Brazilian Journal of Veterinary Research and Animal Science; Vol. 49 Núm. 2 (2012); 146-152 Brazilian Journal of Veterinary Research and Animal Science; Vol. 49 No. 2 (2012); 146-152 Brazilian Journal of Veterinary Research and Animal Science; v. 49 n. 2 (2012); 146-152 Brazilian Journal of Veterinary Research and Animal Science; V. 49 N. 2 (2012); 146-152 Brazilian Journal of Veterinary Research and Animal Science Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (FMVZ-USP) instacron:USP