Embryo Transfer in Beef Cattle Research

Embryo transfer techniques have been utilized to increase the number of desirable animals (e.g., exotic breeds) or to study factors influencing embryonic development. Embryo transfer is predominantly used at the Research Center as a research tool to answer questions about embryonic development and maternal influence on subsequent growth of the newbom calf. Embryo transfer utilizes the techniques of 1)superovulation; 2)surgical or nonsurgical embryo collection and transfer; and 3)handling the embryo between collection and transfer. Therefore follicular development as well as fertilization rates play important roles in the production of viable embryos. A large variation in response to the superovulatory procedure exists among females in ovulation rate and number of transferable embryos. Approximately one-third of the female cattle induced to superovulate do not respond with transferable embryos. Only 40 to 60 percent of the embryos transferred develop into calves. Therefore we conducted several studies to investigate superovulatory and embryo transfer procedures. In addition, embryo transfer technology was employed to study maternal influences on postnatal (after birth) growth in calves