1. Cornell University Department of Population Medicine and Diagnostic Sciences Cornell College of Veterinary Medicine Ithaca New York USA
2. Department of Large Animal Clinical Sciences, College of Veterinary Medicine Michigan State University East Lansing Michigan USA
3. Cornell University Department of Clinical Sciences Cornell College of Veterinary Medicine Ithaca New York USA
4. Department of Veterinary Clinical Science Washington State University Pullman Washington USA
5. Rood & Riddle Equine Hospital Lexington Kentucky USA
6. Department of Veterinary Microbiology and Pathology Washington State University Pullman Washington USA