Effects of distillers grains with high sulfur concentration on ruminal fermentation and digestibility of finishing diets.

Twelve ruminally cannulated crossbred Angus steers were used to evaluate ruminal fermentation characteristics and diet digestibility when 30% (DM) corn dried distillers grains with solubles (DDGS) containing 0.42 or 0.65% (DM) of dietary S was incorporated into finishing diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC). The study was a replicated, balanced randomized incomplete block design with a 2 × 2 factorial arrangement of treatments. Factors consisted of dietary S concentration (0.42 and 0.65% of DM; 0.42S and 0.65S, respectively) and grain processing method (SFC or DRC). The 0.65S concentration was achieved by adding H(2)SO(4) to DDGS before mixing rations. Steers were assigned randomly to diets and individual, slatted-floor pens, and fed once daily for ad libitum intake. Two 15-d experimental periods were used, each consisting of a 12-d diet adaptation phase and a 3-d sample collection phase. Samples were collected at 2-h intervals postfeeding during the collection phase. Ruminal pH was measured immediately after sampling, and concentrations of ruminal ammonia and VFA were determined. Fecal samples were composited by steer within period and used to determine apparent total tract digestibilities of DM, OM, NDF, CP, starch, and ether extract. Feeding 0.65S tended (P = 0.08) to decrease DMI but resulted in greater apparent total tract digestibilities of DM (P = 0.04) and ether extract (P = 0.03). Ruminal pH increased (P < 0.05) in steers fed 0.65S diets, which may be attributable, in part, to decreased (P = 0.05) VFA concentrations and greater (P < 0.01) ruminal ammonia concentrations when 0.65S was fed, compared with feeding 0.42S. These effects were more exaggerated in steers fed DRC (interaction, P < 0.01), compared with steers fed SFC. Steers fed DRC-0.65S had greater (P < 0.01) acetate concentration than steers fed DRC-0.42S, but acetate concentration was not affected by S concentration when SFC was fed. Propionate concentration was decreased (P < 0.01) in steers fed SFC-0.65S compared with steers fed SFC-0.42S, but dietary S concentration had no effect on propionate concentration when DRC was fed. Butyrate concentration was less (P < 0.01) in steers fed 0.65S diets than in steers fed 0.42S. Lactate concentrations tended (P = 0.06) to decrease in steers fed 0.65S diets. Feeding DDGS with increased S concentration may decrease feed intake and ruminal VFA concentration but increase ruminal ammonia concentration.

Evaluation of sulfur content of dried distillers grains with solubles in finishing diets based on steam-flaked corn or dry-rolled corn.

Crossbred yearling steers (n=80; 406 ± 2.7 kg of BW) were used to evaluate the effects of S concentration in dried distillers grains with solubles (DDGS) on growth performance, carcass characteristics, and ruminal concentrations of CH(4) and H(2)S in finishing steers fed diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC) and containing 30% DDGS (DM basis) with moderate S (0.42% S, MS) or high S (0.65% S, HS). Treatments consisted of SFC diets containing MS (SFC-MS), SFC diets containing HS (SFC-HS), DRC diets containing MS (DRC-MS), or DRC diets containing HS (DRC-HS). High S was achieved by adding H(2)SO(4) to DDGS. Ruminal gas samples were analyzed for concentrations of H(2)S and CH(4). Steers were fed once daily in quantities that resulted in traces of residual feed in the bunk the following day for 140 d. No interactions (P ≥ 0.15) between dietary S concentration and grain processing were observed with respect to growth performance or carcass characteristics. Steers fed HS diets had 8.9% less DMI (P < 0.001) and 12.9% less ADG (P=0.006) than steers fed diets with MS, but S concentration had no effect on G:F (P=0.25). Cattle fed HS yielded 4.3% lighter HCW (P = 0.006) and had 16.2% less KPH (P=0.009) than steers fed MS. Steers fed HS had decreased (P=0.04) yield grades compared with steers fed MS. No differences were observed among treatments with respect to dressing percentage, liver abscesses, 12th-rib fat thickness, LM area, or USDA quality grades (P ≥ 0.18). Steers fed SFC had less DMI (P < 0.001) than steers fed DRC. Grain processing had no effect (P > 0.05) on G:F or carcass characteristics. Cattle fed HS had greater (P < 0.001) ruminal concentrations of H(2)S than cattle fed MS. Hydrogen sulfide concentration was inversely related (P ≤ 0.01) to ADG (r=-0.58) and DMI (r=-0.67) in cattle fed SFC, and to DMI (r=-0.40) in cattle fed DRC. Feeding DDGS that are high in dietary S may decrease the DMI of beef steers and compromise the growth performance and carcass characteristics of feedlot cattle.

Evaluation of in vitro gas production and rumen bacterial populations fermenting corn milling (co)products.

The objective of this study was to evaluate the fermentation dynamics of 2 commonly fed corn (co)products in their intact and defatted forms, using the in vitro gas production (IVGP) technique, and to investigate the shifts of the predominant rumen bacterial populations using the 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) technique. The bTEFAP technique was used to determine the bacterial profile of each fermentation time at 24 and 48 h. Bacterial populations were identified at the species level. Species were grouped by substrate affinities (guilds) for cellulose, hemicellulose, pectin, starch, sugars, protein, lipids, and lactate. The 2 (co)products were a dried distillers grain (DDG) plus solubles produced from a low-heat drying process (BPX) and a high-protein DDG without solubles (HP). Chemical analysis revealed that BPX contained about 11.4% ether extract, whereas HP contained only 3.88%. Previous studies have indicated that processing methods, as well as fat content, of corn (co)products directly affect fermentation rate and substrate availability, but little information is available regarding changes in rumen bacterial populations. Fermentation profiles of intact and defatted BPX and HP were compared with alfalfa hay as a standard profile. Defatting before incubation had no effect on total gas production in BPX or HP, but reduced lag time and the fractional rate of fermentation of BPX by at least half, whereas there was no effect for HP. The HP feed supported a greater percentage of fibrolytic and proteolytic bacteria than did BPX. Defatting both DDG increased the fibrolytic (26.8 to 38.7%) and proteolytic (26.1 to 37.2%) bacterial guild populations and decreased the lactate-utilizing bacterial guild (3.06 to 1.44%). Information regarding the fermentation kinetics and bacterial population shifts when feeding corn (co)products may lead to more innovative processing methods that improve feed quality (e.g., deoiling) and consequently allow greater inclusion rates in dairy cow rations.

Evaluation of protein fractionation and ruminal and intestinal digestibility of corn milling co-products.

Novel corn milling co-products developed from technological advancements in ethanol production vary widely in chemical composition and nutrient availability. The objectives of this study were to characterize feed protein fractions and evaluate differences in rumen-undegradable protein (RUP) and its digestible fraction (dRUP), amino acid concentration, and in vitro gas production of 7 corn milling co-products. The crude protein (CP; % of dry matter) of co-products was 12.7 for germ, 26.9 for dried distillers grains plus solubles that had no heat exposure before fermentation (DDGS1), 45.4 for high-protein dried distillers grains (HPDDG), 12.7 for bran, 30.2 for wet distillers grains plus solubles (WDGS), 23.1 for wet corn gluten feed (WCGF), and 26.0 for dried distillers grains plus solubles that had heat exposure before fermentation (DDGS2). Two ruminally and duodenally fistulated Holstein steers weighing 663+/-24 kg were used to determine RUP and dRUP with the in situ and mobile bag techniques. Samples of each feed were ruminally incubated for 16 h, and mobile bags were exposed to simulated abomasal digestion before insertion into the duodenum and subsequent collection in the feces. Protein fractions A, B(1), B(2), B(3), and C were characterized as follows (% CP): germ=30.0, 15.0, 38.1, 13.5, 3.4; DDGS1=17.0, 7.0, 67.0, 4.8, 4.2; HPDDG=7.4, 0.6, 82.4, 8.8, 0.8; bran=33.5, 4.0, 54.3, 6.0, 2.2; WDGS=18.6, 2.4, 53.1, 11.0, 14.9; WCGF=36.6, 15.9, 33.2, 10.1, 4.1; and DDGS2=17.9, 2.1, 41.1, 11.1, 27.9. The proportions of RUP and dRUP were different and are reported as follows (% CP): DDGS2=56.3, 91.9; HPDDG=55.2, 97.7; WDGS=44.7, 93.1; DDGS1=33.2, 92.1; bran=20.7, 65.8; germ=16.5, 66.8; and WCGF=11.5, 51.1. The concentrations of Lys and Met in the RUP were different and are listed as follows (% CP): germ=2.9, 2.0; DDGS1=1.9, 2.0; HPDDG=2.0, 3.2; bran=3.2, 1.5; WDGS=1.9, 2.3; WCGF=3.5, 1.6; and DDGS2=1.9, 2.4. In vitro gas production (mL/48h) was highest for germ (52.1) followed by bran (50.1), WDGS (40.7), DDGS2 (40.1), WCGF (39.0), DDGS1 (38.6), and HPDDG (37.5). Comparison of co-products defined differences in chemical composition, protein fractionation, ruminal availability, and microbial fermentation.

Response of lactating dairy cows to high protein distillers grains or 3 other protein supplements.

This study compared high protein dried distillers grains (HPDDG) with soybean meal (SBM), canola meal (CM), and dried distillers grains with solubles (DDGS) as protein supplements in dairy diets. A lactation trial used 12 multiparous cows averaging 78 d in milk at the start of the experiment in a 4 x 4 Latin square design with 28-d periods. Weeks 1 and 2 of each period were used for adjustment and wk 3 and 4 for data collection. Each treatment diet consisted of 55% forage and one of the 4 protein supplements in a concentrate mix. Total mixed diets averaged 15.3% crude protein, with 38% of the protein from one of the 4 protein supplements. Dry matter intake (24.4 kg/d) and crude protein intake (3.57 kg/d) were similar for all 4 diets. Milk production (31.8 kg/d), protein yield (1.05 kg/d), fat yield (1.29 kg/d), and protein percentage (3.31) were similar for all 4 treatment diets. Milk fat percentage was lower when fed DDGS (3.78) than when fed SBM or HPDDG (4.21), but similar with CM (4.07). Feed efficiency (1.44kg of energy-corrected milk/kg of dry matter intake) and nitrogen efficiency (0.29) were not affected by diet. Total milk nitrogen and true milk protein were highest when fed the HPDDG diet. Molar proportions of acetate, propionate, and the acetate to propionate ratio in ruminal contents and ruminal ammonia concentrations were similar for all diets. Arterial and venous concentrations of total essential AA tended to be lower when fed CM, reflecting lower concentrations of His, Ile, Leu, and Val when fed the CM diet. Extraction efficiency of AA from blood by the mammary gland indicated that Met was the first limiting AA when fed the SBM diet, whereas Lys was first limiting for the other diets. Phenylalanine was third limiting with all diets. Feeding HPDDG was equally as effective as feeding SBM, CM, and regular distillers grains as a protein supplement for lactating cows.

Dried distillers grains with solubles with reduced corn silage levels in beef finishing diets.

Two finishing experiments were conducted to evaluate the use of 25% dried corn distillers grains with solubles (DDG) in beef cattle finishing diets by partially replacing a portion of the grain and soybean meal in the control diets. In Exp.1, crossbred heifers (n = 377; BW 378 +/- 4.1 kg) were fed diets consisting of steam-flaked corn (SFC) with a control diet containing 0% DDG and 15% corn silage (CS), 25% DDG and 15% CS, or 25% DDG and 5% CS. Compared with the control treatment, heifers fed DDG and 15% CS had a greater proportion of USDA yield grade 4 and 5 carcasses (P = 0.04; 5.68 vs. 14.12), and smaller LM area (P = 0.04; 86.09 vs. 82.48 cm(2)). In Exp. 2, crossbred heifers (n = 582; BW = 377 +/- 27.09 kg) were fed diets similar to Exp. 1 except dry-rolled corn (DRC) and SFC were compared as the basal grain sources. Treatments included DRC or SFC: with control diets containing 0% DDG and 15% CS, 25% DDG and 15% CS, or 25% DDG and 5% CS. Feeding SFC decreased DMI (P < 0.01), improved G:F (P < 0.01) and final shrunk BW (P = 0.05) compared with DRC. Average USDA yield grade was greater for cattle fed DRC than for those fed SFC (P = 0.02), but calculated yield grade was not different among treatments (P = 0.71). Feeding DDG and 5% CS, regardless of grain source, led to decreased DMI and greater G:F than feeding DDG and 15% CS (P = 0.02). When comparing the control treatments with the diets containing 25% DDG and 15% CS shrunk final BW, ADG, and G:F were decreased (P < or = 0.05); however, carcass-adjusted measurements were not different (P > 0.52). Results indicate that roughage levels can be reduced in feedlot diets containing 25% DDG with no adverse effects on BW gain, feed efficiency, or carcass quality.

Effect of thiamine concentration on animal health, feedlot performance, carcass characteristics, and ruminal hydrogen sulfide concentrations in lambs fed diets based on 60% distillers dried grains plus solubles.

Limited data are available regarding the influence of thiamine supplementation on the incidence of polioencephalomalacia (PEM) in lambs fed diets containing increased concentrations of S in the diet (>0.7%). Therefore, our objective was to evaluate the influence of thiamine supplementation on feedlot performance, carcass quality, ruminal hydrogen sulfide gas concentrations, and incidence of PEM in lambs fed a finishing diet containing 60% distillers dried grains with solubles (DDGS; DM basis). Two studies were conducted using completely randomized designs to evaluate the influence of concentration of thiamine supplementation. Study 1 used 240 lambs fed in 16 pens, whereas study 2 used 55 individually fed lambs. Lamb finishing diets contained 60% DDGS, which resulted in a dietary S concentration of 0.73% (DM basis). Treatments diets were based on the amount of supplemental thiamine provided: 1) no supplemental thiamine (CON), 2) 50 mg/animal per day (LO), 3) 100 mg/animal per day (MED), or 4) 150 mg/animal per day (HI). Additionally, in study 2, a fifth treatment was included, which contained 0.87% S (DM basis; increased S provided by addition of dilute sulfuric acid) and provided 150 mg of thiamine/animal per day (HI+S). In study 1, ADG decreased quadratically (P = 0.04), with lambs fed the CON, LO, and MED diets gaining BW at a greater rate than lambs fed the HI diet. In study 1, DMI responded quadratically (P < 0.01), whereas G:F tended to differ linearly (P = 0.08) to concentration of thiamine supplementation, with MED lambs having greater DMI and decreased G:F. No differences (P > or = 0.17) in lamb performance were observed in study 2. In both studies, most carcass characteristics were unaffected, with the exception of a tendency for decreased carcass conformation (study 1; P = 0.09) and greater flank streaking (study 2; P = 0.03). No differences in ruminal hydrogen sulfide concentration (P > 0.05) among treatments were apparent until d 10, at which point lambs fed the LO diet had less hydrogen sulfide concentrations than all other treatments. Lambs fed HI had the greatest concentrations of hydrogen sulfide on d 31 (1.07 g of hydrogen sulfide /m(3); P < 0.009). Ruminal pH did not differ (P = 0.13) and averaged 5.6 +/- 0.06. No clinical cases of PEM were observed during the course of either study. The use of thiamine as a dietary additive to aid in the prevention of PEM in finishing lambs does not appear to be necessary under the conditions of this study.

Evaluation of dried distillers grains and roughage source in steam-flaked corn finishing diets.

Two studies were conducted to evaluate effects of dried distillers grains with solubles (DDGS) and alfalfa hay (AH) or corn silage (CS) on feedlot performance, carcass characteristics, ruminal fermentation, and diet digestibility in cattle fed steam-flaked corn (SFC) diets. In trial 1, crossbred heifers (n = 358; BW = 353 +/- 13 kg) were used in a finishing trial to evaluate interactions between corn-DDGS and roughage source (AH or CS) in terms of impact on feedlot performance and carcass characteristics. Experimental diets (DM basis) consisted of SFC and 11% CS without DDGS (SFC-CS), SFC and 11% CS with 25% DDGS (DDGS-CS), SFC and 6% AH without DDGS (SFC-AH), and SFC with 25% DDGS and 6% AH (DDGS-AH). Heifers were fed for ad libitum intake once daily for 97 d. Results indicated no interaction between DDGS and roughage source with respect to animal performance. Feeding DDGS did not affect ADG (P = 0.19), DMI (P = 0.14), or feed conversion (P = 0.67). Heifers fed CS had greater DMI than those fed AH (P = 0.05), but ADG (P = 0.56) and G:F (P = 0.63) were not different. There were no differences among treatments with respect to HCW, dressing percentage, subcutaneous fat thickness, quality grades, or yield grades (P > 0.20). Cattle fed CS tended (P = 0.10) to have greater marbling scores than those fed AH. There was an interaction (P = 0.02) between roughage and DDGS with respect to incidence of liver abscess. The greatest incidence was observed in cattle fed diets without DDGS when CS was fed, and the least was observed in cattle fed diets without DDGS when AH was used. In the second trial, ruminal fermentation characteristics and diet digestibility were examined in 12 cannulated Holstein steers fed similar diets to those fed in the finishing trial. Ruminal pH for all treatments was below 5.8 for 14 h after feeding. Acetate:propionate ratios were less (P = 0.02) in steers fed 25% DDGS but had greater (P = 0.02) ruminal lactate concentrations compared with cattle fed 0% DDGS. Feeding 25% DDGS decreased (P < 0.01) ruminal ammonia concentrations, and digestion of DM and OM was less (P < 0.01) compared with diets without DDGS. The decrease in digestibility was largely attributable to decreases in digestion of CP (P = 0.03) and NDF (P < 0.01). Feeding strategies aimed at increasing ruminal pH and ruminally available protein may improve digestion of DDGS in steam-flaked corn-based finishing diets.

Effects of distillers dried grains with solubles on growing and finishing steer intake, performance, carcass characteristics, and steak color and sensory attributes.

Seventy-two crossbred and purebred beef steers (296 +/- 9 kg initial BW) were used in a completely randomized design to determine effects of 30% distillers dried grains with solubles (DDGS; 29.2% CP, 9.7% fat, DM basis) inclusion during the growing or finishing period on DMI, performance, carcass, and meat quality traits. The resulting treatments were 0:0, 30:0, 0:30, and 30:30 (diet DDGS percentage fed during growing and finishing periods, respectively). Steers were individually fed a growing diet (65% concentrate) for 57 d, then acclimated to and fed a finishing diet (90% concentrate) for 80 or 145 d. Dietary ingredients included dry-rolled corn, corn silage, grass hay, concentrated separator by-product, and supplement. Diets included 27.5 mg/kg of monensin and 11 mg/kg of tylosin and were formulated to contain a minimum of 12.5% CP, 0.70% Ca, and 0.30% P. During the growing period, DMI was not different (P >or= 0.63; 10.22 +/- 0.23 kg/d; 2.42 +/- 0.06% of BW). Steer performance, including ADG (1.75 +/- 0.05 kg/d) and G:F (174.1 +/- 6.8 g/kg), was not affected (P >or= 0.14) by treatment during the growing period, and final BW at the end of the growing period was not different (425 +/- 7 kg; P = 0.99). During the finishing period, DMI was not different (P >or= 0.54; 8.47 +/- 0.66 kg/d; 1.57 +/- 0.09% BW). During the finishing period, no differences (P >or= 0.22) were observed for ADG (1.54 +/- 0.07 kg/d) or G:F (202.4 +/- 28.3 g/kg). As a result, final BW was not different (P >or= 0.28; 551 +/- 15 kg). Longissimus muscle area (77.8 +/- 3.3 cm(2)), 12th-rib fat thickness (1.26 +/- 0.10 cm), and KPH (2.48 +/- 0.16%) were not different (P >or= 0.16). There were no differences (P >or= 0.35) in yield grade (3.33 +/- 0.17) or marbling (431 +/- 21; Small(0) = 400). Results from the trained panel indicated no differences (P >or= 0.16) in tenderness, which averaged 6.03 +/- 0.16 (8-point hedonic scale); however, steaks from steers fed 0:30 or 30:30 tended (P = 0.10) to be juicier and more flavorful than steaks from steers fed 0:0 or 30:0 (6.01 vs. 5.83 +/- 0.11; 6.02 vs. 5.89 +/- 0.08, respectively). Inclusion of 30% DDGS in the growing period tended to reduce L (P = 0.08; 48.6 vs. 48.9 +/- 0.2) and b (P = 0.01; 8.24 vs. 8.65 +/- 0.18) of steaks. Feeding DDGS during growing or finishing reduced b (P = 0.02; 8.35 vs. 8.74 +/- 0.18) compared with 0:0. Feeding DDGS during the finishing period reduced a (P < 0.001; 20.1 vs. 22.0 +/- 0.24) of steaks. Furthermore, feeding DDGS during growing or finishing reduced a (P < 0.001; 20.9 vs. 21.7 +/- 0.24) compared with 0:0. Feeding 30% DDGS did not affect any performance or carcass characteristics but did influence steak sensory attributes and color.

Effects of level of condensed distillers solubles in corn dried distillers grains on intake, daily body weight gain, and digestibility in growing steers fed forage diets1.

Three experiments were conducted examining the effects of feeding different levels of dried distillers grains (DDG) and different proportions of condensed distillers solubles (CDS) added to DDG on performance and digestibility in forage-fed steers. In Exp. 1, a total of 120 individually fed crossbred steers (276 +/- 31 kg) were used in a randomized complete block design with a 4 x 5 factorial arrangement of treatments. Factors included DDG supplementation level (0.25, 0.50, 0.75, or 1.0% of BW daily) and proportion of CDS in DDG (0.0, 5.4, 14.5, 19.1, and 22.1% of DDG DM). A basal diet of 58.8% alfalfa hay, 39.2% sorghum silage, and 2% vitamin and mineral supplement (DM basis) was fed for ad libitum intake. As the level of DDG increased, intake of forage decreased linearly (P < 0.01), intake of DDG increased linearly (P < 0.01), and total DMI increased quadratically (P = 0.06). A DDG level x CDS level interaction (P < 0.01) was observed for ADG and G:F. The 0.0, 5.4, 14.5, 19.1, and 22.1% CDS treatments had the greatest ADG when DDG was supplemented at 0.75, 1.0, 1.0, 0.75, and 0.50% of BW daily, respectively. In Exp. 2, four crossbred steers (295 +/- 19 kg) were used in a 3-period switchback design. A basal diet of 58.8% alfalfa hay, 39.2% brome hay, and 2% vitamin and mineral supplement (DM basis) was fed at 95% of ad libitum intake. Treatments were DDG containing 0.0 or 22.1% CDS supplemented at 1.0% of BW daily. Apparent total tract digestibility was measured by total fecal collection. No differences between treatments were observed for digestibility of DM, OM, or NDF (P >/= 0.14). Digestibility of ether extract was greater (P = 0.02) in steers supplemented with DDG containing 22.1% CDS. In Exp. 3, two ruminally and duodenally cannulated Holstein steers (663 +/- 24 kg) were used to estimate DM and CP digestion of the DDG fed in Exp. 1 using the mobile bag technique. Basal diets were the same as fed in Exp. 1 and steers were supplemented with DDG at 0.5% of BW daily. Ruminal DM digestibility increased linearly (P < 0.01), and postruminal and total tract DM digestibility increased quadratically (P = 0.02 and P = 0.03, respectively) as the level of CDS increased. Level of CDS may affect growing steer performance because depressions in ADG and G:F were observed as intake of ether extract increased. A clear explanation for the interaction between the DDG supplementation level and the CDS level on growing steer performance was not evident in the digestion experiments.

Effects of feeding three types of corn-milling coproducts on milk production and ruminal fermentation of lactating Holstein cattle.

Two experiments were conducted to determine the effects of feeding 3 corn-milling coproducts on intake, milk production, ruminal fermentation, and digestibility of lactating Holstein cows. In experiment 1, three corn-milling coproducts were fed at 15% of the diet dry matter (DM) to 28 Holstein cows averaging (+/-SD) 625 +/- 81 kg of body weight and 116 +/- 33 d in milk to determine effects on DM intake and milk production. In experiment 2, the same rations were fed to 4 ruminally fistulated, multiparous Holstein cows averaging 677 +/- 41 kg of body weight and 144 +/- 5 d in milk to determine the effects on ruminal fermentation and digestibility. In both experiments, cows and treatments were assigned randomly in 4 x 4 Latin squares over four 21-d periods. Treatments were formulated by replacing portions of forage and concentrate feeds with 15% coproduct and included 1) 0% coproduct (control), 2) dried distillers grains plus solubles (DDGS), 3) dehydrated corn germ meal (germ), and 4) high-protein dried distillers grains (HPDDG). Feed intake was recorded daily, and milk samples were collected on d 19 to 21 of each period for analysis of major components. Rumen fluid was collected at 10 time points over 24 h post feeding on d 21 of experiment 2. In experiment 1, DM intake was greater for the germ (24.3 kg/d) and DDGS treatments (23.8 kg/d), but DDGS was not different from the control (22.9 kg/d) and HPDDG treatments (22.4 kg/d). Milk production paralleled DM intake and tended to be greater for the germ (32.1 kg/d) and DDGS treatments (30.9 kg/d), but the DDGS treatment was not different from the control (30.6 kg/d) and HPDDG treatments (30.3 kg/d). However, yields of milk fat, milk protein, and 3.5% FCM were similar and averaged (+/-SEM) 1.1 +/- 0.1, 0.9 +/- 0.03, and 31.7 +/- 1.3 kg/d. Milk urea nitrogen was greater for the HPDDG (15.9 mg/dL) and germ treatments (15.5 mg/dL) than for the control (15.0 mg/dL) and DDGS treatments (14.9 mg/dL). In experiment 2, DM intake and milk production were not different across treatments and averaged 26.1 +/- 2.3 and 28.3 +/- 3.9 kg/d. Ruminal pH (6.26 +/- 0.08) and total concentration of volatile fatty acids (125.3 +/- 4.2 mM) were similar. Acetate concentration was higher for the control treatment than the DDGS, germ, and HPDDG treatments (81.7 vs. 75.8, 75.0, and 78.4 mM). Concentrations of propionate and butyrate were not different and averaged 27.8 +/- 1.2 and 14.3 +/- 0.9 mM across treatments. The acetate:propionate ratios for the control, germ, and HPDDG treatments were greater than for the DDGS treatment (3.02, 2.88, and 2.91 vs. 2.62). Dry matter, organic matter, and neutral detergent fiber digestibilities were similar across treatments and averaged 63.5 +/- 2.7, 67.3 +/- 2.2, and 43.5 +/- 4.2%. Milk production followed DM intake in experiment 1, and yield of major milk components was not affected. Results of these experiments indicate that dairy rations can be successfully formulated to include 15% of diet DM as corn-milling coproducts while maintaining or increasing DM intakes and yields of milk and milk components.

Effects of dry-rolled or steam-flaked corn finishing diets with or without twenty-five percent dried distillers grains on ruminal fermentation and apparent total tract digestion.

A metabolism study was conducted to evaluate ruminal fermentation and apparent total tract digestibilities of cattle finishing diets. Holstein steers (n = 16, 351 kg of BW) with ruminal cannulas were fed diets consisting of 0 or 25% dried corn distillers grains (DDG), using dry-rolled corn (DRC) or steam-flaked corn (SFC) as the principal energy source (2 x 2 factorial arrangement). The study was conducted in 2 periods, with 4 steers per treatment in each period. Periods consisted of a 12-d adaptation phase and a 3-d collection phase. Compared with DRC, feeding SFC decreased intakes of DM, OM, starch, NDF, and ether extract (P < 0.01), and steers fed SFC excreted less DM, OM, starch, NDF, and ether extract (P < 0.01). Compared with SFC, feeding DRC decreased ruminal concentrations of acetate, butyrate, isobutyrate, and isovalerate, and decreased the acetate-to-propionate ratio (P < 0.01). Compared with SFC, DRC decreased ruminal propionate, valerate, and lactate concentrations (P < 0.01). When compared with cattle fed SFC, ruminal pH of cattle fed DRC was less at 0 h and greater at 6 h postfeeding (P < 0.01). Ruminal ammonia concentrations were greater for DRC vs. SFC at h 0, 6, 10, 12, 14, 16, 18, 20, and 22 postfeeding (P < 0.05). Feeding DDG decreased consumption of starch and ether extract, but increased NDF intake (P < 0.01). Fecal excretion of ether extract was increased by adding DDG compared with diets without DDG (P < 0.05), resulting in less apparent total tract digestibility of ether extract for cattle fed DDG (P < 0.01). Ruminal lactate concentrations were increased with addition of DDG compared with diets without DDG (P = 0.01). Ruminal ammonia concentrations were less for steers fed 25 vs. 0% DDG at 2, 4, 6, 8, and 10 h postfeeding (P < 0.05). We conclude, based on these results, that ruminal fermentation and apparent total tract digestibility of DDG are affected by grain processing.

Effects of increasing levels of corn distillers dried grains with solubles to steers offered moderate-quality forage.

Supplementation of forage-fed livestock has been studied for decades; however, as by-products become available research is needed to determine optimal feeding rates for increased efficiency. Five ruminally and duodenally cannulated beef steers (446 +/- 42 kg of initial BW) were used in a 5 x 5 Latin square to evaluate effects of increasing level of supplemental corn distillers dried grains with solubles (DDGS; 25.4% CP, 9.8% fat, DM basis) on DMI, rate and site of digestion, ruminal fermentation, and microbial efficiency. Diets consisted of ad libitum quantities of moderate-quality smooth brome hay (10.6% CP; DM basis), free access to water and trace mineral salt block, and 1 of 5 levels of DDGS (0, 0.3, 0.6, 0.9, and 1.2% of BW daily of DDGS; DM basis). Diets were formulated to meet or exceed the estimated rumen degradable protein requirements (assumed microbial yield = 10.5%). All supplements were fed at 0600 h before forage was fed. Steers were adapted to diets for 14 d followed by a 7-d collection period. Hay OM intake decreased (linear; P < 0.001), whereas total OM intake increased (linear; P < 0.001) with increasing DDGS level. Total CP intake, duodenal OM and CP flows, and total tract OM and NDF digestibilities increased (linear; P

Effects of increasing level of corn distillers dried grains with solubles on intake, digestion, and ruminal fermentation in steers fed seventy percent concentrate diets.

Five ruminally and duodenally cannulated steers (500 +/- 5 kg of initial BW) were used in a 5 x 5 Latin square to evaluate effects of increasing level of corn distillers dried grains with solubles (DDGS) in growing diets (70% concentrate) on OM intake, site of digestion, ruminal fermentation, and microbial efficiency. Diets consisted of 30% grass hay, 6% concentrated separator by-product, 4% supplement, and 60% dry-rolled corn, sunflower meal, urea, or DDGS (DM basis). Treatments consisted of increasing DDGS at 0, 15, 30, 45, or 60% of diet DM replacing a combination of dry-rolled corn, sunflower meal, and urea. Diets were balanced for growing steers gaining 1.22 kg/d and included 0.25% (DM basis) chromic oxide as a digesta flow marker. Diets were offered to the steers for ad libitum intake each day (10% above the intake of the previous day). Each period consisted of 14 d for adaptation and 7 d for collections. Intake of OM responded quadratically (P = 0.004) with greatest intakes at 15% DDGS and least at 60% DDGS. No differences (P >or= 0.14) were observed in CP intake or duodenal flow of OM, CP, and NDF. Apparent and true ruminal OM digestibilities decreased (linear; P or= 0.19). A cubic (P = 0.02) effect was observed for total ruminal fill (as is basis) with the greatest fill at 0% DDGS and the least fill at 45% inclusion. Replacing dry-rolled corn with up to 60% DDGS in 70% concentrate diets resulted in no adverse effects on total tract OM digestion, although OM intake was reduced at 60% DDGS inclusion.

Short communication: The effect of feeding high protein distillers dried grains on milk production of Holstein cows.

The objectives of this study were to evaluate the effects of feeding high-protein distillers dried grains (HPDDG) on rumen degradability, dry matter intake, milk production, and milk composition. Sixteen lactating Holstein cows (12 multiparous and 4 primiparous) averaging 80 +/- 14 d in milk were randomly assigned to 1 of 2 dietary treatments in a 2 x 2 crossover design. A portion of forage and all soy-based protein in the control diet were replaced by HPDDG (20% dry matter). Milk production and dry matter intake were recorded daily and averaged for d 19 to 21 of each 21-d period. Milk samples were collected on d 20 to 21 of each period. Milk yield increased with the inclusion of HPDDG (33.4 vs. 31.6 +/- 2.13 kg/d), and 3.5% FCM was higher for the ration containing HPDDG (36.3 vs. 33.1 +/- 2.24 kg/d). Percentage protein was not affected by treatment (average 3.04 +/- 0.08%), but protein yield increased with inclusion of HPDDG (0.95 to 1.00 +/- 0.05 kg/d). Milk fat concentration was not different between treatments (average 3.95 +/- 0.20%), but fat yield increased for the ration containing HPDDG (1.35 vs. 1.21 +/- 0.09 kg/d). Dry matter intake was not affected and averaged 21.9 +/- 0.80 kg across treatments. Because of greater milk production, feed conversion was improved by the inclusion of HPDDG (1.47 to 1.73 +/- 0.09). Milk urea N was greater for the HPDDG ration than the control (14.5 vs. 12.8 +/- 0.67 mg/dL). This research suggests that HPDDG may effectively replace soy-based protein in lactating dairy cow diets.

Evaluation of corn germ from ethanol production as an alternative fat source in dairy cow diets.

Sixteen multiparous cows (12 Holstein and 4 Brown Swiss, 132 +/- 20 d in milk) were used in a replicated 4 x 4 Latin square design with 4-wk periods to determine the effects of feeding corn germ on dairy cow performance. Diets were formulated with increasing concentrations of corn germ (Dakota Germ, Poet Nutrition, Sioux Falls, SD) at 0, 7, 14, and 21% of the diet dry matter (DM). All diets had a 55:45 forage to concentrate ratio, where forage was 55% corn silage and 45% alfalfa hay. Dietary fat increased from 4.8% in the control diet to 8.2% at the greatest inclusion level of corn germ. The addition of corn germ resulted in a quadratic response in DM intake with numerically greater intake at 14% of diet DM. Feeding corn germ at 7 and 14% of diet DM increased milk yield and energy-corrected milk as well as fat percentage and yield. Milk protein yield tended to decrease as the concentration of corn germ increased in the diet. Dietary treatments had no effect on feed efficiency, which averaged 1.40 kg of energy-corrected milk/kg of DMI. Increasing the dietary concentration of corn germ resulted in a linear increase in milk fat concentrations of monounsaturated and polyunsaturated fatty acids at the expense of saturated fatty acids. Milk fat concentration and yield of cis-9, trans-11 and trans-10, cis-12 conjugated linoleic acid were increased with increased dietary concentrations of corn germ. Although milk fat concentrations of both total trans-18:1 and cis-18:1 fatty acids increased linearly, a marked numeric increase in the concentration of trans-10 C18:1 was observed in milk from cows fed the 21% corn germ diet. A similar response was observed in plasma concentration of trans-10 C18:1. Feeding increasing concentrations of corn germ had no effect on plasma concentrations of glucose, triglyceride, or beta-hydroxybutyrate; however, the concentration of nonesterified fatty acids increased linearly, with plasma cholesterol concentration demonstrating a similar trend. Germ removed from corn grain before ethanol production provides an alternative source of fat for energy in lactating dairy cows when fed at 7 and 14% of diet DM. Our results suggest that fat from corn germ may be relatively protected with no adverse effect on DM intake, milk production, and milk composition when fed up to 14% of diet DM.

Effects of chemical composition variation on the dynamics of ruminal fermentation and biological value of corn milling (co)products.

The objectives of this study were to evaluate the dynamics of gas production of several corn (co)products, to develop equations to predict the rate of ruminal fiber digestion, to estimate total digestible nutrients (TDN) and net energy for lactation (NE(L)), and to assess the stochasticity of chemical composition and nutritive value variability. Four corn milling (co)products were evaluated in this study: high protein dried distillers grains (HP-DDG), corn bran (BRAN) and dehydrated germ (GERM), and a dried distillers grains plus soluble produced with a low-heat drying process (BPX). Alfalfa hay was used as an internal standard feed in the in vitro fermentation dynamics analysis. Standard chemical analyses, in vitro digestibility, and in vitro gas production techniques were used to obtain the necessary physicochemical characterization of feeds. The in vitro dry matter digestibility at 24 and 48 h of incubation decreased exponentially as acid detergent insoluble nitrogen increased. However, the degree of in vitro dry matter digestibility reduction was more accentuated at 24 than at 48 h of incubation. The difference among these feeds regarding the dynamics of the anaerobic fermentation within different substrates (intact feed, and fiber and defatted residues) was evaluated. Results suggested that the proportion of fiber digested in the rumen was affected by the degree of sample processing and fat removal. Fractional fermentation rate (kf) of neutral detergent residue (without sodium sulfite) and defatted fiber residue for BRAN, GERM, HP-DDG, and BPX was estimated to be 0.0635 and 0.0852 h(-1), 0.0803 and 0.0914 h(-1), 0.118 and 0.117 h(-1), and 0.0695 and 0.0844 h(-1), respectively. The most influential variables affecting kf(NDR) of HP-DDG and BPX also affected the predicted TDN, suggesting that fiber quality is essential to ensure higher TDN values for these feeds. Our study indicated that it is possible to routinely quantify the rate of fiber digestion and this approach may be based on common analytical procedures namely estimates of neutral detergent fiber, acid detergent fiber, acid detergent insoluble nitrogen, ether extract, and acid detergent lignin. Our simulations of TDN values demonstrated that differences in fermentability and chemical composition of these corn (co)products might considerably affect the supply of energy to lactating dairy cow. The analytical methods developed in this study may serve as a valuable tool to assess nutrient quality and uniformity when samples differ in chemical composition.

Conjugated linoleic acid increases in milk from cows fed condensed corn distillers solubles and fish oil.

Twelve lactating Holstein cows were randomly assigned to 1 of 4 experimental diets in a replicated 4 x 4 Latin square design with 4-wk periods to ascertain the lactational response to feeding fish oil (FO), condensed corn distillers solubles (CDS) as a source of extra linoleic acid, or both. Diets contained either no FO or 0.5% FO and either no CDS or 10% CDS in a 2 x 2 factorial arrangement of treatments. Diets were fed as total mixed rations for ad libitum consumption. The forage to concentrate ratio was 55:45 on a dry matter basis for all diets and the diets contained 16.2% crude protein. The ether extract concentrations were 2.86, 3.22, 4.77, and 5.02% for control, FO, CDS, and FOCDS diets, respectively. Inclusion of FO or CDS or both had no effect on dry matter intake, feed efficiency, body weight, and body condition scores compared with diets without FO and CDS, respectively. Yields of milk (33.3 kg/d), energy-corrected milk, protein, lactose, and milk urea N were similar for all diets. Feeding FO and CDS decreased milk fat percentages (3.85, 3.39, 3.33, and 3.12%) and yields compared with diets without FO and CDS. Proportions of trans-11 C18:1 (vaccenic acid), cis-9 trans-11 conjugated linoleic acid (CLA; 0.52, 0.90, 1.11, and 1.52 g/100 g of fatty acids), and trans-10 cis-12 CLA (0.07, 0.14, 0.13, and 0.16 g/100 g of fatty acids) in milk fat were increased by FO and CDS. No interactions were observed between FO and CDS on cis-9 trans-11 CLA although vaccenic acid tended to be higher with the interaction. The addition of CDS to diets increased trans-10 C18:1. Greater ratios of vaccenic acid to cis-9 trans-11 CLA in plasma than in milk fat indicate tissue synthesis of cis-9 trans-11 CLA in the mammary gland from vaccenic acid in cows fed FO or CDS. Feeding fish oil at 0.5% of diet dry matter with a C18:2 n-6 rich source such as CDS increased the milk CLA content but decreased milk fat percentages.

Corn distillers grains with solubles derived from a traditional or partial fractionation process: Growth performance and carcass characteristics of finishing feedlot heifers.

Six hundred ten crossbred-yearling heifers (347 +/- 5 kg of initial BW) were obtained and used in a randomized complete-block design finishing study. Finishing diets were based on steam-flaked corn and ground alfalfa hay. The control (CONT) treatment contained no distillers grains with solubles (DGS), the second diet was formulated to contained 13% (DM basis) dried corn DGS derived from a traditional dry-grind ethanol process (TRAD), and the third diet was formulated to contained 13% (DM basis) dried corn DGS derived from a partial fractionation dry-grind process (FRAC). Dry matter intake, ADG, and gain efficiency were not different (P >/= 0.48) for yearling heifers fed CONT when compared with heifers fed DGS. Heifers fed TRAD consumed more (P = 0.01) feed than heifers fed FRAC. However, ADG and feed efficiency were not different (P >/= 0.07) for heifers fed DGS. Moderate inclusion levels of DGS in finishing flaked corn diets yielded satisfactory performance. Growth performance was not different for heifers fed DGS originating from either ethanol processing method.

The feeding value of corn distillers solubles for lactating dairy cows.

Fifteen Holstein cows (10 multiparous and 5 primiparous) in early to mid lactation (79.3 +/- 9.2 d in milk) were used in a multiple 5 x 5 Latin square design with 4-wk periods to evaluate and compare the use of condensed corn distillers solubles (CCDS) and dried distillers grains with solubles (DDGS) in the total mixed ration. The forage portion of the diets was kept constant at 27.5% corn silage and 27.5% alfalfa hay (dry matter basis). Diets were 1) 0% distillers grains products (control); 2) 18.5% DDGS; 3) 10% CCDS; 4) 20% CCDS; and 5) a combination diet of 18.5% DDGS with 10% CCDS. Diets 2 and 3 contained 2% fat from DDGS or CCDS, whereas diet 4 contained 4% fat from CCDS and diet 5 contained 4% fat from the blend of DDGS and CCDS. The diets were balanced to provide 17% crude protein with variation in acid detergent fiber, neutral detergent fiber, and fat concentration. Dry matter intake (21.5 kg/d) was similar for all diets. Milk yield (33.8, 36.2, 35.5, 36.0, and 36.0 kg/d) tended to be greater for diets 2 to 5 than for diet 1, whereas yields of fat (1.04 kg/d), protein (1.02 kg/d), fat percentage (2.94), and protein percentage (2.98) were similar for all diets. Energy-corrected milk (32.2 kg/d) and feed efficiency (1.58 kg of energy-corrected milk/kg of dry matter intake) were similar for all diets. Milk urea nitrogen (15.0, 10.9, 11.1, 11.0, and 11.4 mg/dL) as well as blood urea nitrogen (15.6, 12.5, 14.6, 13.8, and 14.2 mg/dL) were decreased in diets 2 to 5 compared with diet 1. Milk concentrations of long-chain fatty acids as well as polyunsaturated fatty acids were greater and medium-chain fatty acid concentrations were lower for diets 2 to 5 compared with diet 1. Concentrations of cis-9, trans-11 conjugated linoleic acid (CLA; 0.33, 0.68, 0.51, 0.85, and 1.07 g/100 g of fatty acids) as well as trans-10, cis-12 CLA (<0.01, 0.01, <0.01, 0.02, and 0.02 g/100 g of fatty acids) were greater for diets 2 to 5 compared with diet 1. Molar proportions of ruminal acetate decreased and propionate increased for diets 2 to 5 compared with diet 1. The results showed that CCDS is as effective as DDGS in replacing soybean meal and corn grain in the total mixed ration.