Ungerfeld R, Forsberg M, Rubianes E
Departamento de Fisiología, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay.
Reprod Fertil Dev. 2004;16(4):479-90. doi: 10.10371/RD04039.
The present review summarises knowledge of the reproductive response of anoestrous ewes to the introduction of rams - in other words, the ram effect. The ovarian and endocrine response, the factors that determine whether ewes will respond or not (associated with both the stimulus and the receptivity of the ewes) and some aspects of practical management are discussed. Information on the use of the ram effect to stimulate post-partum, prepubertal and cyclic ewes is also given. New insights are provided on ovarian response patterns, including recently collected information on luteal responses. The existence of delayed ovulation (5-7 days after the introduction of the rams) followed by luteal phases of normal or short length, luteal cysts and luteinised follicles is reported after scanning the ovaries with ultrasound. Endocrine parameters for depth of anoestrus, such as LH pulsatility and FSH concentrations, and how the concentrations of these hormones should be considered are discussed. Particular attention is paid to the observation of spontaneous, higher LH pulsatility and higher FSH concentrations in anoestrous ewes that respond to rams with luteal phases than in those that fail to respond. The use of progestogen priming and single progestogen administration and the possible advantages for synchronisation of oestrus are also discussed. Other factors that should be considered before the ram effect is applied, such as the strength of the stimulus and some practical considerations, are also included.
本综述总结了关于乏情母羊对公羊引入的生殖反应的知识——换句话说，即公羊效应。文中讨论了卵巢和内分泌反应、决定母羊是否会产生反应的因素（与刺激因素和母羊的接受能力均相关）以及一些实际管理方面的内容。还给出了关于利用公羊效应刺激产后、青春期前和处于发情周期的母羊的信息。文中提供了关于卵巢反应模式的新见解，包括最近收集到的有关黄体反应的信息。在用超声扫描卵巢后，报告了存在延迟排卵（引入公羊后5 - 7天），随后是正常或较短长度的黄体期、黄体囊肿和卵泡黄素化的情况。讨论了用于评估乏情深度的内分泌参数，如促黄体生成素（LH）的脉冲性和促卵泡生成素（FSH）的浓度，以及应如何看待这些激素的浓度。特别关注了以下观察结果：与未产生反应的乏情母羊相比，对公羊产生反应并进入黄体期的乏情母羊会自发出现更高的LH脉冲性和更高的FSH浓度。文中还讨论了孕激素预处理和单次孕激素给药的使用以及对发情同步化可能具有的优势。在应用公羊效应之前应考虑的其他因素，如刺激的强度和一些实际考量，也包含其中。
