Corn Distillers Grains Research Articles

Effects of dietary protein concentration and balance of absorbable amino acids on productive responses of dairy cows fed corn silage-based diets

A cyclical changeover design experiment (3-wk periods; 12-wk total) was conducted to evaluate whether improving the balance of absorbable AA would allow the feeding of less crude protein (CP) without compromising production, thereby reducing the potential environmental pollution from dairy farms. Sixteen multiparous Holstein cows were assigned to 1 of 8 dietary treatments as total mixed rations (TMR) containing [dry matter (DM) basis] 45% corn silage, 5% coarsely chopped wheat straw, and 50% concentrate mixture. The 8 treatments were formulated to differ in dietary CP (14 and 16%; DM basis) and in the balance of absorbable AA achieved by changing the main protein source (MPS) of the concentrate mixtures [replacing soybean meal (SBM) with corn byproducts (CBP), dried corn distillers grains (DDG), and some corn gluten meal], and by adding a mixture of rumen-protected Lys and Met (RPLM). Feeding lactating dairy cows corn silage-based diets with 16% CP promoted significantly higher DM intakes and milk yields, and lower feed N-use efficiency than feeding diets with 14% CP. Replacing SBM with CBP significantly increased milk yields and decreased milk fat and protein concentrations, but had no effect on the efficiency of conversion of feed N into milk N. With 16% CP diets, the addition of RPLM decreased feed N use efficiency. A significant effect was observed for the MPS × RPLM interaction on milk protein concentrations. Plasma Lys concentration was lower with diets based on CBP, and plasma Met increased with RPLM. We did not find clear benefits of RPLM in facilitating a reduction of dietary protein without loss of production.

Evaluation of rumen methanogen diversity in cattle fed diets containing dry corn distillers grains and condensed tannins using PCR-DGGE and qRT-PCR analyses

Condensed tannins (CT) and corn distillers grains from ethanol production have the potential to reduce enteric CH4 production from ruminants because of their anti-microbial properties and high lipid contents, respectively. However, their effects on the community of rumen methanogens in cattle rumens have not been investigated. Our objective was to evaluate effects of dry corn distillers grain with solubles (DDG) and CT from Acacia mearnsii added to the diet of cattle on rumen methanogens using PCR denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real time (qRT)-PCR. Eight ruminally cannulated beef heifers were used in a replicated 4×4 Latin square design with four 35d periods. Diets were (g DDG dry matter [DM]/kg DM): control (Ctrl; 0 DDG), 200 DDG, 400 DDG and 400 DDG plus 25g CT (400 DDG+CT). Rumen digesta samples were collected before feeding on d 25 and 28 of each period from 4 sites in the rumen. Total DNA extracted from rumen digesta samples (i.e., 0.5ml liquid+0.5g solid pooled by heifer for each period) was used to generate amplicons of partial 16S rRNA genes. The PCR products obtained were subjected to PCR-DGGE. Detectable methanogenic PCR-DGGE profiles from periods 1 and 2 clustered while periods 3 and 4 formed a second cluster. A total of 25 distinct PCR-DGGE bands were identified, of which 16 bands were successfully cloned and sequenced. The sequences of 11 bands had 97–100% similarity with Methanobrevibacter sp., and this was supported by clustering of 10 of these bands with this species upon phylogenetic analysis of the sequences. The remaining bands clustered with Methanosphaera stadmanae. Although no effect of diet on total methanogenic PCR-DGGE profiles occurred, the proportion of bands 4, 5, 6, 7, 9 and 11 increased and bands 16 and 18 decreased with increased DDG in the diet. Bands 13 and 19 were in all diets except 400 DDG+CT. Quantitative RT-PCR analysis revealed that the copy numbers of total methanogenic 16S rRNA gene did not differ among diets. Findings from PCR-DGGE and qRT-PCR analysis suggest that inclusion of DDG or a mixture of DDG and CT altered the diversity of rumen methanogens without affecting total methanogen associated 16S rRNA copy numbers thereby indicating that copy numbers of particular species of methanogens may be required to explain the altered diversity of rumen methanogens.This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

Diet fermentability influences lactational performance responses to corn distillers grains: A meta-analysis

Increasing supply of corn distillers grains (CDG) raises questions about the extent to which they can be used in diets of lactating dairy cows. A database of treatment means (n=44) reported in 16 peer-reviewed journal articles published from 1985 to 2008 was developed. The database included response (within study) to a CDG diet compared with the control (no CDG) for milk yield (MY), milk fat concentration and yield, CDG content of the diet, and dietary composition of control and CDG diets (% of dietary dry matter). Additionally, corn grain fermentability was classified as high moisture (n=7) or dry (n=37). Data from studies with diets including more than one grain source (n=8) had been eliminated from the analysis. Dietary concentrations of CDG ranged from 4.2 to 42% across studies. Dietary concentrations in diets containing CDG were 16.8±1.91% (mean ± standard deviation) crude protein, 36±15.5% corn silage, 23±8.8% corn grain, and 28±5.8% starch. Responses to CDG were 0.5±2.10 kg/cow per day (mean ± standard deviation) for MY, 0.05±0.178 percentage units for milk fat concentration, and 26±77.6g/cow per day for milk fat yield. Only MY response was related to increasing concentrations of CDG in diets and peaked at 1.2 kg/cow per day for 21% CDG. Diet fermentability was associated with responses. The greatest MY response to CDG was with 24% corn silage or 23% starch, and concentrations greater than 47% corn silage or 32% starch resulted in negative MY responses. Responses in MY differed by level of MY and were often more evident in higher- (>30.0kg MY/d) than in lower-producing cows. Milk fat concentration response was not related to dietary CDG, but was correlated linearly with milk fat concentration of cows fed the control diet. Milk fat concentration greater than 3.6% for the control treatment was related to a negative milk fat concentration response to CDG, regardless of dietary concentration of CDG. Partially replacing high-moisture corn with CDG increased milk fat concentration by 0.16 percentage units compared with that from dry corn. When formulating diets with CDG, diet fermentability and level of MY (higher vs. lower) must be considered. Concentrations of corn silage and starch must be moderate to optimize lactational responses to CDG. Overall, lactational response to CDG in this database was dependent on diet fermentability and milk fat concentration in the control.

Dietary protein quality and quantity affect lactational responses to corn distillers grains: A meta-analysis

Diet fermentability influences lactational responses to feeding corn distillers grains (CDG) to dairy cows. However, some measures of diet fermentability are inherently related to the concentration and characteristics of corn-based ingredients in the ration. Corn-based feeds have poor protein quality, unable to meet the essential AA requirements of lactating cows. We conducted a meta-analysis of treatment means (n=44) from the scientific literature to evaluate responses in milk yield (MY) and milk true protein concentration and yield to dietary CDG. The test variable was the difference in response between the CDG diet mean and the control diet mean (0% CDG) within experiment. Fixed variables were CDG concentration of the diet [% of dietary dry matter (DM)] and crude protein (CP) concentration and fractions of CP based on origin (corn-based versus non-corn-based feeds) of control and CDG diets. Diets with CDG ranged from 4 to 42% CDG, DM basis. Non-corn-based dietary CP averaged 6.3±3.32% of total DM. Milk yield and milk true protein yield responses to added CDG were maximized when approximately 8.5% of the total dietary DM was non-corn-based CP. Milk yield response peaked for higher-producing cows (>30.0kg MY/cow per day) at 4.3% dietary corn-based CP, but decreased linearly for lower-producing cows (<30.0kg MY/cow per day) as corn-based dietary CP increased. Milk true protein yield response decreased as corn-based dietary CP concentration increased but milk true protein concentration response was not decreased when CDG diets had more than 6.5% dietary non-corn-based CP. Overall, 8.5% dietary non-corn-based CP was necessary in lactation diets to maximize lactational responses to dietary CDG. The necessity of dietary non-corn-based CP to maximize milk and milk protein yields limits the amount of dietary corn-based CP, including that from CDG, which can be included in rations without overfeeding N.

The effect of corn or sorghum dried distillers grains plus solubles on growth performance and carcass characteristics of cross-bred beef steers

Sixty cross-bred steers (Angus ×; n=36 and Charolais ×; n=24) were used in a split-plot design to investigate the effects of feeding corn (Zea mays) or sorghum (Sorghum bicolor) dried distillers grains plus solubles in growing and finishing diets on growth performance and carcass traits. Steers were randomly assigned to one of three dietary treatments used in both feeding periods: a control diet containing soybean meal (n=20; CON), a diet containing 200g/kg (DM basis) corn dried distillers grains+solubles (n=20; CDDGS) and a diet containing 200g/kg (DM basis) sorghum dried distillers grains+solubles (n=20; SDDGS). Steers were fed a corn silage (CS) based grower diet (∼750/kg CS) for 56d and then switched to a high grain finisher diet (150g/kg CS). Feed intakes were measured using Insentec (n=48) and Calan gate (n=12) feeding systems. Animals were weighed every 28d and slaughtered at an estimated backfat of 10mm as estimated by ultrasound. Total trial average daily gain (ADG) was 1.56kg/d±0.04 for CON, 1.54kg/d±0.04 for CDDGS, and 1.51kg/d±0.04 for SDDGS and did not differ (P>0.68) between treatments. Dietary treatment did not affect (P>0.14) dry matter intake (DMI) in the growing phase, although ADG was lower for SDDGS vs. CON (P=0.008) and CDDGS (P=0.02). There was a lower gain:feed in the growing phase for SDDGS vs. CDDGS (P=0.04). In the finishing phase, inclusion of corn or sorghum DDGS did not affect (P>0.41) ADG, DMI or G:F. However, fewer days on feed were required for SDDGS to reach the target backfat for slaughter than CDDGS (P=0.03) and CON (P=0.05). These results indicate that sorghum dried distillers grains plus solubles can be included at 200g/kg inclusion level, similar to corn distillers grains plus solubles, in grower and finisher diets, without negatively influencing overall growth or carcass traits, although feeding SDDGS may result in reduced performance when corn silage based diets are fed and results in earlier fattening at a lighter body weight.

Fermentation characteristics and aerobic stability of wet corn distillers grains with solubles ensiled in combination with whole plant corn

Wet corn distillers grains with solubles (WDG) are prone to aerobic spoilage when stored for an extended period of time. The objective of this study was to evaluate the fermentation characteristics of ensiling WDG with whole plant corn (WPC) using the following combinations: (1) 100% WPC; (2) 75% WPC + 25% WDG; (3) 50% WPC + 50% WDG; and (4) 100% WDG. The initial pH was greatest for 100% WPC and lowest for 100% WDG (5.7, 4.6, 4.0, and 3.1, respectively). Concentrations of ammonia nitrogen (12.0, 26.8, 40.7, and 50.8 g kg(-1) dry matter (DM)) and Crude protein (CP) (98.7, 155.8, 206.8, and 307.9 g kg(-1) of DM) increased with increasing concentrations of WDG. Lactic acid concentration prior to ensiling was greatest for 100% WDG (9.0 g kg(-1) DM) and decreased with WPC in the silage. Acetic, propionic, and butyric acids were not present prior to ensiling. The pH of the ensiled feeds dropped below 4.0 by day 3, with no further decrease over time. Acetic acid increased from undetected amounts at day 0 to 38.8, 43.9, 43.2, and 2.2 g kg(-1) of DM at day 129 as concentration of WDG increased. Aerobic stability was enhanced with increasing WDG concentration in the silage. Fermentation, nutrient profile, and aerobic stability can be improved when ensiling wet distillers grains with whole plant corn.

Operating Characteristics of a High-Efficiency Pilot Scale Corn Distillers Grains Dryer

The rapidly expanding U.S. corn ethanol industry produces huge quantities of wet distillers grains and about 70% of this material is dried to 10% moisture. Drying this material requires about one-third of the energy used to operate a dry-grind corn ethanol plant. Tri-Phase Drying Technologies of Norwalk, Iowa has developed a rotary drum dryer which reclaims energy from the exhaust air stream. The objective of this research was to determine the energy requirement of the Tri-Phase dryer by pilot scale drying tests with wet distillers grains. Multiple tests of the pilot-scale dryer showed an energy input requirement of about 2890 kJ/kg (846 Btu/lb) of water removed when drying wet distillers grains from about 28% to 24% moisture. This is less than half the energy usually required for a drum dryer or a grain dryer. Use of this dryer design, scaled up to dry distillers grains at ethanol plants, has the potential for large energy savings for the corn ethanol industry.

