James R. Crabtree, Independent Veterinary Consultant, Equine Reproduction & Stud Medicine, Equine Reproductive Services (UK) Ltd., Malton, North Yorkshire, UK.Eric Klaui, The Flying Dutchman QLD Pty Ltd, Equine Reproduction Medicine & Surgery, Warwick, QLD, Australia.Marta de Ruijter-Villani, Specialist Equine Reproduction, Assistant Professor in Equine Reproduction, Department of Equine Sciences, Section Reproduction and Obstetrics, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.