1. Department of Theriogenology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
2. Laboratory of Animal Breeding and Reproduction, Department of Animal Science, Graduate School of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
3. Laboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan