Sample records for dinoprost

  1. Low-dose natural prostaglandin F2α (dinoprost) at timed insemination improves conception rate in dairy cattle. (United States)

    Ambrose, Divakar J; Gobikrushanth, Mohanathas; Zuidhof, Sjoert; Kastelic, John P


    The primary objective was to determine if low doses of PGF2α (dinoprost) given intramuscularly (im) concurrent with timed artificial insemination (TAI) would improve conception rates in dairy cattle. A secondary objective was to determine if body condition score (BCS) and parity would influence conception rates, either independently or in interaction with PGF2α treatment. In experiment I, 307 lactating Holstein cows were randomly assigned to receive either 5-mg PGF2α im (PGF2α treated, n = 154) or 0-mg PGF2α (control, n = 153) at TAI (Day 0). Blood samples were obtained on Days -10, -3, 0, and 7 to determine plasma progesterone (P4) concentrations. Pregnancy was confirmed 30 to 32 days after insemination by transrectal ultrasonography. In experiment II, 451 cows were randomly assigned to receive either 10-mg PGF2α im (PGF2α treated, n = 226) or 0-mg PGF2α (control, n = 225) at TAI, and pregnancy was confirmed 45 to 50 days after TAI by palpation per rectum. Pregnancy data were analyzed by CATMOD (SAS). In experiment I, PGF2α treatment, BCS, and parity did not affect conception rate (35.7% vs. 37.0% for PGF2α treated vs. control; P > 0.05). However, in experiment II, conception rates were higher in cows given 10-mg PGF2α than those in control cows (45.8% vs. 36.0%; P conception rates. In summary, 5 mg of PGF2α given im concurrent with TAI failed to enhance conception rate in lactating dairy cows, whereas 10 mg of PGF2α significantly increased conception rate. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. The influence of the induction of farrowing on live birth, body mass, appearance of dystocia, mortality and surviving of neonatal pigs in litter during the first ten days

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    Jović Slavoljub


    Full Text Available The objective of this work was to investigate the influence of the the day of farrowing induction on the number of newborn piglets (live born and dead born, body mass and mortality of neonatal pigs in litter by the tenth day of age. For the investigation purpose, there were chosen 167 pregnant animals, 34 gilts and 133 sows, divided into 3 groups each, according to the day of pregnancy when prostaglandin analogue, dinoprost-tromethamine, was applied (from 112th to 114th day. Fastest- induced parturition was in gilts which were administered dinoprost on the 113th day of pregnancy, (34,30 ± 6,23 h after application, that is, in sows which were administered prostaglandin on the 114th day of pregnancy, (29,57 ± 4,14 h after application of dinoprost. Most gilts (75 % and sows (90,91% started farrowing 24-36 h after dinoprost application, when it was given on the 113th day of pregnancy. During daily twelve-hour working time (7-19 h, 67,07% out of all the treated animals started farrowing. When farrowing was induced on the 112th day of pregnancy, 17 sows (12,78% needed obstetric assistance for dystocia, while 47 (35,34 % sows had troublesome farrowing. Along with the delayed induction, body mass of newborn pigs increased, and the largest recorded weight was 1,27 kg in sows, that is 1,38 kg in gilts, which were given dinoprost on the 114th day of pregnancy, with the lowest number of live born pigs of body mass less than 1 kg (23,76%. In this experiment there was determined the connection between the body mass and vitality of newborn piglets, so the lowest mortality rate of the pigs by the 10th day of age was noticed in sows and gilts which were given dinoprost on the 114th day of pregnancy (11,05%, in regard to the pigs born of sows and gilts which were given dinoprost on the 112th day of pregnancy (15,39 %.

