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Because dairies across the United States have rapidly adopted breeding to beef breed sires, the use of beef semen has increased dramatically in recent years. The objective of this survey was to gather information about the use of beef semen by dairy producers in the Northeast United States to generate beef × dairy cattle for beef markets. The survey was conducted using the services of the Center for Survey Research at the Pennsylvania State University—Harrisburg campus. Respondents had two options for returning their responses: 1) mail the paper survey to CSR in the postage-paid business-reply envelope included in the mailing, or 2) complete the survey online via an open-access web survey link. A total of 669 surveys were received and a final number of 617 surveys were included in the responses based on completeness and validity of the responses. Because of the broad electronic distribution, a true response rate cannot be calculated. Of these, 463 (75.0%) were completed via returned paper survey, and 154 (25.0%) were completed via web, between November 9, 2021 and February 16, 2022. Of the 617 respondents, 539 were from Pennsylvania. Due to the large variations in returned survey copies by state, results are reported without state separation. Across all respondents, 69.7% reported milking 100 or fewer cows and over 90% of collected responses reported Holsteins as the predominant dairy breed in the Northeast. Only 18.8% of the respondents did not currently, nor plan to, breed with beef semen. Deciding which beef bulls to use on Northeast dairy farms was primarily based on the recommendation of the semen sales representative (54.5%) and the price of the semen purchased (42.3%). In addition, 89.7% of respondents cited using Angus genetics in their beef bull selections. However, there was no difference in reported profitability of crossbreeding between respondents who indicated using other beef breeds vs. those who indicated just using Angus (P ≥ 0.19). In conclusion, using beef sires on dairy females, regardless of the breed of beef sire, adds value to the resulting progeny from dairy farms in the Northeast. [ABSTRACT FROM AUTHOR]

Restricted-feeding may be a useful management tool available to reduce environmental impact in feedlots. Therefore, the objectives of the present study were to determine the effects of the duration of restricted-feeding on nitrogen (N) and phosphorus (P) excretion, growth performance and carcass characteristics of finishing steers. Twenty-five Holstein × Zebu steers (average initial bodyweight (BW) = 319 ± 16.2 kg; age = 19 ± 1 months) were used. Five steers were slaughtered to provide baseline empty BW (EBW) and empty body composition at Day 0. The remaining steers were randomly allotted to four groups of five steers, which were restricted to 85% ad libitum feed intake for either 0 (R0), 28 (R28), 42 (R42) or 84 (R84) days of an 84-day finishing period. All steers were fed a diet of 40% corn silage and 60% concentrate (DM basis) for 84 days. Total excretion of faeces and urine were collected during two periods: Days 25 to 27 (period 1) and Days 73 to 75 (period 2). The DM intake, average daily gain (ADG) and gain-to-feed ratio (G : F) were evaluated in three blocks, Days 0 to 28, Days 28 to 42 and Days 42 to 84. As expected, DM, N and P intakes were greater (P < 0.05) for R0 steers than R28, R42 and R84 steers when steers in R28, R42 and R84 treatments were restricted. When transitioned to ad libitum feeding, R28 and R42 steers had similar (P > 0.05) DM, N and P intakes compared with R0 steers. Faecal N and urinary P excretions did not differ (P ≥ 0.40) among restricted and ad libitum -fed steers in either period evaluated. However, greater (P < 0.05) faecal P excretions were observed in steers fed ad libitum intake in period 2 (R0). Phosphorus retention in period 2, and whole-body N retention were greatest (P < 0.05) in steers fed R28 and least (P < 0.05) in steers fed R84, steers fed R0 and steers fed R42 were intermediate and not different (P > 0.05). Final BW, overall ADG, G : F and carcass characteristics were not affected (P ≥ 0.11) by treatments. Restricted-feeding Holstein × Zebu steers to 85% of ad libitum intake for 84 days in the feedlot reduced DM intake and P excretion, without impairing steer growth performance or carcass characteristics. Nevertheless, it is important to highlight that the small sample size was one limitation of this present experiment. The environmental impact of beef production intensification is a growing concern in developing countries. Environmental impact declines with increased feed efficiency and productivity. Thus, restricted-feeding has the potential to improve the sustainability of beef production. Results indicate that using restricted-feeding (intake restricted to 85% of ad libitum dry matter intake) for the entire finishing phase in Brazilian feedlot systems reduced feed intake and phosphorus excretion, without impairing steer growth performance or carcass characteristics. Therefore, restricted-feeding may be a management tool available to reduce P pollution in Brazil. [ABSTRACT FROM AUTHOR]

Five ruminally fistulated steers were used in a 5 × 5 Latin square design to determine the effects of increasing dietary fat and sulfur from condensed distiller’s solubles (CDS) on the ruminal microbiome. Treatments included a corn-based control (CON) and 4 levels of CDS (0, 10, 19, and 27%) in a coproduct-based (corn gluten feed and soybean hulls) diet. Fat concentrations were 1.79, 4.43, 6.80, and 8.91% for diets containing 0, 10, 19, and 27% CDS, respectively. Steers were fed for ad libitum intake once daily. After feeding each diet for 18 d, ruminal samples were collected 3 h after feeding on d 19. Samples were separated into solid and liquid fractions. Microbial DNA was extracted for bacterial analysis using paired-end sequencing of the V3 through V4 region of the 16S rRNA gene on the MiSeq Illumina platform and quantitative PCR of selected species. Orthogonal contrasts were used to determine linear and quadratic effects of CDS inclusion. Increasing CDS inclusion decreased (linear, P < 0.05) α-diversity and species richness in the liquid fraction. Analysis of Bray–Curtis similarity indicated a treatment effect (P = 0.01) in the liquid fraction. At the phyla level, relative abundance of Bacteroidetes decreased in steers fed increasing dietary inclusion of CDS as Firmicutes increased to 82% of sequences for the 27% CDS treatment. Family Ruminococcaceae increased (linear, P < 0.01) 2-fold in the liquid fraction when feeding CDS increased from 0 to 27% CDS, yet genera Ruminococcus tended (P = 0.09) to decrease in steers fed greater CDS. The most abundant family of sulfate-reducing bacteria, Desulfovibrionaceae, increased (P < 0.03) in the solid and liquid fraction in steers fed additional dietary CDS and sulfur. Relative abundance of family Veillonellaceae and Selenomonas ruminantium were increased (linear, P ≤ 0.02) in the solid fraction as steers were fed increasing CDS. There were no effects (P > 0.10) of feeding increasing dietary fat from CDS on fibroylytic genus Fibrobacter in either fraction. Results demonstrate increasing fat and sulfur from CDS in a coproduct-based diet markedly alters the liquid fraction ruminal microbiome but does not elicit negative effects on relative abundance of identified fiber-fermenting bacteria. [ABSTRACT FROM AUTHOR]

The objectives of this research were to test interactions of supplement type, liquid versus dry, and forage type, hay versus corn stover, on digestibility and ruminal metabolism of beef cattle. Ruminally fistulated steers were fed in a replicated 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments: 1) hay with liquid supplement, 2) hay with dry supplement, 3) corn stover with liquid supplement, and 4) corn stover with dry supplement. The liquid supplement was molasses and glycerin based (23.3% CP and 1.63 Mcal/kg NEm) whereas the dry supplement was ground corn based (16.8% CP and 1.81 Mcal/kg NEm). Each period, steers were adapted to diets for 14 d and samples were collected for 8 d. In situ disappearance was determined by a 24-h incubation of Dacron bags, containing soybean hulls, in the rumen. There were no interactions (P ≥ 0.25) of supplement and forage type on DMI, apparent total tract digestibility, or ruminal pH. There was a tendency (P = 0.08) for a forage × supplement type interaction for in situ NDF disappearance (ISNDFD). There were no differences in ISNDFD in steers fed hay, but liquid supplement increased ISNDFD in steers fed corn stover. There were no main effects (P ≥ 0.12) of supplement type on DMI, apparent total tract or in situ digestibility, or ruminal pH. There was a supplement × hour interaction (P = 0.04) for acetate concentrations. Although no effect occurred at 0 h after feeding, at 3 and 6 h after feeding, acetate concentrations were reduced in steers fed liquid supplements when compared with those fed dry supplements. In addition, there was a supplement × hour (P = 0.02) interaction for butyrate concentrations, where at all time points, butyrate concentrations increased (P ≤ 0.01) in steers fed liquid supplements when compared with those fed dry supplements. Steers fed hay had increased DMI (P < 0.01) and apparent total tract NDF digestibility (P = 0.07) when compared with steers fed corn stover, regardless of supplement type. At 0, 1.5, and 18 h after feeding, ruminal pH was greater (P ≤ 0.01) in cattle consuming corn stover when compared with those fed hay, regardless of supplement type. However, steers fed hay had increased (P < 0.01) concentrations of acetate and total VFA compared with steers fed corn stover, regardless of supplement. Feeding liquid supplement increased ISNDFD when steers were fed corn stover; however, these changes were not associated with differences in total tract digestibility. Regardless of forage type fed, the liquid supplement increased ruminal butyrate concentrations. [ABSTRACT FROM AUTHOR]

Objectives of this experiment were to: 1) determine appropriate test length, timing, and repeatability of DMI, ADG, and efficiency over different biological time points; 2) determine the efficacy of using decoupled performance and intake data to generate accurate feed efficiency measures; and 3) determine the relationship between forage-and grain-feed efficiency measures. Over 2 yr, Charolais crossbred heifers (n = 308) and steers (n = 320) were fed for two 70 d periods and DMI, ADG, and 12th rib fat thickness were recorded. Steers were fed grain-based diets during the growing and finishing periods to determine the effects of test period and timing on DMI and feed efficiency. Heifers were fed forage during the growing period and grain during the finishing period to test the effect of diet type on measures of DMI and feed efficiency. For each 70 d test period, individual DMI was recorded using the GrowSafe (Airdrie, AB) system. Residual feed intake (RFI) was calculated for each test period. Total feeding period ADG (FP_ADG) was calculated for steers by regressing all weights taken from feedlot arrival to final BW, which was calculated by dividing HCW by a standard dressing percentage (63%). Dry matter intake and RFI were correlated (r = 0.56; P < 0.01, and 0.63; P < 0.01, respectively) for the growing and finishing periods of grain-fed steers. Average daily gain was not repeatable (r = 0.11; P = 0.06) across both test periods for steers. However, growing and finishing ADG were correlated (r = 0.58; P < 0.01, and r = 0.69; P < 0.01, respectively) to FP_ADG. To assess the potential of shortening the intake test, DMI was analyzed in 7 d increments for grain-fed steers during the growing and finishing periods. Regardless of test length, from 7 to 70 d, DMI was strongly correlated (r ≥ 0.87; P < 0.01) to total DMI during the growing period. Heifer forage DMI was correlated (r = 0.58; P < 0.01) to grain DMI; subsequently, forage and grain RFI were moderately correlated (r = 0.40; P < 0.01). This study suggests that DMI is repeatable across varying stages of maturity in cattle, and accurate feed efficiency measures can be obtained in either the growing or finishing period. The relationship of forage and grain DMI and efficiency in heifers suggests that measures of DMI and feed efficiency in heifers are relevant, regardless of diet fed. Intake evaluation periods can be shortened with minimal effects on the accuracy of predicting individual animal DMI. [ABSTRACT FROM AUTHOR]

Objectives were to determine the effects of feeding ractopamine hydrochloride (RAC) with zinc (Zn) and chromium (Cr) on feedlot growth performance, carcass characteristics, and meat quality. Steers (n = 179; initial BW = 533 ± 94 kg) were blocked by BW and allotted to 30 pens, and pens were randomly assigned 1 of 5 treatments: (1) control (CONT), (2) RAC only (RO), (3) RAC + Zn (RZ), (4) RAC + Cr (RC), or (5) RAC + Zn + Cr (RZC). Trace minerals were fed from d 0 to 63 to target 1 g of Zn/steer·d-1 (KemTRACE Zn; Kemin Industries, Inc., Des Moines, IA) and 3 mg Cr/steer·d-1 (KemTRACE Chromium; Kemin Industries, Inc.) for Zn and Cr treatments, respectively. Dry-rolled corn, 0.605 kg/steer, was removed from the diet and 400 mg RAC, per 0.605 kg of ground corn carrier, was top dressed per steer immediately following feed delivery to pens fed RAC. There were no effects (P ≥ 0.45) of trace mineral supplementation on DMI, ADG, or G:F before RAC feeding. There were also no treatment effects (P ≥ 0.46) over all 63 d of the trial on DMI, ADG, or G:F. Despite the lack of differences in live performance, steers fed RO and RC averaged 0.10 kg/d greater (P = 0.10) carcass ADG than steers fed RZC and CONT, while steers fed RZ were intermediate and not different. Steers fed RO had the greatest (P = 0.09) carcass G:F, while steers fed CONT had the least carcass G:F, 0.0875 and 0.0774, respectively. Steers fed RO and RC averaged 5.5 kg heavier (P = 0.09) HCW than steers fed RZC and CONT, while steers fed RZ were intermediate and not different. There were no treatment effects (P ≥ 0.32) on LM area, 12th rib fat, marbling score, KPH, carcass yield, or USDA yield grade and distribution. However, carcasses from steers fed RC had the greatest (P = 0.10) percentage grading USDA Select. There were no treatment effects (P ≥ 0.20) on shear force, intramuscular fat, pH, a*, and b*. Steaks from steers fed RO and RC had 11.4% greater (P = 0.08) cook loss than steaks from steers fed CONT and RZC, whereas steaks from steers fed RZ were intermediate and not different. Also, steaks from steers fed RC had 2.11 units greater (P = 0.03) L* values (i.e., were lighter) than steaks from steers fed RZ; steaks from steers fed CONT, RO, and RZC were intermediate. In feedlot steers, the addition of both Cr and Zn supplementation did not improve growth performance or meat quality when fed in combination with 28 d of RAC supplementation; however, RAC, fed alone or in combination with Cr, did increase HCW. [ABSTRACT FROM AUTHOR]

The objectives were to determine the optimum inclusion of NaOH necessary to buffer the acidity of dried distillers' grains with solubles (DDGS) and its effects on digestibility, ruminal metabolism, and metabolic acidosis in feedlot steers. Rumen cannulated Angus-crossed steers were blocked by BW (small: 555 ± 42 kg initial BW, n = 4; large: 703 ± 85 kg initial BW, n = 4) over four 21-d periods in a replicated 4 × 4 Latin square design. Steers were assigned to 1 of 4 dietary treatments: 1) 50% untreated DDGS, 2) 50% DDGS treated with 0.5% (DM basis) sodium hydroxide (NaOH), 3) 50% DDGS treated with 1.0% (DM basis) NaOH, and 4) 50% DDGS treated with 1.5% (DM basis) NaOH. The remainder of the diets, on a DM basis, was composed of 20% corn silage, 20% dry-rolled corn, and 10% supplement. Ruminal pH was not affected by treatments (P = 0.56) or by a treatment × time interaction (P = 0.15). In situ NDF and ruminal DM disappearance did not differ (P ≥ 0.49 and P ≥ 0.47, respectively) among treatments. Similar to in situ results, apparent total tract DM and NDF digestibility were not affected (P ≥ 0.33 and P ≥ 0.21, respectively) by increasing NaOH inclusion in the diets. Urinary pH increased (linear, P < 0.01) with increasing NaOH concentration in the diet. Blood pH was not affected (P ≥ 0.20), and blood total CO2 and partial pressure of CO2 were similar (P ≥ 0.56 and P ≥ 0.17, respectively) as NaOH increased in the diet. Increasing NaOH in the diet did not affect (P ≥ 0.21) ruminal concentrations of total VFA. There were no linear (P = 0.20) or quadratic (P = 0.20) effects of treatment on ruminal acetate concentrations, nor was there a treatment × time interaction (P = 0.22) for acetate. Furthermore, there were no effects (P ≥ 0.90) of NaOH inclusion on ruminal propionate concentration. However, there was a quadratic response (P = 0.01) of ruminal butyrate concentrations as NaOH inclusion increased in the diet; ruminal butyrate concentrations were greatest with the 0.5 and 1.0% NaOH treatments of DDGS. In the current study, feeding DDGS treated with NaOH did not increase fiber digestibility nor was it necessary to alleviate a possible metabolic acidosis. Alkali treatment of DDGS did not increase average ruminal pH or blood pH. [ABSTRACT FROM AUTHOR]

Objectives were to determine the effects of chromium propionate supplementation on growth performance, insulin and glucose metabolism, and carcass characteristics of beef cattle. Steers (n = 34) were stratified by BW and assigned to 1 of 2 treatments: 1) no supplemental Cr (Cont) or 2) 3 mg supplemental Cr.steer-1.d-1 (CrP). Both supplements, Cont and CrP, were delivered via 0.454 kg ground corn top-dressed on the basal diet. There was no effect (P ≥ 0.45) of CrP on ADG, DMI, G:F, or final BW. However, steers fed CrP needed more (P = 0.10) days on feed (DOF) to achieve the same carcass back fat (BF) as steers fed Cont. There were no effects (P ≥ 0.41) of CrP on HCW, BF, or KPH. Steers fed CrP had increased (P = 0.01) dressing percentage (DP) and tended to have a 4.21 cm2 greater LM area (P = 0.15), decreased marbling scores (P = 0.11), and decreased intramuscular fat (P = 0.11) compared to steers fed Cont. There were no differences (P ≥ 0.25) in quality or yield grade distributions. A glucose tolerance test was conducted early (21 DOF) and late (98 DOF) in the finishing phase. There was a feedlot treatment (FT) × time × DOF interaction (P = 0.08) for glucose concentrations, but no other interactions (P ≥ 0.21) for glucose or insulin concentrations. There were no FT × DOF interactions (P ≥ 0.21) for insulin area under the curve (iAUC), insulin:glucose ratio, insulin or glucose baseline, or peak insulin or glucose concentrations. At 21 DOF, steers fed CrP had decreased glucose area under the curve (gAUC; P = 0.01), decreased glucose clearance rate (k; P = 0.02), and increased glucose half-life (T1/2; P = 0.07) compared to steers fed Cont; however, by 98 DOF, no differences were observed between treatments. At 98 DOF, all steers, regardless of treatment, had increased (P < 0.01) peak glucose and insulin, k, iAUC, insulin:glucose ratio, and baseline insulin when compared to values at 21 DOF, but gAUC and T1/2 decreased (P < 0.01). Although steers fed CrP tended (P = 0.11) to have increased baseline glucose concentrations compared to steers fed Cont, CrP supplementation did not affect (P ≥ 0.17) other measures of glucose or insulin. Results of this study indicate that CrP increased DP and tended to increase LM area but tended to decrease intramuscular fat, with no effect on growth performance. With increased DOF, all steers became more insulin resistant, using more insulin to clear less glucose, and these effects were not mitigated by CrP supplementation. [ABSTRACT FROM AUTHOR]

Objectives were to determine the interaction of prepartum dam supplement level and age at weaning on growth performance, glucose and insulin concentrations, and carcass characteristics of steers (134 steers in yr 1; 147 steers in yr 2). Mature, multiparous Angus x Simmental cows were used in a split-plot design that included 3 supplement levels (no supplement [NS], 2.16 kg⋅cow-1⋅d-1 [LS], and 8.61 kg⋅cow-1⋅d-1 [HS]) and 2 ages at weaning (78 ± 11 d of age [early weaned; EW] or 186 ± 11 d of age [normal weaned; NW]). Cows grazed endophyteinfected tall fescue/red clover pastures and were bunk fed supplement (70% dried distiller's grains plus solubles and 30% soybean hulls) 103 ± 11 d prepartum to 2 ± 11 d postpartum. Dam prepartum supplement level did not affect (P ≥ 0.29) finishing phase growth performance or morbidity. The percentage of steers grading Average Choice or greater was increased (P = 0.04) for steers from cows fed HS compared to the percentage of steers from cows fed NS. Early weaning increased (P < 0.01) finishing phase initial BW and final BW and reduced (P < 0.01) G:F compared to normal weaning. A year x wean interaction (P = 0.04) occurred for ADG; EW resulted in reduced (P < 0.01) ADG compared to NW in yr 2. At slaughter, EW steers had greater (P < 0.01) HCW, yield grade, and back fat than NW steers. A year x wean interaction (P ≤ 0.05) occurred for quality grade distribution; in yr 2, EW steers had a greater (P < 0.01) proportion of carcasses that graded Low Choice or greater and Average Choice or greater than carcasses from NW steers. The EW steers had greater (P ≤ 0.05) occurrence of single antibiotic treatments in yr 2 and mortality due to respiratory disease than NW steers. A trend for a year x wean interaction (P ≤ 0.07) occurred for plasma insulin concentration and insulin:glucose; EW steers had numerically greater plasma insulin concentrations and insulin:glucose than NW steers in yr 1. In conclusion, these data suggest that there is no interaction between maternal level of supplement during late gestation and age at weaning on steer finishing phase performance, glucose and insulin concentrations, and carcass yield and quality characteristics. Overfeeding supplement to the dam did not affect finishing phase growth performance but did improve quality grades of steers. Early weaning increased HCW and improved carcass quality. Both dam supplement level and age at weaning are effective strategies in increasing beef quality and are independent of each other. [ABSTRACT FROM AUTHOR]

