The practice of shipping stallions’ semen across the country, and even around the world, is a mainstay in today’s equine reproduction industry. Collecting and transporting mares’ oocytes (egg cells) in a similar fashion, then fertilizing and implanting them into donor mares could save breeders money—and donor mares from having to take long, expensive, and potentially health-compromising trailer rides. Veterinarians are determining whether this technique could be a viable approach for saving time and money.

Intracytoplasmic sperm injection (ICSI) is a form of in vitro fertilization in which a single sperm is injected directly into an egg. The technique is not commonly used in equine medicine, but Rob Foss, DVM, of Equine Medical Services, Inc., in Colombia Mo., said, “Its use is increasing for mares that are unable to produce embryos any other way and also for stallions whose available sperm numbers are low.” But, because only a handful of facilities offer the procedure, horse owners often have to transport their mares great distances at great cost, racking up hefty price tags even before procedures get under way.

At the 2013 American Association of Equine Practitioners’ Convention, held Dec. 7-11 in Nashville, Tenn., Foss described a study he and colleagues performed to determine the effect of shipping oocytes on the eventual fertilization rate.

The team incubated two types of oocytes—those recovered from dominant (mature) follicles after inducing ovulation via deslorelin administration (and those from subordinate (immature) follicles—overnight in various media and at varying temperatures to mimic the effects of transport. Then the team performed ICSI using the incubated oocytes and compared the groups’ blastocyst (early embryo) production rates