1. Laboratory of Theriogenology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
2. Department of Theriogenology, Faculty of Veterinary Medicine, University of Mansoura, Mansoura 35516, Egypt
3. Nishimorokata Agricultural Mutual Aid Association, Miyazaki 886-0004, Japan
4. Sumiyoshi Science Field, Faculty of Agriculture, University of Miyazaki, Miyazaki 880-0121, Japan