Optimizing the use of fibrous residues in beef and dairy diets

Increased corn prices over the past decade have altered land use away from traditional forage in favor of corn. Accordingly, beef and dairy producers have had to adopt non-traditional forage resources into their production systems, many of which have become available as a result of increased corn production. Byproducts of the wet and dry milling industries have been used to replace both corn and forage in beef and dairy diets. Byproducts containing corn bran have large amounts of readily digestible hemicellulose. The use of byproducts may increase milk production, ADG, and G:F in dairy, beef growing, and beef finishing diets, respectively. In beef finishing diets, byproducts allow for use of low quality forages or partial replacement of traditional forages with minimal losses in ADG or G:F by formulating for equal NDF concentrations. Corn residues have become more available due to increases in corn acres and yield. The individual plant components (i.e., husk, leaf, stem) vary in fiber digestibility (NDF digestibility estimates = 40.5%, 31.4%, and 0.6% ± 0.8 for husk, leaf, and stalk, respectively). Selectivity for husks and leaves by grazing cattle likely improves their performance. New technologies that allow for selective harvesting of husk and leaf may result in a higher value feed product. Alkaline treatment is another technology that may improve the feeding value of residues. Concentrations of up to 20% harvested corn residue treated with calcium oxide may be included in finishing diets with an average of 2.3% reduction in G:F when diets contain 40% wet or modified distillers grains. Conversely, when untreated corn residues are included in similar finishing diets, G:F may be reduced by 20%. Calcium oxide treated residues included in beef growing diets increases DMI and ADG without significant improvements in G:F. Calcium oxide treatment of corn residues has been evaluated in dairy diets by replacing corn or corn silage with variable results. Harvesting corn silage rather than separate harvest of corn grain and residue may allow for greater total net energy per acre to be captured. The use of wet and modified corn milling byproducts enhances the use of corn silage in finishing diets. While G:F may be reduced, feeding greater concentrations of corn silage may be economical. Efficient use of non-traditional fiber sources, like corn milling by products and corn residue, are critical to the future viability of ruminant animal production

Influence of Corn Hybrid Traits and Processing Method on Nutrient Digestibility

Two experiments were conducted to determine the effects of corn hybrid and processing method on the site and extent of nutrient digestibility and ruminal fermentation. Treatments consisted of 2 processing methods, dry-rolled corn (DRC) and high-moisture corn (HMC), and 3 hybrids, H-8562 (1), 33P67 (2), and H-9230 (3), in a 2 × 3 factorial arrangement. In Exp. 1, six ruminally cannulated crossbred steers (436 ± 8 kg) were used in a 6 × 6 Latin square design. Total tract DM, OM, and starch digestibility (STD) were greater (P \u3c 0.10) for HMC compared with DRC. A hybrid × processing method interaction (P \u3c 0.10) was observed for propionate concentration and the acetate-to-propionate ratio. In Exp. 2, two ruminally and duodenally fistulated steers were used to determine the site and extent of nutrient digestion using the mobile bag technique at 2 ruminal incubation times. Ruminal STD was not different (P = 0.14) among hybrids but was greater (P \u3c 0.01) for HMC compared with DRC. Postruminal and total tract STD were greater (P \u3c 0.01) for hybrids 1 and 3 than for hybrid 2, and were greater (P \u3c 0.01) for HMC than DRC. In both experiments the geometric mean diameter and geometric SD were influenced (P \u3c 0.05) by both hybrid and processing method. More intense processing methods or selection of hybrids with softer kernels will result in greater digestibility and ruminal propionate concentrations. Digestibility of corn samples can be characterized using the mobile bag technique but particle size can influence results

Effect of Corn Processing in Finishing Diets Containing Wet Distillers Grains on Feedlot Performance and Carcass Characteristics of Finishing Steers

