1. United Graduate School of Veterinary Science, Gifu University, Gifu 501-1193, Japan
2. Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
3. Icomes Lab, Morioka 020-0857, Japan
4. Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan