Brazilian Journal of Veterinary Research and Animal Science; Vol. 42 Núm. 5 (2005); 339-346 Brazilian Journal of Veterinary Research and Animal Science; Vol. 42 No. 5 (2005); 339-346 Brazilian Journal of Veterinary Research and Animal Science; v. 42 n. 5 (2005); 339-346 Brazilian Journal of Veterinary Research and Animal Science; V. 42 N. 5 (2005); 339-346 Brazilian Journal of Veterinary Research and Animal Science Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (FMVZ-USP) instacron:USP