1. Genossenschaft zur Förderung der Schweinehaltung; Ascheberg Germany
2. Institute for the Reproduction of Farm Animals Schönow Inc.; Bernau Germany
3. Unit for Reproductive Medicine of Clinics/Clinic for Pigs and Small Ruminants; University of Veterinary Medicine Hannover; Hannover Germany
4. Department of Equine Sciences; Faculty of Veterinary Medicine; Utrecht University; Utrecht The Netherlands