The objective ofthe present study was to evaluate the performance of beef cattle in feedlotsfed diets containing either whole-crop maize silage or sugarcane silage, andwith different formulations. Five diets were evaluated: MSF - diet containingwhole-crop maize silage, with fixed formulation during feedlot period; MSV-diet containing whole-crop maize silage, with variable formulation accordingto feedlot phase; SCSF - diet containing sugarcane silage with fixed formulation;SCSV- diet containing sugarcane silage, with variable formulation; SCSV/MSV-SCSV diet in initial half of fedlot and MSV diet in final half of feedlot period,respectively. It was used a complete random experimental design, with five treatmentsand three replicates (pens). It was used 285 steers at 36 months of age, withan initial body weight of 362.4 kg. Diets with whole-crop maize silage promotedgreater intake of dry matter (10.5 kg and 2.4% BW) compared with diets containingsugarcane silage (10.1 kg and 2.3% BW). There was no effect of the silages onaverage daily gain (1.348 kg/animal/day) and live weight at slaughter (481.2kg BW). SCSV/MSV diet promoted the worst feed conversion (8.0 kg DM/kg BW).Animals fed diets composed of whole-crop maize silage presented greater weightof hot carcass, of carcass yield and subcutaneous fat thickness (262.1 kg, 54.1%and 6.2 mm) compared with the animals fed sugarcane silage (252.5 kg, 52.7%and 4.8 mm). The use of sugarcane silage in diets for finishing beef cattleis feasible and the adjustment of formulation during confinement period doesnot influence performance of the animals. Replacement of sugarcane silage bywhole-crop maize silage during the feeding period affects negatively feed conversion.
