Effect of corn processing methods and dietary concentrations of sugarcane bagasse fiber on finishing Nellore bulls performance

Abstract Text: The objective of this experiment was to evaluate processing methods of flint corn grain (ground corn, particle size: 3.18 mm and steam-flaked corn with bulk density of 360 g/L) combined with dietary contents of 4, 7, 10 or 13% roughage NDF (DM basis) using sugarcane bagasse as source of fiber on performance of Nellore bulls finished in feedlot. Two hundred and forty Nellore bulls (initial BW = 350 ± 2.4 kg) were fed diets containing 76-86% corn and were randomly allocated to 32 pens in a factorial arrangement of 2 x 4. Animals were blocked based on initial BW. The parameters evaluated were dry matter intake (DMI), average daily gain (ADG), feed efficiency (ADG/DMI) and final BW after 120 d on feed. The data were analyzed using PROC MIXED of SAS and means were compared by F test considering the block as random effect and corn grain processing method, roughage NDF and corn grain processing method * roughage NDF effects. There was no interaction between the concentrations of sugar cane bagasse NDF and processing methods. Cattle fed steam flaked corn diets presented less (P < 0.05) DMI (8.57 vs. 9.31 kg.d^-¹), 26.3% greater (P < 0.05) final BW (509 vs. 493.3 kg), 12.3% greater (P < 0.05) ADG (1.37 kg.d^-¹ vs. 1.22 kg.d^-¹) and 21.97% greater (P < 0.05) feed efficiency (0.161 vs. 0.132) than cattle fed coarsely ground corn. Increasing roughage NDF content of the diets caused a quadratic response (P = 0.01) for DMI (8.37, 9.13, 9.02 and 9.25 respectively), had no effect (P > 0.05) on cattle final weight (496.8, 506.3, 498.4 and 503.9 kg, respectively) and cattle ADG (1.26, 1.34, 1.28 and 1.31 kg.d^-¹respectively) and it caused a linear decrease (P = 0.04) in feed efficiency (0.150, 0.148, 0.142 and 0.144 respectively). In conclusion, steam flaking of flint corn improved performance of finishing Nellore bulls in comparison to ground corn with particle size of 3.18 mm. Nellore bulls were mor efficient when diets containing 4% sugar cane bagasse NDF were fed compared to diets with greater roughage NDF contents.

Keywords: Ground corn, stea-flaked corn, feedlot