The article discusses the role and particular importance to highly productive cows in the breeding of dairy cattle. Currently, one of the priorities of the agricultural sector is the creation of highly productive dairy herd, since it is by far a priority, and it is the country’s food security. We have studied the question of variability genotype bulls under the influence of the physiological state of the mothers, in particular the impact of the intensity and duration of maternal lactation dairy cows in the tribal days Quality sons. The physiological condition of cows is characterized by the level of activity of lactation, and reproductive functions, ie fertility, duration of service period and the number of milking days. As is known, there is a very close link between these functions. Cow fertility depends primarily on coherence of physiological functions. The beginning of all this is a normal metabolism in the body, which is of utmost importance for selection vysokomolochnyh cows. Metabolic disorders in the body vysokomolochnyh cows (ketosis), caused by an unbalanced feeding, shortage of certain nutrients and elements, as well as excessive razdaivaniem with a high proportion of concentrated feed leads to the breakdown of the body’s physiological functions, especially the reproductive organs. In this regard, we consider these factors creates unfavorable conditions for the normal maturation of the egg, the birth and fetal growth retardation. Therefore, when selecting herd replacements necessary to conduct a comprehensive assessment, including whether the physiological state of the mother during the birth of offspring.