Use of probiotic lactobacilli as alternative to monensin in beef feedlot cattle

In an effort to substitute antibiotics in high-energy diets fed to feedlot cattle, probiotics have emerged as a viable alternative.In this study, increase of animals body weight (BW) and average daily gain (ADG) were used as indicators of probiotics Limosilactobacillus (L.) fermentum CRL2085 and L. mucosae CRL2069 (10 8 -10 9 CFU/g) supplementation (individually or combined) to grain-based diets containing or not monensin during different periods of feedlot fattening cycle.Results showed that the greatest cattle BW (116.6 kg) and ADG (1.19 ± 0.17 kg/animal/day) were achieved when CRL2085 probiotic was individually supplied during 56 days (after adaptation period) in the absence of monensin (p  0.01).In the presence of monensin, reduced BW and ADG mean values were obtained during the whole feedlot cycle (98 days) by probiotics supplementation.Thus, L. fermentum CRL2085 probiotic strain administered to feedlot cattle fed diets without monensin may result in a greater cumulative BW and ADG with a shorter administration time comparing with diets containing the ionophore.