Two experiments were conducted to evaluate the performance and metabolism responses of finishing cattle to dietary inclusion of corn ethanol byproducts. All diets were isonitrogenous and contained 15% corn silage, 12% soyhulls, 0.55 to 0.85% urea and 2.25% mineral supplement. Treatments were (dry basis): Control [8% whole cottonseed, 5% soybean meal and 56.9% ground corn (GC)]; High Protein Distillers Grains (HPDG; 10.3% HPDG and 59.65% GC); Dry Distillers Grains plus Solubles (DDBS; 30% DDBS and 39.65% GC); Wet Distillers Brain plus Solubles (WDGS; 30% WDGS and 39.65% GC). In Exp. 1, 268 Nellore bulls were blocked by initial body weight (423.3 kg ± 36.6 kg), assigned to 44 pens in a randomized complete block design and fed for 110 days. Dry matter intake (DMI) tended (P = 0.058) to be greater for DDBS compared with WDBS (11.2 vs. 10.3 kg, respectively). Average daily gain was greater (P < 0.05) for DDBS compared with HPDG (1.62 vs 1.45 kg respectively) and tended (P = 0.086) to be greater for DDBS compared with control (1.62 vs. 1.48 kg respectively). Hot carcass weight was greater (P < 0.05) for DDBS compared with the other treatments (332 vs. 321 kg respectively). Feed efficiency, carcass dressing, ribeye area and back fat thickness were not affected (P > 0.05) by treatments. In Exp. 2, four rumen cannulated Nellore steers (389 ± 37 kg) were used in a 4 × 4 Latin square design. Total tract digestibility of dry matter was greater (P < 0.05) for HPDG compared with DDBS (76.8 vs. 68.5% respectively). Rumen acetate:propionate ratio was less (P < 0.01) for HPDG and DDBS (2.01) compared to control and WDBS (2.72). The greater HCW of bulls fed DDBS may be the result of its positive effect on DMI and rumen VFA profile.
展开▼
