Abstract
Producers wishing to background cattle may not have access to grain in certain regions of the country or when grain price is high. Sugar sources may replace grain under these circumstances. The objective of this study was to determine optimum sugar concentration based on daily gain and feed conversion in high-forage diets fed to growing cattle. Ninety-two Angus crossbred (Ranch 1) steers (n = 60; 339 + 11 kg BW) and heifers (n = 32; 309 + 14 kg BW), and 89 Red Angus crossbred (Ranch 2) steers (338 + 16 kg BW) were randomly allocated (5 to 7 hd/pen) within ranch and sex to one of 15 pens in each of two (north or south side) locations within a deep bedded confinement feedlot. Target dietary treatments were designed to contain supplemental sugar inclusion of 0%, 3.5%, 7% or 10.5% (8, 7, 8 or 7 replicate pens in each treatment, respectively) using a molasses-based supplement containing 56.8% sugar and 7.4% urea. Diets were comprised (DM basis) of hay (12%), corn silage, dry distillers grains (14.5%), dry rolled corn and a liquid supplement (5%); corn grain and corn silage inclusion varied from 21% to 32% and from 29% to 36%, respectively, to accommodate supplemental sugar. This resulted in dietary sugar concentrations of 4.3%, 7.3%, 10.3% and 13.3% or 0%, 3%, 6%, and 9%, respectively, as supplemental sugar. As concentration of sugar increased, DMI increased linearly (P < 0.006) with no change in ADG (P = 0.22) resulting in linearly decreasing feed conversion efficiency (P = 0.032). Iterated ME concentration of supplemental sugar was similar to that of corn grain (P > 0.06). Given the appropriate conditions, sugar may replace dry rolled corn and corn silage in high roughage diets for growing cattle.
221 Optimizing sugar inclusion in high roughage diets for growing cattle
