Makin’ Babies: The Influence of Breeding Technologies, Part II

by Kristin Berkery

part I | part II | part III | part IV

The first installment of Makin’ Babies examined how breeding technologies could improve the Thoroughbred breed and how artificial insemination (AI) and transported semen have affected the Arabian breed over the last 30+ years.

Another significant technology approved for Arabians is embryo transfer. With this procedure, a mare is bred (typically through AI) and the resulting embryo is removed from her uterus around day 7. Then it’s frozen for future use or implanted in the uterus of a surrogate mare who delivers and nurtures the foal. This frees the dam to be used in competition or bred again, and it can allow previously infertile mares to produce foals.

In 2002, the Arabian Horse Association registry removed the limit of one foal per dam, per year via embryo transfer. Currently, only the cost of the procedure limits how many times it’s done on a mare.

There’s one question that’s lingered since the early days of artificial insemination: Is it a good idea to use technology to get foals from mares who are subfertile? For mares who struggle to produce good quality eggs or carry a foal to term, AI and embryo transfer allows them another opportunity to contribute to the gene pool. But those mares may pass on their reproductive faults to their foals, which may make AI and embryo transfer necessary for their offspring to reproduce as well. Over the long term, we may find a growing number of horses that are unable to reproduce without costly human intervention — and if you put that into evolutionary terms, those horses would become extinct in nature.

But in the case of those older, valuable mares who are past their breeding prime, embryo transfer could mean preserving their influence longer than ever before.

Since dams are now able to produce multiple foals a year through embryo transfer, a mare has the opportunity to have a greater impact on bloodlines than in the past. Of course there is always the risk that those additional foals will flood the market, especially if the dam’s bloodlines are common or her quality is less desirable.

Certain conditions need to be in place for a horse market to be “flooded.” First, horse owners are stressed by challenging economic conditions (like we have currently) and they struggle to cover the growing costs of vet bills, feed bills, board, and training. As a result, many owners try to sell excess horses to recoup their costs, but the high price of ownership makes it difficult for new buyers to enter the market. Sellers lower their prices more and more until they become close to killer market prices. Some send their horses to auctions and cross their fingers that they’ll find loving homes rather than a feedlot buyer. In the saddest cases, sellers abandon or neglect their herds and the horses end up being euthanized after suffering, or are very slowly (and expensively) rehabilitated by rescue programs.

If you’ve been a long-time horse lover, you’ve no doubt heard of or seen desperately sad situations where horses were severely neglected by owners who could no longer afford to keep them.

With all these risks in a depressed horse market like we’re currently facing, why would a registry allow multiple foals a year from one mare? For one thing, registries also feel the money crunch and they depend on fees from registrations and AI, transported semen, and embryo transfer certificates. The more foals bred, the more revenue for the registry. In addition, breed popularity is often measured by how many horses are registered in a given year, so registries rely on greater numbers of registrations to make the breed look more desirable to newcomers.

>So how can embryo transfer be used to benefit the Arabian breed over the long haul? Most importantly, profits should be moved farther down the list of priorities. Breeders need to take an objective look at whether a mare’s impact on the breed is truly beneficial. Is her pedigree available from many other sources? Or is her breeding harder to find? Is her conformation good for a specific use, other than standing in a halter class and looking pretty? Ideally, a mare with quality, athletic conformation and a pedigree that’s not “trendy” or common is the best candidate for embryo transfer. Her foals stand less of a chance of flooding the market. (Of course the same ideals apply to breeding stallions as well.)

Just as with AI and transported semen, there is a chance of breeding fraud with embryo transfer. To prevent incorrect parentage assignments, registries that permit breeding technologies also require DNA testing of all breeding horses and their foals. Registries have staff members that handle and investigate DNA records, which takes time and money. And it’s not foolproof.

One very surprising example of incorrect parentage that managed to slip by the Arabian Horse Association’s purebred registry is the mare RWR Sonora, who was registered as a 2005 bay purebred Arabian mare, registration number 627880. In the photo shown here, she’s clearly a tobiano — which is not possible in purebred Arabians. Allegedly DNA typing was done on the mare and no questions were raised, but the registry later requested to have her blood typed. The results of the blood typing led the registry to cancel the mare’s purebred papers and ban her from the Half-Arabian registry for suspected fraud.

How did this happen? The registry doesn’t require photos of horses during the registration process, which would have revealed a discrepancy from the very beginning, but photos of another horse could have been substituted by an unethical breeder. As stated in the previous installment of this article, DNA typing is accurate about 96% of the time in Arabians. So either RWR Sonora’s DNA was mishandled, falsified, or DNA typing didn’t work correctly, and her complete markings were not recorded accurately either. Seen at right, her body markings are clearly missing from her registration papers. Even more surprising, the owner who registered her is a former regional director and breeding committee member of the American Shagya-Arabian Verband (registry and breed association).

Regardless of whether RWR Sonora was a product of natural service, AI, transported semen, or embryo transfer, the situation shows how it’s possible to defeat safeguards in an effort to cheat the system.

In the next installment, let’s discuss the advent of cloning horses for breeding purposes. It sounds like an oxymoron, but it’s already been done once before in the Arabian breed.

part I | part II | part III | part IV