The objective of this study was to evaluate the effect of probiotic based on lactate-producing bacteria (DBR) and sodium monensin (MON) on feedlot performance and carcass traits of feedlot Nellore cattle. The experiment was designed as a completely randomized design, replicated 6 times, in which 18 18-months-old yearling Nellore bulls (362,0 ± 30,0kg) were fed in individual pens for 84 days (1 animal/pen) in Calan gate system according to the treatments: 1) 2g of DBR; 2) 1g of DBR + 138mg of MON and; 3) 275mg of MON. The experiment lasted 84 days; the animals were both weighed and evaluated by ultrasound every 28 days. There was no effect of feed additives on final body weight and dry matter intake, expressed as percentage of body weight. The average daily gain was lower in the first 28 and 56 days of the study for animals fed MON and MON+DBR, but overall, no differences were observed between treatments were detected. Animals fed MON+DBR showed higher dry matter intake throughout the study, but lower feed conversion than those fed with DBR or MON. Animals fed MON+DBR had decreased dressing percentage than those supplemented with DBR only. In addition, animals fed only MON had thicker back fat by the end of the study. Supplementation with DBR may eventually be an alternative to replace MON.
ionophore; feed additives; Zebu