Productive responses of European crossbred and zebu cattle fed whole shelled corn diets, with or without sugarcane bagasse.

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]