Abstract: The inclusion of probiotics in the technology of growing young animals is the latest way of preventing gastrointestinal diseases based on environmentally friendly mechanisms of maintaining a high level of colonization resistance of the intestine. The aim of the research was to study the effect of probiotic preparations of different composition on the dynamics of normoflora and opportunistic pathogenic microflora of newborn calve’s and weaning age piglet’s intestinal microbiome. To achieve this goal, four groups of newborn calves were formed which received a synbiotic based on medicinal plant raw material and lactobacilli, "Sporovit" and "Enzymsporin" and four groups of 45 days old piglets that also received the above preparations. Prior to the beginning of the experiment then on the 10-30th days from the beginning of the experiment, feces were taken for microbiological studies. The use of the synbiotic based on medicinal plant raw material and lactobacilli, probiotics "Sporovit" and "Enzymsporin" in newborn calves and piglets at weaning increased the activity of bifid and lactoflora by 1.8 and 2.4 times; Inhibited the content of E. coli by 1.2 and 1.8 times, Enterococci by 1.4 and 1.5 times, Staphylococci by 1.4 and 1.9 times, yeast-like fungi of Candida by 1.7 and 1. 9 times, Clostridia by 1.4 and 1.5 times.