1. Farm Animal Medicine, Faculty of Veterinary Medicine, Okayama University of Science, Ikoinooka 1-3, Imabari, Ehime 794-8555, Japan
2. Department of Veterinary Associated Science, Faculty of Veterinary Medicine, Okayama University of Science, Ikoinooka 1-3, Imabari, Ehime 794-8555, Japan
3. Veterinary Pathology, Faculty of Veterinary Medicine, Okayama University of Science, Ikoinooka 1-3, Imabari, Ehime 794-8555, Japan
4. Veterinary Physiology, School of Veterinary Medicine, Rakuno Gakuen University, Bunkyodai-Midori 582, Ebetsu, Hokkaido 069-8501, Japan
5. Laboratory of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Aoba, Sendai, Miyagi 980-8572, Japan