The suckling period in sows is a very important stage in the realization of their productivity. In the course of its implementation, hematological parameters are of great importance, but their normal level has not been fully clarified, especially taking into account the conditions in which animals are kept. In sows, which are located in central Russia, the content of total protein and albumin in the blood gradually increased during suction. They also have a slight decrease in the content of urea, which indicated a tendency to inhibition of protein metabolism. During the entire sucking period, a slight increase in the amount of triglycerides and cholesterol developed in the blood of the examined animals, while the glucose content remained unchanged. During the observation, the biological activity of alkaline phosphatase remained unchanged in sows and the enzymatic properties of gamma-glutamyltransferase slightly decreased. At the same time, they developed a weakening of the activity of enzymes in the blood, including transaminases and creatine kinase. The amounts of traceable substances and activity levels of individual enzymes identified during the observation should be considered optimal for sows kept during suckling at pig farms located in central Russia.