The effect of byproducts from the corn grain processing on the postprandial dynamics of rumen pH

The effects of two fiber-rich byproducts of the corn grain processing on the postprandial dynamics of rumen pH were studied on three rumen cannulated non-lactating cows, within a 3x3 Latin square experimental design. The two byproducts, dried corn gluten feed (dCGF) and dried corn distillers grains (dCDG) replaced corn grains (C) in high concentrate diets, which suddenly replaced a standard diet (designed to ensure appropriate rumen activity) and were feed once a day. Rumen content was sampled every two hours, two days after the diet changes, during first 14 postprandial hours and pH was measured immediately. Average, pHmin and pHmax as well as duration and intensity of pH decrease were calculated for each series of pH measurements. Diets containing dCGF and dCDG led to higher average pH comparing to the corn-based diet: 6.26 ? 0.03 and 6.12 ? 0.12 versus 6.02 ? 0.2, respectively (P&lt;0.05). Differences were more marked when duration and intensity of pH decrease were considered: corn diet led to a pH decrease below 6.0 of 8.02?2.58 hours, whereas for dCDG and dCGF diets the decreases were of 6.71?3.59 and 3.02?2.17 hours only. Relative differences were even higher when a lower pH threshold (5.8) was considered: observed values were 5.33?4.02, 3.14?3.64 and 0.83?1.24 for C, dCDG and dCGF diets, respectively. Of the two by-products, dCGF was more efficient against pH decrease after the sudden change from a low concentrate to a high concentrate diets. It is concluded that both by-products are feasible solutions to help limiting the pH decrease while allowing formulation of high energy and highly digestible diets for ruminants.

Contribution of exogenous dietary carbohydrases to the metabolizable energy value of corn distillers grains for broiler chickens

The objectives of this study were to determine the ileal digestible energy (IDE), ME, and ME(n) contents of corn distillers grains (CDG) for broiler chickens and to quantify these energy utilization responses to carbohydrase supplementation by the regression method. The CDG sample used in the current experiment contained (by analysis) 936 g/kg of DM, 4,894 kcal/kg of gross energy, 315.1 g/kg of CP, 94.6 g/kg of crude fat, 94.8 g/kg of crude fiber, 495.6 g/kg of neutral detergent fiber, 179.1 g/kg of acid detergent fiber, 0.19 g/kg of Ca, and 4.8 g/kg of P. The studies were conducted at 2 locations (Purdue or Louisiana State University) and CDG were incorporated into a practical corn-soybean meal diet at 3 levels (0, 300, or 600 g/kg) without or with added carbohydrase in a 2 x 3 x 2 factorial arrangement. The carbohydrase premix was added to supply 2,000 U of xylanase + 1,800 U of amylase/kg of feed. The diets were fed to 288 broiler chickens from d 15 to 22 posthatch with 6 birds per cage and 8 replicate cages per diet in a randomized complete block design at each of 2 locations. The broiler chicks were fed a standard broiler starter diet from d 1 to 15 posthatch. The IDE of diets decreased both linearly (P < 0.01) and quadratically (P < 0.05) as CDG increased from 0 to 600 g/kg regardless of carbohydrase supplementation. There was a linear (P < 0.01) decrease in ME of diet from 3,239 to 2,510 kcal/kg as CDG increased from 0 to 600 g/kg in the diets without added carbohydrase, whereas for birds fed the carbohydrase-supplemented diets, there were both linear (P < 0.01) and quadratic (P < 0.01) decreases from 3,398 to 2,613 kcal/kg as CDG increased from 0 to 600 g/kg. Dietary ME(n) linearly decreased (P < 0.01) regardless of carbohydrase supplementation as CDG increased from 0 to 600 g/kg. Supplementation with carbohydrase improved (P < 0.01) IDE, ME, and ME(n). Regressions of CDG-associated IDE, ME, or ME(n) intake in kilocalories against kilograms of CDG intake without added carbohydrase generated the following: IDE = 44 + 2,340X, r(2) = 0.953; ME = 10 + 2,315X, r(2) = 0.993; and ME(n) = 10 + 2,132X, r(2) = 0.991. Corresponding regressions when carbohydrase was added were as follows: IDE = -17 + 2,622X, r(2) = 0.985; ME = -25 + 2,448X, r(2) = 0.979; and ME(n) = -22 + 2,264X, r(2) = 0.978. These data indicate that the respective IDE, ME, and ME(n) values (kcal/kg of DM) of the CDG sample evaluated were 2,340, 2,315, and 2,132 when carbohydrase was not added and 2,622, 2,448, and 2,264 when carbohydrase was added. Comparison using ANOVA procedures indicated that the slope when carbohydrase was added was greater (P < 0.05) than when carbohydrase was not added. This response implies that carbohydrase supplementation improved (P < 0.05) the IDE, ME, and ME(n) of CDG in practical corn-soybean meal-based diets used in this current study by 12, 5.7, and 6.2%, respectively.

