1 Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, 712110, China. xiaolongwang@nwafu.edu.cn.
2 Institute of Farm Animal Genetics, Friedrich-Loeffler-Institute (FLI), Mariensee, 31535, Germany. bjoern.petersen@fli.de.