1. Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate 020–8550, Japan
2. Institute of Agriculture and Animal Science, Tribhuvan University, Chitwan, Nepal
3. United Graduate School of Veterinary Science, Gifu University, Gifu 501–1193, Japan
4. Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889–2192, Japan