In recent years, the cows of Black-and-White Dairy breed display a short performance period, fertility reduction and metabolic diseases occurrence. To find methods of high performance animal’s selection the authors studied specific of cows use in ontogenesis. The studied of Black-and-White Dairy cows life-long use under conditions of Kyiv region. It was studied of milk yield age dynamics, maximal performance age, udder type and cows elimination during their use. The daily yield, its heritability (h2) and repeatability (r and rw) were investigated of first-calving cows. It has been established that the absolute majority (96 %) of cows have bowlshaped udder and bath-shaped udder. The cows reach maximal lactation performance during the fourth lactation, after that the milk yields decrease. The cows’ performance after the 8th calving does not differ from first-calving cows. In 51% of animals brought into the herd the first lactation remains the highest. Most highly-productive cows are disposed a
dairy cattle breeding, milk yield, fertility, udder, heritability