1. Faculty of Animal Health Technology, Department of Animal Health Technology, Yamazaki Gakuen University, Tokyo 150-0046, Japan
2. Laboratory of Large Animal Medicine, School of Veterinary Medicine, Kitasato University, Aomori 034-8628, Japan
3. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Florida 32610, USA
4. Misawa Air Base Veterinary Clinic, US Army Public Health Command-Japan, APO, AP96319, Japan
5. Equine Research Institute, Japan Racing Association, Tochigi 320-0856, Japan