Study On CIDR+PMSG Treatment In Estrus Synchronization Of Ewes In Different Conditions

In this paper, the exogenous hormone was injected into different sheep breeds which were fed in different ecological environment, feeding conditions& seasons, to realize synchronization of estrus. Estrus ewes were treated with artificial insemination in the right time. Estrus time, transport time, second insemination time in estrus return, lambing time and litter size were record in detail. The ewes of Small-tailed Han Sheep were classified to core group and production group according to the existence or absence of mutate B gene.The fecundity ewes in the offspring were the supplement of the ewe group. The results were as follows:1. The CIDR 12d + PMSG 200IU treatment got high synchronized estrus rate in the 1st estrus time, 87.61%, 84.17%, 92.5% and 84.60%respectively. The mean synchronized estrus rate was 89.33%.2. The estrus rate of the primiparous ewes'1st estrus cycle is significantly lower than the multiparous ewes'.3. The respective estrus rate of 24h,48h and 72h after injecting PMSG are 13.61%,55.0% and 31.39%.4. changing CIDR in 8th day, injecting 200IU PMSG can significantly improve the estrus rate & CR of the primiparous ewes'1st estrus cycle.