Three-hundred sixty calf-fed steers (BW = 318 ± 15 kg) were used in a completely randomized design to evaluate corn processing methods in finishing diets containing wet distillers grains plus solubles (WDGS). Whole corn (WC) was compared with corn processed by different methods, consisting of dryrolled corn (DRC), high-moisture corn (HMC), a 1:1 DRC:HMC combination (DM basis), steam-flaked corn (SFC), and finely-ground corn (FGC). The SFC with a flake density of 0.33 kg/L was obtained from a commercial feedlot. Basal dietary ingredients consisted of ground alfalfa hay (5.6% of DM) and dry supplement (3.0% of DM), with the balance being WDGS (30% of DM) and corn (61.4% of DM). Final BW and ADG were greater (P \u3c 0.05) for the cattle fed DRC (1.84 kg/d) compared with cattle fed FGC (1.53 kg/d), SFC (1.63 kg/d), and WC (1.75 kg/d), but was not different (P = 0.11) from cattle fed DRC:HMC (1.78 kg/d). Cattle fed HMC (0.185) had greater (P \u3c 0.05) G:F compared with cattle fed FGC (0.166), SFC (0.176), and WC (0.166). No differences (P \u3e 0.30) were detected between cattle fed HMC and DRC:HMC for ADG and G:F; however, cattle fed DRC tended to have greater (P = 0.08) ADG, yet lower (P = 0.08) G:F than cattle fed HMC. Carcass characteristics reflected performance. These data indicate that steam flaked and finely ground corn processing methods, or no processing, are not as effective as high-moisture or dry-rolled corn processing methods in finishing diets containing 30% WDGS

Reduction of tannin level in a tropical legume (Desmodium ovalifolium) with polyethylene glycol (PEG): effects on intake and N balance, digestion and absorption by sheep

Three feeding trials were conducted to determine the effect of reducing the concentration of condensed tannins (CT) in Desmodium ovalifolium Wallick ex Gagnep (CIAT 350) on voluntary feed intake, N digestion, absorption and balance in sheep. Polyethylene glycol (PEG) was used as a tannin-binding agent to reduce extractable CT. In Trial 1, 12 growing lambs were assigned at random to one of four treatments: ad libitum feeding of Centrosema macrocarpum Bentham (CIAT 5713), C. macrocarpum plus PEG (50 g kg-1 DM), D. ovalifolium, or D. ovalifolium plus PEG (50 g kg-1 of DM). Extractable CT values were 46 and 17 g kg-1 for D. ovalifolium and D. ovalifolium plus PEG, respectively. Forage of C. macrocarpum contained 1.7 g kg-1 extractable CT and was not affected by PEG addition. Voluntary DM intake did not differ (P > 0.05) between C. macrocarpum treatments, but was higher (P<.10) for D. ovalifolium low in CT than for D. ovalifolium high in CT (23 vs. 19 g kg-1 BWd-1). When D. ovalifolium high in CT was fed fecal N excretion (4.4 vs 2.8 g d-1) was higher and N retained (1.3 vs. 4.3 g d-1) was lower (P<.10). In Trial 2, three ruminally and duodenally fistulated sheep were used in a 3 x 3 latin square design. Treatments were restricted feeding of D. ovalifolium (Control, 41 g kg-1 CT), D. ovalifolium plus 3.5% - PEG (17 g kg-1 CT) or D. ovalifolium plus 7.0% - PEG (16 g kg-1 CT). Mean rumen NH3-N concentrations (mg dL-1) were 5.2, 12.2, and 12.7 for the control, 3.5 - PEG and 7.0 - PEG diets, respectively. Fecal N was lower (P<.05) for the low CT diets, but apparent N absorption increased (P<.10) with increasing levels of extractable CT in the diet. In Trial 3, three sheep, fistulated at the rumen, duodenum, and ileum, were used in a switch-back design. Treatments were restricted fedding of D. ovalifolium (Control, 46 g kg-1 CT) and D. ovalifolium plus 5.0% - PEG (18 g kg-1 CT). Sheep fed forage high in extractable CT had higher (P < 0.01) N flux to the duodenum than those fed forage low in CT (8.3 vs. 5.9 g d-1). Nitrogen absorption in the small intestine was also higher (P<.05) with the diet high in CT (3.0 vs 3.8 g d-1). High levels of extractable CT in this tropical legume reduced voluntary intake and protein degradation in the rumen (i.e. less rumen ammonia), but in combination with feed restriction, increased N flow and absorption in the small intestine

Impact of Manure Application on Phosphorus in Surface Runoff and Soil Erosion

Effects of method of manure management and dietary P were compared on 21 natural runoff plots to monitor the long-term impact of dietary P to P losses in runoff and erosion. Reducing feed P resulted in a 33% reduction in manure P content and soil test P buildup and runoff losses of P also were directly proportional to feed P inputs. The timing and management of manure are also important considerations for controlling P losses in runoff in the year of application. However, residual effects of timing and management are probably small. Management criteria designed to assess the potential for landscape P-loading (i.e. “P-index”) correctly weight winter applications as more detrimental than planting time applications

Grazing Evaluation of Big Bluestems Bred for Improved Forage Yield and Digestibility

