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Context: Grain-based diets result in lower starch utilisation compared with traditional diets with corn silage. The best use of yellow dent corn starch, in addition to increasing animal performance, can be obtained by the inclusion of an effective fibre source in grain-based diets and/or the use of more efficient genetic groups in a tropical feedlot. Aims: We assessed productive responses of young Nellore (N) bulls and 1/2 Angus × 1/2 Nellore (AN) bulls fed whole shelled corn diets, with or without sugarcane bagasse (SB). Methods: A completely randomised design in a 2 × 2 factorial arrangement (two genetic groups and two diets) was used. Twenty-eight young bulls (14 N and 14 AN) were fed diets containing 0 or 31.6 g of SB/kg DM in a feedlot. Key results: The average daily gain and gain:feed ratio were not affected by the diets, but AN bulls showed greater average daily gain and gain:feed ratio than N bulls (P = 0.001 and P = 0.006, respectively). The genetic groups did not affect nutrient intake, but N bulls had greater (P = 0.016) DM digestibility than AN bulls. The consumption of DM, crude protein and digestible energy was not affected by the diets. The digestibility of neutral detergent fibre, crude protein and NFC was lower (P = 0.001) for the diet with SB. The neutral detergent fibre intake was greater (P = 0.001) in the diet with SB. The DM intake variation was smaller (P < 0.05) in diets with SB and for N bulls. Conclusions: The inclusion of SB up to 31.6 g/kg DM in whole shelled corn diets did not affect the productive responses of young bulls. Crossbred bulls, despite expressing lower digestibility of some nutrients and larger DM intake variation, have greater productive potential compared with Nellore bulls in a tropical feedlot with whole shelled corn diets. Implications: The use of crossbred young AN bulls in tropical feedlots is a viable alternative for increasing productivity and global meat production. Flint corn is widely cultivated in tropical countries, but little is known about its use without processing or as whole shelled corn in feedlot diets. Inclusion of an effective fibre source in diets with yellow dent corn, and the use of crossbreeds can increase feedlot productivity, contributing to the increase of global meat production. [ABSTRACT FROM AUTHOR]

We assessed the productive performance, blood parameters, and carcass characteristics of young crossbreed dairy bulls kept in feedlots and fed with diets containing 0, 60, 120, and 240 g/kg of crude glycerin, replacing a mixture of ground pearl millet grain (50%) and babassu mesocarp bran (50%). Twenty-four bulls with an average age of 24 months and an average initial weight of 390 ± 31.5 kg were used. The experimental design was completely randomised with six replications. Dry matter and digestible energy intake were not influenced by diets. Feed conversion linearly decreased with increasing glycerin levels. The increase in the levels of glycerin resulted in a linear increase in blood glucose and in average daily weight gain. Carcass weight was not affected, but trimming fat increased and carcass yield decreased linearly, with increasing glycerin levels. The addition of crude glycerin at levels up to 240 g/kg of dry matter to diets containing babassu mesocarp bran and ground pearl millet grain increased the performance of young feedlot bulls, and improved feed efficiency and carcass subcutaneous fat thickness. [ABSTRACT FROM AUTHOR]