1. Range Cattle Research and Education Center; Univ. of Florida; Ona FL 33865 USA
2. Dep. of Agronomy; Univ. of Florida; Gainesville FL 32611 USA
3. Dep. of Animal Science; Maringa State Univ.; Maringa Paraná Brazil 87020-900
4. Dep. of Animal Sciences; Univ. of São Paulo; Pirassununga São Paulo Brazil 13635-900
5. Dep. of Animal Breeding and Nutrition; Sao Paulo State Univ.; Botucatu São Paulo Brazil 18618-000