1. Department of Veterinary Surgery, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
2. Ishikawa Zoo, 600 Tokusan, Tatsunokuchi, Nomi, Ishikawa 923-1222, Japan
3. Nagano Station, National Livestock Breeding Center, The Ministry of Agriculture, Forestry and Fisheries of Japan, 1889 Oaza-Shinkoden, Saku, Nagano 385-0007, Japan
4. Department of Veterinary Internal Medicine, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
5. Department of Veterinary Internal Medicine, Faculty of Agriculture, Iwate University, Iwate 020-8550, Japan