Canadian Journal of Animal Science

Transcription

1 EFFECT OF GRAIN TYPE AND DRIED DISTILLERS GRAINS WITH SOLUBLES OIL CONCENTRATION ON SITE OF DIGESTION IN CATTLE FED FINISHING DIETS Journal: Manuscript ID CJAS R1 Manuscript Type: Article Date Submitted by the Author: 22-Nov-2017 Complete List of Authors: Rodenhuis, Mary Keomanivong, Faithe; North Dakota State University, Animal Sciences Bauer, Marc; North Dakota State University, Animal Sciences Swanson, Kendall ; North Dakota State University, Animal Sciences Keywords: Digestion, Distillers grains, Finishing cattle, Oil Concentration, Grain source

2 Page 1 of 18 EFFECT OF GRAIN TYPE AND DRIED DISTILLERS GRAINS WITH SOLUBLES OIL CONCENTRATION ON SITE OF DIGESTION IN CATTLE FED FINISHING DIETS Mary A. Rodenhuis, Faithe E. Keomanivong, Marc L. Bauer, and Kendall C. Swanson M. A. Rodenhuis, F E. Keomanivong, M. L. Bauer, and K. C. Swanson: Department of Animal Sciences, North Dakota State University, Fargo ND Corresponding author: Kendall Swanson ( kendall.swanson@ndsu.edu) Abbreviations: ADF, acid detergent fibre; ADG, average daily gain; BW, body weight; CDS, corn condensed distillers solubles; CP, crude protein; DDGS, dried corn distillers grains plus solubles; DM, dry matter; DMI, dry matter intake; MP, metabolizable protein; OM, organic matter; NDF, neutral detergent fibre. 1

3 Page 2 of 18 ABSTRACT: The objective of this experiment was to determine the effects of grain type (rolled corn vs. rolled barley) and oil concentration of dried corn distillers grains plus solubles (DDGS; moderate = 7.9% vs low = 4.5% ether extract) on site of digestion. Seven ruminally- and duodenally-cannulated Holstein steers (716 ± 8.9 kg) were used in a 4 7 Youden square with experimental periods of 24 days. True ruminal organic matter (OM) and crude protein (CP) digestibility (% of intake) as well as intestinal (% of entering duodenum) and total tract starch digestibility was greater (P 0.03) in steers fed diets containing barley than in steers containing corn. Ruminal disappearance and ruminal, intestinal, and total tract OM, CP, and starch digestibility was not influenced (P 0.11) by feeding diets containing DDGS with differing oil concentration. Total tract lipid digestibility (%) was greater (P < 0.001) in steers fed diets containing moderate-oil DDGS than low-oil DDGS. These data indicate that including a loweroil DDGS as compared to a moderate-oil DDGS in finishing diets containing rolled corn or rolled barley does not influence intake or site of digestion of non-lipid components. Key words: digestion, distillers grains, finishing cattle, grain source, oil concentration 2

4 Page 3 of 18 INTRODUCTION Feed costs represent a large proportion of the expenses in beef production. Utilizing different grain types can influence feed efficiency which is important for optimizing cattle performance (Gozho and Mutsvangwa 2008; Owens et al. 1997). Dried corn distiller grains plus solubles (DDGS) is a valuable feed product utilized in finishing diets (Klopfenstein et al. 2008). Including corn DDGS has been shown to increase dry matter intake (DMI) and average daily gain (ADG) with increasing levels in a rolled barley-based diet (Anderson et al. 2011) and optimal inclusion may differ depending on grain source (Klopfenstein et al. 2008). The ethanol industry is evolving and changing their production practices. This has resulted in changes in the nutrient composition, such as decreased oil concentration, of the final coproduct available as a feedstuff. Increasing fat in the diet has been shown to increase ADG in finishing steers (Zinn 1989). However, increasing oil concentration in the diet can also have a negative effect on digestibility of non-lipid energy sources (Jenkins 1993) which could be detrimental. We hypothesized that grain type and DDGS oil concentration would have an effect on site of digestion. Our objectives were to determine the effect and interaction of grain type and DDGS oil concentration on ruminal, intestinal and total tract digestibility. MATERIALS AND METHODS All animal care and handling procedures were approved by the North Dakota State University Animal Care and Use Committee. Animals, Experimental Design, and Dietary Treatments Seven ruminally- and duodenally-canulated Holstein steers (716 ± 8.9 kg) were used in a 4 x 7 Youden square design consisting of 4 periods and 4 dietary treatments and 7 steers assigned randomly per treatment per period (1 or 2 steers per period per treatment) to determine 3

