1. Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima Street, Olsztyn 10-748, Poland
2. Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke Straße 17, 10315 Berlin, Germany
3. Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland