The patterns of the biochemical composition of the blood and the relationship of the live masses of the consecious cows in the process of section are studied. Outdoor animals on the first lactation amounted to 6784, 7187 and 7487 kg of milk in it with fat in it 4.04-4.09% and protein 3.39-3.49%. At the same time, highly productive cows are more intensely using tissue reserves of their organism on milk synthesis. The effectiveness of the use of feed nutrients is observed during lactation. Highlighted on Holstein (1/16C + 1/16A+7 / 8kpg) Animals The surveillance occurs more actively, the decrease in the live weight occurs within four months of lactation, during which time they lost in weight by an average of 56.6 kg, cows genotype1/8c + 1/8a + 3/4kpg reduced the living mass for three months, during which time they stuck a weight of 47.3 kg and the cow genotype 1/4c + 1/4a + 1/2kpg also reduced the living mass for three months, losses were 37.9 kg. Losses of the live mass in the first month of lactation are 19.4-25.0 kg, after the second month, respectively, 12.4-20.3 kg and for the third month 5.9-10.2 kg. Cows genotype 1/4c + 1/4a + 1/2kpg and 1/8c + 1/8a + 3/4kpg The initial living mass that they had after the calves were reached on the ninth month lactation, and the cows genotype 1/16c + 1/16A + 7/8kpg on the tenth month lactation. In this case, the biochemical indicators of blood in experimental animals are closely linked to their lively mass and productivity indicates the strength of the biochemical exchange processes in experimental animals.