Embryo Transfer History
Embryo transfer (ET) was first done in rabbits in the 1890 when Walter Heape transferred two Angora rabbit embryos to a gestating Belgian doe. The Belgian doe produced a litter of Angora and Belgian bunnies. Although ET was used in sheep and goats in the 1930's it was not until the 1950's that successful ET was reported in cattle and pigs (Rowson; Cambridge, England).
Non-surgical recovery and transfer of the embryo was developed in the 1970's and led to an explosion in the ET industry in cattle (O.J. Ginther, R.F. Rowe and M.R. DelCampo; UW-Madison). The first ET in horses was in 1972 (Allen and Rowson) and has been used extensively in research projects:
- Role of oviduct vs uterus in embryo survival;
- Subfertility in old vs young mares;
- Study of endometrial cup formation using cross species transfers;
- Role of progesterone in pregnancy maintenance;
- Uterine capacity
Applied uses of ET have developed as other reproductive technologies have been developed. Some of these uses include:
- Genome preservation (Przewalski's horse)
- Obtaining pregnancy from oleder mares
- Allowing mare to reproduce while still in competition
- Allow a late foaling mare to still have a foal bur remain open for an early breeding the next season
- Used in conjection with other technologies such as sexed semen, ICSI, cloning, etc
Embryo transfer has become more accepted by the Horse industry although registry may be limited in some breeds (US Trotting Association, Standardbred; Lipizzan). Embryo transfer is not accepted by the Jockey Club (Thoroughbred). Rules in the breed associations change regularly, so breeders must check with their association. (see Breed Regulations-2004)
