1. Clinic for Obstetrics, Gynecology and Andrology of Large and Small Animals; Justus-Liebig-University; Gießen Germany
2. Department of Large Animal Sciences; Section of Veterinary Reproduction; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
3. Clinic for Obstetrics, Reproduction and Reproductive Disorders of Veterinary Faculty of Veterinary Medicine; Trakia University; Stara Zagora Bulgaria