Biofuel feedstock and blended coproducts compared with deoiled corn distillers grains in feedlot diets: Effects on cattle growth performance, apparent total tract nutrient digestibility, and carcass characteristics

Crossbred steers (British x Continental; n = 192; initial BW 391 +/- 28 kg) were used to evaluate the effects of feeding ethanol coproducts on feedlot cattle growth performance, apparent nutrient digestibility, and carcass characteristics. Steers were blocked by initial BW and assigned randomly to 1 of 6 dietary treatments within block. Treatments (replicated in 8 pens with 4 steers/pen) included 1) control, steam-flaked corn-based diet (CTL), 2) corn dried distillers grains with solubles (DGS; DRY-C), 3) deoiled corn dried DGS (DRY-CLF), 4) blended 50/50 corn/sorghum dried DGS (DRY-C/S), 5) sorghum dried DGS (DRY-S), and 6) sorghum wet DGS (WET-S). Inclusion of DGS was 25% (DM basis). The DGS diets were isonitrogenous, CTL was formulated for 13.5% CP, and all diets were balanced for ether extract. Final shrunk BW, ADG, and DMI did not differ among CTL and DGS treatments (P >= 0.19). Overall G:F did not differ from CTL for DRY-C, DRY-CLF, or WET-S (P >= 0.12); however, G:F was 9.6% less for DRY-S compared with CTL (P < 0.01) and tended (P = 0.09) to be less for DRY-C/S than CTL. For grain source, ADG and G:F were less for DRY-S vs. DRY-C (P < 0.05), but blending DRY-C/S tended (P = 0.07) to increase ADG and increased (P = 0.05) carcass-adjusted G:F vs. DRY-S. For WET-S, final BW and ADG were greater (P < 0.05), and G: F tended (P = 0.06) to be greater than for DRY-S. There was no difference in ADG, DMI, or G: F of steers fed DRY-C vs. DRY-CLF (P >= 0.35). Apparent DM and OM digestibility did not differ for CTL, DRY-C, DRY-CLF, and WET-S (P >= 0.30) but were lower for DRY-C/S and DRY-S (P < 0.05). Nutrient digestibility was lower for DRY-S vs. DRY-C (P < 0.01), but apparent digestibility of OM, DM, NDF, ADF, CP, ether extract, and starch were increased (P < 0.01) for DRY-C/S vs. DRY-S. Although starch digestibility did not differ between DRY-S and WET-S (P = 0.18), digestibility of other measured nutrients was greater for WET-S vs. DRY-S (P < 0.01). Ether extract digestibility was greater for DRY-CLF vs. DRY-C (P < 0.05). Carcass weight, dressing percent, and marbling score did not differ between CTL and DGS diets (P >= 0.23). For DRY-S, HCW was lower than for DRY-C (P = 0.02); however, compared with DRY-S, HCW tended to be greater for DRY-C/S (P = 0.10) and WET-S (P = 0.07). At a moderately high (25% DM) inclusion, blending C/S or feeding WET-S resulted in cattle growth performance and carcass characteristics similar to those of CTL and corn-based coproducts.