The research aim was to correct colostral immunity using the immunostimulator “Immunat” in connection with vaccination for improving the young animals safety and increasing body weight gain. 20 pregnant cows of black-and-white breed, as well as calves born to them from birth to two months of age were the research object. Blood serum samples serological tests for the presence of anti-rotavs, anti-coronavirus, and anti-diarrhea virus antibodies prior to vaccination, 40 days before calving, 20 days before calving, before calving, and in the colostrum of the first milk yield were performed in dams. Serological studies of blood serum samples taken from calves born to vaccinated cows were performed before colostrum intake, one day after its first intake, as well as on the 7 ,14 , 21 days of the calf’s life and at the age of 30 and 60 days for the anti-rotavirus, anti-coronavirus, and anti-diarrhea virus antibodies presence; quantitative determination of the concentration of immunoglobulins A, M, G in animal sera on the 25 , 35 , 65 and 75 days of the calf’s life was carried out. It was found that the immunostimulator “Immunat” application to pregnant cows before vaccination and to newborn calves increases the vaccination effectiveness against associative infections of young animals resulting in the increase in the immunoglobulins content in colostrum and serum, as well as in the increase in antibody titer against rotavirus, coronavirus, and diarrhea virus. The use of the drug “Immunat” improves the calves safety in the postnatal period and drives up growth and development. th th st th th th th