1. Department of Animal Molecular Biology, National Research Institute of Animal Production , 32-083 Balice n. Kraków , Poland
2. Swiss Institute of Equine Medicine, ALP-Haras , University of Berne , Länggasstrasse 124, Postfach 8466, Berne CH-3001 , Switzerland
3. Department of Emergency Medicine, University Hospital Bern , Inselspital, 3010 Bern , Switzerland
4. Institute of Veterinary Sciences , University of Agriculture in Krakow , Al. Mickiewicza 24/28, 30-059 Kraków , Poland