D. Dimov1*, Tch. Miteva1, I. Marinov2, Zh. Gergovska2, Т. Penev1, A. Enchev3 1Department of Applied Ecology and Animal Hygiene, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, T