The effects of high intake supplementation on the performance of Nellore cattle finished on Brachiaria brizantha ‘Marandu’ pastures was evaluated. It was hypothesized that the performance Nellore cattle finished under high intake supplementation and with a high forage allowance is improved when corn is used as the source of energy, and that under conditions of low forage allowance, citrus pulp is the most suitable source of energy. Two forage allowances (FA; 2.5 and 4.5 kg DM kg^–1 BW) and 2 sources of energy (SE; corn and pulp included in the diet at 2% of the BW) were evaluated. In the experiment, were used 48 (48) uncastrated Nellore cattle at 30 mo of age, with an initial BW of 430.0 ± 2.7 kg. The animals were blocked according to body weight and the data evaluated in randomized blocks in a 2 × 2 factorial arrangement (FA and SE). The paddock was considered the experimental unit, with 3 replicates per treatment (4 animals/paddock). There was no interaction between SE and FA (P > 0.10). None of the factors led to any differences (P > 0.10) in carcass yield (58.8%), average daily gain (1.22 kg day^–1) or gain yield (carcass gain/weight gain: 805.6 g kg^–1). The higher FA resulted in an increase in BW (559.0 kg; P = 0.06) as compared with the animals on lower FA (534.0 kg). However, no difference was detected for carcass gain (0.98 kg day^–1; P = 0.28), carcass weight (322.2 kg; P = 0.11), subcutaneous fat thickness (SFT; 4.31 mm; P = 0.24), or loin eye area (LEA; 78.4 cm²; P = 0.49) for the animals under different FA. Corn and pulp did not alter the final BW (546.5 kg; P = 0.19). Contrastingly, the carcass gain (1.02 kg day^–1vs 0.93 kg day^–1; P = 0.09), the carcass weight (327.6 kg vs 316.8 kg; P = 0.09), and the SFT (4.72 mm vs 3.89 mm; P = 0.18) were greater in the animals fed corn as compared with pulp. Citrus pulp provided animals with a larger LEA (P < 0.01) as compared with corn (81.0 cm²vs 75.8 cm²). It is recommended to use a forage allowance of 4.5 kg DM kg^–1 BW and corn as the source of energy. Nutreco/Bellman provided support.