Abstract:

Thirteen German Simmental donor cows for 4 times repeated superovulation, 654 embryos were obtained (the average number of embryos per cow was 50.31), and the available embryo was 335 (the average number of embryos per cow was 25.77). The result of donors were flushed repeatedly for four times showed the average recovery of embryos, transferable embryos had no significantly different (P>0.05).278 recipients were transplanted (115 use fresh embryo,118 use frozen embryo, 45 use pairs of demi-embryos) followed by pregnancy rate of 55.04% (135/278), total of 137 calves. Both pairs of demi-embryos and fresh embryos transfer pregnancy rate were significantly higher than that of frozen embryos (64.44%, 60.87% vs 45.76%) (P<0.05).45 fresh Pairs of demi-embryos were transferred to 45 recipients, 29 were pregnant, among them, there were 11 identica1 twins with twin rate of 37.93% (11/29), 29 calves survived.