1. Department of Veterinary Biochemistry; Rakuno Gakuen University; Ebetsu Hokkaido 069-8501 Japan
2. Department of Veterinary Pathology; School of Veterinary Medicine; Rakuno Gakuen University; Ebetsu Hokkaido 069-8501 Japan
3. Equine Research Institute; Japan Racing Association; Utsonomiya Tochigi 320-0856 Japan