, 27 (90%) samples (n=17 sheep and n=10 goats) were positive. The given band sizes of sheep and goats were 172 and 152 bp, respectively. PCR assay depended on RPO30 gene can be used lonely for the

  15. A flocking algorithm for multi-agent systems with connectivity preservation under hybrid metric-topological interactions.

    He, Chenlong; Feng, Zuren; Ren, Zhigang

    2018-01-01

    In this paper, we propose a connectivity-preserving flocking algorithm for multi-agent systems in which the neighbor set of each agent is determined by the hybrid metric-topological distance so that the interaction topology can be represented as the range-limited Delaunay graph, which combines the properties of the commonly used disk graph and Delaunay graph. As a result, the proposed flocking algorithm has the following advantages over the existing ones. First, range-limited Delaunay graph is sparser than the disk graph so that the information exchange among agents is reduced significantly. Second, some links irrelevant to the connectivity can be dynamically deleted during the evolution of the system. Thus, the proposed flocking algorithm is more flexible than existing algorithms, where links are not allowed to be disconnected once they are created. Finally, the multi-agent system spontaneously generates a regular quasi-lattice formation without imposing the constraint on the ratio of the sensing range of the agent to the desired distance between two adjacent agents. With the interaction topology induced by the hybrid distance, the proposed flocking algorithm can still be implemented in a distributed manner. We prove that the proposed flocking algorithm can steer the multi-agent system to a stable flocking motion, provided the initial interaction topology of multi-agent systems is connected and the hysteresis in link addition is smaller than a derived upper bound. The correctness and effectiveness of the proposed algorithm are verified by extensive numerical simulations, where the flocking algorithms based on the disk and Delaunay graph are compared.

  16. A flocking algorithm for multi-agent systems with connectivity preservation under hybrid metric-topological interactions.

    Chenlong He

    Full Text Available In this paper, we propose a connectivity-preserving flocking algorithm for multi-agent systems in which the neighbor set of each agent is determined by the hybrid metric-topological distance so that the interaction topology can be represented as the range-limited Delaunay graph, which combines the properties of the commonly used disk graph and Delaunay graph. As a result, the proposed flocking algorithm has the following advantages over the existing ones. First, range-limited Delaunay graph is sparser than the disk graph so that the information exchange among agents is reduced significantly. Second, some links irrelevant to the connectivity can be dynamically deleted during the evolution of the system. Thus, the proposed flocking algorithm is more flexible than existing algorithms, where links are not allowed to be disconnected once they are created. Finally, the multi-agent system spontaneously generates a regular quasi-lattice formation without imposing the constraint on the ratio of the sensing range of the agent to the desired distance between two adjacent agents. With the interaction topology induced by the hybrid distance, the proposed flocking algorithm can still be implemented in a distributed manner. We prove that the proposed flocking algorithm can steer the multi-agent system to a stable flocking motion, provided the initial interaction topology of multi-agent systems is connected and the hysteresis in link addition is smaller than a derived upper bound. The correctness and effectiveness of the proposed algorithm are verified by extensive numerical simulations, where the flocking algorithms based on the disk and Delaunay graph are compared.

  17. Factors affecting litter size in Texel sheep

    Sharafeldin, M.A.

    1960-01-01

    The effect of age of ewes and of different lambing years on fertility expressed as number of lambs born and surviving to 2 months per lambing has been studied in field data collected by the herdbook for Texel sheep in North Holland. The fertility of ewes was compared when first bred at about 8

  18. Estimating phosphorus intake by grazing sheep

    phosphorus levels in various organs, tissues, bones, body fluids or excretory products of sheep reflected dietary ... did decrease bone mineral deposition slightly. Rumen fluid P and total daily urinary P levels did .... which were alike in composition except for their levels of. P and Ca. After 98 days rib biopsy specimens were.

  19. The current status of sheep pox disease.

    Bhanuprakash, V; Indrani, B K; Hosamani, M; Singh, R K

    2006-01-01

    Sheep are the moving banks of shepherds and their economic contribution in terms of meat, wool and skin/hide is immense. Various infectious diseases jeopardize the optimum productivity; among which sheep pox is more important as the disease restricts the export of sheep and their products besides other economic losses. Although, clinical signs are indicative of the disease but a laboratory confirmation is necessary for unequivocal diagnosis and studying epidemiology. The causative agent, sheep pox virus (SPV), is antigenically and genetically closely related to goat pox virus (GPV) and lumpy skin disease virus (LSDV), the other members of the genus capripox virus. In some countries, SPV and GPV are cross infective to small ruminants posing problem in diagnosis and epidemiology. However, recent studies have showed that the viruses are phylogenetically distinct and can be differentiated by molecular tools. Prophylaxis using attenuated vaccines is the choice of control measure as the immunity is long lasting. Detailed information on isolation, identification, pathology, epidemiology, diagnosis and prophylaxis would not only help in updating the knowledge of scientific fraternity but will be useful to the policy makers in order to formulate appropriate measures for control and eradication of the disease. This synthesis is to present an up-to-date review of the disease and its control to provide the reader with an overview of the problem.

  20. Coxiella burnetii infections in sheep or goats

    Brom, Van den R.; Engelen, van E.; Roest, H.I.J.; Hoek, van der W.; Vellema, P.

    2015-01-01

    Q fever is an almost ubiquitous zoonosis caused by Coxiella burnetii, which is able to infect several animal species, as well as humans. Cattle, sheep and goats are the primary animal reservoirs. In small ruminants, infections are mostly without clinical symptoms, however, abortions and