Recently, the topic of allowing multiple foals from mares came up on Haynet, the on-line forum for discussing model horses. A newcomer to PA made the statement that she allowed unlimited numbers of foals from mares because "ET technology made it possible". A lively discussion followed about the realism of unlimited foals. The following is an excerpt from a post written by hobbyist Jackie Arns. For those that do not know Jackie, she is a fourth-year veterinary student at Cornell specializing in equine reproduction. She has worked in Cornell's Theriogenology (reproduction) department, and has been involved with embryo transfer. She offered the following information for those doing pedigree assignment:
"What I've read today from everyone who's been replying has been a combination of truth, wishful thinking, and misunderstandings. So.... here we go....equine theriogenology in a nutshell!
EMBRYO TRANSFER (ET) -- This is the technique you use when you feel you have a genetically superior female, or your chosen female cannot carry a pregnancy for some reason.
Give this information, it is obvious that many have misconceptions of just what is involved in Embryo Transfer. It is not enough to be able to 'transfer' the embryos to donor mares. The mares must also be made to superovulate -- something that, as Jackie pointed out, is not currently possible. The idea that females have infinite ovum that can be harvested and implanted into donors is unrealistic; the ovum still must be fertilized in the original mare's follicle and then flushed for implantation, and that limits the number of possible embryos to two. Statistical probability makes even that number less likely.
IPABRA does not ban the practice of multiple foals from mares. That is still the choice of each individual. However, those interested in strict standards of realism should be aware that unlimited foals from mares cannot currently by justified by "advances in technology".