Commercial equine embryo transfer in the United States

The basic aspects of embryo transfer in the mare have not changed in several decades. Embryo recovery is usually attempted 7 or 8 days after ovulation and recovered embryos are preferably transferred into a recipient that ovulated 1-2 days after the donor mare. Embryo transfer continues to be a common technique to enhance reproduction in subfertile and performance mares in many breeds. Alterations in breed regulations and the ability to superovulate donor mares have significantly changed the equine embryo transfer industry over the past year. The objective of this review is to provide an update on recent alterations in techniques or industry trends as it relates to embryo transfer in the United States.