Recipient Mares

Nutrition to Support Embryo Transfer


By , Platinum Performance®

Focus on the Recipient Mare to Maximize a Foal’s Genetic Potential

Embryo transfer, utilized since the 1970s, is an equine reproduction technique where the donor mare is inseminated (naturally or artificially), and, as opposed to carrying a foal to term, the 6- to 8-day-old embryo is flushed from the uterus and implanted into a recipient mare that carries, delivers and often nurses the foal until weaning. The process offers many benefits. It allows the donor mares, often with desirable genetics, to continue performance careers while still producing foals with their bloodlines. It can allow the production of more than one foal from a mare per season. It can be used if a donor mare has reproductive issues and is unable to carry a pregnancy to term. Embryo transfer also allows older mares to continue reproducing as female equines can produce eggs into their 20s but may be unable to carry a foal at that age.

Essentially a surrogate, the recip, or recipient mare, carries a valuable investment, and, although not genetically related, still importantly exerts great influence as the embryo progresses from fetus to foal. The health of the offspring relies significantly on the health of the broodmare, and nutrition is a critical factor. What she consumes directly influences the growth and development of the fetus — in utero and after foaling. Providing optimal nutrition for the recipient broodmare can be impactful, yet should not be complicated. Maintaining a healthy body condition throughout gestation and lactation based on a forage diet, with supplements filling nutrient gaps, will set mare and foal up and for success.

Proper care and management of the recipient mare not only affects the developing foal but also that of the mare. Healthy mares kept in good body condition have improved conception rates and shorter rebreeding cycles. It is a very worthwhile undertaking to keep the broodmare healthy and happy throughout all the stages of reproduction — maintenance, gestation, lactation, rebreeding — and everything in between.

What is a Recipient Mare?

A recipient mare is the surrogate that an embryo is transferred into via the embryo transfer reproductive technique. Commonly referred to as a “recip,” this type of broodmare is ideally under 15 years old, in good physical condition and is easy to handle.

ICSI in Horses

In recent years, intracytoplasmic spermatazoal injection (ICSI), a technique first performed in the late 1990s, has become much more accessible. In this technique, multiple unfertilized eggs (oocytes) are harvested from a mare’s ovaries, and under microscopic guidance a single sperm is injected into each viable oocyte. The resulting embryos are incubated until they are mature enough to transfer, then the embryos are transferred into recipient mares or frozen for later use.