I. Valchev1*, D. Kanakov1, Ts. Hristov1, L. Lazarov1, N. Grozeva2, Y. Nikolov1 1Department of Internal Non-Infectious Diseases, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of General and Clinical Pathology, Faculty of Veterinary Medicine,