Objectives were to determine the interaction of prepartum supplement level and age at weaning on cow BW, BCS, milk production, reproduction, and calf performance up to weaning in a fall-calving system over 2 yr. Mature, multiparous, Angus x Simmental cows (yr 1: 326 cows, 9 pastures, BW = 632 ± 67 kg, and BCS = 5.7 ± 0.58; yr 2: 383 cows, 9 pastures, BW = 606 ± 70 kg, and BCS = 5.8 ± 0.74) were used in a split-plot design that included 3 supplement levels--no supplement (NS), low supplement (LS; 2.16 kg⋅cow-1⋅d-1), or high supplement (HS; 8.61 kg⋅cow-1⋅d-1)--and 2 ages at weaning--78 ± 11 d of age (early weaned; EW) or 186 ± 11 d of age (normal weaned; NW). Cows grazed endophyte-infected tall fescue/red clover pastures and were bunk fed supplement (70% dried distillers' grains with solubles and 30% soybean hulls) 103 ± 11 d prepartum to 2 ± 11 d postpartum. Cow BW was greater (P < 0.01) for cows fed HS at precalving (49 ± 11 d prepartum), postcalving (26 ± 11 d postpartum), and postbreeding (81 d after AI) compared with cows fed NS and LS. Prepartum supplementation did not affect (P ≥ 0.62) calf birth BW, percent of calves dead at birth, or percent of cows calving unassisted. Prepartum supplementation tended (P = 0.10) to improve AI conception. Early weaning increased (P ≤ 0.05) AI conception and postbreeding cow BW and BCS compared with cows with NW calves. Neither prepartum supplementation nor age at weaning affected (P ≥ 0.28) overall pregnancy rate. At time of early weaning, BW was increased (P = 0.05) for steers from cows fed LS compared with steers from cows fed NS. Steer BW at time of normal weaning and ADG between early and normal weaning was greater (P < 0.01) for EW steers compared with NW steers. A year x age at weaning interaction occurred (P < 0.01) for ultrasound marbling score at time of normal weaning. In yr 1, marbling was decreased (P = 0.04) for EW steers compared with NW steers; however, in yr 2, marbling was increased (P < 0.01) for EW steers compared with NW steers. In conclusion, there was no interaction between level of supplement during late gestation and age at weaning on cow BW, BCS, milk production, AI conception, and overall pregnancy rate in mature beef cows nor in their steer progeny's BW or ultrasound marbling. Both prepartum supplementation and early weaning improved cow BW, BCS, and reproduction. Minimal effects of dam prepartum supplement level on calf performance up to weaning were observed. Early weaning improved calf growth but had inconsistent effects on ultrasound marbling across years. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the effect of fat concentration from corn distillers' solubles (CDS), fed during the growing phase, on DMI, gain, carcass traits, digestibility, ruminal metabolism, and methane emissions of steers. In Exp. 1, 40 steers (age = 136 ± 20 d; BW = 185 ± 11 kg) were randomly allotted to 1 of 5 dietary treatments: 1) a cornbased growing diet (CNT), 2) 0% CDS, 3) 10% CDS, 4) 19% CDS, or 5) 27% CDS. Diets 2 through 5 included coproducts (corn gluten feed and soybean hulls) and were formulated to achieve fat concentrations of 3, 5, 7, and 9%, respectively. Diets were fed once daily for 106 d (growing phase). All steers were fed a corn-based diet from d 107 to 196. Contrasts were used to examine 1) the difference between CNT and 10% CDS and 2) linear and quadratic effects of CDS inclusion. During the growing phase, steers fed CNT had increased (P < 0.01) ADG and G:F compared with steers fed 10% CDS. Increasing CDS inclusion increased (linear, P = 0.02) ADG and G:F. Overall, steers fed CNT had increased (P < 0.01) ADG compared with steers fed 10% CDS, but increasing CDS inclusion had no effect (P = 0.19) on overall ADG. Overall DMI and G:F were not different (P = 0.16) in any contrast. There was a trend (Linear; P = 0.08) for ultrasound marbling at d 196 to increase as CDS inclusion increased; however, there were no effects (P = 0.20) of treatment on carcass marbling or quality grade. In Exp. 2, 5 steers (BW = 335 ± 56 kg) were fed Exp. 1 diets for ad libitum intakes in a 5 × 5 Latin square design. Apparent DM digestibility increased (linear, P = 0.02) with increasing dietary CDS inclusion. Steers fed CNT had greater (P = 0.01) DM digestibility than those fed 10% CDS. Fat digestibility increased (linear, P < 0.01) in steers with increasing CDS, but NDF and ADF digestibility were not affected (P = 0.17) by treatment. Similarly, ruminal pH and VFA concentrations were not affected (P = 0.13). Also, there was no difference (P = 0.37) in ruminal methane emissions (g/h). In conclusion, feeding corn during the growing phase increased overall ADG compared with 10% CDS coproduct-based diet but did not affect carcass traits or methane production. Increasing dietary fat inclusion from CDS in coproductbased diets linearly increased DM and fat digestibility and predicted marbling scores via ultrasound but did not affect marbling at slaughter, NDF digestibility, propionate, or methane production. [ABSTRACT FROM AUTHOR]

Objectives were to evaluate the effects of replacing corn in feedlot finishing diets with processed corn stover (CS), processed by various combinations of chemical and physical methods, and modified wet distillers grain with solubles (MWDGS) on growth performance, carcass characteristics, digestibility, and ruminal metabolism of cattle. Corn stover was physically processed (ground or extruded) and chemically processed with alkaline agents (CaO and NaOH) to reduce the crystallinity of the lignocellulosic structure. In Exp. 1 steers (n = 18, initial BW = 385 ± 32 kg) and heifers (n = 41, initial BW = 381 ± 27 kg) were allotted to 1 of 5 dietary treatments: 1) 55% dry, cracked corn, 35% MWDGS, 5% vitamin-mineral supplement, and 5% untreated ground CS (CON), 2) CS treated with 5% CaO (DM basis) and stored in an Ag-Bag (BGCS), 3) CS treated with 5% CaO (DM basis) and extruded (5 EXCS), 4) CS treated with 4% CaO and 1% NaOH (DM basis) and extruded (4,1 EXCS), or 5) CS treated with 3% CaO and 2% NaOH (DM basis) and extruded (3,2 EXCS). Extruded CS was hydrated to 34% moisture, then an additional 16% water was added, as a solution carrying CaO or NaOH or both, via a calibrated pump during processing through a dual-shafted encased extruder (Readco Kurimoto Continuous Processor, York, PA) with the desired exiting temperature of 76.7°C ± 2.8°C. All treated CS diets contained 20% CS and 40% MWDGS (DM basis) to replace 20% corn when compared to CON. There were no effects (P = 0.20) of dietary treatment on ADG, G:F, 12th-rib back fat, marbling score, LM area, or yield grade. However, cattle fed CON had increased (P = 0.02) DMI compared to cattle fed the treated CS diets. In Exp. 2, using the same diets as fed in Exp. 1, ruminally cannulated steers (n = 5; initial BW = 417 ± 21 kg) were fed for 90% of ad libitum intake in a 5 × 5 Latin square design. Apparent digestibility of NDF and ADF increased (P < 0.01) when cattle were fed treated CS diets compared with CON, regardless of the treatment applied. Ruminal pH was reduced (P = 0.02) in cattle fed BGCS from 0 to 6 h postfeeding compared with cattle fed all other diets. Cattle fed the treated CS diets had the greatest (P < 0.01) mean acetate concentrations, which increased (P = 0.01) total VFA concentrations. Replacing a portion of the corn with treated CS in feedlot diets containing MWDGS increased fiber digestibility without affecting feedlot cattle gain, efficiency, marbling score, or LM area. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the effects of feeding dried com distillers grains (DDGS) or modified wet com distillers grains (MDGS) with or without CaO treatment to feedlot steers on 1) growth performance and carcass characteristics and 2) diet digestibility, pattern of intake, and meal distribution. In Exp. 1, steers (n = 139; average initial BW = 336 ± 75 kg) were used in a randomized complete block design. Treatments were arranged in a 2 x 2 factorial design, and pens were randomly allotted to 1 of the 4 dietary treatments (DM basis): 1) 50% DDGS untreated, 2) 48.8% DDGS treated with 1.2% CaO, 3) 50% MDGS untreated, or 4) 48.8% MDGS treated with 1.2% CaO. The remainder of the diet was com husklage, dry rolled corn, and vitamin and mineral supplement. In Exp. 2, fistulated steers (n = 8; average initial BW = 540 ± 250 kg) were used in a replicated 4 x 4 Latin square design with the same dietary treatments as in Exp. 1. There was no interaction (P ≥0.14) between distillers grains plus solubles (DGS) and CaO inclusion for DMI, ADG, final BW, or USDA yield and quality grades. However, steers fed CaO-treated DGS had decreased (P <0.01) DMI, regardless of DGS type. Because CaO treatment decreased DMI without affecting (P = 0.66) ADG, steers fed CaO-treated DGS had increased (P < 0.01) G:F compared to steers not fed CaO. The variation in DMI found in this experiment could be explained by differences in meal size and distribution. Steers fed CaO-treated DGS ate a similar (P = 0.36) number of meals but ate smaller (P< 0.01) meals. No effects (P &#8805>; 0.55) of CaO treatment or its interaction with DGS type were found for apparent total tract DM or NDF digestibility. However, steers fed MDGS had increased (P< 0.01) NDF digestibility compared to steers fed DDGS. In conclusion, CaO treatment of DGS improved feed efficiency when DGS-based diets were fed but did not improve digestibility. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to detennine the effect of increasing dietary CaO on ruminai fermentation, diet digestibility, performance, and carcass characteristics of feedlot steers fed 60% dried distillers grains with solubles (DDGS). In Exp. 1, 120 steers were allotted by weight (355 ± 7.9 kg) to 1 of 4 treatments containing 60% DDGS, 20% com silage, 13.5 to 14.4% ground com, 4% supplement, and 0 to 2.5% limestone on DM basis to detennine the effects of CaO on performance and carcass characteristics. Treatments consisted of 0,0.8,1.6, or 2.4% CaO inclusion in the diet (DM basis), with CaO replacing limestone. Steers were slaughtered at a target BW of approximately 641 kg. In Exp. 2, 4 steers (initial BW = 288 ± 3 kg) were randomly allotted to the same diets in a 4 x 4 Latin square design (14-d periods) to detennine the effects of CaO on ruminai pH, VFA, and nutrient digestibility. Statistical analyses were conducted using the MIXED procedure of SAS. Inclusion of CaO at 0.8, 1.6, and 2.4% increased ADG by 5.0,3.9, and 0%, respectively, compared to 0% CaO (quadratic; P = 0.03). Intake was linearly decreased (P = 0.04) and G:F was linearly increased (P = 0.02) by CaO inclusion. Dressing percentage increased as CaO increased from 0 to 1.6% and then decreased for 2.4% CaO (quadratic; P < 0.01). In Exp. 2, steers fed 0% CaO had the greatest prefeeding ruminai pH, steers fed 0 and 0.8% CaO exhibited the most rapid postfeeding decline in ruminai pH, and steers fed 2.4% CaO exhibited a relatively stable ruminai pH throughout the 24-h period (treatment x time; P < 0.01). Acetate, butyrate, and total VFA concentrations increased linearly (P < 0.05) at 0, 3, 6, and 12 h postfeeding with increasing CaO. Propionate at 3 h postfeeding increased from 0 to 1.6% CaO and decreased from 1.6 to 2.4% CaO (quadratic; P = 0.10). Urine pH increased linearly (P < 0.01) while urine output and urine ammonia decreased linearly (P < 0.05) as CaO inclusion increased. Apparent NDF digestibility tended to increase (P = 0.07) and ADF digestibility did (P = 0.01) increase linearly with increasing concentrations of CaO. In conclusion, CaO improved ruminai pH variation, increased fiber digestibility, and decreased metabolic acid load in cattle fed 60% DDGSbased diets. Inclusion of CaO up to 1.6% was effective in improving performance of feedlot cattle. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the interaction of feeding dry (DDGS) or modified wet (MDGS) distillers grains with solubles (DGS) with or without supplemental CaO on in situ DM and NDF disappearance; ruminai pH, VFA, and methane concentration; and cellulase and xylanase activity. Fistulated steers (n = 8; average initial BW = 540 ± 250 kg) were used in a replicated 4 x 4 Latin square design. Treatments were arranged in a 2 x 2 factorial, and steers were randomly allotted to 1 of 4 dietary treatments: 1) 50% DDGS with 0% CaO, 2) 48.8% DDGS supplemented with 1.2% CaO, 3) 50% MDGS with 0% CaO, or 4) 48.8% MDGS supplemented with 1.2% CaO (DM basis). The remainder of the diet was husklage, dry-rolled corn, and vitamin and mineral supplement. There were no interactions (P≥0.12) of DGS type and CaO addition on any parameters measured. Steers fed DDGS had a 17% increase (P < 0.01 ) in DMI compared to steers fed MDGS; however, CaO supplementation reduced (P = 0.03) DMI by 12%, regardless of DGS type. As expected, addition of CaO increased the pH of the diet by 1.82 pH units. This caused a time by CaO interaction (P = 0.05) for ruminai pH. Regardless of DGS type, steers supplemented with CaO tended to have increased (P = 0.09) ruminai pH at 1.5 h and had increased (P = 0.03) ruminai pH at 3 h postfeeding; however, ruminai pH did not differ (P ≥ 0.24) for the remainder of the day. There was no difference (P = 0.46) in ruminai cellulase activity when comparing type of DGS fed. However, there was a time by CaO interaction (P < 0.01); cattle fed 1.2% CaO diets had 28% greater ruminai cellulase activity only at 0 h postfeeding when compared to cattle fed 0% CaO. Furthermore, feeding supplemental CaO increased (P = 0.04) acetate to propionate ratio (A:P) regardless of type of DGS fed. Increased initial ruminai pH and cellulase activity from supplemental CaO did not increase (P = 0.48) in situ NDF disappearance. No differences (P ≥ 0.48) in ruminai methane concentration were found when comparing DGS type or supplemental CaO. In conclusion, the type of DGS fed had little effect on ruminai metabolism. Even though CaO increased ruminai pH and cellulase activity at some times postfeeding, it was not enough to affect in situ fiber disappearance. [ABSTRACT FROM AUTHOR]

Objectives of this study were to determine the effects of feeding ractopamine hydrochloride (Optaflexx) with or without supplemental Zn propionate (KemTRACE Zn) and Cr propionate (KemTRACE Cr) to finishing steers on growth performance, carcass characteristics, and meat quality. Angus cross steers (n = 142; BW = 527 ± 14 kg) were blocked by BW into 4 blocks (6 pens/block, 5 to 6 steers/pen). Steers targeted at an average 12th rib back fat thickness of 1.3 cm via ultrasound, by block, were randomly assigned to 1 of 3 dietary supplements for the final 35 d of feeding before slaughter: 1 ) no supplementation, where analyzed Zn and Cr were 49.82 and 0.98 mg/kg (DM basis), respectively (CONT), 2) 300 mg ractopamine hydrochloride steer"1 -d"1, where analyzed Zn and Cr were 49.38 and 0.96 mg/kg (DM basis), respectively (RAC), or 3) 300 mg ractopamine hydrochloride, 1.0 g of Zn supplied as Zn propionate (KemTRACE Zn), and 3 mg of Cr supplied as Cr propionate (KemTRACE Cr) steer"'-d"1, where analyzed Zn and Cr were 159.73 and 1.25 mg/kg (DM basis), respectively (RAC+TM). All steers were fed the same basal diet of 20% com silage, 20% dried distillers grains, 50% com, and 10% mineral-vitamin supplement (DM basis). Data were analyzed as a randomized complete block design with a fixed effect of treatment and a random effect of block. Average daily gain and G:F were increased {P <0.01) by 16% in steers fed RAC when compared with steers fed CONT. However, ADG and G:F were not different (P > 0.61) between steers fed RAC and RAC+TM. Furthermore, HCW was increased (P = 0.04) by 1.87% (6.61 kg) in steers fed RAC when compared with steers fed CONT, whereas HCW was not different (P = 0.80) between steers fed RAC and RAC+TM. Back fat thickness and marbling were not different (P > 0.14) between steers fed RAC and CONT or (P > 0.34) between steers fed RAC and RAC+TM. Warner-Bratzler shear force tended to be greater (less tender; P = 0.06) in steers fed RAC when compared with steers fed CONT yet was not different (P = 0.34) between steers fed RAC and RAC+TM. However, meat quality, as measured by pH, objective color, and moisture composition, did not differ (P > 0.55) between steers fed RAC and CONT. Although steers fed RAC had improved ADG, feed efficiency, and HCW in this study, feedlot growth performance and carcass characteristics were not further improved by additional supplemental Zn and Cr. [ABSTRACT FROM AUTHOR]

The objective of these experiments was to determine adaptation by ruminants to dietary sulfur. In Exp. 1, lambs (n = 54; BW = 33.6 ± 0.4 kg) were allotted to 3 treatments: 1) 0% added dietary S (0%S), 2) 0.2% added dietary S (0.2%S), or 3) 0.4% added dietary S (0.4%S). Sulfur was added to the diet as Na2S04. Lambs fed the 0.2%S and 0.4%S diets had greater (P <0.01) ADG and G:F compared to those fed the 0%S diet. There was time x diet interaction (P <0.01) on luminal hydrogen sulfide gas (H2S) concentrations. Ruminai H2S was not detected in lambs fed 0%S at any time. Ruminai H2S were not affected (P > 0.19) by diet on d 1 or 8; however, H2S were greater (P <0.01) for lambs fed 0.2%S and 0.4%S than for lambs fed 0%S on d 15,22, and 29 (0.2% was 931, 846, and 1,131 mg/L and 0.4% was 975, 737, and 1,495 mg/L on d 15, 22, and 29, respectively). These data suggest it takes at least 29 d for peak ruminai H2S to occur after exposure to Na2S04. In Exp. 2, lambs (n = 66; BW = 51.1 ± 0.4 kg) were allotted to 3 treatments: 1) 60% dried distillers grains with solubles (DDGS), 2) corn-based diet with Na2S04, or 3) corn-based diet with H,S04. All diets were fonnulated to contain 0.4%S. Lambsfed Na2S04 had greater (P < 0.05) ADG, DMI, and G:F than those fed H2S04 or 60% DDGS. A time x diet interaction occurred (.P < 0.01) for ruminai H2S. There was no difference (P = 0.82) in H9S of lambs on d 1. However, at d 14 and 27 lambs fed supplemental Na2S04 had the lowest ILS concentrations while lambs fed"60% DDGS had the greatest (P < 0.01 on both d); lambs fed H2S04 were intermediate and different than both. These data suggest that at the same dietary S concentration, acidic S sources increased H2S and decreased DMI and ADG. In Exp. 3, Angus cross calves (w = 72; average initial BW = 324 ± 3 kg) were allotted to 3 treatments: 1) corn-based control d 0 through 85 (0%DDGS), 2) gradual step up to 60% DDGS diet (20% DDGS d 0 to 6, 40% DDGS d 7 to 13, 50% DDGS d 14 to 20, and 60% DDGS d 21 to 85; Step-up), or 3) 60% DDGS d 0 to 85 (60%DDGS). Overall, cattle fed 0%DDGS had increased (P < 0.05) DMI and ADG compared with those fed 60%DDGS or Step-up, and G:F was not affected (P = 0.42) by dietary treatment. On d 14, ruminai H0S concentrations were greater (P <0.01) for cattle fed 60%DDGS and Step-up than for those fed 0%DDGS, and they did not differ (P ≥ 0.22) between DDGS-containing diets. These data illustrate that source of S impacts ruminai S metabolism and that S from DDGS is more readily reduced than S from Na2S04 or H2S04. [ABSTRACT FROM AUTHOR]

Negative interactions of the acidity and S content of dried distillers grains with solubles (DDGS) have not been quantified. The objectives of this study were to determine the effects of dietary S, dietary acidity, and their interactions on growth, feed efficiency, ruminal H2S concentration, and apparent nutrient digestibility in lambs fed DDGS-based diets. To neutralize acidity, the DDGS was untreated or treat-ed with 2% NaOH. Dietary S content was adjusted with Na2S04 to achieve a 0.2 percentage unit differ-ence in dietary S. Experiment 1 included 72 ewe and wether lambs (BW = 24.9 ± 0.4 kg) penned by sex in 24 pens, blocked by BW, and allotted in a 2 x 2 factorial arrangement of treatments for a 60 d feeding trial. On a DM basis, diets were: i) 60% DDGS + 0% Na2S04, ii) 60% DDGS + 0.88% Na2S04, iii) 62% NaOH-treat-ed DDGS + 0% Na2S04, and iv) 62% NaOH-treated DDGS + 0.83% Na2S04. There were no interactions (P > 0.19) of dietary S concentration and NaOH treat-ment. Lambs fed DDGS treated with 2% NaOH had 4% greater (P = 0.05) final BW and tended (P < 0.07) to have greater DMI and ADG than lambs fed untreated DDGS; however, NaOH treatment did not affect (P = 0.42) G:F. Increasing dietary S with Na2S04 tended (P = 0.07) to reduce DMI; however, dietary S did not affect (P >0.17) ADG, G:F, or final BW. Rumen H2S concentration in gas samples collected on d 32 and 60 were not (P > 0.17) affected by dietary S or NaOH treatment. Experiment 2 included 24 lambs (initial BW = 43.0 ± 4.4 kg) used to determine the effects of NaOH treatment of DDGS and sulfur (Na9S04) supplemen-tation on N retention and the apparent digestibility of NDF, ADF, and OM. Treatments were similar to those used in Exp. 1, except that dietary DDGS was reduced to 45% of DM. Intake of DM, NDF, ADF, and N was not affected (P > 0.16) by NaOH treatment of DDGS or dietary S (Na2S04) content. Treating DDGS with 2% NaOH reduced (P = 0.05) NDF digestibility by 10% compared with lambs fed untreated DDGS. Urine pH for lambs consuming DDGS treated with 2% NaOH was increased (P = 0.01) 1.74 pH units compared with urine from lambs fed untreated DDGS. Nitrogen intake and retention were not affected (P > 0.35) by dietary S concentration or NaOH treatment of DDGS. For feedlot lambs, treating DDGS with 2% NaOH did not lower ruminal H2S concentrations, but tended to increase ADG and DMI. Although treating DDGS with 2% NaOH was an effective way to neutralize the acidity in DDGS, this treatment reduced NDF digestibility. [ABSTRACT FROM AUTHOR]

Dried distillers grains with solubles (DDGS) can decrease rumen pH because of their inherent acidity. Two replicated 4x4 Latin square experiments were conducted with ruminally fistulated heifers to determine the effects of dietary inclusion and NaOH treatment of DDGS on rumen metabolism. In Exp. 1, dietary treatments were 0%, 20%, 40%, or 60% DDGS on a DM basis. The remainder of the diet was 15% corn silage, 20% vitamin-mineral supplement, and com (to replace DDGS) on a DM basis. Dry mat-ter intake decreased (linear; P < 0.01) with increasing dietary inclusion of DDGS. Rumen pH was less than 5.3 from 1.5 to 12 h after feeding regardless of dietary DDGS inclusion, and mean rumen pH tended to decrease (linear; P = 0.08) with increasing DDGS. Rumen fluid S2- and rumen H2S gas concentrations increased (P < 0.01) with increasing DDGS inclusion at all time points postfeeding. At 3 h after feeding, ruminal concentrations of acetate, propionate, and total VFA increased linearly (P < 0.04) with increasing dietary inclusion of DDGS. Acetate to propionate ratio (A:P) ranged from 0.97 to 1.25 and was not affected (P = 0.88) by diet over time. In Exp. 2, dietary treatments were 1) 25% DDGS inclu-sion, untreated, 2) 60% DDGS inclusion, untreated, 3) 25% DDGS inclusion, treated with 2% NaOH, and 4) 60% DDGS inclusion, treated with 2% NaOH. Dry matter intake decreased (P < 0.01) when 60% DDGS was included in the diet regardless of NaOH treatment. Mean rumen pH was greater (P < 0.01) when NaOH-treated DDGS was fed regardless of dietary inclusion level. There were interactions (P< 0.06) of NaOH treat-ment by DDGS inclusion by time for mean H,S and S2~ concentrations. These interactions occurred because the magnitude of the response to NaOH treatment was greater for the 60% DDGS diets than for the 25% DDGS diets only from 1.5 to 9 h postfeeding. There were no interactions (P > 0.05) of NaOH treatment by DDGS inclusion on VFA concentrations. Acetate concentration decreased (P = 0.04) in cattle fed 60% DDGS diets at 0 h, but at 3 h postfeeding it tended to increase (P = 0.06). Total lactate was less than 1.30 for all dietary treatments at all time points. Treating DDGS with 2% NaOH may increase rumen pH and decrease H2S, thereby alleviat-ing polioencephalomalacia. [ABSTRACT FROM AUTHOR]

Mature Angus-cross beef cows (n = 228) were used to evaluate effects of prepartum dietary energy source on postnatal growth and carcass composition of progeny in a 2-yr study. Starting at approximately 160 d of gestation, cows were fed diets consisting of 1 of 3 primary energy sources: grass hay (HY), corn (CN), or dried corn distillers grains with solubles (DG). The CN and DG diets were limit-fed to achieve similar energy intakes as cows fed HY. Following parturition, cows were fed a common diet and managed as a single group. Calves were weaned at an average of 185 ± 6 d of age and backgrounded for 28 d. A subset of progeny (n = 134) was individually fed a common finishing diet until slaughter, when each calf reached 1.2 ± 0.05 cm of backfat. A glucose tolerance test (GTT) was conducted in year 2 on 4 calves/treatment after 41 and 111 d on the finishing diet (DOF). Calf birth weights were greater (P = 0.002) in calves from cows fed CN and DG than calves from cows fed HY, and weaning BW (P = 0.08) was less for calves from cows fed HY vs. CN. Receiving BW, final BW, and HCW did not differ (P ≥0.16) among treatments. No difference (P ≥ 0.28) in ADG, morbidity, and mortality from birth to slaughter was observed among treatments. In response to a GTT, increased DOF resulted in greater (P ≤ 0.005) fasting insulin, faster glucose disappearance rate, and greater insulin:glucose area under the curve ratio. Glucose disappearance rate was greater (P = 0.01) in calves from cows fed CN than in calves from cows fed HY or DG. A greater initial insulin response (P = 0.005) was observed in calves from cows fed CN or DG than in calves from cows fed HY. Carcass traits used to measure yield grade did not differ (P ≥ 0.19) among treatments. Calves from dams fed CN had the lowest marbling score (P = 0.03) and intramuscular fat content (P = 0.07). These results indicate that prepartum maternal dietary energy source can alter fetal adipose tissue development and insulin sensitivity resulting in long-term effects on progeny's intramuscular fat deposition. Moreover, present findings suggest that increasing the number of days on a com-based finishing diet increases insulin resistance in beef cattle. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate the effects of monensin and dried distillers grains with solubles (DDGS) on ruminal metabolism in 8 fistulated steers. In Exp. 1, treatments were (DM basis): 1) 0 mg monensin/kg diet DM, 2) 22 mg monensin/ kg diet DM, 3) 33 mg monensin/kg diet DM, and 4) 44 mg monensin/kg diet DM. The remainder of the diet was 10% com silage, 60% DDGS, 10% com, and 20% mineral supplement that used ground com as the carrier. There was no effect (P > 0.80) of dietary monensin inclusion on DMI. Increasing dietary monensin did not affect (P > 0.05) ruminal VFA concentrations or lactic acid concentrations. There was no effect (P > 0.15) of increasing dietary monensin concentration on ruminal hydrogen sulfide gas (H2S) and liquid sulfide (S2~) concentrations, or ruminal pH. In Exp. 2, treatments were arranged in a 2 x 2 factorial and contained (DM basis): 1) 0 mg monensin/kg diet DM + 25% DDGS inclusion, 2) 0 mg monensin/kg diet DM + 60% DDGS inclusion, 3) 44 mg monensin/kg diet DM + 25% DDGS inclusion, and 4) 44 mg monensin/kg diet DM + 60% DDGS inclusion. The remainder of the diet was 15% com silage, com, and 20% mineral suplement that used ground com as a carrier. With 60% dietary DDGS inclusion, DMI decreased (P < 0.01) when compared with 25% DDGS inclusion. With 25% DDGS in the diet, 0 h postfeeding acetate concentration was decreased compared with when 60% DDGS was fed (P < 0.01). A similar response (P < 0.01) occurred for total VFA concentrations at 0 h postfeeding. However, at 3 and 6 h postfeeding, propionate concentrations increased (P < 0.05) in cattle fed the 60% DDGS diets, regardless of monensin inclusion. This increase in propionate concentrations contributed to the increase (P = 0.03) in total VTA concentrations at 3 h postfeeding when 60% DDGS diets were fed. There was no interaction detected (P > 0.05) for H2S or S2- concentrations in Exp. 2. Feeding 60% DDGS diets increased mean H0S by 71% when compared with feeding 25% DDGS diets. Similar to the response observed for H,S, feeding 60% DDGS diets increased mean S2- by 64% when compared with feeding 25% DDGS diets. Although these studies did not show beneficial effects of monensin supplementation on ruminal pH, VFA, or H,S concentrations, adverse rumen conditions, notably low ruminal pH, when high DDGS diets were fed may have precluded the effects of monensin from being realized. [ABSTRACT FROM AUTHOR]

The effects of 3 supplemental Cu concentrations on feedlot performance, mineral absorption, carcass characteristics, and ruminai S metabolism of cattle fed diets containing 60% dried distillers grains with solubles (DDGS) were evaluated in 2 experiments. Experiment 1 was conducted with 84 Angus-cross yearling steers and heifers (initial BW = 238 ± 36 kg), which were blocked by gender and allocated to 12 pens. Supplemental dietary Cu (tribasic copper chloride) treatments were: 1) 0 mg Cu/kg diet DM, 2) 100 mg Cu/kg diet DM, 3) 200 mg Cu/kg diet DM. The remainder of the diet was DDGS (60%), grass hay (10%), pelleted soy hulls (15%>), and a vitamin-mineral supplement (15%). Diets were offered ad libitum throughout the finishing phase (168 d). Three cattle from each pen (n = 36) were harvested on d 168 and carcass data and liver samples were collected. Copper supplementation did not affect ADG (P = 0.22). However, the nonsignificant trend for increased ADG and decreased DMI led to a linear increase (P = 0.02) feed efficiency (G:F = 0.167, 0.177, and 0.177 for 0, 100, and 200 mg Cu/kg diet DM, respectively). The apparent absorption of Cu decreased quadratically (P=0.07) and the apparent absorption of Mn and Zn were decreased linearly (P = 0.03 and P = 0.05, respectively) with increased Cu supplementation. Cattle supplemented with 100 or 200 mg Cu/kg diet DM had greater liver Cu concentrations (P < 0.01) than cattle that were not supplemented with Cu. There were no treatment effects (P > 0.10) on HCW, LM area, USD A yield grade, backfat, or marbling score. Experiment 2 was conducted with 6 ruminally fistulated steers that were fed the same diets as in Exp 1 in a replicated 3x3 Latin Square design. Copper supplementation did not affect (P > 0.10) ruminai pH or liquid S2- concentrations in steers consuming 60% DDGS diets (total dietary S = 0.55%). From 3 to 9 h after feeding, H2S gas concentration was decreased in those cattle supplemented with 100 mg Cu/kg diet. Concentration of H2S gas did not differ among cattle supplemented with 0 or 200 mg Cu/kg diet DM on 60% DDGS diets. Supplemental Cu improved feed efficiency in cattle consuming diets containing 60% DDGS; however, effects of Cu on rumen S metabolism were minimal even when supplemented at twice the maximum tolerable limit for beef cattle (NRC, 2000). [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine the effects of 0, 20, 40, or 60% dietary dried distillers grains with solubles (DDGS) on 1) growing lamb performance, carcass characteristics, and tissue minerals, and 2) nutrient digestibility and retention in growing lambs. In Exp. 1, ninety-six lambs were blocked by sex (ewes, n = 48; wethers, n = 48) and BW, housed in 24 pens (4 lambs per pen), and used in a 92-d feedlot trial (initial BW = 26.4 ± 9.3 kg). Lambs were fed 1 of 4 dietary treatments 1) 0% DDGS, 2) 20% DDGS, 3) 40% DDGS, or 4) 60% DDGS. The DDGS replaced primarily corn, and diets were fed as a complete pellet. There was a quadratic effect of DDGS inclusion on ADG; lambs fed the 20% DDGS diet had the greatest (P = 0.04) gains at 0.358 kg/d. This effect on ADG led to a quadratic (P = 0.03) effect of DDGS on final BW. Increasing dietary DDGS did not affect (P > 0.13) DMI and resulted in a linear (P = 0.02) decrease in G:F. In the liver, S increased linearly (P = 0.05), whereas Cu decreased linearly (P < 0.01) with increasing dietary DDGS; other liver minerals were not affected (P > 0.05). Carcass backfat, yield grade, and marbling score were not affected (P > 0.05) by dietary DDGS. In Exp. 2, twenty-four lambs (initial BW = 43.0 ± 4.4 kg) were used in a metabolism study. Lambs were adapted to the same diets described above for 17 d before a 5-d sampling period during which total feces and urine were collected. Apparent digestibility of dietary DM decreased linearly (P < 0.01) with increasing dietary inclusion of DDGS. Digestibility of fat followed a similar pattern, whereas N, S, and P absorption increased linearly (P < 0.03) with increasing dietary DDGS. The digestibility of NDF was not affected (P > 0.05) by dietary treatment. Apparent retentions (as a percentage of intake) of N, K, Mg, Cu, Fe, and Zn were not affected (P > 0.05) by dietary DDGS inclusion, whereas the retention of S and P decreased (P < 0.04). Daily urine output increased linearly (P < 0.01) and urine pH decreased linearly (P < 0.01) with increasing DDGS (urine pH was 7.46, 5.86, 5.52, and 5.32 for treatments 1 to 4, respectively). These data suggest urine is a major route for excretion of acid when high-S diets containing DDGS are fed. Increases in dietary DDGS resulted in decreased digestion of DM and fat, which may be partially responsible for decreased lamb feedlot performance for 40 and 60% dietary DDGS when compared with 20% DDGS. [ABSTRACT FROM AUTHOR]

The objectives of this research were to determine the interaction of monensin and haylage supplementation for steers fed 60% dried distillers grains (DDGS) on 1) mineral status, performance, and carcass characteristics, and on 2) ruminal pH, H2S, and short-chain fatty acid concentrations. In Exp. 1, Angus-cross steers (n = 168; BW = 277 ± 67 kg) were blocked by BW and allotted in a 2 × 2 factorial arrangement of treatments to 24 pens. Dietary treatments were 1) 0 mg of monensin/kg of diet + 0% haylage, 2) 33 mg of monensin/kg of diet + 0% haylage, 3) 0 mg of monensin/kg of diet + 10% haylage, and 4) 33 mg of monensin/kg of diet + 10% haylage. The remainder of the diet was 60% DDGS, 10% corn silage, 15% supplement, and corn (either 5 or 15%) on a DM basis. When supplemented with 0 mg of monensin/kg of diet, added haylage increased ADG by 5.7%, whereas when supplemented with 33 mg of monensin/kg of diet, added haylage increased ADG by 13% (P < 0.01). No interactions of monensin and haylage were observed for DMI or G:F (P = 0.36). Haylage inclusion increased (P < 0.01) DMI and decreased (P < 0.01) G:F. No interactions (P > 0.05) on plasma mineral concentrations were observed; however, over time, plasma Cu concentrations decreased (P < 0.01), whereas plasma ceruloplasmin and S concentrations increased (P < 0.01). There were no treatment effects (P = 0.08) on carcass characteristics. Cattle fed the 60% DDGS diets benefitted from increased dietary forage, and the effects of monensin and forage were additive for ADG and final BW. In Exp. 2, ruminally fistulated steers (n = 8; BW = 346 ± 34 kg) were used in a replicated 4 × 4 Latin square design and were randomly assigned to the diets used in Exp. 1. Haylage inclusion increased ruminal pH from 1.5 through 12 h postfeeding, and the effects of monensin supplementation were additive (P < 0.05). From 1.5 through 9 h postfeeding, steers fed 33 mg of monensin/kg of diet tended to have reduced (P = 0.10) concentrations of H2S when compared with steers fed 0 mg of monensin/kg of diet. Acetate:propionate ratios at 6 h postfeeding were 0.94, 0.93, 1.29, and 1.35 for diets 1 to 4, respectively (P < 0.01); total lactate was decreased regardless of treatment (range: 0.94 to 1.42 μmol/mL). Sulfuric acid in DDGS, not ruminal short-chain fatty acids, may be responsible for the low rumen pH observed and may influence the maximum inclusion of DDGS in cattle diets. Monensin supplementation decreased H2S concentration and may decrease the risk of polioencephalomalacia for cattle fed high-DDGS diets. [ABSTRACT FROM AUTHOR]

Energy density in growing diets may affect carcass quality of cattle; however, few reports have described the impact of energy source. The objectives of this research were to determine effects of source [dried distillers grains with solubles (DDGS) vs. corn] and amount (limit-fed to gain 0.9 vs. 1.4 kg of BW/d) of energy during the growing phase on feedlot performance and marbling. Angus-cross steers (144 head) were blocked by BW (average initial BW = 252 ± 36 kg), allotted within each block to 8 pens (6 steers/pen, 24 pens total), and randomly assigned to 1 of 4 feeding systems in a 2 × 2 factorial arrangement of treatments: 1) 65% DDGS fed to gain 0.9 kg of BW/d, 2) 65% DDGS fed to gain 1.4 kg of BW/d, 3) 65% corn fed to gain 0.9 kg of BW/d, and 4) 65% corn fed to gain 1.4 kg of BW/d. Fecal grab samples were collected on d 52 of the growing phase to determine digestibility of DM, ADF, NDF, ether extract (EE), and CP. After the 98-d growing phase, all steers were fed the same finishing diet. Steers were slaughtered by pen when average BW within the pen was 544, 522, and 499 kg for the large, medium, and small BW blocks, respectively. Average daily gain and DMI differed (P < 0.01) by design during the growing phase. Compared with the corn-based diets, digestibilities of DM, NDF, and EE were decreased (P < 0.02) when DDGS-based diets were fed during the growing phase, whereas the digestibility of N was increased (P < 0.01). The ADG was greatest (P = 0.02) during the finishing phase for steers fed to gain 0.9 kg of BW/d initially, but source of energy during the growing phase did not affect (P = 0.24) finishing phase ADG. Steers fed to gain 0.9 kg of BW/d during the growing phase also had less backfat (P = 0.08), decreased USDA yield grades (P = 0.03), and greater LM area (P < 0.01) than steers fed to gain 1.4 kg of BW/d. There was an interaction between energy source and amount for marbling scores (P = 0.02). Steers fed corn-based diets to gain 0.9 kg of BW/d during the growing phase had the most marbling, whereas those fed to gain 0.9 kg of BW/d on DDGS had the least marbling; the remaining feeding systems were intermediate. Overall ADG and DMI were affected (P < 0.06) by both source and amount of energy fed during the growing phase. Feeding the DDGS-based diet to achieve greater ADG during the growing phase increased marbling, whereas feeding the corn-based diet to increase ADG during the growing phase decreased marbling. [ABSTRACT FROM AUTHOR]

Mature pregnant crossbred ewes (n = 90) were used in a randomized complete block design experiment and were assigned to 1 of 3 winter-feeding systems differing in primary feed source: haylage (HL), limit-fed corn (CN), or limit-fed dried distillers grains (DDGS). Effects of these winter-feeding strategies on postweaning progeny performance were determined. Lamb progeny (n = 96) were weaned at 61 ± 4 d of age and fed a common high-concentrate diet. Lambs were assigned to feedlot pen (n = 18) based on dam mid-gestation pen. Growth rate, DM1, and ADG were determined for the first 40 d of the finishing period. At 96 ± 4 d of age, 1 weather lamb was randomly selected from each pen (n = 18) for a glucose tolerance test. The experiment was terminated, and lambs were slaughtered individually when they were determined to have achieved 0.6-cm 12th-rib fat thickness. After a 24-h chill, carcass data were collected and a 2.54cm chop was removed from each lamb from the LM posterior to the 12th rib for ether extract analysis. Additional carcass measurements of bone, muscle, and fat from the shoulder, rack, loin, and leg were collected on 35 carcasses. At weaning, lamb BW was not different among treatments, whereas final BW tended to be greater (P = 0.09) for lambs from ewes fed DDGS and CN during gestation than from those fed HL. Overall lamb growth rate from birth to slaughter was not different among treatments. Lambs from ewes fed DDGS vs. CN or HL tended to have a greater initial insulin response (P = 0.09). Dressing percent was less (P 0.04) in lambs from ewes fed DDGS, but no difference (P = 0.16) was detected in HCW among treatments. As expected, 12th rib fat thickness was similar among treatments, whereas LM area was largest to smallest (P = 0.05) in lambs from ewes fed CN, HL, and DDGS, respectively. Proportion of internal fat tended to be greatest to smallest (P = 0.06) in lambs from ewes fed DDGS, CN, and HL, respectively. Calculated boneless trimmed retail cuts percentage was less (P = 0.04) in lambs from ewes fed DDGS than CN or ilL. Loin muscle weight as a percentage of wholesale cut tended (P = 0.10) to be greater in lambs from ewes fed CN and HL than, DDGS, whereas other muscle, bone, and fat weights and proportions were similar (P> 0.24) among treatments. Prepartum diet during mid to late gestation of ewes altered postnatal fat and muscle deposition and may be associated with alterations in insulin sensitivity of progeny. [ABSTRACT FROM AUTHOR]

Objectives were to compare DM, NDF, and starch in situ disappearance in Angus and Holstein steers using 3 corn grains: a floury corn (FC), steam flaked corn (SFC), and a standard yellow dent number 2 corn (YDC). Holstein (n=4) and Angus (n=4) steers (average BW = 400 ± 30 kg; age = 14 ± 1 mo), fitted with rumen cannula, were used. Whole grains (FC and YDC) were ground using a Wiley mill with no screen, to mimic cattle mastication of the grain. Corn grain (15 ± 0.2 g) was weighed into dacron bags with 4 replicate bags per treatment in each time point (3, 6, 12, 24, 48, and 72 h incubation). Bags were tied shut with nylon string, grouped by hour within steer, and placed in larger mesh sacs. Weights were inserted in the mesh sacs, and mesh sacs were placed in the rumen of steers to achieve 72, 48, 24, 12, 6, and 3 h of incubation. All bags were removed at the same time (0700) and immediately place in cold (~4°C) water. Samples were dried in a 55⁰ C oven for 3 d. Bags were composited by steer and hour, ground using a Wiley mill (1 mm), and analyzed for DM, NDF, and starch. Data were analyzed using the MIXED procedures in SAS (SAS Inst. Inc., Cary, NC) with repeated measures. A single degree of freedom contrast was used to compare FC to YDC. There were no effect (P ≥ 0.16) of breed, no interactions of breed and treatment (P ≥ 0.15), nor were there 3-way interactions with breed, treatment, and hour (P ≥ 0.28). However, there was an interaction of treatment and hour for DM (P < 0.01) and starch (P < 0.01) disappearance. The in situ rate of DM disappearance was increased in SFC when compared to FC and YDC, and DM disappearance of FC and YDC were not different (P = 0.13) from one another. The in situ rate of starch disappearance was increased in SFC when compared to FC and YDC; and, rate of starch digestion was increased (P < 0.01) by 20% for the first 24 h after ruminal incubation in FC when compared to YDC. In conclusion, SFC had greater in situ ruminal disappearance of DM and starch than YDC or FC. However, the rate of in situ ruminal starch disappearance increased 20% in FC when compared to YDC corn. [ABSTRACT FROM AUTHOR]

Objectives were to test the interaction of supplement type, liquid versus dry, and forage type, hay versus corn stover, on diet digestibility and ruminal metabolism of cattle. Rumen fistu-lated steers were used in a replicated 4x4 Latin square with a 2x2 factorial arrangement of treatments: 1) hay with a liquid supplement (HL), 2) hay with a dry supplement (HD), 3) stover with a liquid supplement (SL), and 4) stover with a dry supplement (SD). Steers were fed once daily for ad-libitum intake. Each period began with 14 d dietary adaptation, followed by 7 d of collections (5 d of fecal and 2 d of ruminal collections). In situ disappearance was determined by placing dacron bags, containing soybean hulls, in the rumen for 24 h There were no interactions (P ≥ 0.25) of supplement and forage type on DMI, apparent total tract digestibility, or ruminal pH. Nor were there effects (P ≥ 0.12) of supplement type on DMI, apparent total tract or in situ digestibility, or ruminal pH. However, steers fed hay had increased (P < 0.01) DMI and increased (trend; P = 0.07) apparent total tract NDF digestibility when compared to steers fed stover, regardless of supplement type. Although apparent total tract NDF digestibility was driven by forage type, there was a tendency (P = 0.09) for a forage by supplement type interaction for in situ NDF disappearance (IS-NDFD). There were no differences in ISNDFD in steers fed hay; but, liquid supplementation increased ISNDFD in steers fed stover. At 0, 1.5, and 18 h postfeeding, ruminal pH was greater (P < 0.01) in cattle consuming stover when compared to those fed hay, regardless of supplement type. There was a supplement by hour interaction (P = 0.04) on acetate concentrations (Ac). At 0 h postfeeding, there was no effect; however, at 3 and 6 h postfeeding Ac were reduced in steers fed liquid when compared to those fed dry supplements. In addition there was a supplement by hour (P = 0.02) interaction for butyrate concentration (Bu); where, at all time points, Bu increased (P ≤ 0.01) in steers fed liquid when compared to those fed dry supplements. Steers fed hay, regardless of supplement, had increased (P ≤ 0.01) concentrations of Ac and total VFA compared to steers fed stover. In the present trial, there tended to be an increase in ISNDFD when steers were fed SL, but this did not affect total tract digestibility. [ABSTRACT FROM AUTHOR]

The objectives were to determine the efficacy of sheep as a digestibility model for cattle using two diets, forage or concentrate-based, with modern genetics and management. Diets, with ingredients of grass hay, corn grain, soybean meal, and urea, were formulated to contain either 80% forage or 80% concentrate on DM basis to compare digestibility between wethers and steers. Twelve Suffolk wethers were blocked into 2 blocks with 6 wethers in each block. Wethers within a block were divided into 2 groups (A and B) with 3 wethers in each group. Wethers in group A were fed 80% forage diet while group B wethers were on 80% concentrate diet. Six Angus steers were also blocked in 2 groups (A and B) with 3 steers in each group. In period 1, steers from group A were fed 80% forage diet while group B steers were on 80% concentrate diet. Steers were fed in a switchback design. Wethers and steers were fed for ad libitum intake. After 3 weeks of adaptation on diets, feed intake, refusals, and feces were collected and measured. Feed and fecal DM, OM, NDF, and ADF were analyzed. Refusals were analyzed for DM. Data were analyzed using Proc Mixed in SAS with diet, species, and block as fixed effects and then with Proc Corr in SAS. There was an interaction (P<0.01) between species and diet for DM and OM digestibility. When fed the concentrate-based diet, DM and OM digestibility did not differ in wethers and steers; however, when fed forage-based diet wethers digested less (P<0.05) than steers. Although lambs and steers had similar (P>0.05) OM and DM digestibility when fed concentrate-based diet, OM and DM were not correlated (OM r=0.45, P>0.45; DM r=0.32, P>0.36). There were no interactions (P≥0.83) for fiber digestibility; NDF and ADF digestibility were greater (P<0.05) in steers than wethers. Due to differences between NDF digestibility in steers and wethers, NDF digestibilities between species were not correlated when fed either concentrate (r=0.76, P=0.13) or forage-based diets (r=0.10, P=0.85). Similarly, ADF digestibilities between species were not correlated when fed concentrate (r=0.40, P=0.50) or forage-based diets (r=-0.02, P=0.97). Present-day sheep and cattle fed concentrate-based diets appear to have more digestibility parameters in common than when they are fed forage-based diets. For that reason, sheep used a model for cattle digestibility when forage-based diets are fed should be considered with caution. [ABSTRACT FROM AUTHOR]

Objectives of the study were to evaluate impacts of breed (Holstein vs. Angus) and diet (forage vs. grain) on digestibility of DM, NDF, ADF, and starch; and on ruminal pH over time. Holstein (n=6) and Angus (n=6) steers (initial BW = 450 ± 30 kg; age = 14 ± 1 mo) fitted with rumen cannulae were blocked by diet, 80% forage diet or 80% concentrate diet, and breed, and fed in a switchback design with 2 periods. Each 35 d period had 28 d of diet adaption and 9 d of sample collection. Cattle were fed twice a day to target intake at 2% of BW. On d1 of collection, rumen contents were sampled to measure ruminal pH at 0, 3, 6, 12, and 18 h after feeding. During d 4 to 7 of the collection period, total feces excretion (96 h), feed, and refusals samples were collected, frozen, composited by steer, and analyzed for DM, ADF and NDF, and starch. Data were analyzed using the MIXED procedures in SAS (v9.4 SAS Inst. Inc., Cary, NC). Repeated measures were used to analyze changes in ruminal pH over time. There was a treatment by period interaction (P < 0.01) for ruminal pH. Ruminal pH was reduced in period 2 regardless of treatment, but the magnitude of this response was greatest in steers fed grain-based diets. There was a treatment by period interaction (P ≤ 0.05) for DMI and DM, NDF, ADF, and starch digestibility. Cattle that were fed grain-based diets in period 1 had greater (P ≤ 0.01) DM, NDF, and ADF digestibility in period 2, when they transferred to forage-based diets, than cattle that were a fed forage-based diets prior to being fed grain-based diets. Cattle fed grain-based diets in period 2, following forage-based diets, had decreased starch digestibility when compared to cattle fed grain-based diets first. There was no interaction (P ≥ 0.17) of period, treatment, and breed for fiber digestibility. However, a period by treatment by breed trend (P = 0.12) for starch digestibility was observed in steers fed grain-based diets. Feedings Angus steers forage-based diets in period 1 decreased starch digestibility by 10% when compared to feeding Angus steers grain-based diet in period 1, but treatment order did not affect Holstein starch digestibility. Order of treatments in a switchback design affected digestibility results, and these effects were greater in Angus steers than they were in Holstein steers. [ABSTRACT FROM AUTHOR]

