1. Department of Reproduction, University of Zurich, Zurich, Switzerland
2. *Department of Internal Medicine, University of Zurich, Zurich, Switzerland
3. †Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland
4. ‡Clinic of Veterinary Surgery, Section of Diagnostic Imaging, Faculty of Veterinary Medicine, University of Zurich, Zurich, Switzerland
5. §Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Bern, Bern, Switzerland
6. ¶Department of Gynaecology and Obstetrics, University Hospital, Zurich, Switzerland