Khan Sami Ullah, Jamal Muhammad Ameen, Su Yanhua, Wei Hong-Jiang, Qing Yubo, Cheng Wenmin
Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China.
Yunnan Key Laboratory of Porcine Gene Editing and Xenotransplantation, Yunnan Agricultural University, Kunming 650201, China.
Vet Sci. 2022 Mar 4;9(3):117. doi: 10.3390/vetsci9030117.
Considerable improvements in sheep multiple ovulation and embryo transfer (MOET)protocols have been made; however, unlike for cattle, MOET is poorly developed in sheep, and thus has not been broadly applicable as a routine procedure. The tightly folded nature of the ewe cervix, the inconsistent ovarian response to various superovulatory treatments, and the requirement of labor to handle animals, particularly during large-scale production, has limited the implementation of successful MOET in sheep. Moreover, several extrinsic factors (e.g., sources, the purity of gonadotrophins and their administration) and intrinsic factors (e.g., breed, age, nutrition, reproductive status) severely limit the practicability of MOET in sheep and other domestic animals. In this review, we summarize the effects of different superovulatory protocols, and their respective ovarian responses, in terms of ovulation rate, and embryo recovery and transfer. Furthermore, various strategies, such as inhibin immunization, conventional superovulation protocols, and melatonin implants for improving the ovarian response, are discussed in detail. Other reproductive techniques and their relative advantages and disadvantages, such as artificial insemination (AI), and donor embryo recovery and transfer to the recipient through different procedures, which must be taken into consideration for achieving satisfactory results during any MOET program in sheep, are also summarized in this article.
绵羊的多次排卵和胚胎移植（MOET）方案已经有了显著改进；然而，与牛不同的是，MOET在绵羊中的发展并不完善，因此尚未广泛应用于常规程序。母羊子宫颈紧密折叠的特性、对各种超排处理的卵巢反应不一致，以及处理动物（特别是在大规模生产期间）需要人工，这些都限制了MOET在绵羊中的成功实施。此外，一些外在因素（如促性腺激素的来源、纯度及其给药方式）和内在因素（如品种、年龄、营养、生殖状态）严重限制了MOET在绵羊和其他家畜中的实用性。在这篇综述中，我们根据排卵率、胚胎回收和移植情况，总结了不同超排方案及其各自的卵巢反应的影响。此外，还详细讨论了各种提高卵巢反应的策略，如抑制素免疫、传统超排方案和褪黑素植入。本文还总结了其他生殖技术及其相对优缺点，如人工授精（AI），以及供体胚胎回收和通过不同程序移植到受体，在绵羊的任何MOET计划中，为了取得满意的结果都必须考虑这些。
