I. Marinov*, Zh. Gergovska Department of Animal Science – Ruminants and Dairy Farming, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria Abstract. The study included 514 Black-and-White cows from 14 farms of different regions of the country. The cows are on Ist (2

Zh. Gergovska Abstract. The research has been carried out with cows of the Bulgarian black-and-white cattle in 10 farms from various regions in the country. The cows calved in the period 1995 – 2006. A total of 1460 cows are included with 2852 lactations from І-st to ІІІ-rd and respec

The research has been carried out with cows of the Bulgarian black-and-white cattle in 10 farms from various regions in the country. The cows calved in the period 1995 – 2006. A total of 1460 cows with 2852 lactations from І-st to ІІІ-rd and respectively 27228 controls have been inclu