1. Department of Animal Production-Ruminants, School of Veterinary Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico.
2. Department of Microbiology and Immunology, School of Veterinary Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico.
3. Department of Genetics and Biostatistics, School of Veterinary Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico.
4. Department of Physiology and Pharmacology, School of Veterinary Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico.