1. Department of Animal Nutrition, Autonomous Agrarian University Antonio Narro, Saltillo, Mexico
2. Department of Botany, Autonomous Agrarian University Antonio Narro, Saltillo, Mexico
3. Department of Parasitology, Ecology and Genetics, University of La Laguna, La Laguna, Tenerife, Spain
4. University Regional Unit of Arid Zones, Autonomous University Chapingo, Bermejillo, Mexico