The embryos were collected after mated 6 days. Blood samples were collected at different stages and the main reproduction hormone (LH, FSH, E_2, P_4) were in vestigated using RIA method.

• 在同期发情、超数排卵和配种后的不同生理阶段分别进行颈静脉采血11次,每次约8mL,静置30min后,以3500转/min转速离心10min,分离血清,然后用放射免疫法(RIA)测定血清中促黄体素(LH)、促卵泡素(FSH)、雌二醇(E_2)、孕酮(P_4)的含量。