1. Oregon State University, Eastern Oregon Agricultural Research Center, Burns 97720
2. Faculdade de Medicina Veterinária e Zootecnia, UNESP – Univ. Estadual Paulista, Programa de Pós-Graduação em Zootecnia, Botucatu, SP, Brazil, 18618-970
3. Department of Animal Science, South Dakota State University, Brookings 57007
4. Nutrition Program, School of Biological and Population Health Sciences, Linus Pauling Institute, Oregon State University, Corvallis 97331