Objectives were to evaluate test period length and repeatability of intake and efficiency measures during the growing and finishing phases, and determine the relationship between intake and efficiency evaluated in cattle fed different diet types. Over a 2-yr period, DMI, ADG, and 12th rib fat thickness were evaluated in crossbred cattle (n = 628) fed for two 70 d periods. During the growing period (first 70 d), a forage-based diet (equal parts corn silage and alfalfa haylage) was fed to heifers and a grain-based diet (50% corn, 15% DGS) was fed to steers. All cattle were fed the grain-based diet for the finishing period (last 70d). Individual DMI was recorded using the GrowSafe (Airdrie, AB, CAN) system. Residual feed intake (RFI) was calculated for each period and was assumed to represent a multiple regression equation, regressing DMI on mid-test metabolic BW, ADG and 12th rib fat thickness. Overall wean to slaughter ADG was calculated for steers by regressing all weights from the start of the growing phase to final BW, calculated as HCW divided by standard dressing percentage (63%). Dry matter intake and RFI were correlated (r = 0.56; P < 0.01, and r = 0.63; P < 0.01, respectively) for growing and finishing periods of steers fed grain. Although, steer ADG was not repeatable (r = 0.11; P = 0.06) across test periods. Growing and finishing ADG were both correlated (r = 0.58; P < 0.01, and r = 0.69; P < 0.01, respectively) to overall ADG. To test the potential of shortening the intake period, DMI for grain-fed steers were evaluated for 7, 14, 21, 28, 35, 42, 49, 56, or 63d. All intake evaluation periods were correlated (r > 0.72; P < 0.01) to total DMI during the growing phase and overall DMI. Intake of forage and forage RFI during the growing phase were correlated (r = 0.58; P < 0.01, and r = 0.42; P < 0.01, respectively) to intake of grain and grain RFI during the finishing period in heifers. Forage ADG was negatively correlated (r = -0.30; P < 0.01) grain ADG. In conclusion, intake and efficiency were repeatable from growing to finishing periods. Although gain was not repeatable for growing and finishing periods, each test period was correlated to gain over the entire feedlot phase. Correlations between shorter duration intake evaluation periods and overall DMI suggest that the intake evaluation period can be shortened to 35 d. Intake and feed efficiency on forage and grain were moderately correlated. [ABSTRACT FROM AUTHOR]

Objectives of this study were to determine the effects of co-ensiling high moisture corn stover (HMCS) with co-products on pack density, spoilage, aerobic stability, nutrient composition, and in situ digestibility. Plastic barrels (n = 4) were used to ensile 5 combinations: 1) CON; HMCS only, 2) CCDS; HMCS and corn condensed distillers solubles, 3) MIX30; HMCS and Mx30 liquid supplement (Agridyne, LLC, Springfield, IL), 4) MWDGS; HMCS and modified wet distillers grains and solubles, 5) STEEP; HMCS and corn steep water. Each combination was individually mixed in a feed truck and then manually packed into barrels. Barrels were packed to the same height then covered with plastic. Barrels were stored in an open-sided building for 183 d. After storage, the spoilage depth was measured and weighed. Pack density was calculated for each barrel. A subsample from each barrel was placed in an open bucket at room temperature. Subsample temperatures were assessed every 12 h for 4 d to determine aerobic stability. Additional subsamples were dried at 55°C, ground through a 4 mm screen, and incubated in 2 ruminally fistulated steers for 12,24, and 48 h to determine in situ DM disappearance (DMD) and NDF disappearance (NDFD). Pack density, spoilage, aerobic stability, nutrient composition, DMD, and NDFD were analyzed using the MIXED procedure in SAS (SAS Inst. Inc., Cary, NC), with repeated measures for aerobic stability, DMD, and NDFD. There were no differences (P > 0.21) in spoilage. Pack density was greater (P < 0.01) for all co-ensiled combinations compared to CON. There was a combination by time interaction (P < 0.01) for aerobic stability. At 96 h, STEEP had the greatest (P < 0.01) temperature, CCDS and CON were intermediate, and MLX30 and MWDGS had the lowest temperature. Samples of CON had greatest (P < 0.01) NDF and ADF concentrations whereas CCDS, MIX30, and STEEP had least; MWDGS was intermediate and different from CON. The CP concentration differed (P < 0.01) among treatments (6.4, 11.7, 12.7, 14.1, and 14.8% for CON, CCDS, MWDGS, STEEP, and MIX30, respectively). The MWDGS DMD was greater (P = 0.01) than STEEP, CCDS, and MIX30, with CON being intermediate and not different. However, CON and MWDGS had greater (P = 0.03) NDFD than MIX30, with STEEP and CCDS intermediate and not different. Co-ensiling high moisture corn stover with co-products reduced fiber concentration, increased protein concentration, and increased pack density of the mix. Co-ensiling with Mix30 liquid supplement and MWDGS improved aerobic stability. [ABSTRACT FROM AUTHOR]

Objectives were to test the feedingvalue of com plant residue, harvested at 2 maturities, and the effects of silage additive, propionic acid or lactobacillus, on in situ fiber disappearance, and growth performance and carcass characteristics of growing feedlot cattle. InExp. 1, steers were allotted to 1 of 4 treatments: 1) com stover wetted to 40% DM and ensiled (SV), 2) com stalklage, harvested at 40% DM and ensiled (ST), 3) com stalklage plus lactobacillus (STL; SiloKing at 0.225 kg/ ton applied at bagging), or 4) com stalklage plus propionic acid (STPA; Silage Savor plus at 0.5 kg/ton applied at bagging). Com stover (71.5% NDF, 6.12% CP, and 5.88% lignin) was harvested on October 20, after dry com (88% DM). Com stalklage (68.3% NDF, 6.24% CP, and 5.39% lignin) was harvested on September 22, after harvesting high moisture com (HMC; 77% DM). Diets were fed for 85 d, and contained 25% com plant residue, 30% modified wet distillers grain with solubles (MWDGS), 35% HMC, and 10% supplement (DM basis). From d 86 to 186, all steers were fed a common finishing diet that contained 20% silage, 20% MWDGS, 50% HMC, and 10% supplement (DM basis). In Exp. 2, composite com plant residue samples (SV, ST, STL and STPA) from Exp. 1 were incubated in 2 ruminally fistulated steers for 12, 24, 36, and 48 h to determine in situ DM disappearance (DMD) and NDF disappearance (NDFD). There were no treatments effects (P > 0.19) on ADG, DMI and G:F from d 0 to 85. During the first 85 d, when fed 25% of com residue, steers gained 1.69, 1.80, 1.74, and 1.67 kg/d when fed SV, ST, STL, and STPA, respectively. There were no carry-over effects (P > 0.66) of treatment from d 86 to 186; thus, there were no effects (P > 0.78) of treatment on overall steer performance for the entire 186 d. Yield and quality grade distributions, HCW, marbling, back fat, ribeye area and dressing percentage also did not differ (P > 0.14) among treatments. There were no effects of treatment on DMD (P = 0.40) and NDFD (P = 0.34) over time. Average NDFD at 48 h were 27.39, 30.59, 32.50, and 29.45% for SV, ST, STL, and STPA, respectively. Feeding wetted com stover resulted in similar luminal fiber degradation, and steer growth and carcass performance as feeding com stalklage, harvested after HMC harvest. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effects of alkali-treatment (CaOH2) or water addition to corn stover on in situ DM and NDF digestibility (DMD and NDFD) and growth performance of cattle during a backgrounding phase. Fifty-one lightweight Angus steers (average BW 197 kg), fed individually in a Calan-Broadbent feeding system, were randomly allotted to 1 of 3 corn stover (30% of diet DM) feeding treatments: 1) dry, untreated corn stover (85% DM), 2) corn stover treated with CaOH2 at 6% inclusion (as-fed basis) and water hydrated to 50% DM, or 3) corn stover water hydrated to 50% DM. Legume-grass silage (15%), dry rolled corn (25%), dry distillers grains and solubles (25%), and a vitamin and mineral supplement (5%) constituted the balance of the diet DM. Steers were fed once daily at 0600 h, and orts were weighed and sampled during this time. Body weight was measured on d land 49 after withdrawing feed and water for 16 h In situ DMD and NDFD were measured at 12, 24, 36, and 48 h in 2 ruminally cannu-lated steers. Averaged over time, DMD and NDFD differed (P < 0.05). Digestibility of DM and NDF of calcium hydroxide-treated corn stover were greater (38.1% and 45.7%), that of untreated corn stover was intermediate (28.1% and 32.8%), and that of water-treated corn stover was lowest (16.9% and 15.5%). Similar results were observed using an in vitro gas production batch culture. Cattle fed water-treated corn stover consumed more (P < 0.05) feed DM and had faster rates of gain (P < 0.05) than those fed untreated corn stover. Cattle fed calcium hydroxide-treated corn stover had intermediate rates of gain that were similar (P > 0.05) to those of cattle fed water-treated or untreated corn stover. Feed conversion was not affected (P > 0.05) by corn stover treatment. An alternative to alkali-treatments, albeit when forage supply is not limiting, may be simple water addition as cattle fed water-treated corn stover gained weight more rapidly while consuming more DM. [ABSTRACT FROM AUTHOR]

Ractopamine is a beta-adrenergic agonist that is approved for use in beef cattle, pigs and turkeys as a repartitioning agent to increase lean muscle deposition and decrease lipogenesis. Although the effects of dietary ractopamine on the proteome profile of post-mortem pork muscles have been examined, its influence on beef muscle proteome has not been studied. Therefore, the objective of this study was to examine the effect of ractopamine on the proteome profile of post-mortem beef longissimus lumborum (LL) muscle. LL muscle samples were obtained from the carcasses of six (n = 6) steers fed ractopamine (RAC; 400 mg ractopamine hydrochloride for 28 days) and six (n = 6) steers fed no ractopamine (CON). The muscle proteome was analysed using two-dimensional gel electrophoresis and tandem mass spectrometry. Five differentially abundant spots were identified, and all the spots were over-abundant in RAC. The identified proteins were involved in muscle structure development (F-actin-capping protein subunit beta-2; PDZ and LIM domain protein-3), chaperone activity (heat shock protein beta-1), oxygen transport (myoglobin), and glycolysis (L-lactate dehydrogenase A chain). These results suggested that dietary ractopamine could influence the abundance of enzymes associated with muscle development and muscle fibre type shift in beef LL muscle. [ABSTRACT FROM AUTHOR]