5 Page 4 of 18 the influence of grain type (corn vs barley) and DDGS oil concentration (DDGS; moderate = 7.9% vs low = 4.5%; Table 1) on intake and total tract digestibility. Eight steers were initially used in the experiment but one was removed because of a failing duodenal cannula. Steers were housed in individual tie stalls (1.0 x 2.2 m) in a temperature-controlled room. Dietary treatments (Table 2) were offered to ensure ad libitum intake and 6% feed refusal daily. Treatments were arranged as a 2 2 (grain type DDGS oil concentration) factorial arrangement and included 1) dry-rolled corn with moderate-oil DDGS, 2) dry-rolled corn with low-oil DDGS, 3) dry-rolled barley with moderate-oil DDGS, and 4) dry-rolled barley with low-oil DDGS. Diets were formulated to meet or exceed requirements for ruminally degradable intake protein (DIP), metabolizable protein (MP), minerals, and vitamins (NRC 1996). Before the initiation of the experiment, steers were adapted from a high-forage diet to a high-concentrate diet over a 21-d period. Each treatment period consisted of 24 d allowing for 7 d of diet adaptation, 7 d of sample collection, and a 10-d rest period in which all steers were offered an intermediate dietary transition (50% of previous and 50% of following diet) before being provided the next dietary treatment. Collection of Feed, Orts, Feces, and Digesta Diets were mixed prior to each period and stored in a cold room. Chromic oxide (Cr 2 O 3 ) was used as an external marker to determine nutrient flows and was included in the ration at 0.25% of diet DM. A sample of feed was collected after mixing for later analysis (Table 3). Orts were collected at 0800 daily and sampled (2% of weight). Each steer s consumption was calculated and steers were offered fresh feed by 0800 daily. Feed samples were collected immediately after mixing rations while orts were composited over each collection period. Samples were stored at -20 C until analyses. 4

6 Page 5 of 18 Steers were fitted with fecal collection bags for the duration of the 7-d collection period. Feces were collected twice daily (0600 and 1800) and mixed by hand to ensure a representative sample. A sample (2% of weight on a wet basis) was collected to represent the entire collection period. Fecal samples were stored at -20 C until analyses. Ruminal fluid and post ruminal chyme samples (approximately 200 ml) were collected into bags (532-mL; Nasco, Fort Atkinson, WI) from d 3 to 5 in a manner that allowed a sample to be collected every other h in a 24-h cycle. Samples were taken at 0200, 0800, 1400, and 2000 h on d 3; 0400, 1000, 1600, and 2200 h on d 4 and 0600, 1200, 1800, and 0000 h on d 5. Samples were stored at -20 C until the end of the collection period and then thawed, composited, and dried in a freeze drier (VirTis Co., Gardiner, NY). On the final d of the collection period, a 4-kg sample of ruminal contents was collected from each animal for the isolation of bacterial cells. Random grab samples were gathered from several locations inside the rumen to ensure representation of the liquid and fibre phases. Samples were placed in containers and mixed with approximately 2 L of a solution containing 3.7% formaldehyde and 0.9% NaCl. They were then blended at medium speed for at least 5 min using a commercial, heavy-duty blender (model 37BL19CB6, Waring Products division, New Hartford CT), strained through 4 layers of cheese cloth, and frozen at -20 C until chemical analyses. Laboratory Analyses Feed, orts, and fecal samples were dried for 48 h at 60 C in a forced-air oven (Grieve SB- 350, The Grieve Corporation, Round Lake, IL) and ground to pass a 2-mm screen (Wiley mill, Model #3; Arthur H. Thomas, Philadelphia, PA). Feed and orts samples were analyzed (AOAC 1990) for DM, ash, and N using the Kjeldahl method. Feed samples also were analyzed for NDF 5

