1. Maxwell H. Gluck Equine Research Center Department of Veterinary Science University of Kentucky Lexington Kentucky USA
2. Rood and Riddle Equine Hospital Lexington Kentucky USA
3. Department of Statistics University of Kentucky Lexington Kentucky USA
4. Department of Small Animal Clinical Sciences Michigan State University College of Veterinary Medicine East Lansing Michigan USA
5. University of Kentucky Veterinary Diagnostic Laboratory, Department of Veterinary Science University of Kentucky Lexington Kentucky USA