1. Department of Animal Health and Anatomy, Faculty of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
2. College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766, USA
3. Institute of Animal Health and Cattle Development (INDEGSAL) and Department of Molecular Biology (Cell Biology), Universidad de León, 24009 León, Spain
4. Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology, Spanish National Research Council (INIA-CSIC), 28040 Madrid, Spain