The aim of this work was to study the effectiveness of boluses as a form of feed / medicinal suplementation for dairy cows. The studies were carried out in livestock farms of the Leningrad Region (the first and second stages of the studies were carried out at ZAO PZ "Krasnoozernoe" (n = 25 cows, n = 25 calves), the third stage – ZAO PZ “Pobeda’ (n=15 cows), fourth stage - at the SEC "Polyany" (n = 160 cows). The first stage of the research was to study the effectiveness of the use of vitamin and mineral boluses (Mg, Zn, Cu, Co, Se, I, Vitamin A, D3, E, Holland Animal Care, Holland) of prolonged action (120-180 days) to dairy cows. conducted a biochemical blood test (determination of zinc, copper, iodine and carotene). The task of the second stage of the research was to study the effect of vitamin-mineral feeding of prolonged action of mother cows on protein metabolism of calves. A clinical examination and immunobiological analysis of the blood of calves (the level of total protein, albumin, globulin). The task of the third stage of research was the development and further testing of short-term calcium-containing boluses of pressed and loose forms (bioavailable calcium lactate, lactose) in order to prevent hypocalcemia in cows in the postpartum period. Conducted biochemical analysis of blood (concentration of calcium, phosphorus, total protein and alkaline phosphatase activity). The task of the fourth stage of research was to study the effect of plant-mineral boluses (Mg, Zn, Cu, Co, Se, plant components (calendula, cinnamun, suisque), Techn a France Nutrition S.A.S., France) on the reproductive function of dairy cows during the milking period. An obstetric-gynecological clinical examination of cows was carried out in the new calving period, as well as an analysis of the effectiveness of insemination. The results of the first stage of the research suggest that such a form of a vitamin and mineral supplement of prolonged action as a bolus is an effective way of vitamin and mineral nutrition of cows during dry periods, freshness periods and the period of milk production. The results of the second stage of the research indicate a positive effect of vitamin and mineral supplements of prolonged action in the form of boluses administered to cows 60 days before calving on the health of the resulting offspring. Analysis of the results of the third stage of research suggests that the most effective is the compressed form of calcium-containing boluses. According to the results of the fourth stage of research, it can be concluded that the use of a plant-mineral supplement in the form of a bolus to cows in the postpartum period promotes timely postpartum recovery, which affects the effectiveness of the first insemination.