Effects of twenty percent corn wet distillers grains plus solubles in steam-flaked and dry-rolled corn-based finishing diets on heifer performance, carcass characteristics, and manure characteristics

Two hundred sixty-four crossbred heifers (initial BW = 354 kg +/- 0.5) were used to determine effects of corn processing method and wet distillers grains plus solubles (WDGS) inclusion in finishing diets on animal performance, carcass characteristics, and manure characteristics. The study was conducted as a randomized complete block with a 2 x 2 factorial arrangement of treatments. Dietary treatments included steam-flaked corn (SFC)- and dry-rolled corn (DRC)-based finishing diets containing 0 or 20% WDGS (0SFC, 20SFC, 0DRC, and 20DRC, respectively). Heifers averaged 154 d on feed and were marketed in 3 groups. There were no interactions between corn processing method and WDGS detected (P >= 0.29) for any performance or carcass response variables. Heifers fed diets containing WDGS tended to have greater final BW (P = 0.10) and increased G: F (P = 0.08) compared with heifers fed diets without WDGS. Heifers fed SFC-based diets consumed 7% less feed (P < 0.01) and were 9% more efficient (P < 0.01) than heifers fed DRC-based diets. Carcass characteristics were not affected by corn processing method or WDGS inclusion (P >= 0.16). Intakes of OM, N, P, and K were greater (P <= 0.05) for heifers fed DRC-based diets than those fed SFC-based diets, which resulted in greater net accumulation of the nutrients in the manure (P <= 0.04). Heifers fed diets containing WDGS had greater (P < 0.01) intakes of N, P, and K than heifers fed diets without WDGS. As a result, a greater net accumulation of P and K (P <= 0.03) and N (P = 0.10) were present in the manure from cattle fed diets containing WDGS compared with those fed diets without WDGS. There was no interaction (P >= 0.16) between corn processing and WDGS on N volatilization losses. Nitrogen volatilization losses from manure (expressed as a percentage of intake and g.heifer(-1).d(-1)) were greater (P < 0.01) for heifers fed SFC-based diets than heifers fed DRC-based diets. Feeding DRC-based finishing diets to heifers resulted in increased manure production and nutrient excretion and decreased N volatilization. Both corn processing method and WDGS inclusion affected animal performance and manure characteristics.