Wet distiller’s grains with solubles (WDGS) are a common by-product feedstuff generated by the grain–ethanol industry, and it is used extensively by the cattle feeding industry. Distillers grains are typically high in protein; however, the protein in WDGS has a low ruminal degradability, and thus may result in a deficiency of RDP in the diet even when dietary CP concentrations are high. Assessment of the RDP needs in diets containing WDGS is needed to aid the cattle feeding industry in managing feed costs and potential environmental issues. To that end, we conducted 2 feeding studies to evaluate the supplemental RDP requirements of beef cattle fed steam-flaked corn-based finishing diets. In Exp. 1, 525 yearling steers (initial body weight = 373 ± 13 kg) received treatments in a 2 × 3 + 1 factorial. Dietary factors included WDGS (15 or 30% of DM) and nonprotein N (NPN; 0, 1.5, or 3.0% of DM) from urea (0, 0.52, and 1.06%). The control diet without WDGS contained 3.0% NPN (1.06% urea) and cottonseed meal. Diets were formulated to have equal crude fat concentrations. Overall gain efficiency among steers fed 15% WDGS was greatest for 1.5% NPN and least for 0% NPN (P = 0.07, quadratic), whereas gain efficiency decreased linearly (P < 0.09) as NPN increased in the 30% WDGS diets. Dressing percent was greater (P < 0.01) for the Control diet than for 15 or 30% WDGS. In Exp. 2, 296 steer calves (initial BW = 344 ± 12 kg) were fed 1 of 4 experimental diets that included a Control diet without WDGS (contained 3% NPN from urea, and cottonseed meal) and 15% WDGS diets with either 1.50, 2.25, or 3.00% NPN (0.52, 0.78, and 1.04% urea, respectively, on a DM basis). Overall gain efficiency on either a live or carcass-adjusted basis was not different among treatments (P > 0.15). Dietary NPN concentration did not influence growth performance (P > 0.21). Increasing dietary WDGS concentration resulted in decreasing (P < 0.05) diet digestibility (determined with an internal marker) and increasing (P < 0.05) N volatilization losses (determined by diet and manure N:P ratio); however, the effects of NPN level on digestibility and N losses were somewhat inconsistent across experiments. Results suggest that optimum performance for cattle fed 15% WDGS occurred when the diet contained between 1.5 and 2.25% NPN. However, no supplemental NPN was needed to support optimum performance in diets containing 30% WDGS.

With increased concern over the effects of livestock production on the environment, a number of new technologies have evolved to help scientists evaluate the environmental footprint of beef cattle. The objective of this review was to provide an overview of some of those techniques. These techniques include methods to measure individual feed intake, enteric methane emissions, ground-level greenhouse gas and ammonia emissions, feedlot and pasture emissions, and identify potential pathogens. The appropriate method to use for measuring emissions will vary depending upon the type of emission, the emission source, and the goals of the research. These methods should also be validated to assure they produce accurate results and achieve the goals of the research project. In addition, we must not forget to properly use existing technologies and methods such as proper feed mixing, feeding management, feed/ingredient sampling, and nutrient analysis.

Grain processing has been used for many decades to improve the digestibility of feed grains fed to finishing beef cattle and to improve animal performance ( Owens et al., 1997). The most common corn processing methods currently used by feedyards in the United States are dry rolling (DRC) and steam flaking (SFC; Samuelson et al., 2016). For many years, SFC has been the dominant form of grain processing in the Southern Great Plains and West, whereas DRC has dominated in the Corn Belt and Northern Great Plains. This has been primarily dictated by the price of natural gas (less expensive in the south) and corn (less expensive in the north), as well as the size of feedyards. However, the use of SFC has increased somewhat in the Northern Plains as natural gas prices have declined. Macken (2006) noted that SFC generates economic returns in both small and large feedlots.

The use of distiller’s grains (DG) in beef cattle finishing diets is a common practice. However, the effects of supplemental fat on performance and nutrient losses of cattle fed diets containing DG are not known. Therefore, we fed 398 crossbred yearling heifers (initial BW = 373.5 kg) for 106 d to determine the effects of dietary fat concentration and sorghum-based wet distiller’s grains with solubles (SWDGS) on performance, carcass characteristics, and nutrient losses of finishing cattle. Treatments included two 92% concentrate, steam-flaked corn (SFC)-based diets with 0% or 3% added fat from yellow grease and 3 SFC-based diets with 15% SWDGS (DM basis) that contained either 0%, 1.5%, or 3% added fat (8 pens per treatment) in a randomized block design. Overall DMI and ADG were 5% to 6% greater (P < 0.01) for heifers fed 15% SWDGS than for those fed 0% SWDGS. Among heifers fed 15% SWDGS, DMI was greatest (P = 0.04; quadratic effect) and ADG tended (P = 0.12; quadratic effect) to be greatest for heifers fed 1.5% fat. The ADG:DMI did not differ between 0% SWDGS with 0% or 3% fat, and was not altered by replacing a portion of SFC with SWDGS (P > 0.36). However, ADG:DMI tended to increase as more fat was added to diets with 15% SWDGS (P = 0.06). Average hot carcass weight (HCW) was 5 kg greater (P = 0.05) when SWDGS was fed, but HCW tended to be greatest for heifers fed 15% SWDGS with 1.5% fat (P = 0.09, quadratic effect). Heifers fed 0% SWDGS with 0% fat tended to have a lower marbling score, less rib fat, lower average yield grade (P < 0.08), and more (P < 0.01) yield grade 1 carcasses than heifers fed 0% SWDGS with 3% fat. Averaged across fat levels, heifers fed 15% SWDGS had more rib fat and a higher yield grade (P < 0.03) than heifers fed 0% SWDGS. Feeding 15% SWDGS did not alter carcass quality grade distribution compared to feeding 0% SWDGS, but 15% SWDGS produced fewer yield grade 3 carcasses (P = 0.03) than 0% SWDGS. The calculated NEg of SWDGS (1.36 Mcal/kg) was 91% of the tabular value for dry rolled corn (1.50 Mcal/kg) and 84% of the tabular value for SFC (1.62 Mcal/kg). Nitrogen intake, and N excretion were greater (P < 0.05) in heifers fed 15% SWDGS than in heifers fed the 0% SWDGS diets, but N loss as a % of N intake was less (P < 0.05). Our results suggest adding 1.5% fat to diets containing 15% SWDGS may improve beef cattle performance; however, feeding logistics need to be considered when pricing wet DG.

An indirect calorimetry trial examined energy metabolism, apparent nutrient digestibility, C retention (CR), and N retention (NR) of cattle supplemented with zilpaterol hydrochloride (ZH). Beef steers (n = 20; 463 ± 14 kg) blocked (n = 5) by weight and source were individually fed and adapted to maintenance energy intake for 21 d before allotment to ZH (90 mg/steer∙d) or no β₂–adrenergic agonist treatment (control [CONT]) for 20 d (455 ± 14 kg at the start of treatment). Respiration chambers = 4 were used to quantify heat production (HP) during maintenance (d 12 to 16 of the ZH period) and fasting heat production (FHP; d 19 to 20 of ZH period; total 4 d of fast). Steers were harvested after a 6-d ZH withdrawal and carcasses were graded 24 h after harvest. Control cattle lost more BW (P < 0.01; 9 kg for CONT and 2 kg for ZH-treated) during maintenance whereas the BW loss of ZH-treated steers was greater (P < 0.01; 9 kg for ZH-treated and vs. 4 kg, for CONT) during FHP; no differences (P ≥ 0.76) were detected for G:F, ADG, and end BW. No differences in DMI, apparent nutrient digestibility, O₂ consumption, or CH₄ production (P ≥ 0.12) were detected; however, ZH-treated cattle had greater CO₂ production during maintenance (P = 0.04; 23.6 L/kgBW for ZH-treated and 22.4 L/kg BW^0.75 for CONT). Digestible energy and ME did not differ (P ≥ 0.19); however, urinary energy was greater (P = 0.05; 0.091 Mcal for CONT and 0.074 Mcal for ZH-treated) in CONT cattle. Steers treated with ZH tended to have greater HP (P = 0.09; 12.44 Mcal for ZH-treated and 11.69 Mcal for CONT), but the effect was reduced on a BW^0.75 basis (P = 0.12; 0.126 Mcal/kg BW0.75 for ZH-treated and 0.120 Mcal/kg BW0.75 for CONT vs. 0.120 Mcal/kg BW^0.75). No treatment difference in FHP was observed (P ≥ 0.32) although CO₂ production (L/steer) increased with ZH treatment (P = 0.04; 1,423 L/steer for ZH-treated and 1,338 L/steer for CONT). Control cattle excreted more (P = 0.05) N in urine (39.8 g/d for CONT and 32.4 g/d for ZH-treated); therefore, NR (P = 0.07; 22.14 g/d for ZH-treated and 14.12 g/d for CONT steers) tended to be greater for ZH-fed steers. Steers treated with ZH lost more C via CO₂ (P = 0.04; 1,036.9 g/d for ZH-treated and 974.3 g/d for CONT) although total CR did not differ (P ≥ 0.23). Empty BW, HCW, and harvest yields (g/kg empty BW) were not different (P ≥ 0.13), whereas ZH increased dressed yield (P = 0.02; 62.12 % for ZH-treated and 60.65% for CONT) and LM area (P = 0.02; 77.81 cm² for ZH-treated and vs. 70.90 cm² for CONT). Separable carcass lean and actual skeletal muscle protein (SMP) were increased with ZH (P ≤ 0.04; 201.6 and 41.2 kg, respectively for ZH-treated and 196.0 and 38.4 kg, respectively for CONT). Results from this trial indicate that ZH treatment increased (P = 0.03) SMP and tended (P ≥ 0.07) to increase NR and modify HP during maintenance by increasing CO₂ production. Copyright © 2016. American Society of Animal Science .

Grain sorghum grown in 38-cm rows (high density [HD]) or 76-cm rows (normal density [ND]) was treated as follows: steam-flaked (SF), high-moisture-harvested followed by rolling and ensiling (HM), or dry-rolled (DR). Resulting grains were evaluated using lambs in two 5 × 5 Latin square digestion trials. Treatment diets contained either SF-HD, SF-ND, HM-HD, HM-ND, or DR-ND grain sorghum in two trials; a 90 or a 60% concentrate diet was fed in each trial. High-density planting increased (P < 0.10) the apparent absorption of P relative to ND planting for both 60 and 90% concentrate diets. Steam flaking decreased (P < 0.10) the apparent absorption of P in the 90% concentrate diet and decreased (P < 0.10) the apparent absorption of N in both the 90 and 60% concentrate diets. Despite differences in N digestibility, steam flaking and HM ensiling resulted in similar (P > 0.10) N retention as a percentage of N intake in both trials. However, changes in the distribution of N between feces and urine among processing methods could affect N content of manure and alter nutrient management strategies. These results indicate that both planting density and grain processing can alter the apparent absorption of grain sorghum P by ruminants. Furthermore, it seems that grain processing can alter the route of N excretion in ruminants without changing total N retention.