The analysis of homeostasis was carried out on the basis of hematological blood parameters of highly productive Holstein cattle (average milk yield is 9300 kg, robotic farm, n = 106) which made it possible to establish average indicators and their variability in new, to a certain extent, extreme conditions. Analysis of the results obtained indicates that contrary to the established opinion about the relative stability of indicators of the hematological composition of blood, the organism of imported animals is experiencing rather strong overloads as evidenced by the high degree of variability of different blood elements. Some animals lose their fatness dramatically, even against the background of an average nutritional value of a balanced daily diet, sufficient for a milk yield of 30-33 kg of milk. High variability was noted in the number of lymphocytes (lim) - 64.3, medium cells (Mid) - 56.5 and granulocytes (Gran) - 42.5 percent. More stable indicators for the average volume of erythrocytes - 5.3, the content of hemoglobin in erythrocytes (MCH) - 8.7, the concentration of hemoglobin (HGB) - 9.1 and hematocrit number (NBT) - 10.6 percent.