Influence of two fat levels of dry distillers grains in diets with corn or barley on growing and finishing feedlot and carcass performance of steers

Abstract Text: A 189 d growing ( 57 d) and finishing  (132 d) study using 154 crossbred steers (initial BW = 310 kg) evaluated the effects of dry-rolled corn or dry-rolled barley and two fat levels of dry distillers grains with solubles (DDGS) on growing and finishing cattle performance.  Steers were blocked by initial BW into 4 blocks and assigned randomly to 1 of 16 pens and 1 of 4 dietary treatments within block.  In the 2 x 2 factorial study, factors were grain type (corn or barley; 30% and 51% diet DM, growing and finishing diets) and DDGS type (med-fat, 9.6% or low-fat, 5.8% fat; 26% diet DM for growing and finishing diets).  Growing diets included 19% grass hay, 22% corn silage, and 3% supplement (DM basis).  Finishing diets included 20% corn silage, and 3% supplement (DM basis).  Steers were weighed on d 0 and every 28 d until harvest.   No grain type by DDGS fat level interactions were detected (P ≥ 0.29).  Initial and final BW for the growing (P ≥ 0.18) and finishing phases (P ≥ 0.11) were similar for low- and med-fat DDGS.  Similarly, ADG, DMI, and G:F were similar for growing (P ≥ 0.19) and finishing (P ≥ 0.17) phases for low- and med-fat DDGS.  Additionally, dressing percent, HCW, yield grade, Longissimus muscle area, marbling score, and back-fat did not differ among DDGS treatments (P ≥ 0.18).  Corn and barley had similar initial and final growing (P ≥ 0.16) and finishing (P ≥ 0.17) BW and ADG.  Growing DMI was similar (P = 0.37) for corn and barley grain.  However, cattle on corn finishing diets had greater (P = 0.02) DMI than barley resulting in similar (P = 0.26) growing phase G:F but a tendency (P = 0.08) for barley to be more efficient than corn in the finishing phase.  Overall barley-fed steers had greater (P = 0.002) G:F than corn.  The carcass parameters dressing percent, HCW, yield grade, LM area, marbling score and BF were all similar (P ≥ 0.09) for barley and corn fed cattle.  Feeding low or Med fat DDGS at 26% of diet DM, in the growing and finishing phases, appears to influence animal performance and carcass attributes similarly.  When fed at similar diet DM levels, barley appears to provide a slight feed efficiency advantage over corn.   

Keywords: DDGS, Fat levels, beef cattle, corn, barley