1. Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey Street, PA 19104, USA
2. Current address: Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Tennent Drive, Palmerston North 4442, New Zealand
3. Department of Clinical Sciences, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia
4. Department of Clinical Studies, School of Veterinary Medicine, University of Passo Fundo, BR 285, Passo Fundo, RS, Brazil