Ruminal degradability and intestinal digestibility of protein and amino acids in soybean and corn distillers grains products

New fractionation and fermentation technologies in the ethanol industry have resulted in the production of different forms of distillers grains (DG). Such products are reduced-fat, high-protein, and “modified” wet feeds. Characterization of protein fractions of these co-products and other commonly used feedstuffs is important for the formulation of dairy cattle diets. In situ and in vitro techniques were conducted to compare crude protein (CP) availability in 4 DG products with commonly used soybean proteins. Soybean protein products included solvent-extracted soybean meal (SBM; 44% CP), expeller soybean meal (ESBM), and extruded soybeans (ES). The DG products were conventional distillers dried grains with solubles, reduced-fat distillers dried grains with solubles (RFDGS), high-protein distillers dried grains, and modified wet distillers grains with solubles (MWDGS). Nylon bags containing 5g of each feed were incubated in the rumen of 3 cannulated lactating cows for 2, 4, 8, 16, 24, and 48h. The rapidly degradable CP fraction varied from 8.1 to 37.2% for SBM and MWDGS, respectively. The slowly degradable CP fraction was greatest for SBM, ES, and high-protein distillers dried grains (88.0%±3.7), followed by ESBM, distillers dried grains with solubles, and RFDGS (76.8±4.1%). The MWDGS had the lowest slowly degradable CP fraction (61.1%). The rate of degradation of the slowly degradable CP fraction ranged from 11.8 for SBM to 2.7%/h for RFDGS. Rumen-undegradable protein varied widely (32.3 to 60.4%), with RFDGS having the greatest and SBM the lowest concentrations. Intestinal digestibility of rumen-undegradable protein (IDP) was estimated by pepsin-pancreatin digestion of ruminally preincubated (16h) samples. The IDP was greatest for SBM, ESBM, and ES (97.7%±0.75), whereas IDP of DG products was 92.4%±0.87. Similarly, total digestible protein was greatest (99.0%) for soybean products, whereas DG products had a total digestible protein of 96.0%. Intestinal digestibility of most AA in DG products exceeded 92% and was slightly lower than for soybean products, except for Lys, where the digestibility was 84.6% for DG compared with 97.3% for soybean products. Absorbable Lys was lower for DG (7.0 g/kg of CP) compared with ESBM and ES (average of 23.8 g/kg of CP). Dried DG, ESBM, and ES provided more absorbable AA compared with SBM and MWDGS. These results suggest that the AA availability from DG products is comparable with that from soybean products.

Dried distillers grains with solubles with reduced corn silage levels in beef finishing diets1,2

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.

Effects of sulfur and monensin concentrations on in vitro dry matter disappearance, hydrogen sulfide production, and volatile fatty acid concentrations in batch culture ruminal fermentations1

Effects of monensin (MON) and S on in vitro fermentation and H(2)S production were evaluated in 2 experiments. In Exp. 1, 2 ruminally cannulated steers were adapted (>14 d) to a 75% concentrate diet [steam-flaked corn (SFC)-based], and ruminal fluid was collected approximately 4 h after feeding. Substrate composed (DM basis) of 85.2% SFC, 9% alfalfa hay, 5% cottonseed meal, and 0.8% urea was added with ruminal fluid and buffer to sealed 125-mL serum bottles to allow for gas collection. A Na(2)SO(4) solution was added to yield S equivalent to 0.2, 0.4, and 0.8% of substrate DM, and MON was included at 0, 2, 4, and 6 mg/L of culture volume. Bottle head-space gas was analyzed for H(2)S. No MON (P = 0.29) or MON x S interaction (P = 0.41) effects were detected for H(2)S production. Increasing S linearly increased (P < 0.01) H(2)S production (micromoles/g of fermented DM). The IVDMD (average 70.0%) was not affected by MON (P = 0.93), S (P = 0.18), or the MON x S interaction (P = 0.56). Total VFA concentrations were not affected by MON (P = 0.87), S (P = 0.14), or the MON x S interaction (P = 0.86), but increasing MON linearly decreased (P <or= 0.01) molar proportions of acetate, butyrate, and the acetate:propionate ratio (A:P), and linearly increased (P < 0.01) the proportion of propionate. In Exp. 2, 2 additional ruminally cannulated Jersey steers were adapted (>21 d) to a 75% concentrate diet (SFC base) that contained 15% (DM basis) wet corn distillers grains plus solubles (WDGS) and MON at 22 mg/kg of DM. In vitro substrate DM was composed of 75.4% SFC, 15% WDGS, 9% alfalfa hay, and 0.6% urea, and S and MON concentrations were the same as in Exp. 1. No effects of MON (P = 0.93) or the MON x S interaction (P = 0.99) were noted for H(2)S production; however, increasing S linearly increased (P < 0.01) H(2)S production. No effects of MON (P = 0.16), S (P = 0.43), or the MON x S interaction (P = 0.10) were noted for IVDMD (average 70.9%). Total VFA concentrations were not affected by MON (P = 0.40), S (P = 0.26), or the MON x S interaction (P = 0.59). As in Exp. 1, increasing MON linearly decreased (P < 0.05) molar proportions of acetate, butyrate, and A:P and linearly increased (P < 0.01) propionate. Increasing S concentration increased in vitro H(2)S production, but S did not affect VFA concentrations and proportions. Monensin did not affect in vitro H(2)S production, and changes in VFA molar proportions were evident with MON regardless of S concentration.