Two big bluestem (Andropogon gerardii Vitman) strains (Pawnee C3 and Kaw C3) developed by three breeding cycles for increased forage yield and in vitro dry matter digestibility (IVDMD) were compared with the base populations of \u27Pawnee\u27 and \u27Kaw\u27 in a 3-yr grazing trial. Pastures were seeded in May 1998 near Mead, NE. Experimental units were three 0.4-ha pastures of each strain or cultivar in a randomized complete block design. Pastures were burned and fertilized with ammonium nitrate at 112 kg N ha-1 in the spring of 2000, 2001, and 2002 before grazing. Each pasture was continuously stocked with three crossbred yearling steers (Bos taurus) (380 +/- 38 kg) in mid-June 2000, 2001, and 2002 to provide a stock density of 7.5 steers ha-1. Pawnee C3 and Kaw C3 produced 16 and 7% more average daily gain (ADG), respectively, than the base populations during the 3-yr study. Additionally, Pawnee C3 and Kaw C3 produced 14 and 5% more total body weight (BW) gain ha-1, respectively, than the base populations. Pawnee C3 ADG was 1.30 kg hd-1 and produced greater than 455 kg total BW gain ha-1 during a drought period in eastern Nebraska. Pawnee C3 pastures produced more available forage with higher IVDMD, cell soluble, cell wall digestibility, and lower lignin concentration than forages from Pawnee pastures. Kaw C3 pastures differed from Kaw pastures by producing forage with greater crude protein concentration. These results demonstrate the productivity of big bluestem pastures in the eastern Great Plains and document the positive livestock response to moderate increases in forage IVDMD. The strains bred for increased yield and IVDMD provided as much as 26% more total BW gain ha-1 at no additional cost. Pawnee C3 was released as the cultivar Bonanza and Kaw C3 was released as \u27Goldmine\u27

Grazing Evaluation of Big Bluestems Bred for Improved Forage Yield and Digestibility

Two big bluestem (Andropogon gerardii Vitman) strains (Pawnee C3 and Kaw C3) developed by three breeding cycles for increased forage yield and in vitro dry matter digestibility (IVDMD) were compared with the base populations of \u27Pawnee\u27 and \u27Kaw\u27 in a 3-yr grazing trial. Pastures were seeded in May 1998 near Mead, NE. Experimental units were three 0.4-ha pastures of each strain or cultivar in a randomized complete block design. Pastures were burned and fertilized with ammonium nitrate at 112 kg N ha-1 in the spring of 2000, 2001, and 2002 before grazing. Each pasture was continuously stocked with three crossbred yearling steers (Bos taurus) (380 +/- 38 kg) in mid-June 2000, 2001, and 2002 to provide a stock density of 7.5 steers ha-1. Pawnee C3 and Kaw C3 produced 16 and 7% more average daily gain (ADG), respectively, than the base populations during the 3-yr study. Additionally, Pawnee C3 and Kaw C3 produced 14 and 5% more total body weight (BW) gain ha-1, respectively, than the base populations. Pawnee C3 ADG was 1.30 kg hd-1 and produced greater than 455 kg total BW gain ha-1 during a drought period in eastern Nebraska. Pawnee C3 pastures produced more available forage with higher IVDMD, cell soluble, cell wall digestibility, and lower lignin concentration than forages from Pawnee pastures. Kaw C3 pastures differed from Kaw pastures by producing forage with greater crude protein concentration. These results demonstrate the productivity of big bluestem pastures in the eastern Great Plains and document the positive livestock response to moderate increases in forage IVDMD. The strains bred for increased yield and IVDMD provided as much as 26% more total BW gain ha-1 at no additional cost. Pawnee C3 was released as the cultivar Bonanza and Kaw C3 was released as \u27Goldmine\u27

Effect of distillers grains or corn supplementation frequency on forage intake and digestibility

ABSTRACT: Ten ruminally cannulated heifers (BW = 416 kg; SD = 24) were used to test the effect of the form and frequency of supplemental energy on forage DMI and digestibility. Five treatments were arranged in a replicated, 5 × 4 Latin rectangle (n = 8), and included no supplement (control), dry-rolled corn (DRC) fed daily, DRC fed on alternate days (DRC-A), dried distillers grains plus solubles (DDGS) fed daily, and DDGS fed on alternate days (DDGS-A). Supplements fed daily were fed at 0.40% of BW, whereas alternate day-fed supplements were fed at 0.80% of BW every other day. Chopped grass hay (8.2% CP) was fed to allow ad libitum DMI, and the intake pattern was measured. Control heifers had greater (P < 0.01) hay DMI than supplemented heifers (1.88 vs. 1.66% of BW daily, respectively), although total DMI was lower (P < 0.01) for control. Hay DMI did not differ (P = 0.45