Effects of roughage source and inclusion in beef finishing diets containing corn wet distillers' grains plus solubles

Effect of corn silage inclusion with different corn processing on finishing steer performance and carcass characteristics

Objectives were to determine the effect of corn silage inclusion within dry-rolled corn (DRC) or steam-flaked corn (SFC) finishing diets on cattle growth performance and carcass characteristics. The experiment used British and continental crossbred steers (n = 480; initial body weight [BW] = 389 ± 17 kg) in a 4 × 2 factorial arrangement of treatments with six replications per treatment. Treatments consist of four inclusions of corn silage (0%, 15%, 30%, or 45%; dry matter [DM] basis) within either a DRC or SFC diet. A corn silage by corn processing interaction was observed for dry-matter intake (DMI; P = 0.05). As corn silage inclusion increased in the diet, DMI increased linearly (P < 0.01) for both corn processing methods. DM intake was not different between SFC and DRC-fed cattle at 0% (P = 0.33), 30% (P = 0.90), or 45% (P = 0.31) corn silage inclusion. The interaction was due to the DMI of cattle fed 15% silage, as cattle-fed DRC consumed 0.5 kg/d less (P < 0.01) than cattle on the SFC diet. Quadratic effects were observed for final BW, hot carcass weight (HCW), average daily gain (ADG), feed efficiency (G:F), marbling, and fat depth (P < 0.01), regardless of corn processing. Cattle fed 15% or 30% corn silage gained faster (P < 0.01) than those fed 0% or 45% corn silage. Feed efficiency decreased quadratically (P < 0.01) as silage inclusion increased in the diet with G:F similar for cattle fed 0% and 15% silage and decreased curvilinearly for cattle fed 30% and 45% silage. The incidence of liver abscesses was greater (P = 0.03) in cattle fed 0% corn silage than for steers fed 15%, 30%, or 45% corn silage. Corn processing method, independent of silage, had no effect (P = 0.42) on liver abscess incidence. Feeding SFC increased (P < 0.01) steer final BW and HCW when compared to cattle-fed DRC, regardless of silage inclusion. Corn silage inclusion had similar effects on performance in both DRC diets and SFC diets except for DMI. As corn silage inclusion increased in the diet, feed efficiency decreased linearly (P < 0.01). Cattle-fed SFC gained 7.9% more (P < 0.01) and were 6.7% more efficient (P < 0.01) than cattle-fed DRC. In diets containing either DRC or SFC, corn silage can be included at up to 30% of the diet without negative impacts on ADG or HCW.

Evaluation of similar dietary roughage equivalency fed to beef steers during the growing and finishing phase

The objective of this experiment was to determine the influence that similar dietary roughage equivalency offered in a single or two-diet system during a 210-d growing-finishing period has on growth performance, the efficiency of dietary net energy (NE) utilization, and carcass traits in beef steers. Beef steers (n = 46; initial shrunk [4%]; body weight [BW] = 281 ± 40.4 kg) were fed once daily, and bunks were managed according to a slick bunk management system across all 10 pens. Treatments included the following: 1) A single diet program that was formulated to provide 16% (dry matter [DM] basis) dietary roughage equivalency; SD) or 2) multiple diet programs (formulated to provide a dietary roughage equivalency (DM basis) of 25% for 98 d, 16% for 14 d, and 7% for 98 d; MD). Day 1 to 112 was considered the growing period, and day 113 to 210 (the day of harvest) was considered the finishing period, all steers were implanted on day 1 with a 100 mg trenbolone acetate (TBA) and 14 mg estradiol benzoate (EB) implant and implanted with a 200 mg TBA and 28 mg EB implant on day 112. Average daily gain tended (P = 0.06) to be 9.5% greater for SD compared to MD during the growing portion, and average daily gain (ADG) was greater by 11.3% (P = 0.01) for MD compared to SD during the finishing phase of the experiment. Cumulative ADG did not differ (P ≥ 0.86) between treatments (1.61 vs. 1.62 ± 0.046 kg) for SD and MD, respectively. Cumulative dietary NEm and NEg calculated based on performance did not differ (P ≥ 0.96) between treatments. There were no differences (P ≥ 0.18) detected between treatments for hot carcass weight, dressing percent, longissimus muscle area, rib fat, United States Department of Agriculture (USDA) marbling score, kidney, pelvic, heart fat, yield grade, retail yield, empty body fat, or body weight at 28% estimated empty body fat. These data indicate that feedlot producers can feed a single growing-finishing diet to beef steers with minimal effects on overall growth performance or carcass traits.

