1. Epizootic Research Center, Equine Research Institute, Japan Racing Association,1400–4 Shiba, Shimotsuke, Tochigi 329–0412, Japan
2. Equine Science Division, Hidaka Training and Research Center, Japan Racing Association, 535–13 Nishicha, Urakawa-cho, Urakawa-gun, Hokkaido 057–0171, Japan