Estrus Synchronization Introduction Effect Comparison of GnRH and PGF_(2α)

Estrus synchronization is an important technique in AI, Several methods have been used in cow estrus synchronization. However, previous reports showed that the efficiency of estrus synchnization was different due to the situation of the cows as well as other conditions. In the present study, the effect of GnRH on estrus synchnization of cow was examined and compared with that of using PGF 2α method, 153 cows were randomly divided into 3 groups. The first group were treated with a injection of PGF 2α,the second group were treated with twice injection of PGF 2α and the third were treated with twice GnRH and once PGF 2α injection. The results showed that the estrus rates of the three groups were 32.65%(16/49), 45.59%(31/68) and 91.30%(42/46),respectively. The estrus rate of the third group was significantly higher than those of the other group(P0.05).