Relevance. Single-type feeding of dairy cows has a significant advantage over traditional split ration feeding due to the minimal frequency of changes in the composition of the ration and the higher stability of feeding. However, in the process of such a feeding method, it is still necessary to change the diet composition during the seasonal transition from the last year feed to the current year feed. This change leads to significant feed stress for animals, which negatively affects the intensity and nature of cicatricial digestion, and, consequently , productivity. At the same time, at least 100-150 kg of the annual milk yield of a cow is lost. For this reason, the development of a method for eliminating the inevitable cows' stress during the change of feeding seems relevant.Methodology. Scientific and economic experience on dairy cows of the first lactation phase was carried out in accordance with generally accepted methods. The biochemical composition of the blood was studied, observations of the ruminatory processes were carried out, the data were processed by modern methods of variation statistics using the EXCEL program.Results. As a result, it was found that during the transition from one diet composition to another, it is advisable to introduce a probiotic based on lactic acid bacteria into dairy cows diet. The use of a probiotic can be considered as a preventive measure for digestive disorders caused by changes in the composition of the diet. The use of a probiotic helps to stabilize the ruminal processes in cows, which is reflected in an increase in the frequency of cicatricial contractions. Probiotic effect on the intestinal microbial community, increases the immune status of the body by increasing the level of protein, gamma-globulin fractions in its composition, as well as increasing the reserve alkalinity index.