Effects of FSH application methods on super-ovulatory response in Poor Dorset sheep

In order to investigate effects of types and doses of FSH,and times and season of FSH injection on superovulation response,206 Poor Dorset ewes were superovulated with FSH produced in Chinese Academy of Sciences(CAS),Ningbo(NB) or Canada(CA).Estrous rate of donors,number of recovered embryos,number of transferable embryos,percentage of regressed-unfertilized embryos and performance of donors were observed.The effective superovulation response was achieved in suitable dose ranges regardless of the type of FSH,but the number of recovered embryos and transferable embryos were improved by combining use of NB-FSH with CAS-FSH.Compared with 6 times progressive decrease injection,the effect of 7 or 8 times injection was more ideal.The superovulation response in autumn was better than that in spring,summer and winter.The variability of response to FSH treatment and the fertilization failure also occurred.The results showed that the superovulation response is controlled by extrinsic FSH only to a(certain) extent,and further studies should consider the relationship between extrinsic FSH and endocrine(response).