1. Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico
2. The UWA Institute of Agriculture and School of Animal Biology, University of Western Australia, Crawley, WA, 6009, Australia
3. Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford OX3 9DU, UK