Embryo Transfer In Beef Cattle

Embryo transfer in cattle has gained considerable popularity with seed stock beef producers. While most modern applicable embryo transfer technology was developed in the 1970s and 1980s, the history of the procedure goes back considerably farther. ‘‘Walter Heape performed the first embryo transfer in Angora rabbits in 1890’’ (J.C. Remsberg, ‘Herdsmen and vets benefit from E.T. training’). ‘‘Embryo transfer in livestock began in the 1930s with sheep and goats, but it was not until the 1950s that Jim Rowson at Cambridge, England reported successful embryo transfers in cattle and pigs’’ (Bryan M. ‘Reproduction and the Science in Cambridge’). The first commercial embryo transfers (ET) in the United States were done in the early 1970s.
‘‘The breeders who have utilized ET have been pursuing these basic goals: to improve genetic selection by increasing the number of progeny from females that are either proven or perceived to be superior under any number of criteria, to multiply the number of cattle in a program in order to expand the herd, or to meet market demands’’ (Dr. Doug M. ‘Embryo Transfer in Beef Cattle’). There have been additional reasons given to rationalize the use of ET. Supply and demand will always result in semen with increased value. ET will allow a breeder to generate more offspring from rare and valuable female embryos. Current technologies even allow for the application of sexed semen and embryos to give further control over the selection
Take for instance the Angus breed. Registrations of Angus cattle over the past 15 years indicate a substantial increase in the use of ET. ‘‘In 1987, 3.6 percent (5,105 head) of all calves registered in the Angus breed were a result of embryo transfer. In 2002, 25,093 calves resulting from ET were registered. This was 8.9 percent of all calves registered’’ (Monette T. ‘Rancher uses embryo transfers to obtain ‘right kind of cattle’). While Angus is one of the largest breeds in the United States, similar numbers have been documented in other breeds as well, thus we know that the popularity is across the industry and has been recognized as an effective means for retaining exceptional