1. Unit for Reproductive Medicine/Clinic for Pigs and Small Ruminants University of Veterinary Medicine Hannover Hannover Germany
2. Friedrich‐Loeffler‐Institut Institute of Farm Animal Genetics, Neustadt am Rübenberge Germany
3. Department of Animal Sciences University of Göttingen Göttingen Germany
4. Institute for Biometry Epidemiology and Information Processing University of Veterinary Medicine Hannover Hannover Germany