Abstract: The use of antibiotics for growth promotion and for disease prevention in production animals has been banned in countries of European Union since the 1st of January, year 2006. Alternative feed additives were needed to achieve the same or even better results in animal husbandry. As one of the possible antibiotic alternatives, prebiotics are the one that can prevent diseases and provide good health. We know that prebiotics, probiotics and synbiotics have a positive effect on monogastric animal organisms, but their effects on multi-chamber stomach animals have not been sufficiently studied. The studies were carried out to determine the effect of feed on calves at the age of 4-12 weeks, feeding the flour concentrate of Jerusalem artichoke which was produced in Latvia (contains prebiotics - inulin 48.5% -50.1%) and probiotic Enterococcus faecium (1 g (2 * 109 CFU / g) that were added to milk. The study was carried out on 40 calves of average age 23 ± 5 days. Three doses of synbiotics were tested. Once a day was performed a general health check of each calf, with special emphasis on fecal mass consistency and body measurements were performed once a week. The study lasted for 56 days. We found that the calves of the synbiotic group had less cases of alimentary diarrhea than animals of the control group and the average body weight gain in the synbiotic group was significantly higher (p <0.05) than in the control group. The study was carried out within the AGROBIORES State Research Program.