Moller K, Fielden E D
Department of Veterinary Clinical Sciences, Massey University, Palmerston North.
N Z Vet J. 1981 Nov;29(11):214-5. doi: 10.1080/00480169.1981.34848.
Two hundred and ninety two dairy cows received a subcutaneous injection of a 2.5 ml solution containing 10 microg GnRH-analogue (Receptal, Hoechst A.G.) 0-6 hours before insemination, while 284 cows acting as controls were injected with 2.5 ml of sterile pyrogen-free water at the same time. The two groups, the treated and the control, were formed by matching (pairing) each oestrous cow with another on the basis of interval from calving to first mating, condition score, and age on the day of first mating after calving. The cows were in 3 factory supply dairy herds, which were visited daily during the first 3 weeks of the mating season. All the cows presented for mating each day were inseminated by the same technician using 0.5 ml of ambient-temperature semen containing 2 million spermatozoa per insemination. The semen used on any particular day originated from one ejaculate of one bull (same batch number). The cows were manually examined for pregnancy 2 to 3 months after their first insemination. A similar response was seen in all three herds irrespective of the interval from calving to mating. First mating pregnancy rates were 9.3% higher in the Receptal-treated cows than in the control group (P = 0.025). It is suggested that Receptal may have a beneficial effect on the pregnancy rate of cows that have recently ovulated as well as on those having delayed ovulation.
292头奶牛在授精前0 - 6小时接受皮下注射2.5毫升含10微克促性腺激素释放激素类似物（Receptal，赫斯特股份公司）的溶液，而284头作为对照的奶牛在同一时间注射2.5毫升无菌无热原水。处理组和对照组是通过将每头发情奶牛在产犊至首次配种的间隔时间、体况评分以及产犊后首次配种当天的年龄基础上进行配对而形成的。这些奶牛来自3个工厂供应的奶牛群，在配种季节的前3周每天进行检查。每天前来配种的所有奶牛均由同一名技术人员使用0.5毫升常温精液进行授精，每次授精含200万个精子。任何特定一天使用的精液均来自一头公牛的一次射精（相同批号）。在首次授精后2至3个月对奶牛进行人工妊娠检查。在所有三个牛群中均观察到类似的反应，无论产犊至配种的间隔时间如何。接受Receptal处理的奶牛首次配种的妊娠率比对照组高9.3%（P = 0.025）。研究表明，Receptal可能对近期排卵的奶牛以及排卵延迟的奶牛的妊娠率有有益影响。