  3. Estrus response and fertility of Menz and crossbred ewes to single prostaglandin injection protocol. (United States)

    Mekuriaw, Zeleke; Assefa, Habtemariam; Tegegne, Azage; Muluneh, Dagne


    Natural lambing in sheep in Ethiopia occurs throughout the year in a scattered manner negatively affecting survival and growth rates of the lambs born during the unfavorable season of the year. Thus, controlling the time of mating artificially using exogenous source of hormones is considered as one of the ways to mitigated problems related to haphazard lambing. To this end, an experiment was conducted to evaluate efficacy of prostaglandin-based estrus synchronization protocol in local and crossbred ewes. A total of 160 ewes (80 local and 80 crossbreds) which lambed at least once and aged 3-5 years were used. Lutalyse® (dinoprost tromethamine sterile solution equivalent to 5 mg dinoprost per ml) and its analog, Synchromate® (cloprostenol sodium equivalent to 0.250 mg cloprostenol per ml), were tested at different doses. The treatments used were intramuscular injection of (1) 2.50 ml of Lutalyse® (12.5 mg dinoprost tromethamine), (2) 2 ml of Lutalyse® (10.0 mg dinoprost tromethamine), (3) 1 ml of Synchromate® (0.25 mg of cloprostenol Sodium), and (4) 0.8 ml of Synchromate® (0.20 mg of cloprostenol Sodium). Forty ewes (20 local and 20 crossbreds) were allocated per treatment. Following injection of the respective hormones, rams of known fertility were introduced into the flock for the duration of 96 h at the ratio of one ram to 10 ewes. All estrus synchronization protocols except treatment 4 (0.8 ml of Synchromate®) induced estrus (heat) in majority (55-65%) of local and crossbred ewes within 96 h post-hormone injection. The time interval from hormone administration to onset of estrus was also more or less similar for all treatment groups except for treatment group 4 which showed heat quicker. The highest lambing rate was recorded in local ewes (84.62% (11/13) treated with 2.5 ml of Lutalyse®, whereas the least was obtained in crossbreds (33.33% (3/9) treated with 0.8 ml Synchromate®. In conclusion, even though 2.5 ml and 2 ml of Lutalyse® or 1 ml of

  4. Qualitative and quantitative analysis of bacteria from vaginitis associated with intravaginal implants in ewes following estrus synchronization


    Carlos Otávio de Paula Vasconcelos; Felipe Zandonadi Brandão; Gabriel Martins; Bruno Penna; Joanna Maria Gonçalves de Souza-Fabjan; Walter Lilenbaum


    ABSTRACT: This study evaluated the presence of vaginitis and the bacterial load associated with different intravaginal implants in ewes. Twenty-four Dorper and crossbred ewes were allocated into three groups and received intravaginal implant containing 0.3g progesterone (CIDR(r)), 60mg MAP or sponges without progesterone (CONTROL) for six days. Then, CIDR and MAP treated-ewes received 12.5mg dinoprost and 300IU eCG. Vaginal mucus samples were collected at four times: before device insertion, ...


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    Tjok Gde Oka Pemayun


    Full Text Available The aims of this research were to determine PGF2? concentration the produced by bali cattlesendometrial and seminal vesicle monolayer cell culture and in vitro luteolytic ability on luteal monolayercell culture. The endometrial and seminal vesicle epithelial cell of bali cattle were cultured in tissueculture medium (TCM 199 growth medium supplemented with 10% fetal calf serum and 10% EstrusMare Serum. The cells were cultured at 1.9 x 106 density per ml medium. Then Followed by incubation at38.50 C in 5% CO2 atmosphere for 12 days. The level of PGF2? in the cell culture medium were assayed byRadioimmnuassay (RIA technique. The luteal cells were cultured in 9 days incubation and divided into 2groups. Group I were added with 10% of cell culture product and group II were added with 1,25 mgdinoprost/ml. The level of progesterone produced by luteal cell culture was measured at day 9th and 11thincubation. The result showed concentration of PGF2? cell product of seminal vesicle cell culture wassignificantly higher (P < 0.05 compared to endometrial cell culture. There was no significant difference(P>0.05 in luteolytic ability between PGF2? cell culture product and dinoprost. In conclusion, the PGF2?could be produced by monolayer cell culture of bali cattle is endometrial and seminal vesicle epithelialcells more over they have similar ability with dinoprost in luteolytic ability.

