1. Department for Animal Welfare and Disease Control, University of Copenhagen, Frederiksberg, Denmark
2. Pig Improvement Company (PIC), Hendersonville, TN, USA
3. Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus Liebig University, Giessen, Germany
4. Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
5. Institute of Animal Breeding and Husbandry, Kiel University, Kiel, Germany