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Evaluation of distillers grains components singly or in combination for finishing calf feds
A finishing study was conducted to determine the value of the fiber, protein, fat, and solubles components from wet distillers grains with solubles (WDGS) alone or in combination for feedlot cattle in comparison to WDGS diets. Six hundred calf fed steers (309 kg; SD = 18) were utilized in a randomized block design with ten treatments and six replications per treatment. Diets were formulated to contain the same amount of fat, fiber or protein as in WDGS. Control diet had a 1:1 mix of dry rolled corn (DRC): high moisture corn (HMC) with 4% sorghum silage, 3.5% grass hay, and 5% supplement. The WDGS20 and WDGS40 had 20% and 40% of WDGS replacing corn, respectively. The Fiber20 and Fiber40 diets contained corn bran at 7% and 14%, respectively, and solvent extracted germ meal at 1.5% and 3%, respectively, replacing corn to mimic the fiber in WDGS20 and WDGS40. Protein was then added to the fiber diet in the form of corn gluten meal at 17.5% replacing corn to mimic the crude protein in WDGS40. Whole fat germ was then added to the fiber and protein diet to mimic the fat portion at 7.5% inclusion. Lastly, condensed distillers solubles were added to the fiber, fiber plus protein, and the fiber plus protein and fat diets at 8% to evaluate its contribution to energy. The control diet was found to be similar to the Fiber20 and Fiber40 diets. As WDGS replaced corn in the diet G:F increased quadratically (P = 0.02). Feeding WDGS resulted in greater G:F when compared to the cattle fed Fiber20 and Fiber40 diets (P < 0.01). The addition of protein to the fiber diets improved G:F along with the inclusion of fat to the protein plus fiber diets (P < 0.01).With the solubles inclusion, ADG increased (P < 0.01). The addition of protein to the fiber diet and the addition of fat to the fiber and protein diet added 47 % and 2 %, respectively, to the feeding value when compared to the corn control. The diet intended to reconstruct WDGS40 from fiber, protein, fat and solubles gave similar performance for G:F (P ≥ 0.83). However, WDGS40 cattle had greater fat (P = 0.05) and tended to have greater marbling (P = 0.17). The combination of the individual components mimics the feeding value of WDGS with the largest contributor being protein.
Keywords: Fiber, Protein, Wet distillers grains