The paper presents the results of the scientific and economic experiment for the evaluation of the influence of the energy supplement included in the diet of lactating cows of the Brown Swiss breed. During the research period, all animals were kept in the same conditions, corresponding to zootechnical standards. They were divided into two groups differentiated only by the feed ration. The cows of the first (control) group were given rations typical for the farm corresponding to the feeding norms of dry and lactating cows. For the cows of the second group in the dry period (14 days before calving) the feeding ration was changed with a change in structure towards an increase in the proportion of concentrated feed, and immediately after calving, they received an energy feed supplement to maintain the physiological status of dairy cows after calving. Only clinically healthy animals participated in the experiment. It was revealed that the inclusion of the energy feed supplement in the diet of lactating cows in the experimental groups during lactation led to an increase in the productivity of livestock as compared with those in the control group.