Impacts of added roughage on growth performance, digestibility, ruminal fermentation, and ruminal pH of feedlot steers fed wheat-based feedlot diets containing 30% modified distillers grains with solubles

Two experiments were conducted to evaluate the inclusion rate roughage in wheat-based diets containing modified distillers grains with solubles (MDGS) on feedlot performance (Feedlot Experiment), as well as digestibility, ruminal pH, and ruminal fermentation characteristics (Digestibility Experiment). The feedlot experiment utilized 72 Angus steers (392 ± 46.3 kg initial body weight) which were randomly assigned to 1 of 12 pens, 3 pens per treatment, to evaluate feedlot performance and carcass characteristics. Dietary treatments were 1) control; 10% roughage, 2) 12% roughage, 3) 14% roughage, and 4) 16% roughage. The digestibility experiment used four ruminally and duodenally cannulated steers (393 ± 33.0 kg) in a 4 × 4 Latin Square with either 10%, 12%, 14%, or 16% roughage as in the feedlot experiment. However, dietary roughage source was different between these two experiments and included a combination of grass hay and wheat straw (Feedlot Experiment), and corn silage (Digestibility Experiment). All data were analyzed with the Mixed Procedures of SAS. Feed intake was recorded, with duodenal and fecal output calculated using chromic oxide. Ruminal pH and fermentation were assessed. Growth performance and most carcass characteristics were not affected by increasing roughage (P ≥ 0.11). Marbling tended to decrease linearly (P = 0.10) with increasing roughage inclusion. Increasing dietary roughage content had no effect on organic matter intake (P = 0.60) in the digestibility experiment. Intake, duodenal flow, and digestibility of neutral detergent fiber and acid detergent fiber were not affected by treatment (P ≥ 0.16). Ruminal pH increased linearly (P < 0.01) as rate of roughage inclusion increased. Ruminal concentrations of acetate and butyrate increased, and propionate decreased in a linear fashion (P < 0.01) thereby increasing (P < 0.01) acetate and butyrate to propionate ratio with increasing dietary roughage. Our data indicate that increasing roughage inclusion in wheat-based diets including 30% MDGS increased ruminal pH and shifted ruminal fermentation patterns. Additionally, increasing roughage inclusion did not affect feedlot performance in steers fed wheat at 36% to 42% of dietary dry matter in combination with 30% MDGS.

Effects of dietary roughage neutral detergent fiber levels and flint corn processing method on growth performance, carcass characteristics, feeding behavior, and rumen morphometrics of Bos indicus cattle1

Flint corn processing method [coarse ground corn (CGC; 3.2 mm average particle size) or steam-flaked corn (SFC; 0.360 kg/L flake density)] was evaluated in conjunction with 4 levels of NDF from sugarcane bagasse (SCB) as roughage source (RNDF; 4%, 7%, 10%, and 13%; DM basis) to determine impact on growth performance, carcass characteristics, starch utilization, feeding behavior, and rumen morphometrics of Bos indicus beef cattle. Two hundred and forty Nellore bulls were blocked by initial BW (350 ± 37 kg), assigned to 32 feedlot pens and pens within weight block were randomly assigned, in a 2 × 4 factorial arrangement (2 corn processing and 4 levels of RNDF) to treatments. Effects of corn grain processing × RNDF level were not detected (P ≥ 0.14) for growth performance, dietary net energy concentration, carcass traits, rumen morphometrics, and feeding behavior, except for time spent ruminating and time spent resting (P ≤ 0.04), and a tendency for papillae width (P ≤ 0.09). Bulls fed SFC-based diets consumed 7% less (P = 0.001), had 10.6% greater carcass-adjusted ADG (P < 0.001) and 19% greater carcass-adjusted feed efficiency (P < 0.001) compared with bulls fed CGC-based diets. Observed net energy for maintenance and gain values were 14.9% and 19.4% greater (P < 0.001), respectively, for SFC than for CGC-based diets. Fecal starch concentration was less (P < 0.001) for bulls fed SFC compared with those fed CGC. No grain processing effects were detected (P = 0.51) for rumenitis score; however, cattle fed SFC presented smaller ruminal absorptive surface area (P = 0.03). Dry matter intake increased linearly (P = 0.02) and carcass-adjusted feed efficiency tended (P = 0.06) to decrease linearly as RNDF increased. Dietary RNDF concentration did not affect carcass characteristics (P ≥ 0.19), except for dressing percentage, which tended to decrease linearly (P = 0.06) as RNDF in finishing diets increased. Increasing RNDF in finishing diets had no effect (P = 0.26) on time spent eating, but time spent ruminating and resting increased linearly (min/d; P < 0.001) with increased dietary RNDF. Steam flaking markedly increased flint corn energy value, net energy of diets, and animal growth performance, and led to improvements on feed efficiency when compared with grinding, regardless of RNDF content of diets. Increasing dietary RNDF compromised feedlot cattle feed efficiency and carcass dressing.

Alkali addition and roughage inclusion effect on performance and carcass characteristics of feedlot steers fed diets containing 60% dried distillers grains with solubles

Three experiments were conducted to determine the effectiveness of calcium hydroxide (Ca(OH)₂) addition and roughage inclusion on digestibility, performance, and carcass characteristics of steers fed 60% dried distillers grains with solubles (DGS). Statistical analyses for studies were conducted using the MIXED procedures of SAS. In experiment 1, 48 steers (353.5 ± 7.55 kg) were allotted to individual pens and fed 1 of 3 diets (dry matter [DM] basis) containing 60% dried DGS, 20% corn silage, and 4% supplement with: 1) 14.5% corn and no Ca(OH)₂; 2) 14% corn and 2% Ca(OH)₂; and 3) 14.5% additional corn silage and no Ca(OH)₂. Steers fed Ca(OH)₂ consumed the least (P = 0.03) and steers fed added corn silage consumed the most and had the least gain:feed (P = 0.02). Gain and carcass quality were not affected by treatment (P ≥ 0.48). In experiment 2, 112 steers (375.3 ± 19.25 kg) were allotted to pens (four pens per treatment; seven steers per pen) arranged as a 2 × 2 factorial (roughage × Ca(OH)₂) and fed one of four diets (DM basis) containing 60% dried DGS, 17% corn silage, and 4% supplement with: 1) 17.5% corn silage and no Ca(OH)₂; 2) 17% corn silage and 2% Ca(OH)₂; 3) 17.25% corn stover and no Ca(OH)₂; and 4) 17% corn stover and 2% Ca(OH)₂. Added stover decreased average daily gain (ADG) compared to added corn silage (P = 0.04). Ca(OH)₂ increased ADG when steers were fed stover, but not when steers were fed only corn silage (P = 0.05; interaction). In experiment 3, six ruminally cannulated steers (initial body weight = 352 ± 14.8 kg) were randomly allotted to a 6 × 6 Latin square design to determine the effects of roughage inclusion (corn, corn silage, stover) and Ca(OH)₂ addition (0% or 2%) on ruminal characteristics. Feeding stover decreased total volatile fatty acid(s) (VFA) concentration and DM digestibility compared to corn silage or corn (P < 0.01), whereas Ca(OH)₂ resulted in greater total VFA concentrations and DM digestibility (P ≤ 0.02). Stover increased rate of DM degradation (K_d) and rate of particle outflow from the rumen (P ≤ 0.04) but decreased extent of DM digestion and mean retention time (P ≤ 0.02) compared to corn or silage. Ca(OH)₂ increased K_d (P < 0.01) and tended to increase (P = 0.06) liquid passage rate. In conclusion, added roughage did not improve performance of cattle fed 60% dried DGS. Ca(OH)₂ may decrease intake and maintain performance of cattle fed 60% dried DGS with corn silage as the roughage source and increases ADG when corn stover replaces a portion of the corn silage.

