Significantly increase the productivity of cattle can, be based on the continuation of a deep study of the physiology and genetics of highly Productive cows. In the work were formed three groups of cows analogues (by age, duration of pregnancy, origin). After calving of cows dueto the correction of insemination after delivery, the duration of lactation and with the help of single-stage start, three groups of cows were formed purebred cowsa comparable level of milk production of 7000-8000 kg of milk. The first group consisted of cows for Holsteins, in the second group there were cows with 75% blood content for Holsteins, and or the. third group - Holstein blood 50%. In each group there were 30 animals. It was noted that the optimum level of milk for production and resistance of cows was observed in Russian conditions at 75% of blood content. in Holstein breed. This level of blood is able to prevent postpartum complications in animals and reduce the time of involution of the genital organs. It is noted that the restoration of the itireproductiveooswith qualities of high -beef cows after calving also depends on their enetics, It is optimal in Russian conditions on g Holstein blood levels of 75%. This percentage contributes to an increase in 'reproductive. qualities and to obtaining a sufficient amount of viable offspring from highly productive cows. It can be said that only in this case a high level of milk productivity is successfully combined with a high. level of adaptation properties of cows in Russian complexes and ensures the full realization of their. productive potential during. the whole ontogenesis..