摘要
本文调查总结了北美不同区域中4种商业化胚胎移植程序在过去20年以来荷斯坦成母牛及青年母牛胚胎移植实施及其结果情况。随着时间的推移,在一种程序中平均每次冲胚获得的胚胎数下降(P<0.05),但是其它三种程序却无此现象。针对胚胎移植程序中所用的不同类型母牛,不同超排处理次数及所使用不同品牌促性腺激素等复杂因素进行了分析,数据显示,将胚胎移植给荷斯坦青年母牛比移植给泌乳牛的妊娠率(P<0.001)高。目前还不清楚妊娠率下降是否与移植方法从手术法改变到非手术法有关。针对两个程序的妊娠率进行了分析比较,其中一个程序在采用非手术法移植时受胎率下降(P<0.001),然而另一个却没变化。所有胚胎移植程序中最大的变化之一就是从供体收集到的胚胎中有50%以上在采集后作冷冻处理,然而在20年前大部分胚胎都作鲜胚移植。
Embryo transfer practice and results were examined over a 20-year period in Holstein cows and heifers within four eommereial embryo transfer programs located in diffcrent areas of North America. Mean embryo production per collection decreased （P 〈 0.05） in one program over time,but not in the other three. Changes in tile type of cows entering embryo transfer programs, the numberof times they were superstimulated and changes in the brands of gonadotropins used for supcrstimulation all complicated the analysis of embryo produetion over time. Data reveal higher pregnancy rates （P 〈 0.001） following transfer of embryos into Holstein heifers than into lactating dairy cows. It is not clear whether pregnancy rates have decreased over time as a result of the change from surgical to no,l-surgical embryo transfer. In the two progranls in which pregna,lcy rates were analyzed, there was a decrease （P 〈 0.001） when non-surgical transfers wcrc adopted in one program, whilc no change occurred in the other. One of tile biggest changes in all programs was that more than 50% of embryos recovered from donors are now frozen after collection, whereas the majority were transfcrred fresh 20 years ago.
出处
《草食家畜》
2007年第4期19-25,共7页
Grass-Feeding Livestock
基金
"十一五"国家科技支撑计划项目"奶牛良种扩繁技术研究及产业化开发"(2006BAD04A02)
关键词
奶牛
超排
胚胎
胚胎移植
Dairy cows
Superovulation
Embryo
Embryo transfcr
