1. United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
2. Iwate Veterinary Hospital, Iwate-machi, Iwate 028-4307, Japan
3. Cooperative Department of Veterinary Medicine, Iwate University, Morioka, Iwate 020-8550, Japan
4. Institute of Agriculture and Animal Science, Tribhuvan University, Chitwan, Nepal