  6. D-Cloprostenol enhances estrus synchronization in tropical hair sheep. (United States)

    Ramírez, Alejandro Alavez; Villalvazo, Victor Manuel Meza; Arredondo, Emmanuel Sosa; Ramírez, Hugo Alonso Ramírez; Sevilla, Héctor Magaña


    To compare the effects of PGF2α (dinoprost tromethamine) and D-cloprostenol in a two-dose protocol for estrus synchronization in hair sheep during breeding season in Yucatán, México, two experiments were conducted. In experiment 1, 61 cyclic hair sheep were divided into two groups: G1 (control n = 30), two doses of 50 μg of dinoprost tromethamine IM with 12 days between applications, and G2 (n = 31), two doses of 50 μg of D-cloprostenol IM at the same time interval. For determination of progesterone levels, 16 ewes from each group were randomly selected. In experiment 2, 70 cyclic hair sheep were assigned at the same treatments (G1 and G2, n = 35) and 48 h after the second application, the ewes in estrus were detected by two vasectomized rams. Sheep with detected estrus were inseminated, and 45 days after, pregnant animals were identified by ultrasonography. An exact Fisher's test was performed for the analysis of ewes in estrus (experiments 1 and 2) and number of pregnant ewes (experiment 2); for the comparison of time between end of treatment-estrus presentation, a survival analysis was used. Duration of estrus in hours was analyzed using a generalized mixed model (GLM) ANOVA whereas plasma progesterone concentrations were analyzed by non-linear regression. There were significant differences (P  0.05) in duration of estrus (G1, 42 + 6.1 h, vs G2, 41.1 + 11.2 h, experiment 1) and pregnancy in the ewes that presented estrus, and were inseminated (G1, 38.4% vs 52.1%, experiment 2). With regard to concentrations of progesterone, significant differences (P < 0.01) were found between treatments, and progesterone levels before the second application of D-cloprostenol were higher. In consideration of the results, it can be concluded that in a two-dose protocol of a luteolytic agent, more ewes presented estrus in response to D-cloprostenol compared to dinoprost tromethamine with similar pregnancy rates.

  7. Ovarian responses and pregnancy rate with previously used intravaginal progesterone releasing devices for fixed-time artificial insemination in sheep. (United States)

    Vilariño, M; Rubianes, E; Menchaca, A


    The objective was to determine serum progesterone concentrations, ovarian responses, and pregnancy rate in sheep inseminated following a short-term protocol (6 days of treatment) with a previously used controlled internal drug release-G (CIDR-G) device. In experiment 1, 30 ewes were put on a short-term protocol using a CIDR-G of first use (new devices, N = 10), second use (previously used for 6 days, N = 10), or third use (previously used twice for 6 days, N = 10). All ewes were given prostaglandin F(2α) (10 mg dinoprost) and eCG (300 IU) im at device withdrawal. Mean serum progesterone concentrations were greater for ewes treated with new versus reused devices (P synchronization and ovulation, with lower serum progesterone concentrations for reused devices. Three times used CIDR-G yielded a pregnancy rate >70%, which tended to be lower than that obtained with new devices, adding evidence of the detrimental effect of low serum progesterone concentrations on fertility in sheep. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Qualitative and quantitative analysis of bacteria from vaginitis associated with intravaginal implants in ewes following estrus synchronization

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    Carlos Otávio de Paula Vasconcelos


    Full Text Available ABSTRACT: This study evaluated the presence of vaginitis and the bacterial load associated with different intravaginal implants in ewes. Twenty-four Dorper and crossbred ewes were allocated into three groups and received intravaginal implant containing 0.3g progesterone (CIDR(r, 60mg MAP or sponges without progesterone (CONTROL for six days. Then, CIDR and MAP treated-ewes received 12.5mg dinoprost and 300IU eCG. Vaginal mucus samples were collected at four times: before device insertion, at the day of its removal, 24 and 48 hours after. The samples were cultured and the colonies were counted (CFU/mL and identified. The results obtained from the counting of CFU mL-1 were submitted to Kruskal-Wallis H test, with P0.05 in comparison with MAP and CIDR-treated ewes. During the occurrence of vaginitis, the predominant isolates belonged to the coliform group, mainly Escherichia coli (72.7%. Such infection was not determined by the members of the vaginal microbiota that were present before implant insertion and normal microbiota was restored between 24 to 48 hours after insert removal.

