Frisch J E, O'Neill C J
CSIRO, Division of Tropical Animal Production, Rockhampton Mail Centre, Queensland.
Aust Vet J. 1996 Mar;73(3):98-102. doi: 10.1111/j.1751-0813.1996.tb09986.x.
Maiden heifers and lactating cows of known ovarian status and of several breeds were treated with a synthetic prostaglandin, cloprostenol, or a synthetic progestagen, norgestomet, at the start of an artificial insemination (AI) program. Animals in the cloprostenol treatment received 2 injections 10 days apart. Over the next 26 days those animals that showed oestrous behaviour were inseminated. Synchronisation rates and calving rates to insemination over the first 7 days were calculated. Those in the norgestomet treatment received an implant of norgestomet plus an injection of norgestomet and oestradiol valerate. The implant was removed 10 days later and the animals were given an injection of pregnant mare serum gonadotrophin (PMSG). They were inseminated at 48 h (maiden heifers) or 56 h (lactating cows) after implant removal. Calving rates to fixed-time insemination were recorded. After completion of the AI program the animals in both treatments were joined with bulls. Overall calving rates (AI plus bulls) were calculated. By day 7 of the program, 82% of the maiden heifers and 76% of the lactating cows in the cloprostenol treatment had been detected in oestrus. By day 21 the respective figures were 99% and 81%. Norgestomet treatment had an immediate and a prolonged effect on ovarian activity in those females classified as having inactive ovaries at the start of the AI program. Calving rates of those females to fixed-time AI and overall were similar to those of the females with active ovaries in both treatments. Their calving rates to fixed-time insemination, and overall calving rates for the lactating females, were significantly higher than the corresponding values of their contemporaries treated with cloprostenol and inseminated on observed oestrus over 7 days. For those females classified as having active ovaries at the start of the AI program, calving rates to first insemination and overall were similar for both treatments. Overall calving rates of lactating cows of each breed were, with one exception, higher in the norgestomet treatment than in the cloprostenol treatment. Although norgestomet treatment was more expensive than cloprostenol treatment, the advantage in calf crop resulted in an overall monetary advantage to the norgestomet treatment.
在人工授精（AI）项目开始时，对已知卵巢状态的几个品种的未孕小母牛和泌乳母牛分别用合成前列腺素氯前列醇或合成孕激素诺孕美特进行处理。氯前列醇处理组的动物每隔10天注射2次。在接下来的26天里，对表现出发情行为的动物进行授精。计算前7天的同步率和授精后的产犊率。诺孕美特处理组的动物植入诺孕美特并注射诺孕美特和戊酸雌二醇。10天后取出植入物，给动物注射孕马血清促性腺激素（PMSG）。在取出植入物后48小时（未孕小母牛）或56小时（泌乳母牛）进行授精。记录定时授精后的产犊率。AI项目完成后，将两种处理组的动物与公牛混群。计算总体产犊率（AI加公牛配种）。到项目第7天，氯前列醇处理组中82%的未孕小母牛和76%的泌乳母牛出现发情。到第21天，相应数字分别为99%和81%。在AI项目开始时被归类为卵巢不活跃的雌性动物中，诺孕美特处理对卵巢活动有即时和长期影响。在两种处理中，这些雌性动物定时AI和总体的产犊率与卵巢活跃的雌性动物相似。它们定时授精的产犊率以及泌乳母牛的总体产犊率显著高于同期用氯前列醇处理并在观察到发情时授精的同龄动物的相应值。对于在AI项目开始时被归类为卵巢活跃的雌性动物，两种处理的首次授精产犊率和总体产犊率相似。除一个品种外，各品种泌乳母牛的总体产犊率在诺孕美特处理组均高于氯前列醇处理组。尽管诺孕美特处理比氯前列醇处理成本更高，但犊牛产量优势使诺孕美特处理在总体经济效益上更具优势。
