Effect of embryo transfer time on the pregnancy rate of vaccinated recipient cattle
In order to explore the effect of transfer time on the pregnancy rate of vaccinated recipient cow and further improve the conception rate of frozen embryo transfer,the embryo transfer experiments were conducted in June and September 2019,September 2022,and September 2023.The animals from breeds of Red Angus,Wagyu and Holstein cattle were randomly divided into 4 groups as recipients,respectively,in which embryos were transferred at(10 to 15 d,16 to 30 d,31 to 45 d,and ≥60 d)after immunization.On the 35th day of embryo transfer,the pregnancy rate was monitored by B-ultrasound.The results showed as follows:The pregnancy rates of groups of 31 to 45 d and ≥60 d in Angus,Wagyu and Holstein cattle transferred were significantly higher(P＜0.05)than those in groups of 10 to 15 d and 16 to 30 d.It could be concluded that the transfer time could be＞30 d after immunization to avoid a decrease in the pregnancy rate of embryo transfer in cattle.
HolsteinRed AngusWagyuvaccinationpregnancy rateembryo transfer
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NSTL
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