Whereas artificial insemination has contributed immensely to the genetic improvement of farm animals, embryo transfer has also proved to be a powerful technology, primarily for propagating the genetics of females of superior pedigree. In cattle, particularly in the dairy industry, breeding programs were developed that aimed to promote genetic progress by strategic use of elite females through multiple ovulation embryo transfer (MOET) programs. In addition to conventional methods to produce embryos available for transfer, new technologies that produce embryos after cloning by somatic cell transfer or transgenesis are currently available but not yet widely used commercially.
Embryo transfer protocols have also been extensively used in research critical for the understanding of several areas of biology and medicine, such as fetal-maternal interactions, models of human and animal diseases, production of transgenic animals to produce therapeutic proteins for people, etc. However, the following discussion is restricted to the principles and methods currently used in commercial embryo transfer of farm animals. Except in horses, embryo transfer programs in most mammals include the administration of drugs that superovulate females to allow the probability that multiple embryos will be collected per procedure.
Last full review/revision July 2011 by Carlos R. F. Pinto, MedVet, PhD, DACT