  9. Therapeutic efficacy of natural prostaglandin in the treatment of pyometra in bitches

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    Basanti Jena


    Full Text Available Aim: The current study was done to study the therapeutic effect of natural prostaglandin in treatment of canine pyometra. Materials and Methods: Seven bitches were treated with natural PGF2 á i.e. dinoprost tromethamine at the dose rate of 100 μg/kg body weight subcutaneously once daily for 7 days with supportive therapies. The physiological, haematological and biochemical parameters were studied before (0th day and after treatment (8th day. Therapeutic efficacy was assessed in terms of return of abnormal parameters to either normal or near normal value as compared to the untreated control group, intensity of side effects and post treatment reproductive status. Results: All physiological, haematological and biochemical parameters in the seven treated bitches returned to normal range at the end of treatment. The intensity of side effects was quite severe in the treatment group. Six bitches came to estrus within 2 months of treatment and out of them four conceived on subsequent mating. In rest three bitches there was recurrence of pyometra within 4 months of treatment. Conclusion: Though conception rate of recovered bitches is decreased when compared with that of normal healthy bitches still this treatment protocol can be used successfully in treatment of canine pyometra to conserve the breeding capability of bitches. [Vet World 2013; 6(6.000: 295-299

  10. Evaluation of a second uterine flushing on embryo recovery in Nelore cows / Avaliação de uma segunda lavagem uterina sobre a recuperacão de embriões em vacas Nelore

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    Marcelo Marcondes Seneda


    Full Text Available The objective of the present study was to evaluate the effect of a second uterine flushing on number of recovered embryos. Cyclic Nelore cows (n= were used as donors. Animals were kept under grazing conditions in a farm at Mamborê, Paraná state. Cows were submitted to two sessions of multiple ovulation 80 days apart. At a random stage of estrus cycle (Day 0 donors received an intravaginal device with 1.9 g of progesterone (CIDR; Pfizer; Brasil. Twenty four hours later (Day 1 cows were injected with 2.5 mg/ IM of Estradiol Benzoate (Estrogin, Farmavet, Brasil. Between Day 5 and Day 9, donors received decreasing doses of 250 UI of FSH (Pluset; Calier, Brasil. On Days 7 and cows received 25 mg/ IM of dinoprost (Lutalyse, Pfizer, Brasil and progesterone implants were removed 12 hs later. Artificial insemination was performed 12 and 24 hours after estrus detection. The first embryo recovery was performed 7 days after AI with the Foley catheter positioned in the uterine body. A total of 1.000 mL of PBS (Embriocare, Cultilab, Brasil was used in a closed system of uterine flushing, with a 70 µm filter. Recovered uterine fluid was evaluated under a stereomicroscope (SMZ 654, Nikon, Japan and embryos were classified accord to IETS (1998. Twenty four hours later, the second uterine flushing was performed following the same procedure. Results were analyzed by t-Student test (p O objetivo do presente experimento foi verificar a viabilidade de uma segunda lavagem uterina sobre a recuperação de embriões. Doadoras cíclicas da raça Nelore (n= foram mantidas a pasto no município de Mamborê, Estado do Paraná. Os animais foram submetidos a tratamentos de superovulação com intervalo de 80 dias. Em um dia aleatório do ciclo estral (Dia 0 as doadoras receberam um dispositivo intravaginal contendo 1,9 g de progesterona (CIDR; Pfizer, Brasil. Vinte e quatro horas após (Dia 1 administrou-se , mg de benzoato de Estradiol (Estrogin; Farmavet, Brasil por via

  11. Estrous synchronization strategies to optimize beef heifer reproductive performance after reproductive tract scoring. (United States)

    Kasimanickam, Ramanathan K; Whittier, William D; Hall, John B; Kastelic, John P


    Three experiments comparing four estrous synchronization protocols were conducted to determine estrous expression rate and artificial insemination pregnancy rate (AI-PR) in heifers with a range (1-5) of reproductive tract scores (RTSs). At enrollment (Day 0), 1783 Angus cross beef heifers from six locations were given body condition score and RTS. The four protocols were: (1) HRTS-DPGF group-heifers with RTS 5 received prostaglandin F2α (PGF; Dinoprost 25 mg; im) on Days 0 and 14; (2) HRTS-CIDR-PGF group-heifers with RTS 5 received a CIDR (1.3-g progesterone) insert on Day 7, followed by CIDR removal and PGF on Day 14; (3) LRTS-CIDR-PGF group-heifers with RTS 4 or less received a CIDR insert on Day 7, followed by CIDR removal and PGF on Day 14; and (4) HRTS-Select-Synch group-heifers with RTS 5 received 100 μg of gonadorelin diacetate tetrahydrate (gonadotropin releasing homone; im) on Day 7 and PGF on Day 14. In all groups, heifers observed in estrus were artificially inseminated (within 120 hours after PGF) using the AM-PM rule. In Experiment 1, estrus expression rates were 82.2% (282/343) and 88.5% (184/208) for HRTS-DPGF and LRTS-CIDR-PGF, respectively (P  0.1) and AI-PR were 52.1 (110/211), 60.3 (129/214), and 58.4% (122/209; P > 0.05). In Experiment 3, estrus expression rates were 77.5 (131/169), 85.5 (142/166), and 83.3% (219/263) for HRTS-DPGF, HRTS-Select-Synch and LRTS-CIDR-PGF (P > 0.05) and AI-PR were 53.3 (90/169), 60.2 (100/166), and 58.6% (154/263; P > 0.1). Overall, estrus expression rates for HRTS-DPGF, HRTS-Select-Synch, LRTS-CIDR-PGF, and HRTS-CIDR-PGF groups were 80.4 (581/723), 85.5 (142/166), 85.1 (579/680), and 86.9% (186/214), respectively; higher for heifers in LRTS-CIDR-PGF and HRTS-CIDR-PGF groups compared to heifers in HRTS-DPGF group (P reproductive performance was reduced compared with other protocols used in this study. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. [Treatment of chronic bovine endometritis and factors for treatment success]. (United States)

    Feldmann, M; Tenhagen genannt Emming, S; Hoedemaker, M


    In a controlled field trial, 178 dairy cows with chronic endometritis and at least 21 days in lactation were randomly assigned to four different treatment groups: prostaglandin F2alpha intramuscularly (PG, 5 mg dinoprost (5 ml Dinolytic), n = 51), intrauterine antibiotics (AB; 400 mg ampicillin + 800 oxacillin (20 ml Totocillin), n = 49), intrauterine antiseptics (AS; 100 ml 4% Lotagen, n = 50); control (C, no initial treatment, n = 28). Before treatment, uterine swabs for bacteriologic examination and blood samples for determination of serum progesterone concentrations were collected. Two weeks following the first treatment, cows were reexamined. In case no clinical cure was diagnosed, treatment was repeated and control cows were treated for the first time with one of the three treatments mentioned above. The four treatment groups did not differ with respect to the clinical cure or reproductive performance. Therefore, factors that might have an influence on clinical cure and fertility were evaluated. With increasing duration of lactation, the clinical cure after a single treatment increased significantly over all treatment groups from 59.5% (treatment before day 42 postpartum) to 79.6% (treatment following day 42 postpartum) (P conception rate and a lower pregnancy index were obtained when the treatment was performed following day 42 postpartum (P size had a negative effect on clinical cure over all groups (first treatment clinical cure: 68.2% (small uteri) vs 44.4% (large uteri); P 0.05). Isolation of Arcanobacterium (A.) pyogenes negatively influenced first treatment clinical cure over all treatment groups (79.0% vs 31.5%) and within treatment groups (P conception increased compared with the other treatment groups, when A. pyogenes was detected. Isolation of unspecific bacteria and the presence or absence of a corpus luteum only had minor effects over all and within the PG, AS and C group. Within the AB group, presence of luteal tissue was connected with a

  13. Antral follicles population in heifers and cows of Nelore and Girolando breeds

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    Jair Sábio de Oliveira Junior