7 Page 6 of 18 and ADF (Robertson and Van Soest 1981), and Ca and P (AOAC 1990). The methods of Herrera-Saldana and Huber (1989) were used to analyze for starch concentration on a microplate spectrophotometer (Synergy H1 Microplate reader, BioTek Instruments, Winooski, VT). Total lipid concentration was analyzed using a method adapted by Folch et al. (1957). Ruminal fluid samples were centrifuged at 2000 g for 20 min. The liquid portion was filtered through a µm filter and analyzed for ammonia (Broderick and Kang 1980). Bacterial isolation was accomplished by centrifuging samples in 250-mL bottles at 500 g for 20 min to remove protozoa and feed particles. The supernatant was removed and then centrifuged at 30,000 g for an additional 20 min to pellet bacteria. Isolated bacteria were frozen, lyophilized, and analyzed for DM, ash, N (AOAC 1990), and purines (Zinn and Owens 1986). Duodenal samples were analyzed for Cr by a spectrophotometric method of Fenton and Fenton (1979). Calculations Total nutrient flows to the small intestine were calculated based on the ratio of nutrients to Cr in the duodenal digesta as compared to intake (Merchen 1988). Microbial organic matter and N leaving the abomasum were calculated using purines as a microbial marker (Zinn and Owens 1986). Total tract Cr recovery ranged from 92 to 102% and did not differ (P 0.28) among treatments (data not shown). Ruminal organic matter (OM) fermented was calculated as OM intake minus the difference between the amount of total OM reaching the duodenum and microbial OM reaching the duodenum. Feed N escape to the small intestine was calculated by subtracting microbial N from total N and thus includes any endogenous and NH 3 -N contributions. Total tract digestibility was calculated using analysis from intake and total fecal collection. 6

8 Page 7 of 18 Statistical Analysis Data were analyzed as a 4 7 Youden square with a 2 2 factorial arrangement of treatments using the generalized least square means Mixed procedure (SAS Inst. Inc., Cary, NC). The model included the effects of steer (as a random effect), period, grain type (corn vs barley), DDGS oil concentration (moderate vs low), and the interaction between grain type and DDGS oil concentration. A P-value of less than or equal to 0.05 was considered a significant difference while a P-value of greater than 0.05 but less than 0.10 was considered a tendency. RESULTS Intake of OM was not influenced by dietary treatment (Table 3). Duodenal flow of feed and total OM was greater (P 0.01) in steers fed diets containing corn than in steers fed diets containing barley but duodenal flow of microbial OM was not influenced by treatment. Ruminal disappearance of OM was greater (P = 0.04) in steers fed diets containing barley than in steers fed diets containing corn. Fecal output of OM was not influenced by dietary treatment. Apparent and true ruminal, and intestinal OM digestibility (% of intake) was greater (P 0.01) in steers fed diets containing barley than in steers containing corn. Intestinal OM digestibility (% of entering duodenum) was greater (P = 0.01) in steers fed diets containing corn than in steers fed diets containing barley. Total tract OM digestibility was not influenced by dietary treatment. Oil concentration of DDGS did not influence OM flow, or ruminal and intestinal disappearance and digestibility. Intake of CP was not influenced by dietary treatment (Table 4). Duodenal flow of feed CP was greater (P = 0.02) in steers fed diets containing corn than in steers fed diets containing barley but duodenal flow of microbial and total CP was not influenced by grain source. Ruminal disappearance of CP tended (P = 0.07) to be less in steers fed diets containing corn than in cattle 7

9 Page 8 of 18 fed diets containing barley. Fecal output of CP was not influenced by dietary treatment. Apparent ruminal digestibility (% of intake) of OM tended (P = 0.06) to be less, true ruminal digestibility (% of intake) was less (P = 0.01), and intestinal digestibility (% of intake) tended (P = 0.09) to be greater in steers fed diets containing corn than in steers fed diets containing barley. Intestinal digestibility (% of entering duodenum), total tract digestibility of CP, and microbial efficiency was not influenced by treatment. Oil concentration of DDGS did not influence CP flow, or ruminal and intestinal disappearance and digestibility. Intake of starch was greater (P = 0.03) in steers fed diets containing corn than in steers containing barley but was not influenced by DDGS oil concentration (Table 5). Duodenal flow of starch was not influenced by DDGS oil concentration but tended (P = 0.09) to be greater in steers fed low-oil DDGS than in steers fed high-oil DDGS. Ruminal disappearance and fecal output of starch was greater in steers fed corn than in steers fed barley but was not influenced by DDGS oil concentration. Apparent ruminal and intestinal digestibility (% of intake) was not influenced by dietary treatment. There was an interaction (P = 0.05) between grain type and DDGS oil concentration for intestinal digestibility (% of entering duodenum) of starch as digestibility decreased when feeding moderate-oil DDGS when compared to low-oil DDGS in diets containing corn but not in diets containing barley. Total tract digestibility of starch was greater (P = 0.02) in steers fed diets containing barley than in steers fed diets containing corn. There was an interaction (P = 0.03) between grain type and DDGS oil concentration for lipid intake but was likely because intake increased to a greater extent in steers fed diets containing moderate-oil DDGS than in steers fed low-oil DDGS when steers were fed diets containing barley than in steers fed diets containing corn. Duodenal flow of lipids was greater (P = 0.01) in steers fed diets containing corn than in steers fed diets containing barley but was not influenced 8

