1. National Livestock Breeding Center, Fukushima 961-8511, Japan
2. The Robinson Institute, Research Centre for Reproductive Health, School of Paediatrics and Reproductive Health, The University of Adelaide, Adelaide SA 5005, Australia
3. Dai Nippon Printing Co., Ltd., Chiba 277-0871, Japan
4. NARO Institute of Livestock and Grassland Science, Ibaraki 305-0901, Japan