Veterinary Management of Equine Reproduction: Embryo Transfer

Although I have had no experience with embryo transfer, I find the subject very interesting. It is exciting to be able to get multiple foals from a mare in one season, or to be able to have foals from a mare that is unable to carry a foal. This is a great option for breeders that have been unable to breed a mare do to health reasons. You could breed a mare that has issues that involve her carrying a foal, for example, if she has been hurt and cannot carry the extra weight. I have looked into ordering foals that are from mares that I like that are created through embryo transfer. These tend to be expensive options, though, but you can get foals from mares that you admire that may be competing. It is good to have an option when you have a mare that you like the genetics of to be able to breed her even if she is competing. She can continue on with her career and have several foals a season. I am excited because someday I could have a foal from a mare (or stallion) I adore. I have even looked into embryo transfer into local horses. It is still out of my range today, but someday it may be an option to get the bloodlines I am seeking.

In my opinion, there are some issues with it becoming a mainstream and big project. Though the embryos may not be viable due to the mare being resistant to the induction of superovulation. Timing seems hard to arrange, with mares going into estrus at different times. The timing of insemination and the fertility of the donor mare seem to be a challenge to ensure they coincide at the most beneficial time. Since 50-70 embryo flushes should result in a healthy embryo, it also tends to be a number game, although in favor of the breeder. Part of this is made up in numbers. The timing can make the project very time involved. It can be very expensive, and so can  the stud fees. Younger mares carry and donate better, making the attempt to breed aged mares a continued challenge. Transfer centers help with the process making it more commercially available. The timing of implanting the embryo must also be perfectly timed. Hormone therapy is a challenge and  flushing may not happen at the correct time. Folicles can only release so many eggs, and that too, may interfere with the process. Bacterial contamination is a serious issue, and should be monitored closely.

I am surprised and impressed at how many breed associations now accept the process. I know there has been some debate over the use of certain breeding or embryo transfer in some breeds. Most of them accept it now though. Since most people want multiple foals from a mare, they often  have them from different stallions. This greatly increases the gene pool as mares breed with more stallions. Foals cost and are worth more because they come from good quality bloodlines. This allows for multiple horses to be registered as the mare's foal for the season. Since embyos can be transferred and held until inserted into a mare, it can be shipped and this allows for the horse's bloodline to reach further than if the horse was simply put up to be a broodmare. The recipient mare should be 3-12 and healthy with a healthy reproductive tract and cervix and of the correct size to carry a healthy foal.