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

Factors affecting duration of the days open and its relation to productive traits in Black-and-White cows Zh. Gergovska