    Full Text Available The aim of this study was to evaluate ovarian antral follicle populations (OAFP of Nelore and Girolando breed heifers (12–18 months old and cows (24–60 months old. Animals were assigned to four groups: (1 Nelore cows (n = 18, (2 Girolando cows (n = 20, (3 Nelore heifers (n = 7, and (4 Girolando heifers (n = 7. Cows were treated to synchronize follicular wave emergence by implantation of an intravaginal device containing 1.9 g of progesterone, as well as intramuscular administration of 2 mg of estradiol benzoate and 25 mg of dinoprost. This synchronization treatment was administered at a random day of the estrous cycle of each cow, designated D0. Intravaginal devices were removed on D7, and on D11, OAFP counts were performed by transvaginal ovarian ultrasound. For each cow, all follicles ?3 mm in diameter were counted in both ovaries and counts were performed three times at 35-day intervals. Counts were also obtained from heifers, but these animals were not treated for synchronization of follicular wave emergence. Analysis of variance (ANOVA with Tukey’s test and Pearson’s correlation test were used to compare mean OAFPs between counts as well as mean OAFPs between breed and age groups. No differences were observed in mean OAFPs between Nelore and Girolando cows (30.9 vs. 26.7, respectively; P > 0.05 or heifers (16.2 vs. 18.1, respectively; P > 0.05. However, within each breed, there were differences in mean OAFPs between heifers and cows (for Nelore cattle: 16.2 and 30.9, respectively; for Girolando cattle: 18.1 and 26.7, respectively; both P < 0.05. In conclusion, OAFPs were similar between Nelore and Girolando breeds and were influenced by age. Furthermore, we observed a high correlation for individual animals between the mean numbers of follicles counted in both ovaries and total number of follicles counted in either the right or left ovary, indicating that the evaluation of a single ovary is sufficient to estimate the OAFP of an

  14. Follicular dynamics, circulating progesterone, and fertility in Holstein cows synchronized with reused intravaginal progesterone implants that were sanitized by autoclave or chemical disinfection. (United States)

    Melo, L F; Monteiro, P L J; Nascimento, A B; Drum, J N; Spies, C; Prata, A B; Wiltbank, M C; Sartori, R


    This experiment aimed to compare circulating progesterone (P4), follicular dynamics, and fertility during reuse of intravaginal P4 implants that were sanitized by autoclave or chemical disinfection in lactating Holstein cows submitted to fixed-time artificial insemination (FTAI). For this, 123 primiparous and 226 multiparous cows from 2 farms, averaging (mean ± standard deviation) 163.9 ± 141.9 d in milk, 35.7 ± 11.3 kg of milk/d, and a body condition score of 2.9 ± 0.5, were enrolled in the study. Cows were randomly assigned to 1 of 2 treatments using a completely randomized design and each cow received a reused implant (1.9 g of P4; previously used for 8 d) that was either autoclaved (AUT; n = 177) or chemically disinfected (CHEM; n = 172) on d -10. Also on d -10, cows received 2 mg of estradiol benzoate and 100 μg of GnRH. On d -3, cows received 25 mg of dinoprost (PGF 2α ). A second PGF 2α was given on d -2, along with 1 mg of estradiol cypionate and P4 implant removal. Cows received FTAI on d 0. A subset of cows (n = 143) was evaluated by ultrasound on d -10, -8, -6, -3, -2, 0, and 5 to identify ovarian structures, and blood was sampled on d -10, -3, and -2 for P4 concentrations by RIA. Pregnancy diagnoses were performed at d 32 and 60. Statistical analyses was performed using PROC-MIXED for continuous variables and PROC-GLIMMIX of SAS 9.4 (SAS Institute Inc., Cary, NC) for binomial variables. The treatments did not differ in circulating P4 on d -10 or -3, but P4 was greater on d -2 in CHEM cows. Ovulation to the treatments on d -10 was associated with lower circulating P4 on d -10 (2.0 vs. 3.1 ng/mL) and resulted in greater P4 on d -3 (4.0 vs. 2.4 ng/mL) and more cows with a corpus luteum on d -3 (100 vs. 40%) than nonovulating cows. Cows that ovulated to d -10 treatments were more likely to have a synchronized new follicular wave (97.9 vs. 63.2%) and had an earlier wave emergence (1.9 vs. 2.6 d), resulting in less cows ovulating a persistent follicle

  15. Fertility of Angus cross beef heifers after GnRH treatment on day 23 and timing of insemination in 14-day CIDR protocol. (United States)

