Ryszard Mordak1, Peter Anthony Stewart2. 1. Department of Internal Medicine and Clinic of Diseases of Horses, Dogs and Cats, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Grunwaldzki Sq. 47, 50-366, Wrocław, Poland. ryszard.mordak@up.wroc.pl. 2. Veterinary Clinic Stewart and Partners, 2 Brooke Street, Dudley, DY2 8RB, UK.