1. Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 5200, Kihara, Kiyotake, Miyazaki 889-1692, Japan
2. Laboratory of Veterinary Pathology, Faculty of Agriculture, University of Miyazaki, 1-1, Gakuen Kibanadai-nishi, Miyazaki 889-2192, Japan
3. Laboratory of Large Animal Reproduction, School of Agriculture, Tokai University, Kawayo, Minami Aso-mura, Aso-gun, Kumamoto 869-1404, Japan
4. Department of Hygiene and Preventive Medicine, Showa University, School of Medicine, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
5. Laboratory of Veterinary Internal Medicine, Faculty of Agriculture, University of Miyazaki, 1-1, Gakuen Kibanadai-nishi, Miyazaki 889-2192, Japan