The aim of this study was to evaluate the effects of different energy sources on the productive and economic performance and carcass and meat characteristics of Nellore heifers finished on Mombassa grass pasture . One hundred and twenty-six Nellore heifers were used, they were 17 month-old of initial age and 267 ± 12 kg of body weight. Six heifers were slaughtered at the beginning of the experimental period to determine the average carcass gain and dressing gain. The experimental design was the completely randomized with four treatments and 30 replicates, each replicate represented by one animal. The diets were isonitrogenous (140 g kg-1 of crude protein) containing ground millet, ground corn, ground sorghum, and whole corn supplied at the level of 7.5 g kg-1 of body weight. The experiment was conducted during the rainy season in a continuous grazing system. At the end of the trial period 10 animals per treatment were slaughtered based on the average final weight of the treatment. The slaughter weight, average daily gain, average carcass gain and hot carcass weight were not influenced (P>0.05) by energy sources, with a mean of 336 kg; 0.82 kg day-1; 0.518 kg kg-1 average daily gain and 186.93 kg, respectively. The hot carcass dressing and the gain dressing were higher (P<0.05) for animals that received ground corn (52.4 kg/100 kg body weight and 688.3 g kg-1 average daily gain) than for the animals that received ground millet (51 kg/100 kg body weight and 602.3 g kg-1 average daily gain), ground sorghum (51 kg/100 kg body weight and 604.8 g kg-1 average daily gain) and whole corn (51.4 kg/100 kg BW and 629.2 g kg-1 average daily gain), the whole corn did not differ from the others (P>0.05). The treatments did not influence (P>0.05) the fat trimming, Longissimus lumborum area and cooling loss. The subcutaneous fat thickness was greater (P>0.05) for the corn ground treatment in comparison to the ground millet, and had no differences for ground sorghum and whole corn (P<0.05). Except for meat minerals total daily gain, centesimal composition, carcass primary cuts, carcass tissue composition, carcass metric characteristics, and quantitative and qualitative meat characteristics were not influenced (P>0.05) by treatments. The whole corn, ground sorghum and ground millet have potential use in energy diet in comparison to ground corn, these alternative sources of energy do not affect the productive performance, carcass and meat characteristics. The ground millet was the best alternative to replace ground corn, since it improves the profitability of the supplementation. However, in regions where the producers are remunerated for the adequate carcass fatness, the use of pearl millet should be better evaluated, since it proved less efficient for this characteristic in relation to the other alternatives tested.
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