    Kasimanickam, R K; Hall, J B; Whittier, W D


    This study compared artificial insemination pregnancy rate (AI-PR) between 14-day CIDR-GnRH-PGF2α-GnRH and CIDR-PGF2α-GnRH synchronization protocol with two fixed AI times (56 or 72 hr after PGF2α). On day 0, heifers (n = 1311) from nine locations assigned body condition score (BCS: 1, emaciated; 9, obese), reproductive tract score (RTS: 1, immature, acyclic; 5, mature, cyclic) and temperament score (0, calm; and 1, excited) and fitted with a controlled internal drug release (CIDR, 1.38 g of progesterone) insert for 14 days. Within herd, heifers were randomly assigned either to no-GnRH group (n = 635) or to GnRH group (n = 676), and heifers in GnRH group received 100 μg of GnRH (gonadorelin hydrochloride, IM) on day 23. All heifers received 25 mg of PGF2α (dinoprost, IM) on day 30 and oestrous detection aids at the same time. Heifers were observed for oestrus thrice daily until AI. Within GnRH groups, heifers were randomly assigned to either AI-56 or AI-72 groups. Heifers in AI-56 group (n = 667) were inseminated at 56 hr (day 32 PM), and heifers in AI-72 group (n = 644) were inseminated at 72 hr (day 33 AM) after PGF2α administration. All heifers were given 100 μg of GnRH concurrently at the time AI. Controlling for BCS (p < .05), RTS (p < .05), oestrous expression (p < .001), temperament (p < .001) and GnRH treatment by time of insemination (p < .001), the AI-PR differed between GnRH treatment [GnRH (Yes - 60.9% (412/676) vs. No - 55.1% (350/635); p < .05)] and insemination time [AI-56 - 54.6% (364/667) vs. AI-72 - 61.8% (398/644); (p < .01)] groups. The GnRH treatment by AI time interaction influenced AI-PR (GnRH56 - 61.0% (208/341); GnRH72 - 60.9% (204/335); No-GnRH56 - 47.9% (156/326); No-GnRH72 - 62.8% (194/309); p < .001). In conclusion, 14-day CIDR synchronization protocol for FTAI required inclusion of GnRH on day 23 if inseminations were to be performed at 56 hr after PGF2α in order to achieve greater AI-PR.

  16. Circulating progesterone dynamics after intravaginal instillation of prostaglandin-F2α to lactating dairy cows. (United States)

    Wijma, R; Stangaferro, M L; Giordano, J O


    Our objectives were to evaluate circulating progesterone (P4) concentration dynamics and test the feasibility of inducing luteal regression after intravaginal (IVG) instillation of the PGF2α analogue dinoprost (PGF) in lactating dairy cows. In two experiments, cows were synchronized using the Ovsynch protocol to induce the formation of a corpus luteum (CL). Cows with at least one functional (P4 ≥1 ng/mL) CL ≥15 mm 7.5 days after Ovsynch remained in the studies. In experiment 1, cows (n = 31) were stratified by parity group and received 5 mL of saline IVG (SAL-IVG, n = 6), 25 mg of PGF intramuscular (IM) (PGF25-IM, n = 7), 25 mg of PGF IVG (PGF25-IVG, n = 6), 50 mg of PGF IVG (PGF50-IVG, n = 6), and 125 mg of PGF IVG (PGF125-IVG, n = 6). Experiment 2 was conducted to test the hypothesis that IVG instillation of two 25 mg doses of PGF 12 hours apart would be more effective than a 25- or 50-mg dose in a single application. Cows (n = 32) were stratified by parity and received SAL-IVG (n = 7), PGF25-IM (n = 7), PGF25-IVG (n = 6), and PGF50-IVG (n = 6) as in experiment 1, whereas another group received two IVG instillations of 25 mg of PGF 12 hours apart (PGF25-2X-IVG, n = 6). Blood was collected at -1 hour, every 6 hours from 0 hour to 24 hours, and every 12 hours up to 96 hours after treatment (trt). In experiment 1, there was an effect of trt (P cows in the SAL-IVG group from 12 to 96 hours after trt. Although an initial decline in P4 concentrations was induced in all PGF-treated cows, some cows in the IVG-treated groups presented a rebound in plasma P4, indicating CL recovery. More cows in the PGF25-IVG and PGF125-IVG groups than in the PGF50-IVG and PGF25-IM groups presented CL recovery, suggesting that greater doses of PGF may not necessarily improve CL regression. In experiment 2, there was an effect of trt (P Cows in the PGF25-2X-IVG group had a P4 profile that was similar to that of cows in the PGF25-IM group and