Isolipidic additions of fat from corn germ, corn distillers grains, or corn oil in dairy cow diets

Eight multiparous and 8 primiparous Holstein cows were used in a replicated 4 × 4 Latin square design with 4-wk periods to determine the effects on dairy cow performance of feeding corn germ (CG) compared with dried distillers grains with solubles (DDGS) or corn oil (CO). Four isolipidic dietary treatments were formulated: a control diet, a 14% corn germ diet (CGD), a 30% dry distillers grains with solubles diet (DGD), and a 2.5% corn oil diet (COD). All diets were formulated to contain 6.0% fat, with the fat in the control diet provided by a ruminally inert fat source. Dry matter intake was decreased by feeding the COD compared with the CGD; however, no difference in dry matter intake was observed among the control diet, the DGD, and the COD. Dietary treatments had no effect on milk yield, energy-corrected milk, or 4% fat-corrected milk. Feeding CG had no effect on milk fat percentage when compared with the control diet; however, milk fat percentage tended to decrease with DDGS and decreased with CO when compared with the CGD. Milk protein percentage decreased when cows were fed the COD compared with the control diet. Feeding CO tended to decrease milk fat yield compared with CG; however, dietary treatments had no effect on milk protein and lactose yield. Feed efficiency was not affected by dietary treatments and averaged 1.55kg of energy-corrected milk/kg of dry matter intake. Feeding DDGS and CO increased the concentration of vaccenic and conjugated linoleic acid in milk fat. Concentrations of monounsaturated and polyunsaturated fatty acids in milk were increased in response to feeding the 3 corn coproducts. Fat from CG appears to be relatively protected in the rumen when compared with that from DDGS and CO and therefore will not affect the production of milk fat to the degree of the more available fat in DDGS and CO.

Applying technology with newer feed ingredients in feedlot diets: Do the old paradigms apply?1

Use of coproducts such as corn and sorghum distillers grain (DG) and corn gluten feed (CGF) in beef cattle finishing diets has increased significantly in recent years, but research to evaluate the efficacy of traditional feeding practices and feed additives when coproducts are fed has not kept pace. Grain processing methods that increase starch availability seem equally effective in traditional diets and diets with wet CGF; however, in wet DG diets, some studies have shown decreased efficacy of grain processing, whereas others have shown no evidence of an interaction. Limited data are available on the physical and nutritional value of the fiber in wet DG and CGF; however, CGF at concentrations >/=25% of the dietary DM seems to have some degree of "roughage value," whereas fiber in wet DG seems to have less potential to replace traditional roughage sources. There is little evidence that efficacy of ionophores and antibiotics is changed with diets based on wet CGF or that they interact when wet DG is added to finishing diets. In vitro data from our laboratory suggest no loss of monensin efficacy in substrates with 15% (DM basis) corn DG in terms of changes in VFA and gas production. Moreover, efficacy of ionophores was not affected in our data by diet substrates with increasing concentrations of S, and in vitro H(2)S production in substrates containing wet DG seems predictable from substrate S concentrations. Nonetheless, limited in vivo data indicate decreased ruminal acetate-to-propionate ratios in diets with increased wet DG, which may minimize the potential for ionophores to alter propionate. Likewise, in vivo results indicate that feeding wet DG may decrease ruminal pH; thus, to maximize DMI and minimize digestive upsets, optimal concentrations of roughage need to be evaluated in diets containing wet DG. Research is needed on other potential technology interactions with coproducts of biofuel production such as glycerol and condensed distillers solubles. The effects of yeast products and live microbial cultures in diets with coproduct feeds have generally not been determined. Because of the elevated fiber concentrations in CGF and DG, effects of exogenous enzyme preparations on ruminal fermentation and fiber digestion of diets containing these coproducts should be evaluated.

Effects of Adding MIN-AD to Steam-Flaked Corn-Based Diets With or Without Wet Corn Distillers Grain Plus Solubles on Performance by Beef Cattle During Receiving and Finishing Phases

<h2>ABSTRACT</h2> Effects of wet corn distillers grain (WCDG) and MIN-AD (MIN-AD Inc., Amarillo, TX), a commercial source of calcium-magnesium carbonate, on cattle performance and carcass measurements were evaluated in a 42-d receiving phase (220 steers; initial BW=279.3 kg) and a subsequent finishing phase (192 steers). Both phases were arranged as a 2 × 2 factorial using steam-flaked corn-based diets. Factors were MIN-AD (0 or 0.75% of dietary DM) and WCDG (0 or 15% of dietary DM). Few MIN-AD × WCDG interactions were detected in either phase. Neither MIN-AD nor WCDG affected ADG, DMI, G:F, or 42-d BW (P > 0.129) during the receiving period. Compared with control steers, cattle fed WCDG in the finishing phase had greater (P < 0.01) ADG, DMI, final BW, and hot carcass weight (HCW). Fecal pH of cattle fed 15% WCDG was less than that of control steers (P < 0.05). Feeding WCDG had no effect (P ≥ 0.19) on dressing percentage, LM area, 12th-rib fat, KPH, YG, marbling score, QG, or incidence of liver abscesses. Supplementing diets with MIN-AD increased LM area (P = 0.031), but ADG, DMI, G:F, final BW, HCW, dressing percentage, 12th-rib fat, KPH percentage, YG, marbling score, QG, and incidence of liver abscesses were not affected (P ≥ 0.063) by MIN-AD. Results suggest that feeding 15% WCDG in a steam-flaked corn-based diet did not affect cattle performance during the receiving period, but it increased DMI, ADG, final BW, and HCW during the finishing period. Supplementing MIN-AD in combination with WCDG did not affect performance.

Preliminary Investigation of the Association between Feeding Starch-based Ethanol Co-Products and Salmonella Species Shedding in Commercial Feedlots

Fecal shedding of Salmonella spp in feedlot cattle is an important component of pre-harvest food safety. Prevalence of salmonella in feedlot cattle varies and may be influenced by factors affecting hindgut and environmental ecology. Feedlots in the Texas Panhandle have begun to incorporate wet corn distiller's grains (WDGS) in their rations due to the increase in starch-based ethanol production in the region. Previous research has identified an association between feeding distiller's grains and shedding of E.coli O157:H7. These findings indicate that changes in starch, fiber, and fat composition of rations containing WDGS may impact hindgut ecology favoring the colonization and shedding of specific microorganisms. The objective of this study was to estimate the association between feeding WDGS and fecal shedding of Salmonella spp in feedlot cattle.

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 digestion1

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 dried corn distillers grains with solubles on growth performance, carcass characteristics, and meat quality of yearling heifers1

Three hundred forty-seven crossbred heifers (330 +/- 11 kg initial BW) were used in a randomized complete block study to identify the optimal level of dried corn distillers grains with solubles (DGS) in flaked corn finishing diets. Fifty-four pens were used, with 9 pens per treatment and 6 to 7 heifers per pen. Finishing diets were steam-flaked corn-based and were fed once daily for 148 d. Dietary treatments consisted of 6 levels of DGS (0, 15, 30, 45, 60, and 75%, DM basis). Dry matter intake, ADG, and final BW responded quadratically (P < or = 0.03) to increasing levels of DGS and were maximized at 15% DGS. However, G:F decreased linearly (P = 0.01) as level of DGS increased. Longissimus muscle areas were not different (P > or = 0.27), whereas 12th-rib fat thicknesses decreased linearly (P = 0.05) for heifers fed increasing levels of DGS. Marbling score and USDA yield grades were not different (P > or = 0.06) for heifers fed different levels of DGS. Number of carcasses grading USDA Prime or Choice were not different (P > or = 0.07), whereas number of carcasses grading USDA Select increased (P = 0.02; linear) as dietary level of DGS increased from 0 to 75%. Myofibrillar and overall tenderness increased linearly (P = 0.01) as dietary level of DGS increased from 0 to 75%. Juiciness, off-flavor intensity, and thiobarbituric acid reactive substances were not different (P > or = 0.16) among treatments. Redness of steaks (i.e., a*) was not different (P > or = 0.13) for steaks collected from heifers fed different levels of DGS as evidenced by similar instrumental color measurements after d 0, 3, and 5 of display. However, on d 7, steak color was less red (P = 0.04) and had more metmyoglobin. Concentration of linoleic acid (18:2n-6cis), total n-6 fatty acids, and total PUFA linearly increased (P = 0.01) with increasing levels of DGS.