Effects of roughage inclusion and particle size on digestion and ruminal fermentation characteristics of beef steers

Roughage is fed in finishing diets to promote ruminal health and decrease digestive upset, but the inclusion rate is limited because of the cost per unit of energy and feed management issues. Rumination behavior of cattle may be a means to standardize roughage in beef cattle finishing diets, and increasing the particle size of roughage could modulate the ruminal environment and aid in maintaining ruminal pH. Therefore, this experiment was conducted to determine the effects of corn stalk (CS) inclusion rate and particle size in finishing diets on digestibility, rumination, and ruminal fermentation characteristics of beef steers. Four ruminally cannulated steers were used in a 4 × 4 Latin square experiment. Treatments were arranged as a 2 × 2 factorial with treatments consisting of 5% inclusion of a short-grind roughage (5SG), 10% inclusion of a short-grind roughage (10SG), 5% inclusion of a long-grind roughage (5LG), and 10% inclusion of a long-grind roughage (10LG). Differences in particle size were obtained by grinding corn stalks once (LG) or twice (SG) using a commercial tub grinder equipped with a 7.6-cm screen and quantified using the Penn State Particle Separator (PSPS) to estimate physically effective NDF (peNDF). Each period included 14 d for adaptation and 4 d for diet, fecal, and ruminal fluid collections. Animals were outfitted with rumination monitoring collars to continuously measure rumination activity. The 10LG treatment had a greater ( < 0.01) percentage of large particles (retained on the top 3 sieves of the PSPS) compared to the other treatments. This resulted in a greater ( < 0.01) percentage of estimated peNDF for the 10LG diet compared to the others. Feeding diets containing 5% roughage tended to increase ( ≤ 0.09) DM, NDF, and starch total tract digestibility compared to diets containing 10% roughage. Cattle consuming LG treatments had greater ( < 0.01) rumination time and greater ( < 0.01) ruminal pH than cattle consuming diets containing SG roughage. Cattle receiving the 5% inclusion rate of roughage tended to have greater ( = 0.09) time (h/d) under a ruminal pH of 5.6 and a larger ( = 0.03) area under the threshold compared to cattle receiving the 10% roughage treatments. Overall, feeding a lower inclusion of roughage with a larger particle size may stimulate rumination and aid in ruminal buffering similar to that of a higher inclusion of roughage with a smaller particle size, without negatively impacting digestibility and fermentation.

Digestibility and performance of steers fed varying inclusions of corn silage and modified distillers grains with solubles to partially replace corn in finishing diets

Two finishing and 1 digestibility experiment evaluated the partial substitution of corn with corn silage and corn modified distillers grains with solubles (MDGS). Steers were used in Exp. 1 (n = 295; 467 ± 52 kg) and Exp. 2 (n = 225; BW = 348 ± 27 kg) in a 2 × 2 + 1 factorial arrangement of treatments with factors including corn silage (15 or 45%) and MDGS (20 or 40%) plus a control diet consisting of 5% cornstalks and 40% MDGS. In Exp. 1, there were tendencies for a corn silage × MDGS interaction for ADG, final BW, and G:F (P ≤ 0.08). In the overall F-test for G:F, there were no differences between the control treatment and 15:20, 15:40, or 45:40 (P ≥ 0.15), however, steers fed the control treatment had increased G:F compared to steers fed 45:20 treatment diets (P = 0.03). In Exp. 2, there were no corn silage × MDGS interactions (P ≥ 0.12). As corn silage increased in the diet, ADG, final BW, and G:F decreased (P ≤ 0.01). As MDGS increased from 20 to 40%, ADG and G:F tended to improve (P ≤ 0.07). In the overall F-test, the control was not different for G:F from 15:20, 45:20, or 45:40 (P ≥ 0.15), but had a 4.8% poorer G:F compared to 15:40 (P < 0.01). In Exp. 3, ruminally fistulated steers (n = 6) were used in a 5 × 6 Latin rectangle design and fed 15 or 45% corn silage with 20 or 40% MDGS as a 2 × 2 factorial. An additional diet consisting of 95% corn silage and 5% supplement was fed. There were no corn silage × MDGS interactions for nutrient intake, total tract digestibility, ruminal pH measurements, acetate: propionate ratio (A:P), or in-situ disappearance data (P ≥ 0.31) for the 2 × 2 factorial. As corn silage increased in the diet, DMI, NDF intake, ruminal pH, A:P, in-situ NDF disappearance of corn bran, and DM disappearance of corn increased (P ≤ 0.09) with decreases in DM and OM digestibility (P ≤ 0.03). As MDGS increased in the diet, there was an increase in NDF intake, total volatile fatty acid concentration, and NDF disappearance of corn bran (P ≤ 0.03) with no differences for any other tested variables (P ≥ 0.13). In general, increasing corn silage in place of corn in finishing diets containing MDGS results in a modest reduction in ADG and G:F with increases in ruminal pH.

