Embryo transfer (ET) is an accepted and successful technique for obtaining foals from mares without interrupting their competition careers. Recent research, however, suggests that the potential of factors including heat, exercise, repeated embryo flushing and repeated manipulation of the reproductive cycle using exogenous hormones to have a negative impact on fertility may have been underestimated. This paper reviews the evidence base for involvement of these factors in repeated failures to recover embryos from nongeriatric competition mares without obvious clinical or pathological indications of reproductive abnormalities. It concludes that, for some mares at least, a cessation of exercise for the periovulatory period and the period between ovulation and embryo flushing, combined with careful management of flushing-induced endometritis, and minimal hormonal manipulation of the reproductive cycle, may be necessary to optimise embryo recovery rates. Mare owners may have been encouraged to request ET for their mares following high-profile examples in the media of elite mares that have produced foals by ET whilst competing. The veterinarian should educate mare owners about the multiple factors that may affect the chances of recovering an embryo from their mares, and should manage the expectations of mare owners so that they do not approach ET programmes in the expectation that there will be no disruption to their training and competition plans.

中文翻译：

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竞赛马的胚胎移植：管理母马和期望

胚胎移植 (ET) 是一种公认​​且成功的技术，可以在不中断母马的比赛生涯的情况下从母马身上获得小马驹。然而，最近的研究表明，包括热量、运动、反复胚胎冲洗和使用外源激素反复操纵生殖周期等因素对生育能力产生负面影响的潜力可能被低估了。本文回顾了这些因素在反复未能从没有明显生殖异常临床或病理迹象的非老年竞争母马身上恢复胚胎的证据基础。它得出的结论是，至少对于某些母马，在排卵期和排卵期和胚胎潮红之间停止运动，并仔细管理潮红引起的子宫内膜炎，和最小的生殖周期荷尔蒙操纵，可能是优化胚胎恢复率所必需的。母马可能已经被鼓励为他们的母马要求 ET，这是因为精英母马在比赛时通过 ET 生产了小马驹。兽医应教育母马主人了解可能影响从母马恢复胚胎的机会的多种因素，并应管理母马主人的期望，使他们不会因为期望不会对母马造成干扰而接近 ET 计划。训练和比赛计划。母马可能已经被鼓励为他们的母马要求 ET，这是因为精英母马在比赛时通过 ET 生产了小马驹。兽医应教育母马主人了解可能影响从母马恢复胚胎的机会的多种因素，并应管理母马主人的期望，使他们不会因为期望不会对母马造成干扰而接近 ET 计划。训练和比赛计划。母马可能已经被鼓励为他们的母马要求 ET，这是因为精英母马在比赛时通过 ET 生产了小马驹。兽医应教育母马主人了解可能影响从母马恢复胚胎的机会的多种因素，并应管理母马主人的期望，使他们不会因为期望不会对母马造成干扰而接近 ET 计划。训练和比赛计划。