Search

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]

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]

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]

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]

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]