1. Division of Companion Animal Surgery, Veterinary Teaching Hospital, Faculty of Agriculture, Iwate University, Iwate 020-8550, Japan
2. Iwane Animal Hospital, Iwate 020-0634, Japan
3. NORTH LAB, Hokkaido 003-0027, Japan
4. Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Iwate 020-8550, Japan