Two experiments were conducted to determine the effect of corn processing method and corn wet distillers grains plus solubles (WDGS) level on steer performance and metabolism. In Exp. 1, 480 crossbred steer calves (314 +/- 18 kg of BW) were used in a finishing experiment with a randomized complete block design and a 3 x 4 treatment structure. Diets were based on dry-rolled (DRC), high-moisture (HMC), or steam-flaked corn (SFC) with increasing levels of WDGS (0, 15, 27.5, or 40%; DM basis). A corn processing x WDGS level interaction (P < 0.01) was observed for ADG and G:F. Average daily gain and G:F increased linearly (P < 0.01) in steers fed DRC; ADG increased quadratically (P = 0.04) and G:F increased linearly (P = 0.02) in steers fed HMC; and ADG decreased quadratically (P = 0.02) with no change in G:F (P = 0.52) in steers fed SFC as WDGS increased. In Exp. 2, 7 ruminally fistulated steers (440 +/- 41 kg of BW) were used in a 6-period crossover design with 3 x 2 factorial treatment structure. Diets were the same as those fed in Exp. 1, except they contained only 2 levels of WDGS (0 or 40% of diet DM). Total tract starch digestibility was greater (P < 0.01) for steers fed SFC than for steers fed DRC or HMC. Minimum ruminal pH was less (P < 0.01) for steers fed SFC than for steers fed HMC or DRC. Variance of ruminal pH was different among all 3 processing methods with DRC < HMC < SFC (P < 0.10). In situ 22-h DM digestibility of DRC and HMC and starch digestibility of DRC were greater (P < 0.10) in steers fed DRC compared with steers fed HMC or SFC. Steers fed 0% WDGS had less (P < or = 0.02) intake of DM, OM, NDF, and ether extract compared with steers fed 40% WDGS. Total tract digestibility of DM and OM was greater (P < or = 0.08) and digestibility of ether extract tended (P = 0.11) to be less for steers fed 0% WDGS compared with steers fed 40% WDGS. Maximum ruminal pH and pH variance were greater (P < or = 0.08) in steers fed 0% WDGS. A corn processing x WDGS level interaction (P = 0.09) was observed for ruminal acetate to propionate ratio (A:P). Within diets containing 0% WDGS, A:P in steers fed SFC was less (P < or = 0.08). In diets containing 40% WDGS, A:P was similar between processing methods and not different from the SFC with 0% WDGS. The corn processing x WDGS level interaction observed in the finishing experiment may be due to the decreased ruminal A:P in DRC and HMC diets with 40% WDGS.

ABSTRACT:Three experiments evaluated the lipids in distillers grains plus solubles compared with corn or other sources of lipid in finishing diets. Experiment 1 utilized 60 individually fed yearling heifers (349 ± 34 kg) fed treatments consisting of 0, 20, or 40% (DM basis) wet distillers grains plus solubles (WDGS), or 0, 2.5, or 5.0% (DM basis) corn oil in a finishing diet based on high-moisture corn (HMC) and dry-rolled corn (DRC). Cattle fed 20 and 40% WDGS had greater (P < 0.10) G:F than cattle fed 0% WDGS. Cattle fed the 5.0% corn oil had lower overall performance than cattle fed the other diets. Results from Exp. 1 indicated that adding fat from WDGS improves performance, whereas supplementing 5.0% corn oil depressed G:F, suggesting that the fat within WDGS is different than corn oil. Experiment 2 used 234 yearling steers (352 ± 16 kg) fed 1 of 5 treatments consisting of 20 or 40% (DM basis) dry distillers grains plus solubles (DDGS), 1.3% or 2.6% (DM basis) tallow, or HMC. All diets contained 20% (DM basis) wet corn gluten feed (WCGF) as a method of controlling acidosis. No differences between treatments for any performance parameters were observed in Exp. 2. The DDGS may be similar to tallow and HMC in finishing diets containing 20% WCGF. Experiment 3 used 5 Holstein steers equipped with ruminal and duodenal cannulas in a 5 5 Latin square design. Treatments were a 40% WDGS diet, 2 composites, one consisting of corn bran and corn gluten meal (COMP), and one consisting of corn bran, corn gluten meal, and corn oil (COMP + OIL), and 2 DRC-based diets supplemented with corn oil (CON + OIL) or not (CON). Cattle fed the WDGS diet had numerically lower rumen pH compared with cattle fed other treatments.Cattle fed WDGS had greater (P < 0.10) molar proportions of propionate, lower (P < 0.10) acetate:propionate ratios, greater (P < 0.10) total tract fat digestion, and a greater (P < 0.10) proportion of unsaturated fatty acids reaching the duodenum than cattle fed other treatments.Therefore, the higher energy value of WDGS compared with corn may be due to more Page 2 of 38 Journal of Animal Science 3 propionate production, higher fat digestibility, and more unsaturated fatty acids reaching the duodenum.

