Under the conditions in the Vologda region the organization of complete feeding of cows in highly productive herds is especially difficult, since the range of harvested feed is reduced and their quality issues remain problematic. In the region many of the normalized nutrients in the rations of dairy cattle are limiting, which reduces the effi ciency of production of its products. The purpose of the work was to increase the effi ciency of milk production when using the energy additive Tirzana BSK in the rations of highly productive cows of Ayrshire breed. Studies on the eff ectiveness of the use of the energy additive Tirzana BSK were carried out in the winter-stall period of housing cows on the basis of the agricultural complex “Maysky Breeding Farm” in the Vologda region. A comprehensive research of the technology of milk production with the use of an energy additive in the rations of cows was carried out It was found that as a result of feeding the energy additive Tirzana BSK, there is an improvement in the digestibility of nutrients in rations, especially organic matter and fi ber. Higher digestibility coeffi cients in animals of experimental groups are obviously achieved due to the optimization of microbiological processes in the gastrointestinal tract due to the components of the additive, which includes propylene glycol, glycerin, polysaccharides and a complex of biologically active substances. Feeding Tirzana BSK additive has a positive eff ect on increasing milk productivity without reducing product quality. New data on the animal husbandry and economic feasibility of using the energy additive in feeding cows with a milk yield of over 8500 kg of milk per lactation have been obtained, which make it possible to identify additional reserves for increasing milk yields with rational expenditure of feed. The use of the energy additive Tirzana BSK in feeding highly productive cows of Ayrshire is economically justified, especially during periods of late dry period and the first 100 days of lactation.
