A probiotic fermented milk designed with four homologous selected lactic acid bacteria by their beneficial, functional and technology properties was orally administered for seven days to newborn calves. A double mind randomized assay was performed in two farms located in Tucuman-Argentina. Hence, 22 newborn calves were enrolled to the Treated Group (TG) and 26 animals to the Control Group (CG). The animals were evaluated at 2, 7, 30 and 60 days of life, recording weight and signs of intestinal diseases. Weight gain was calculated between the following periods: 2-7, 8-30 and 31-60 days. No significant differences in diarrhea incidence were observed between the groups, but at the last period, no diarrhea was detected in the TG. Also, the average weight gain was significantly different at the end of the trial (31-60 days of life), being the weight gain 0.790kg/day in the TG and 0.600kg/day in CG. The length of the probiotic administration and the farm management could affect these parameters, referred to results previously obtained with 60 days probiotic administration in a different farm in Tucuman