1. Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki 889-2192, Japan
2. Swiss Institute of Equine Medicine, Vetsuisse Faculty Berne, University of Berne, and Agroscope, Länggasstrasse 124, Postfach 8466, CH-3001 Berne, Switzerland
3. School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan
4. Chiba Agricultural and Mutual Aid Association, 462-11 Kirigasaku, Noda, Chiba 270-0213, Japan