The recipient mare is an important part of the ET process; she must have a clean reproductive history and her uterus needs to be healthy. The best age for a recipient mare is between 4 and 12 years old and she must be well handled with no behavioural vices. Although there are no shared genetics between the recipient and the foal she will have an influence over the foal’s initial learned behaviour.
Recipients should ideally be of a similar size to the donor mare. Historically it was believed that using mares who were much larger than the donor would be of benefit but there is increasing evidence to show that this can be detrimental to postnatal growth and development. Transferring an embryo into a mare smaller than the genetic mother can lead to a smaller foal being born, but the foal should eventually reach it’s correct size at a later stage.