| As it plays more and more important roles in exploiting the potential fertility of female animal,the multiple ovulation and embryo transfer(MOET)is now used worldwidely to accelerate the breeding improvement and the number of first-class dairy and beef cattle.In order to provide some useful references for reproductive and administrative technicians in beef MOET,this study was carried out to study the influence factors involved in superovulation and embryo transfer in Wagyu cattle from years 2017 to 2018.The results were as follows:Experiment one: The influenc factors on the superovulation in Wagyu cattleTotal 71 Wagyu were selected as the donors,which included 34 Wagyu heifers(16~20 months)and 37 Wagyu cows(first-calvin).Superovulation was performed by 8 times intramuscular injection of FSH(Follintropin-V)in 4 days as a conventional superovulation procedure.The results showed that:(1)112 superovulations were totally carried out,and the efficiency of donor superovulation was 85.7%.1145 embryos/ova were collectted,and total 832 transferable embryos obtained.(2)The superovulation efficiency of the cow donors(93.4%)was significantly higher than that of the heifers(76%)(P<0.05).(3)There was no significant difference in the first and second superovulation efficiency between heifers and cows.However,the number of embryos(6.20)and tranferable embryos(4.31)collected from second superovulation in heifer were lower than the number from first superovulation.Meanwhile,the number of embryos(12.92)collected from second superovulation in cows were higher than that from first superovulation(11.41),but the number of transferable embryos(8.38)was slightly lower than that from first transferable.(4)Different doses of FSH could significantly affect the superovulation efficiency of Wagyu cattles.The superovulation efficiency of 120 mg group(50%)in heifer donoers was significantly lower than that of 200 mg and 220 mg group(P < 0.05).The superovulation efficiency(86.7%)in 220 mg,240mg and 250 mg groups in cow donoers were significantly lower than that in other groups,and the number of available embryos(7.8)was also lower than that in other groups.(5)The superovulation efficiencies of spontaneous estrus donors,synchronizated estrus donoers by prostaglandin or synchronizated estrus donoers by CIDR were 85.4%,85.7% and 88.9%,respectively.The average number of embryos recovered from donoers were 12.0,10.0 and 12.3,respectively,and there was no significant difference between these groups(P > 0.05).Meanwhile,the number of transferable embryos were 8.7,7.2 and 9.3,respectively,and there also was no significant difference between groups(P > 0.05).Experiment two: The influence factors on embryo transfer of Wagyu cattleThe embryos collected from Wagyu cattle donors were transferred to 321 Hestein heifer recipients in 2017,and 192 in 2018.The results showed that:(1)The pregnant rate of recipients checked by rectal palpation at 60 d after embryo transfer was 40.50% in 2017,and 43.23% in 2018,respectively.(2)The pregnant rate of embryos at morula and blastocyst stage transferred to recipients were32.0% and 38.1%,respectively,and there was no significant difference between them(P >0.05).(3)Checked by rectal palpation at 60 d after embryo transfer,the pregnant rate of the recipients transferred two fresh whole embryos(grade B)was 75.00%,and the pregnancy of the recipients transferred fresh two-half-embryos splitted was 57.2%,while the pregnant rate of the recipiens transferred one fresh whole embryos was 55.00%.There was no significant difference among the three groups(P > 0.05).(4)Althouth the pregnant rate of recipients synchronizated by one prostaglandin treatment was highest,but there was no significant difference between the recipients synchronizated by CIDR and recipients in natural estrus.(5)The pregnant rate of recipients which received fembryos frozen by conventional freezing method(slow freezing method)was significantly lower than that of transferred fresh embryos or vitrified embryos(P < 0.05). |
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