1. Graduate School of Veterinary Sciences, Iwate University, Morioka, Iwate 020-8550, Japan.
2. Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan.
3. Veterinary Teaching Hospital, Faculty of Agriculture, Iwate University, Iwate 020-8550, Japan.
4. Chiba Prefectural Livestock Research Center, Yachimata, Chiba 289-1113, Japan.
5. Toyama Prefectural Agricultural, Forestry and Fisheries Research Center, Toyama 939-8153, Japan.
6. Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-0901, Japan.
7. Department of Large Animal Internal Medicine, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.