In a 3-yr study, corn dried distillers grains plus solubles (DDGS) were evaluated as a substitute for forage and N fertilizer in yearling steers grazing smooth bromegrass. A total of 135 steers (330 +/- 10 kg) were used in a randomized complete block design to measure the effects of DDGS supplementation and N fertilization on animal and pasture performance. Steers were initially stocked at 6.8 animal unit month (AUM)/ha on nonfertilized smooth bromegrass pastures (CONT), at 9.9 AUM/ha on smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT), or at 9.9 AUM/ha on nonfertilized smooth bromegrass pastures with 2.3 kg of DDGS DM supplemented daily (SUPP). Paddock was the experimental unit, with 3 replications per year for 3 yr. Paddocks were strip-grazed and put-and-take cattle were used to maintain similar grazing pressure among treatment paddocks during the 160-d grazing season. In vitro DM disappearance declined quadratically (P < 0.01), whereas CP and standing crop showed cubic responses (P < 0.01) throughout the grazing season. Crude protein was greater (P < 0.05) for FERT compared with CONT and SUPP. Standing crop was 18% greater (P < 0.01) for FERT than CONT and was 10% greater (P < 0.01) than SUPP. Adjusted stocking rates (AUM/ha) were greater (P < 0.01) for FERT and SUPP compared with CONT. Final BW were greater (P < 0.01) for SUPP steers compared with CONT and FERT steers. Similar results were observed for ADG, with SUPP steers gaining more (P < 0.01) compared with CONT and FERT steers. Total BW gain per hectare was increased (P < 0.01) by 53% with FERT and by 105% with SUPP. Feedlot ADG was similar among treatments (P = 0.88), and SUPP steers maintained their BW advantage through the finishing phase. Dried distillers grains can be used to substitute effectively for N fertilizer by increasing the performance of yearling steers grazing smooth bromegrass and increasing stocking rates compared with nonfertilized pastures.

In a 3-yr study, 135 crossbred steers (330 ± 10 kg) were used in a randomized complete block design to evaluate corn dried distillers grains plus solubles (DDGS) fed to yearling steers as a substitute for forage and N fertilizer and its effect on N use efficiency in yearling steers grazing smooth bromegrass pastures. Steers were initially stocked at 6.8 animal unit months (AUM)/ha on nonfertilized smooth bromegrass pastures (CONT), at 9.9 AUM/ha on smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT), or at 9.9 AUM/ha on nonfertilized smooth bromegrass pastures with 2.3 kg (DM) of DDGS supplemented daily per steer (SUPP). Paddock was the experimental unit, with 3 replications per treatment per year for 3 yr. Paddocks were strip-grazed, and put-and-take cattle were used to maintain similar grazing pressure among treatment paddocks during the 160-d grazing season. Steers consumed less forage (P < 0.01), but total N intake for SUPP was greater (P < 0.01) per steer and per hectare than for FERT, and both were greater (P < 0.01) than for CONT. Nitrogen retention for steers in the SUPP treatment was increased (P < 0.01) by 31% compared with N retention in the CONT and FERT treatments. Nitrogen retention per hectare for SUPP was 30 and 98% greater (P < 0.01) than N retention per hectare for FERT and CONT, respectively. Nitrogen excretion per steer and per hectare were also greater (P < 0.01) for SUPP than FERT, and both were increased (P < 0.01) compared with CONT. Animal N use efficiency was similar (P = 0.29) for steers in the CONT, FERT, and SUPP treatments. However, system-based N use improved (P < 0.01) by 144% for SUPP compared with FERT. The DDGS increased N intake and N excretion in yearling steers. However, because of improvements in BW gain and increases in stocking rate of pastures, DDGS can be a useful tool to increase the efficiency of N use in smooth bromegrass grazing systems.

An experiment evaluated the effects of six corn processing methods in feedlot diets containing 30% (DM basis) wet distillers grains plus solubles (WDGS). Treatments consisted of whole corn, dry-rolled corn, a dry-rolled/ high-moisture corn mix, high-moisture corn, steam flaked corn, and fine ground corn. The ADG was highest for steers receiving dry-rolled corn, high-moisture corn, or a 50:50 blend of dry-rolled and high-moisture corn. Feed conversion was best for steers receiving high-moisture corn. Interestingly, cattle fed finely ground corn or steam-flaked corn did not gain or convert as well as expected. Results indicate that there is a performance advantage obtained by processing corn as either dry-rolled or high-moisture when included with WDGS in finishing diets.