The paper is focused on the analysis of the effect of probiotics on the function of the microbiome, growth, health and prevention of diarrheal diseases, the consumption of antimicrobial substances of calves during the milk nutrition period. In experimental and farm operational conditions, the addition of probiotics to the feed ration has been shown to have a positive effect on improving the health status of calves and thereby reducing the consumption of antimicrobials as a result of improving rumen development and stabilizing the microbiome of calves, supporting their growth and at the same time reducing digestive disorders. The effects of probiotic supplementation are variable depending on environmental factors, pathogen load and the level of stress.