R. Petrov1,2*, Y. Andonova1, Y. Gancheva3, I. Klisurov1 1Green Balkans – Stara Zagora NGO, Stara planina str. 9, 6000 Stara Zagora, Bulgaria 2Department of General Livestock Breeding, Faculty of Veterinary Medicine, Trakia University, Student’s campus, 6000 Stara Zagora, Bulgari