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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 (P < 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 (P < 0.01) percentage of estimated peNDF for the 10LG diet compared to the others. Feeding diets containing 5% roughage tended to increase (P = 0.09) DM, NDF, and starch total tract digestibility compared to diets containing 10% roughage. Cattle consuming LG treatments had greater (P < 0.01) rumination time and greater (P < 0.01) ruminal pH than cattle consuming diets containing SG roughage. Cattle receiving the 5% inclusion rate of roughage tended to have greater (P = 0.09) time (h/d) under a ruminal pH of 5.6 and a larger (P = 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. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate the effects of feeding condensed distiller's solubles (DS) and crude glycerin alone or in combination on performance of finishing beef cattle and in vitro fermentation. In both experiments, dietary treatments consisted of a steam-flaked corn-based diet with 0% DS or crude glycerin (CON), 10% DS (CDS), 10% crude glycerin (GLY), or a combination of 5% DS and 5% crude glycerin (C+G) included on a DM basis. All treatment diets contained 15% (DM basis) wet distiller's grains plus solubles. In Exp. 1, crossbred steers (n = 256; 322 ± 15 kg initial BW) were used in a randomized complete block finishing trial. Growth performance and gain efficiency were not different (P > 0.10) across all treatments. Treatment had no effect (P > 0.10) on carcass weight, marbling score, yield grade, LM area, or percent grading USDA choice. In Exp. 2, ruminal fluid was collected from 2 ruminally cannulated steers to evaluate in vitro fermentation characteristics. No differences (P = 0.43) were observed for DM disappearance across all treatments. The GLY and C+G treatments had decreased (P = 0.02 and P = 0.05, respectively) NDF disappearance (NDFD), whereas the CDS treatment tended to have decreased (P = 0.06) NDFD compared with CON. Concentrations of NH3 decreased (P < 0.04) with GLY and C+G treatments compared with CON. Total gas production decreased (P < 0.01) for the C+G treatment compared with other treatments. The CDS treatment had increased (P < 0.02) total VFA compared with the CON or C+G treatments. Treatments had no effect (P > 0.17) on concentrations of acetate, propionate, and butyrate, but valerate concentrations were the greatest (P < 0.04) for the CON treatment. Concentrations of isobutyrate increased (P < 0.05) for the CON and C+G treatments compared with the GLY treatment and tended to increase (P < 0.10) compared with the CDS treatment. Including DS or glycerin in the substrates decreased (P < 0.08) isovalerate compared with CON. Feeding additional byproducts such as DS and crude glycerin alone or in combination in a finishing diet did not alter live animal performance or carcass characteristics; however, feeding a combination of the 2 byproducts may alter in vitro fermentation. [ABSTRACT FROM AUTHOR]

Forty-eight individually fed crossbred steers (initial BW = 381 ± 7.61 kg) were used to determine the effects of glycerin (GLY) concentration in steam-flaked corn (SFC)-based diets with added yellow grease on animal performance and carcass characteristics. Glycerin was included at 0, 2.5, 5, and 10% dietary DM replacing SFC. A completely randomized design was used with steers as the experimental unit, and the model included the fixed effects of diet. Contrast statements were used to determine linear and quadratic effects of GLY inclusion. Final BW and DMI were not affected (P > 0.27) by GLY concentration. Average daily gain and G:F based on live BW did not differ as GLY level increased in the diet from 0 to 10% of DM (P > 0.33). Carcass-adjusted final BW and carcass-adjusted G:F were also not affected by GLY concentration (P > 0.22); however, carcass-adjusted ADG tended to respond quadratically by decreasing from 2.5 to 5% GLY inclusion and increasing thereafter (P = 0.10). Calculated dietary NEm and NEg did not differ as GLY increased in the diet (P > 0.37). Hot carcass weight tended to respond quadratically, decreasing from 2.5 to 5% GLY and increasing thereafter (P = 0.10). Likewise, dressing percentage tended to respond quadratically by decreasing from 2.5 to 5% GLY inclusion and increasing to 10% GLY inclusion (P = 0.09). Fat thickness decreased linearly as GLY inclusion increased in the diet (P < 0.01); however, no differences were detected in marbling score and LM area (P > 0.21). Calculated yield grade (YG) decreased linearly as GLY increased in the diet from 0 to 10% of DM (P = 0.04). Based on our results, there was no animal performance benefit for replacing SFC with GLY in diets containing yellow grease, and the only change in carcass merit was a slight improvement in YG. [ABSTRACT FROM AUTHOR]

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Two hundred sixty-four crossbred heifers (initial BW = 354 kg ± 0.5) were used to determine effects of com processing method and wet distillers grains plus solubles (WDGS) inclusion in finishing diets on animal performance, carcass characteristics, and manure characteristics. The study was conducted as a randomized complete block with a 2 × 2 factorial arrangement of treatments. Dietary treatments included steam-flaked com (SFC)- and dry-rolled corn (DRC)-based finishing diets containing 0 or 20% WDGS (0SFC, 20SFC, 0DRC, and 20DRC, respectively). Heifers averaged 154 d on feed and were marketed in 3 groups. There were no interactions between com processing method and WDGS detected (P ≥ 0.29) for any performance or carcass response variables. Heifers fed diets containing WDGS tended to have greater final B W (P = 0.10) and increased G:F (P = 0.08) compared with heifers fed diets without WDGS. Heifers fed SFC-based diets consumed 7% less feed (P <0.01) and were 9% more efficient (P < 0.01) than heifers fed DRC-based diets. Carcass characteristics were not affected by com processing method or WDGS inclusion (P ≤ 0.16). Intakes of OM, N, P, and K were greater (P ≥ 0.05) for heifers fed DRC-based diets than those fed SFC-based diets, which resulted in greater net accumulation of the nutrients in the manure (P < 0.04). Heifers fed diets containing WDGS had greater CP < 0.01) intakes of N, P, and K than heifers fed diets without WDGS. As a result, a greater net accumulation of P and K (P ≥ 0.03) and N (P = 0.10) were present in the manure from cattle fed diets containing WDGS compared with those fed diets without WDGS. There was no interaction (P ≤0.16) between corn processing and WDGS on N volatilization losses. Nitrogen volatilization losses from manure (expressed as a percentage of intake and g-heifer-1 d-1) were greater (P <0.01) for heifers fed SFC-based diets than heifers fed DRC-based diets. Feeding DRC-based finishing diets to heifers resulted in increased manure production and nutrient excretion and decreased N volatilization. Both com processing method and WDGS inclusion affected animal performance and manure characteristics. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to determine the effects of wet distillers grain plus solubles (WDG; <15% sorghum grain) concentration in steam-flaked corn (SFC) diets on feedlot performance, carcass characteristics, ruminal fermentation, and diet digestibility. In Exp. 1, six hundred crossbred steers (364 ± 35 kg of BW) were used in a randomized complete block design with 8 replications/treatment. Dietary treatments consisted of a dry-rolled corn (DRC) control diet without WDG, a SFC control without WDG, and SFC with 4 WDG concentrations (15, 30, 45, 60% DM basis) replacing SFC, cottonseed meal, urea, and yellow grease. Final BW, ADG, G:F, HCW, and 12th-rib fat depth were greater (P ≤ 0.05) for SFC compared with DRC. Dry matter intake tended (P = 0.06) to be greater for DRC compared with SFC. Final BW, ADG, G:F, HCW, 12th-rib fat depth, and marbling score decreased linearly (P < 0.01) with increasing WDG concentration. In Exp. 2, six ruminally and duodenally cannulated crossbred steers (481 ± 18 kg of BW) were used in a 6 × 6 Latin square design using the same diets as Exp. 1. Ruminal, postruminal, and total tract OM and NDF digestibility were not different (P > 0.14) for DRC compared with SFC. Ruminal and total tract starch digestibility were greater (P < 0.01) for SFC compared with DRC. Dry matter and OM intake were not different (P ≥ 0.43) among WDG treatments. Ruminal and total tract OM digestibility decreased linearly (P < 0.01) with increasing WDG concentration. Intake, ruminal digestibility, and total tract digestibility of NDF increased linearly (P < 0.01) with increasing WDG concentration. Starch intake decreased linearly (P < 0.01) with increasing WDG concentration. Ruminal starch digestibility increased (P = 0.01) with increasing concentration of WDG. Total tract starch digestibility decreased quadratically (P < 0.01) with increasing concentration of WDG. Feeding SFC improved steer performance compared with DRC. The concentration of WDG and corn processing method influences nutrient digestibility and ruminal fermentation. The addition of WDG in SFC-based diets appears to negatively affect animal performance by diluting the energy density of the diet. [ABSTRACT FROM AUTHOR]

Two experiments with a randomized complete block design were conducted to determine the effects of phase feeding of CP on performance, blood urea nitrogen (BUN), manure N:P ratio, and carcass characteristics of steers fed in a feedlot. In Exp. 1, 45 crossbred steers (initial BW = 423 ± 3.3 kg) were individually fed a diet formulated to contain 13.0% CP (DM basis) for 62 d. On d 63, the dietary CP was maintained at 13.0% or formulated to contain 11.5 or 10.0% CP until slaughter. Actual CP values were 12.8, 11.8, and 9.9%, respectively. Reducing the CP concentration of the diet did not affect ADG of steers from d 62 to 109 (P = 0.54) or over the 109-d feeding period (1.45, 1.50, and 1.49 kg/d for 13.0, 11.5, and 10.0% CP, respectively; P = 0.85). No differences (P > 0.12) among treatments were detected for BUN concentrations on d 0, 62, or 109. Gain:feed, DMI, and carcass characteristics did not differ among treatments (P > 0.10). In Exp. 2, 2 trials were conducted using 184 (initial BW = 406 ± 2.6 kg) and 162 (initial BW = 342 ± 1.9 kg) crossbred steers. Data from the 2 trials were pooled for statistical analysis, and trial effect was added to the statistical model. Steers were fed a diet formulated to contain 13.0% CP until reaching approximately 477 kg. When the average BW of the pen was 477 kg, diets were maintained at 13.0% CP or reduced to contain 11.5 or 10.0% CP. Actual CP values were 12.4, 11.5, and 9.3% CP for treatments 13.0, 11.5, and 10.0% CP, respectively. Reducing the CP content of the diet did not affect AIJG after the diet changed (P = 0.16) or throughout the finishing period (P = 0.14). Immediately before slaughter, steers fed the 13.0% CP diet had greater (P < 0.001) BUN concentrations than steers fed the 11.5 and 10.0% CP diets. Carcasses from cattle fed the 11.5% CP diet had greater (P = 0.02) fat thickness than the 13.0 and 10.0% CP treatments, whereas carcasses from cattle fed 13.0% CP had greater (P = 0.004) marbling scores than steers fed the 11.5 or 10.0% CP diets. Other carcass characteristics, DMI, and G:F did not differ (P > 0.10) among treatments. The N:P ratio was increased with the 10.0% CP diet (P = 0.02) compared with the 11.5 or 13.5% CP treatments; however, manure composition did not differ (P > 0.10) among treatments. These results indicate that reduced CP concentration during the finishing period does not affect feedlot performance but can improve the N and P relationship in the manure. [ABSTRACT FROM AUTHOR]