Growth performance, carcass trait, meat quality and oxidative stability of beef cattle offered alternative silages in a finishing ration

As lack of forage resource, alternative roughage sources have been developed for ruminant production and their inclusion would exert a great effect on the dietary nutrition, consequently affecting animal performance. Four silages (corn silage (CS), corn stalk silage (SS), inoculated CS and inoculated SS) were separately offered to 60 Bohai Black cattle (15 cattle/group) during a 24-week finishing period, in which the growth performance, carcass trait, beef quality and oxidative stability of steers were determined. Neither silage material nor silage inoculant exerted a significant effect on the growth performance, carcass trait and oxidative stability of beef cattle (P>0.05). As to beef quality, cattle offered CS had higher (P0.05) on the proximate components and fatty acids profile of beef muscle. There was neither an interaction (P>0.05) between inoculated treatment and silage material. There were no differences (P>0.05) in cholesterol content and meat quality traits in animals fed alternative silages. The collective findings suggest that it is not economical to substitute high-quality forage for relative low-quality forage in a high-concentrate finishing ration of beef cattle and silage inoculant inclusion would not exert a direct effect on animal performance.

Effects of roughage inclusion and particle size on performance and rumination behavior of finishing beef steers

Roughage is typically mechanically processed to increase digestibility and improve handling and mixing characteristics in beef cattle finishing diets. Roughage is fed to promote ruminal health and decrease digestive upset, but inclusion in finishing diets is limited due to the cost per unit of energy. Rumination behavior may be a means to standardize roughage in beef cattle finishing diets, and increasing particle size of roughage may allow a decrease in roughage inclusion without sacrificing animal performance. Therefore, the objectives of this study were to quantify rumination time for a finishing beef animal and to evaluate the effects of corn stalk (CS) inclusion rate and particle size on rumination behavior, animal performance, and carcass characteristics. Fifty-one individually fed steers (385 ± 3.6 kg initial BW) were used in a randomized complete block design feeding study. Corn stalks were passed through a tub grinder equipped with a 7.62-cm screen once to generate long-grind CS (LG-CS) or twice to generate short-grind CS (SG-CS). Dietary treatments were based on steam-flaked corn and included, on a DM basis, 30% wet corn gluten feed (WCGF) with 5% SG-CS (5SG), 30% WCGF with 5% LG-CS (5LG), and 25% WCGF with 10% SG-CS (10SG). The Penn State Particle Separator was used to separate ingredients and treatment diets and to estimate physically effective NDF (peNDF). On d 70, each steer was fitted with a collar (HR Tag; SCR Dairy, Netanya, Isreal), which continuously measured rumination minutes via a sensory microphone. Long-grind CS contained more ( < 0.01) peNDF than SG-CS, and the 10SG diet contained more ( = 0.03) peNDF than the 5LG and 5SG diets. Dry matter intake was greatest ( = 0.03) for steers consuming 5LG and least for steers consuming 10SG, with cattle consuming 5SG being intermediate. Carcass-adjusted ADG and G:F were greatest ( ≤ 0.03) for steers consuming 5LG and 5SG compared with steers consuming 10SG. Hot carcass weight tended ( = 0.10) to be greatest for steers consuming 5LG and least for steers consuming 10SG, with steers consuming 5SG being intermediate. Dressing percent was greater ( = 0.01) for steers consuming 5LG and 5SG than for steers consuming 10SG. A significant interaction ( < 0.01) occurred for rumination minutes × day. Rumination (min/day) were greatest ( = 0.01) for steers consuming 10SG followed by steers consuming 5LG and was lowest for steers consuming 5SG. Increasing particle size of roughage may be a means to decrease roughage inclusion rate while maintaining rumination and performance.