Modifying different components of distillers grains and the impact on feedlot performance.

Abstract Text: The composition of distillers grains has potential to change as corn components are removed for further ethanol production. Crossbred yearling steers (n = 448; initial BW = 364 ± 13 kg) were utilized in a completely randomized block design to determine the effect of altering distillers grains composition on animal performance and carcass characteristics. Treatments were: 1) negative control (CON) with 81.5% blend of high-moisture corn and dry-rolled corn; 2) positive control (DG) replaced corn at 50% of diet with dried distillers grains plus solubles; 3) non-pelleted corn stover (STV), treated with calcium oxide, contained 18.75% solubles, 12.5% treated stover, and 18.75% high-protein distillers grains; 4) pelleted corn stover (PEL-STV) at same DM inclusion as STV; 5) bran (BRN) included 18.75% solubles, 12.5% isolated fiber, and 18.75% high-protein distillers grains; 6) bran medium protein (BRN-MED) contained 24.4% solubles, 16.2% isolated bran, and 9.4% high-protein distillers; and 7) bran low protein (BRN-LOW) had 30% solubles and 20% isolated bran (DM basis). Animal performance and carcass characteristics were analyzed using the PROC MIXED procedures of SAS with pen as the experimental unit. Block was a fixed effect and treatments were evaluated when the F test was significant (P < 0.05). Single degree of freedom contrasts were developed to determine effects of exchanging components in distillers grains. Intakes and ADG were greater for DG compared to CON, but G:F was similar between CON and DG (0.146 vs. 0.147, respectively; P = 0.75). However, combining bran, solubles, and protein together in similar proportions to distillers grains reduced G:F (P < 0.01) compared to DG. Replacing bran with treated corn stover further reduced feed efficiency (P < 0.01). No difference between pelleting corn stover or not (P = 0.60) was observed for ADG and G:F. Intake decreased with pelleting corn stover (P < 0.02) without affecting ADG or G:F. There was a quadratic effect for DMI as protein was removed between BRN, BRN-MED, and BRN-LOW (P< 0.04) but no impact on ADG or G:F. Decreasing proportions of protein did not negatively impact feed efficiency, possibly due to solubles concentration increasing with decreasing protein inclusion. These data suggest that replacing bran normally found in distillers grains with corn stover increases intake and reduces feed efficiency, whether pelleted or not. Diets formulated with isolated ingredients of distillers grains did not mimic performance of distillers grains suggesting some component(s) was missing. 

Keywords: components, corn stover, distillers grains plus solubles