1. Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Berne, Berne, Switzerland
2. Institute of Animal Genetics, Nutrition and Housing, Division of Animal Housing and Welfare, Vetsuisse Faculty, University of Berne, Berne, Switzerland
3. Institute of Zoology, Martin-Luther-University, Halle, Germany
4. Department of Veterinary Morphology and Physiology, University of Turin, Turin, Italy