nd her influen a The Recipient Mare on The Embryo Transfer Foal ce by Kaye Meynell Photo by Anita Norris Does the actual size or ‘roominess’ of a genetic dam or recipient mare have a marked effect on the size of the foal at birth? The use of a recipient or surrogate mare to carry the foal of a high performance mare has become increasingly popular, but just how much influence does that mare have on the resulting foal? E mbryo transfer (ET) is one example of an assisted reproductive technique that is becoming more popular with owners of high performing mares, who wish to breed from these superior performers but avoid the ‘down-time’ associated with carrying a foal to term - around 330 days - and the subsequent period of lactation. By transferring an embryo from their mare (known as the ‘donor’ mare) into the uterus of another mare (the ‘recipient’ mare) owners are now able to sidestep this issue using surrogacy. Research has demonstrated that an important factor in the health of the foal at birth (and into adulthood) is the intrauterine environment of the mare - this essentially being the quality of bloody supply, and therefore nutrients, the mare provides the foetus with whilst it is in the uterus. More specifically, the actual si e of the mare, and as such the si e or roominess’ of its uterus, can have a marked effect on the si e of the foal at birth. Whether the mare carrying the foal is the genetic dam, or the recipient mare, does not matter. This is particularly interesting because one would assume that only the ‘biological parents’, i.e. the donor mare that provided the egg and the sire, would be able to exert any influence over a foal’s physical characteristics. To read more click to purchase this issue or subscribe.