1. Department of Large Animal Internal Medicine, Faculty of Veterinary MedicineGhent University Salisburylaan 133, Merelbeke Belgium
2. Proviron Industries NV Georges Gilliotstraat 60, Hemiksem Belgium
3. Laboratory of Immunology, Faculty of Veterinary MedicineGhent University Salisburylaan 133, Merelbeke Belgium
4. Van Ranst Dairy farm Zeutestraat 3, Puurs Belgium