1. Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
2. Veterinary Practice GALLUVET BVBA Lummen, Belgium
3. Vanden Avenne-Ooigem Ooigem, Belgium
4. Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University Merelbeke, Belgium
5. Belgabroed n.v. Merksplas, Belgium