1. Department of Preventive Veterinary Medicine, Universidade Federal de Santa Maria – UFSM, 97105‐900, Santa Maria, State of Rio Grande do Sul, Brazil
2. Department of Pathology Veterinary Medicine, Universidade Federal de Santa Maria – UFSM, 97105‐900, Santa Maria, State of Rio Grande do Sul, Brazil
3. Department of Veterinary Hygiene and Public Health, Universidade Estadual Paulista UNESP, Box 560, 18618‐970, Botucatu, State of Sao Paulo, Brazil