Cavestany D, Betancour H, Blanc J E, Lemaire C, Slavica J, Moreira F, Piaggio J, Risco C
INIA La Estanzuela and Department of Reproduction, Faculty of Veterinary, Montevideo, Uruguay.
Aust Vet J. 2007 Apr;85(4):141-7. doi: 10.1111/j.1751-0813.2006.00100.x.
To evaluate the effectiveness of a reproductive management program consisting of combinations of Ovsynch/TAI and prostaglandin (PG) F(2alpha) treatments in Holstein dairy cows under a pasture-based dairying system.
Field trial.
A total of 1177 cows in 8 commercial dairy farms were randomly allocated to control and treatment groups. Treatment group cows received one of two interventions depending upon the number of days postpartum (DPP) before the planned start of breeding. Cows more than 50 DPP by the planned start of breeding received the Ovsynch/TAI treatment, consisting of gonadotrophin releasing hormone (GnRH) - PGF(2alpha)- GnRH plus timed artificial insemination. Cows between 40 and 50 DPP received a PGF(2alpha) treatment followed by oestrus detection and, if the cow was not seen in oestrus, the cow received a second PGF(2alpha) 14 days later. Control cows were submitted to twice a day heat detection followed by artificial insemination. The experimental period was the start of the breeding season plus 21 days for cows over 50 DPP at the start of breeding, and was 40-61 DPP for cows that calved later and passed their voluntary waiting period after the start of the breeding season.
Submission rate was higher for the treated group than for the control group (84.9% vs. 55.1%; P < 0.0001), as was the conception rate (51.0% vs. 46.1%; P < 0.03). Due to farm variations, pregnancy rate was similar in both groups (38.5% vs. 28.2%; P > 0.1). Within the treated group, conception rate and pregnancy rate of the cows inseminated after a PGF(2alpha) were higher than for timed artificial inseminated cows (51.4% vs. 32.6%; P < 0.001), and (37.8% vs. 32.6%; P < 0.001).
A programmed reproductive management protocol may improve reproductive efficiency in dairy farms with seasonal breeding, by increasing submission and conception rates at the beginning of the breeding season and/or at the end of the voluntary waiting period. Fertility of cows bred after a PGF(2alpha) synchronised heat was greater than after an Ovsynch/TAI protocol.
评估在以牧场为基础的奶牛养殖系统中，由Ovsynch/定时人工授精（TAI）和前列腺素（PG）F2α处理组合而成的繁殖管理方案对荷斯坦奶牛的有效性。
田间试验。
8个商业奶牛场的1177头奶牛被随机分配到对照组和处理组。处理组奶牛根据计划配种开始前的产后天数（DPP）接受两种干预措施之一。在计划配种开始时产后超过50天的奶牛接受Ovsynch/TAI处理，包括促性腺激素释放激素（GnRH）-PGF2α-GnRH加定时人工授精。产后40至50天的奶牛接受PGF2α处理，随后进行发情检测，如果未观察到奶牛发情，则在14天后再次接受PGF2α处理。对照奶牛每天进行两次发情检测，随后进行人工授精。试验期为配种季节开始时加上配种开始时产后超过50天的奶牛的21天，对于产犊较晚且在配种季节开始后度过自愿等待期的奶牛，试验期为40 - 61天。
处理组的输精率高于对照组（84.9%对55.1%；P < 0.0001），受胎率也是如此（51.0%对46.1%；P < 0.03）。由于农场差异，两组的妊娠率相似（38.5%对28.2%；P > 0.1）。在处理组中，接受PGF2α处理后输精的奶牛的受胎率和妊娠率高于定时人工授精的奶牛（51.4%对32.6%；P < 0.001），以及（37.8%对32.6%；P < 0.001）。
程序化的繁殖管理方案可能通过提高配种季节开始时和/或自愿等待期结束时的输精率和受胎率，提高季节性配种奶牛场的繁殖效率。PGF2α同步发情后输精的奶牛的繁殖力高于Ovsynch/TAI方案后输精的奶牛。
