Industry development has a technogenic impact on the environment, thereby posing a threat to health and welfare of farm animals. As a result, toxic substances accumulate in soil, water, feed, and have a long period of decomposition. At the same time, changes in the metabolic profile occur in animals, leading to a decrease in their resistance to viral and bacterial infections. The search for new means and methods to stop the development of pathological conditions and create conditions for the resistance of cows to technogenic stress seems to be relevant. In this regard, the purpose was to study the effect of аminoseleferon-B on hematological parameters and protein metabolism of cows with immune deficiency under technogenic load caused by the chemical industry producing mineral fertilizers in Voronezh region. During monitoring soil and water bodies near this object, an excess of the maximum permissible concentrations for heavy metal content was established. The studies were carried out in industrial livestock complex on 20 highly productive dairy cows with a secondary immunodeficiency state, located in the zone of exposure to chemical emissions into the atmosphere. Control and experimental groups of animals were formed. Experimental cows were injected with аminoseleferon-B. It was revealed that the presence of cows in conditions of technogenic impact on the environment leads to decrease in total protein, change in blood fractional composition, which negatively affects physiological processes in the body. Insufficient levels of and -globulin fractions in cow blood indicate inhibition of natural resistance factors. A negative reaction of animal organism associated with exposure to toxins is indicated by significant increase in the level of -globulins in blood. It was found that аminoseleferon-B had a corrective effect on blood morphological parameters and protein metabolism, significantly increasing number of erythrocytes, leukocytes, hemoglobin, lymphocytes, monocytes, total protein, -globulins, -globulins and reducing content of neutrophils, eosinophils, -globulins to normal levels. Thus, аminoseleferon-B contributed to increase in natural resistance, adaptation to adverse environmental factors and stimulation of metabolic processes in cows.