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Optimum inclusions of alkaline treated cornstalks and distillers grains fed to calf-fed steers
A 180-d finishing study examined the effect of level of calcium oxide treated corn stalks (TS) in diets containing separate levels of modified distillers grains with solubles (MDGS). Crossbred steer calves (n = 378; BW = 320±7 kg) were separated into 2 BW blocks, stratified by BW within block, and assigned randomly to pens. Pens were assigned randomly to one of seven treatments, with six pens per treatment and nine steers per pen. Treatments were designed as a 2x3 factorial design, with diets containing either 20 or 40% MDGS fed with 10, 20, or 30% TS. In addition, a dry rolled corn, 20% MDGS, and 5% untreated stalks control (CON) was fed. All diets contained 4% supplement. An interaction was observed for G:F on a carcass (P < 0.10) and live BW basis (P < 0.05); therefore, simple effects of TS inclusion within each MDGS inclusions will be presented. However, no significant interaction was observed between TS and MDGS inclusion for DMI (P = 0.47), ADG (P = 0.21), and carcass characteristics (P > 0.21). Intakes were not impacted by treatment (P > 0.18). Gain decreased linearly (P < 0.01) with increasing TS inclusion in the 20% MDGS diets. However, ADG decreased quadratically (P < 0.01) when TS were added to the 40% MDGS diets with ADG equivalent between 10 and 20% and decreasing at 30% inclusion. Similar to ADG, G:F decreased linearly (P < 0.01) when TS were increased from 10 to 30% in diets with 20% MDGS, but decreased quadratically (P < 0.01) when TS increased in diets with 40% MDGS with equal G:F being observed for the 10 and 20% TS diets then decreasing when TS increases to 30%. Dressing percentage decreased linearly when TS were included in the 40% MDGS diets and decreased quadratically when fed with 20% MDGS. A linear decrease in fat depth was observed as TS increased in both 20 and 40% MDGS based diets. Within 20% MDGS, steers fed CON had the greatest final BW, ADG, and G:F compared to any TS inclusion. Previous research evaluated alkaline treated stalks in diets containing greater than 35% distillers. These data suggest that 10 or 20% TS can be fed with 40% distillers included in the diet without negatively impacting ADG and G:F. However, if only 20% distillers is fed, then 10% or less TS should be fed.
Keywords: calcium oxide, distillers, finishing