1. Department of Reproduction, Faculty of Veterinary Medicine, University of Zürich, Winterthurerstrasse 260, 8057 Zürich, Switzerland
2. *Institute of Veterinary Biochemistry, Faculty of Veterinary Medicine, University of Zürich, Winterthurerstrasse 260, 8057 Zürich, Switzerland
3. ‡Institute of Veterinary Pathology, Faculty of Veterinary Medicine, University of Bern, Länggassstrasse 122, 3012 Bern, Switzerland
4. †Institute of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Zürich, Winterthurerstrasse 260, 8057 Zürich, Switzerland