Evaluation of Feeding Dried Distiller's Grains with Solubles and Dry-Rolled Corn on the Fecal Prevalence ofEscherichia coliO157:H7 andSalmonellaspp. in Cattle

Escherichia coli O157:H7 and Salmonella are foodborne pathogens that reside in the gut of cattle and are shed in the feces. Previous work indicated a positive association between feeding cattle distiller's grains (DG) and an increase in E. coli O157:H7 prevalence. Feeding processed grains also has been shown to affect fecal prevalence of E. coli O157:H7. The objective of this study was to evaluate the effect of feeding DG and dry-rolled corn (DRC), alone or in combination, on fecal prevalence of E. coli O157:H7 and Salmonella in finishing cattle. Cattle were allotted to pens (n = 28), and fed dietary treatments (n = 150 days) structured in a 2 x 2 factorial arrangement; the factors were 0% or 25% dried corn DG with solubles (DDGS) and 0% or 25% DRC in steam-flaked corn-based high-grain diets. Fecal samples were collected from each pen floor before initiating dietary treatments and at least once every 2 weeks after final diets began. Overall prevalence of E. coli O157:H7 in fecal samples was 5.1%. There were no significant effects of DDGS, DRC, or sampling time on E. coli O157:H7 prevalence (p > 0.20). Overall prevalence of Salmonella in pen floor fecal samples was 23.7%, and sampling week affected prevalence (p < 0.01), ranging from < 1% (week 1) to 77.5% (week 17). Salmonella prevalence was not affected by cattle diet, and no work had previously reported an association between either DG or DRC and Salmonella prevalence. Lack of an association between E. coli O157:H7 prevalence and feeding DG or DRC is contrary to previous observations. Further research is needed to understand inconsistencies between studies of E. coli O157:H7 prevalence and potential associations with DG and grain-processing methods.

Ensiling characteristics of wet distillers grains mixed with soybean hulls and evaluation of the feeding value for growing Holstein heifers1

Two experiments were conducted to evaluate the fermentation characteristics of ensiled wet corn distillers grains with solubles (WDG) alone or mixed with soybean hulls (SH) and the ability of the mixture to maintain growth performance in dairy heifers. The first experiment was an ensiling study using laboratory silos. Ensiled blends were 100% WDG, 85% WDG with 15% SH, and 70% WDG with 30% SH on an as-fed basis. Silos were opened for analysis on d 0, 3, 7, and 21. The pH was less in the 100% WDG compared with other treatments (P < 0.01), but all treatments had a pH near 4. Lactic acid concentration was greater in 100% WDG compared with the blends of WDG and SH (P < 0.01). Acetic acid was not found in 100% WDG and increased over time in the 2 blends (P < 0.01). Other differences between blends, such as DM, CP, ammonia N, fiber, and fat, were reflective of the different concentrations of WDG and SH in the blends. In the second experiment, the 70% WDG and 30% SH (as-fed) blend was ensiled in a silo bag and then evaluated as a feed for growing dairy heifer diets. Twenty-four heifers were used in a randomized complete block design and assigned to be fed 1 of 3 diets: 1) control, 2) low inclusion of WDGSH, and 3) a high inclusion of WDGSH. All treatment diets consisted of 50% brome grass hay on a DM basis. The control diet had 50% of the diet (DM basis) as a grain mix, which was composed of corn, soybean meal, and minerals. The low WDGSH diet contained 24.4% of the blend and 25.6% grain mix. The high WDGSH diet contained 48.7% of the blend and 1.3% mineral mix. Average daily gain and most of the body growth measures were similar among treatments. However, DMI decreased linearly (P < 0.01) as the WDGSH blends were fed, resulting in improved (P = 0.02) G:F. Results from these experiments indicated that WDG can be effectively ensiled with SH and sustain adequate growth rate when fed to growing dairy heifers.