1. Department of Animal Science, Michigan State University, East Lansing 48824
2. Programa de Ganaderia, Campus Montecillo, Colegio de Postgraduados, Montecillo, Estado de Mexico 56230, Mexico
3. Faculty of Nutrition and Department of Animal Science, Texas A&M University, College Station 77843
4. Department of Fisheries and Wildlife, Michigan State University, East Lansing 48824
5. Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48824