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Assisted Reproductive Technologies Safe in HorsesBy Kentucky Equine Research Staff · August 4, 2017

Despite being used in the equine industry for decades, concerns surrounding the safety of assisted reproductive therapies (ARTs), such as embryo transfer, persist. According to a recent study*, owner and breeder trepidation regarding ART isn’t unfounded due to the occurrence of fetal and placental abnormalities in humans, cows, and sheep. Horses, however, seem relatively immune to the negative impacts of ART.

“In other species, fetuses that are too large or too small have been reported following the use of ARTs,” explained Catherine Whitehouse, M.S., an advisor for Kentucky Equine Research (KER).

In addition to altered fetal size, enlarged placentas with decreased thickness have also been reported. To determine if these changes also occur in horses, one research group bred 30 Quarter Horse mares using natural cover, embryo transfer (ET), or intracytoplasmic sperm injection followed by culture and ET.

After evaluating the foals and placentas from the three different groups, the study authors concluded that no changes in the placental area or volume, foal measurements (e.g., withers height, crown-rump length, etc.), and the expression of placental genes responsible for growth and vascularization occurred between the three breeding techniques.

The study authors therefore concluded, “These data indicate that within this population, use of ARTs was not associated with meaningful changes in foal or placental morphometry or in expression of the placental genes evaluated.”

This is great news for the global equine industry, considering about 20,000 horses are produced via ARTs each year. These technologies allow genetically valuable animals to procreate more extensively than relying on natural cover alone and permit the production of foals from infertile animals that otherwise would not be able to breed.

“Regardless of how a mare is bred, one of the most important factors to consider is her overall health prior to conception, including her body condition score,” advised Whitehouse.

When planning your breeding, don’t forget about the benefits that omega-3 fatty acid supplements have to offer, such as combating the development of placentitis, expediting involution of the nonpregnant horn after foaling, and boosting colostrum quality.

“Consider offering broodmares EO•3, a potent marine-derived oil rich in the omega-3 fatty acids EPA and DHA,” Whitehouse recommended.

*Valenzuela, O.A., A. Couturier-Tarrade, Y.H. Choi, et al. Impact of equine assisted reproductive technologies (standard embryo transfer or intracytoplasmic sperm injection (ICSI) with in vitro culture and embryo transfer) on placenta and foal morphometry and placental gene expression. Reproduction, Fertility, and Development. In press.