本实验利用GnRH+PG+GnRH对荷斯坦奶牛进行同期发情。A组:成母牛肌注GnRH200mg,B组:育成牛肌注GnRH100mg,7d后A和B组均肌注PG0.5mg,注射PG2d后两组均再次肌注同等剂量GnRH100微克,利用GnRH同期方法A、B组同期发情率、第一次输精排卵率差异均不显著。

This experiment applies GNRH+PG+GNRH and CIDR+EB+P4+PG to do estrus synchronization to Holstein.A group: mature cow intramuscularly inject 200ug.B group: hefers intramuscularly inject 100 ug;Seven days later,A group and B group both intramuscularly inject 0.5mg PG.After two days of intramuscular injection,muscle inject identical GNRH 100ug again for the two groups,applying GNRH to do synchronous estrus processing at the same time,the rate of estrus synchronization and the first insemination ovulation rate exist little difference.