This experiment was carried out to evaluate the effect of corn stalk (CS) silage diet (145 g CP/kg DM; 2.4 Mcal/kg DM) plus 3 nitrogen sources (pig excreta, PE; poultry litter, PL; urea, UR) and 2 energy sources (sugar cane molasses, CM; bakery by-products, BBP). Composition (g/kg DM) of silages was (1) 384. Six CS; 384.6 PL; 230.8 CM or BBP; (2) 294.1 CS; 529.4 PE; 176.5 CM or BBP; (3) 630.0 CS; 30 UR; 340 CM or BBP. Diet contained (g/kg DM) silage 400:600 supplement (corn grain, soybean meal, wheat bran, fish meal, vitamins and minerals). The experimental design was completely randomized, using 30 Criollo lambs (24.05 ± 3.68 kg initial BW) housed in individual cages during 60 d. Data were analyzed with PROC MIXED for average daily gain (ADG) and dry matter intake (DMI) utilizing initial body weight as covariable, whereas PROC GLM and Tukey test (P < 0.05) were used for carcass variables. Qualitative variables (color of meat and fat) were analyzed by U-Mann-Withney test. No differences (P > 0.05) were found for ADG (161, 175, 163, 160, 161, 150 g/day), DMI (792, 856, 894, 962, 961, 767 g DM/day) for PL-CM, PL-BBP, PE-CM, PE-BBP, UR-CM and UR-BBP, respectively. Rib eye area was larger for lambs fed PE-BBP (14.26 cm²), as compared with UR-CM (9.34 cm²). Empty BW was lower (P < 0.05) for lambs fed corn stalk silage plus UR and CM (27.7 kg), as compared with those fed CS, PE and CM (34.8 kg). Corn stalk silage plus UR and CM decreased (P < 0.05) carcass width (23.04 cm), as compared with corn stalk silage plus PE and BBP. No differences were found for the qualitative variables among treatments (P > 0.05). Therefore, it may be concluded that lambs fed corn stalk silage plus pig excreta and bakery by-products showed better carcasses.