In this study different energy supplements for feedlot calves weaned at 80 days of age and averaging 90 kg of body weight were evaluated. The following energy sources were used: corn grain (CG), rice bran (RB), soybean hulls (SH), corn grain + rice bran (CG + RB), soybean hulls + rice bran (SH + RB) or corn grain + soybean hulls (CG + SH). The diets were isonitrogenous (13% crude protein) with a 50:50 forage:concentrate ratio. Sorghum silage (AG-2005E) constituted the forage portion of the diet. No significant differences were observed for dry matter intakes (DMI) expressed in kg (4.43 kg), per 100 kg of body weight (3.17%) or per unit of metabolic weight (109.10 g). Calves fed SH showed greater intake of NDF than those fed CG expressed in kg per day, per 100 kg of body weight and per unit of metabolic weight (2.41 kg, 1.73% and 59.46 g vs. 1.44 kg, 1.02% and 35.01 g, respectively). Daily digestible energy intake (DEI) was similar among treatments as well as the average daily weight gain (.986 kg), feed conversion (4.52 kg DMI/kg of weight gain) and energy efficiency (12.23 Mcal DEI/kg of weight gain). However, when compared by contrast analyses both diets with SH (SH and SH + RB) and both diets with CG (CG and CG + RB), it was observed that animals receiving diets with soybean hulls consumed more DM than animals fed corn grain expressed either per 100 kg of body weight (3.28 vs. 3.06%) or per unit of metabolic weight - MW (112.67 vs. 105.59 g). It was also observed differences in DEI, being greater for diets containing corn grain (12.47 Mcal/day and .304 Mcal/MW) compared to those containing SH (11.67 Mcal/day and .288 Mcal/MW). Feed conversion improved on calves fed diets with CG (4.21) than on those fed soybean hulls (4.80).
corn grain; early weaning; feedlot; rice bran; soybean hulls
