Part 1: Donor and recipient selection and preparation

Since its original description by Oguri and Tsutsumi in 1972, ¹ the application of embryo transfer in the field of equine reproduction has progressively gained acceptance among practitioners, horse owners/breeders as well as breed and performance registry associations. The objective of this series is to provide an overview of the current techniques and the commercial applications of embryo transfer in equine practice. In conjunction with this review, a practitioner-based survey was completed at the termination of the 1997 breeding season to assess the practical application of embryo transfer. Donor mare selection, embryo recovery rates, source and type of recipient mares, embryo transfer techniques and pregnancy rates as well as client and veterinary economics were evaluated. The practitioner-based survey includes five equine exclusive practices in Oregon, Washington, California and Colorado. Part 1 of the review and survey is devised to aid practitioners and their clients in identifying donor selection criteria, recipient selection criteria and donor breed and performance registry restrictions prior to embarking on an embryo transfer project. Having defined donor and recipient mare selection criteria, an overview of breeding preparation and synchronization of the mares will be discussed.