Forty eight steers (BW = 296 ± 16.7 kg) were individually fed to evaluate the effects of different growing diets on performance of feedlot cattle. Steers were fed one of four treatments for 56d: 1 - limit fed (LF) high starch, 2 - ad lib (AL) low starch, 3 - AL intermediate starch, and 4 - AL high starch. On d57, steers were placed on treatment 4 for finishing until d140. Orthogonal contrasts were used to compare LF to all other treatments. Linear and quadratic contrasts were applied across increasing starch content of the diets within AL treatments. During d0-56, LF reduced ADG (P < 0.01) compared to AL treatments. Increasing starch concentration increased ADG quadratically in AL treatments (P = 0.04; 1.86, 2.40, 2.32 ± 0.12 kg/d for 2, 3, and 4, respectively). By design, LF resulted in reduced DMI (P < 0.01). Increasing starch content resulted in a quadratic DMI response (P < 0.01; 10.0, 11.6, 10.2 ± 0.28 kg/d). LF tended to increase G:F, and increasing starch resulted in a linear increase in G:F (P = 0.02; 0.17, 0.21, and 0.22 ± 0.01). During d57-140, LF steers had ADG similar to AL treatments (P = 0.9). Increasing starch resulted in a quadratic ADG response in AL treatments (P = 0.06; 1.88, 1.63, 1.70 ± 0.07). DMI was reduced for previously LF steers (P = 0.04) but was not different among AL treatments (P > 0.5; 10.6, 10.5, 10.9 ± 0.4). LF resulted in increased G:F (P = 0.04) and increasing starch resulted in a linear decrease in G:F (P = 0.02; 0.18, 0.15, 0.15 ± 0.004). Across the 140-d trial, LF reduced ADG (P < 0.01), reduced DMI (P < 0.01), and tended to improve G:F (P = 0.07), while minimum separations were observed among AL treatments. LF enhanced feed efficiency at the expense of productivity. These data suggest that growing systems relying on low starch diets do not affect productivity of feedlot cattle when compared to intermediate and high starch based growing systems. [ABSTRACT FROM AUTHOR]

Records from steers enrolled in the New Mexico Ranch to Rail program (n = 813) from 2001 to 2004 were utilized to evaluate feedlot morbidity effects on performance, carcass characteristics and profitability. Steers were classified based on number of medical treatments during the finishing period. Classifications were: zero medical treatment (HEALTHY), one medical treatment (ONE), and two or more medical treatments (TWO(+)). Data were analyzed by analysis of variance and contrasts evaluated differences between HEALTHY and sick (ONE and TWO(+)) steers and between ONE and TWO(+). Initial calf market value, carcass grid value structure, and unit feed cost were standardized to remove market variation. Steers were assigned to marketing groups based on ultrasonagraphic prediction of individual optimum marketing dates. Twenty-two percent (177 hd) of 813 steers received medical treatment. Net income (Table 1) was greatest among HEALTHY steers and declined among steers for ONE and TWO(+) (HEALTHY vs. sick, P < 0.01; ONE vs. TWO(+), P < 0.01). Sick steers (ONE and TWO(+)) exhibited lower ADG, spent more days on feed, and had lower carcass values than HEALTHY steers (HEALTHY vs. sick, P < 0.01). Total cost of gain increased as the number of medical treatments increased (HEALTHY vs. sick, P < 0.01; ONE vs. TWO(+), P < 0.01). Analysis of records from steers in the New Mexico Ranch to Rail program confirms and quantifies the effects of morbidity on feedlot performance, carcass value and profitability. Zero (HEALTHY), one (ONE), or two or more (TWO(+)) medical treatments. Contrasts: H vs S = HEALTHY vs. sick (ONE and TWO(+)); 1 vs 2+ = ONE vs. TWO(+). [ABSTRACT FROM AUTHOR]