MOET技术在阿尔巴斯白绒山羊选育中的应用

通过对阿尔巴斯白绒山羊供体选择、同期发情、超数排卵、手术采卵、受体羊同期发情处理、手术移植等技术的应用,探索了规模化阿尔巴斯白绒山羊MOET技术的组装配套,以加快胚胎移植在养羊业生产中的推广与应用。试验移植供体羊发情率99.0%,可利用率98.5%;平均冲胚胎13.6枚/只;可用胚胎平均9.50枚/只,鲜胚可利用率71.35%。受体羊发情率88.3%,可利用率98.4%,受胎率60.09%,产羔率114.8%,初生重平均2.65 kg。本次移植各项指标均达到较高水平,配套技术比较成熟,稳定性强,具有可操作意义,因此阿尔巴斯白绒山羊规模化应用MOET技术可在畜牧业生产实践中大面积推广应用。     

Genotyping strategies of selection candidates in livestock breeding programmes

Benefits of genomic selection (GS) in livestock breeding operations are well known particularly where traits are sex‐limited, hard to measure, have a low heritability and/or measured later in life. Sheep and beef breeders have a higher cost:benefit ratio for GS compared to dairy. Therefore, strategies for genotyping selection candidates should be explored to maximize the economic benefit of GS. The aim of the paper was to investigate, via simulation, the additional genetic gain achieved by selecting proportions of male selection candidates to be genotyped via truncation selection. A two‐trait selection index was used that contained an easy and early‐in‐life measurement (such as post‐weaning weight) as well as a hard‐to‐measure trait (such as intra‐muscular fat). We also evaluated the optimal proportion of female selection candidates to be genotyped in breeding programmes using natural mating and/or artificial insemination (NatAI), multiple ovulation and embryo transfer (MOET) or juvenile in vitro fertilization and embryo transfer (JIVET). The final aim of the project was to investigate the total dollars spent to increase the genetic merit by one genetic standard deviation (SD) using GS and/or reproductive technologies. For NatAI and MOET breeding programmes, females were selected to have progeny by 2 years of age, while 1‐month‐old females were required for JIVET. Genomic testing the top 20% of male selection candidates achieved 80% of the maximum benefit from GS when selection of male candidates prior to genomic testing had an accuracy of 0.36, while 54% needed to be tested to get the same benefit when the prior selection accuracy was 0.11. To achieve 80% of the maximum benefit in female, selection required 66%, 47% and 56% of female selection candidates to be genotyped in NatAI, MOET and JIVET breeding programmes, respectively. While JIVET and MOET breeding programmes achieved the highest annual genetic gain, genotyping male selection candidates provides the most economical way to increase rates of genetic gain facilitated by genomic testing.     

Cervical transposition test using Hegar dilator at oestrus as a tool to select ewes for transcervical embryo collection

This study evaluated the cervical transposition method as a tool to select ewes for embryo collection by transcervical route. Adult Santa Inês ewes (n = 50) received Day 0 protocol for superovulation treatments. The cervix transposition test was performed both at oestrus and at the embryo collection time. The latter was preceded by hormonal cervical dilation. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85.7%, 66.6%, 85.7%, 66.6% and 80.0%, respectively. The kappa index yielded a moderate score (κ = 0.52). In conclusion, the high sensitivity and accuracy indicate that the cervical transposition test is a screening option to select ewes for embryo collection by transcervical route.     

动物育种方法的研究进展

传统的数量遗传学理论在过去的动物育种实践中起到了非常重要的作用。生物技术的应用,特别是超数排卵和胚胎移植(MOET)技术的应用,大大提高了畜群的整体遗传水平和育种效益。分子遗传学的发展,使得通过标记辅助选择(MAS)直接对基因型进行选择成为可能,动物分子育种将成为21世纪动物育种的主要方法之一。     

牛MOET技术研究现状与进展

本文介绍了MOET技术在家畜育种中的应用情况,包括在国内外家畜育种中的同期发情、超数排卵、胚胎保存等的进展以及同期发情与超数排卵研究的难点。     

中国北方肉绵羊新品种MOET育种计划方案的设计及遗传进展预估

以正在培育的中国北方肉绵羊新品种为研究对象,设计了新品种MOET育种计划方案,并对MOET育种计划的遗传进展进行了预估,目的在于缩短世代间隔和增加遗传进展,为新品种的培育成功提供技术支撑.     

布尔山羊MOET品系繁育方案设计及遗传进展预估

以陕西省布尔羊繁育中心纯种布尔山羊为对象,设计了ＭＯＥＴ品系繁育方案,内容包括：（１）ＭＯＥＴ品系繁育的特点及其在山羊繁育上的重要性;（２）ＭＯＥＴ品系繁育方案,应用群体继代选育法建立高产羊核心群;（３）选择优秀母羊做供体母关,进行ＭＯＥＴ闭锁繁育;（４）进行品系杂交;（５）选择出理想型个体;（６）经过２～３代的横交固定,利用ＭＯＥＴ核心群品系繁育技术进行扩繁。     

Genomic selection strategies in dairy cattle breeding programmes: Sexed semen cannot replace multiple ovulation and embryo transfer as superior reproductive technology

The aim of this study was to test whether the use of X-semen in a dairy cattle population using genomic selection (GS) and multiple ovulation and embryo transfer (MOET) increases the selection intensity on cow dams and thereby the genetic gain in the entire population. Also, the dynamics of using different types of sexed semen (X, Y or conventional) in the nucleus were investigated. The stochastic simulation study partly supported the hypothesis as the genetic gain in the entire population was elevated when X-semen was used in the production population as GS exploited the higher selection intensity among heifers with great accuracy. However, when MOET was applied, the effect was considerably diminished as was the exchange of females between the nucleus and the production population, thus causing modest genetic profit from using X-sorted semen in the production population. In addition, the effect of using sexed semen on the genetic gain was very small compared with the effect of MOET and highly dependent on whether cow dams or bull dams were inseminated with sexed semen and on what type of semen that was used for the bull dams. The rate of inbreeding was seldom affected by the use of sexed semen. However, when all young bull candidates were born following MOET, the results showed that the use of Y-semen in the breeding nucleus tended to decrease the rate of inbreeding as it enabled GS to increase within-family selection. This implies that the benefit from using sexed semen in a modern dairy cattle breeding scheme applying both GS and MOET may be found in its beneficial effect on the rate of inbreeding.     

AI+MOET技术获得双胎犊牛技术的初探

本实验采用AI与MOET相结合的方法诱导双胎,供受体牛的同期发情,是根据已知供体牛的情期,来推算受体牛的同期发情处理时间,供体牛用一次PGF2α的处理,受体牛用两次PGF2α处理的方法,处理的三头牛全部发情。超数排卵采用FSH减量法,处理供体牛1头获得10枚胚胎,其中可用胚9枚,对2头受体牛先进行人工授精,然后在人工授精后第7天进行胚胎移植,处理后两头受体牛都怀孕,产下5头犊牛。