This study aimed to examine the productive and metabolic parameters, carcass and meat characteristics of lambs fed sorghum silage treated with urea and Lactobacillus buchneri. Forty whole male Santa Inês lambs fed a diet with a 50:50 roughage: concentrate ratio, and randomly assigned to four groups considering roughage treatments SS - sorghum silage without additive; SSI - sorghum silage with inoculant (Lactobacillus buchneri, 105 CFU/g fresh matter); SSU - sorghum silage with urea [1% dry matter (DM)]; or SSUI - sorghum silage with urea and inoculant. The experiment was a completely randomized design with ten replicates, each animal represented an experimental unit. The intakes of DM (DMI) (P<0.001), as a percentage of BW, DMI %BW (P<0.001), neutral detergent fiber corrected for ash and protein (P=0.005) and non-fiber carbohydrates (NFCI; P<0.001) were lower in SSUI compared to SS and SSU. NFCI was lower in SSI compared to other diets, the same observed for crude protein intake (P<0.001), however, ether extract intake of (EE) did not differ (P=0.076). The highest final body weight (P<0.001), total weight gain (P=0.003), and average daily weight gain (P=0.003) were observed in the groups fed SSUI. Feedlot lambs fed sorghum silage treated with urea and Lactobacillus bucnheri promoted higher animal performance with higher feed efficiency without negative effects on meat characteristics.