Yániz J L, Murugavel K, López-Gatius F
Department of Animal Production, University of Zaragoza, Huesca, Spain.
Reprod Domest Anim. 2004 Apr;39(2):86-93. doi: 10.1111/j.1439-0531.2004.00483.x.
This report reviews the most recent developments in prostaglandin-based oestrous synchronization programmes for postpartum dairy cows and addresses the efficiency of controlled breeding protocols based on such developments for cows with abnormal ovarian conditions. A double prostaglandin protocol applied 11-14 days apart seems to be capable of bringing most cows to oestrus. Because of varying oestrus onset times, improved conception rates are obtained following artificial insemination (AI) at detected oestrus rather than fixed-time AI in prostaglandin-treated cows. The administration of oestradiol or human chorionic gonadotrophin, or both these hormones, after prostaglandin treatment, improves the synchrony of oestrus yet does not enhance the conception rate. Progesterone-based treatments for oestrous synchronization are considered the most appropriate for non-cyclic or anoestrous postpartum dairy cows; prostaglandin alone being ineffective because of the absence of a mature corpus luteum in these cows. Improved oestrus synchrony and fertility rate have been reported using short-term progesterone treatment regimes (7-9 days) with or without oestradiol benzoate combined with the use of a luteolytic agent given 1 day before, or at the time of, progesterone withdrawal. The ovulation synchronization (Ovsynch) protocol, based on the use of gonadotrophin releasing hormone and prostaglandin, was developed to coordinate follicular recruitment, CL regression and the time of ovulation. This protocol allows fixed time insemination and has proved effective in improving reproductive management in postpartum dairy cows. However, timed AI following Ovsynch seems to have no beneficial effects in heifers, because of an inconsistent follicle wave pattern, and in anoestrous cows, given their lack of prostaglandin responsive CL. To date, there are several prostaglandin based, fixed-time insemination oestrous synchronization protocols for use in early postpartum dairy cows with ovarian disorders such as ovarian cysts and acyclicity.
本报告回顾了基于前列腺素的产后奶牛发情同步程序的最新进展，并探讨了基于这些进展的针对卵巢状况异常奶牛的控制繁殖方案的效率。间隔11 - 14天应用的双前列腺素方案似乎能够使大多数奶牛发情。由于发情开始时间不同，在检测到发情时进行人工授精（AI）比在前列腺素处理的奶牛中进行定时AI能获得更高的受孕率。在前列腺素处理后给予雌二醇或人绒毛膜促性腺激素，或同时给予这两种激素，可改善发情同步性，但不会提高受孕率。基于孕酮的发情同步处理被认为最适合非周期性或产后不发情的奶牛；仅使用前列腺素无效，因为这些奶牛缺乏成熟的黄体。据报道，使用短期孕酮处理方案（7 - 9天），无论是否联合苯甲酸雌二醇，并在孕酮撤药前1天或撤药时使用溶黄体剂，可改善发情同步性和生育率。基于促性腺激素释放激素和前列腺素使用的排卵同步（Ovsynch）方案，旨在协调卵泡募集、黄体退化和排卵时间。该方案允许定时授精，并已证明在改善产后奶牛繁殖管理方面有效。然而，由于卵泡波型不一致，Ovsynch后的定时AI对小母牛似乎没有有益影响，而对于不发情的奶牛，由于它们缺乏对前列腺素敏感的黄体，定时AI也没有效果。迄今为止，有几种基于前列腺素的定时授精发情同步方案可用于产后早期患有卵巢囊肿和无排卵等卵巢疾病的奶牛。
