1. Laboratory of Animal Anatomy & Tissue Embryology, Department of Basic Veterinary Medicine, Faculty of Veterinary Medicine; Gansu Agricultural University; Lanzhou Gansu China
2. College of Animal Science; Anhui Science and Technology University; Fengyang Anhui China
3. Gansu Province Livestock Embryo Engineering Research Center, Department of Clinical Veterinary Medicine, Faculty of Veterinary Medicine; Gansu Agricultural University; Lanzhou Gansu China