1. Departamento de Producción Animal Facultad de Agronomía UBA Buenos Aires 1417 Argentina
2. Department of Animal Science Michigan State University East Lansing MI 48824‐1225 USA
3. USDA/ARS U.S. Meat Animal Research Center Clay Center NE 68933‐0166 USA
4. Consejo Nacional de Investigaciones Cientificas y Tecnicas – CONICET Buenos Aires Argentina
5. Department of Fisheries and Wildlife Michigan State University East Lansing MI 48824‐1225 USA