10 Page 9 of 18 by DDGS oil concentration. Ruminal disappearance and fecal output were not influenced by dietary treatment. Apparent ruminal digestibility (% of intake) of lipids was not influenced by grain type but was greater (P = 0.02) in steers fed diets containing moderate-oil DDGS than in steers fed diets containing low-oil DDGS. Intestinal digestibility (% of intake) of lipids was not influenced by grain source but was greater (P = 0.04) in steers fed diets containing low-oil DDGS than in steers fed diets containing moderate-oil DDGS. Intestinal digestibility (% of entering duodenum) of lipids was not influenced by treatment. Total tract digestibility tended (P = 0.07) to be greater in steers fed diets containing corn than in steers fed diets containing barley and was greater (P < 0.001) in steers fed diets containing moderate-oil DDGS than in steers fed diets containing low-oil DDGS. DISCUSSION Corn dried distillers grains plus solubles is commonly used in finishing diets because of its availability and feeding value. Changes in the nutrient composition of DDGS, such as decreased oil concentration, could potentially influence the value for use as a feed ingredient. Nutrient composition and digestibility are primary factors influencing feed quality and value. This raises the question, does the removal of oil alter nutrient digestibility of DDGS when fed in diets based on different grains for finishing cattle. As generally there were no interactions between grain type and DDGS oil concentration, our results would suggest that similar responses to feeding DDGS with differing oil concentrations results occurs in corn- or barley-based diets. Past research has shown that starch in barley grain is more digestible in the rumen than starch in corn grain (Ferraretto et al. 2013) with similar total tract digestibility. This would lead to the conclusion that site of digestion of starch for corn shifts more to the small or large intestine than for barley. Research has also shown that ruminal digestibility, intestinal digestibility and 9

11 Page 10 of 18 total tract digestibility of barley is greater than that of corn (Tothi et al. 2003). Our data show somewhat similar results in that intestinal (% entering duodenum) and total tract starch digestibility, as well as true ruminal OM and CP digestibility, was greater in steers fed diets containing barley than diets containing corn. This improvement in digestion could result in increased energy supply to the animal resulting in improved growth or efficiency. These results are likely because of increased energy supply as no differences were observed in microbial or total CP flow to the duodenum. This theory is supported by our results from a companion growth performance study (Rodenhuis et al. 2017) utilizing the same diets with the results showing that steers fed diets containing barley had decreased DMI with the same ADG resulting in improved G:F. Little is known about how the oil concentration of DDGS affects site of digestion in finishing cattle. Jolly-Breithaupt et al. (2015) reported no differences in total-tract DM, OM, NDF, or oil digestibility when comparing low-oil modified distillers grains plus solubles (MDGS; 8.7% oil) with normal-oil MDGS (15.4% oil). They also found no differences in totaltract DM or OM total tract digestibility in low-oil condensed distillers solubles (CDS; 9.2% oil) versus normal-oil CDS (12.3% oil). However, they did report a decrease in total tract digestibility of oil in de-oiled CDS versus normal CDS. Ceconi et al. (2013) also studied the effect of lowering oil concentration of DDGS on site of digestion. Their treatments were diets containing 35% moderate-oil DDGS (6.7% total dietary oil) or low-oil DDGS (4.5% total dietary oil) as well as a control which included no DDGS in the diet (3.7% total dietary oil). They found differences in OM intake where the low-oil DDGS and traditional DDGS treatments had greater intake than the control diet but there were no differences between DDGS treatments. Digestibility of OM or CP and microbial CP flow did not differ between DDGS treatments or 10

12 Page 11 of 18 DDGS treatments compared to the control treatment. Our results are in agreement with the previous two studies suggesting that there is no difference in total tract digestibility of DM, OM, CP, or starch when comparing low-oil DDGS with moderate-oil DDGS. Our results suggest that reducing the oil concentrations in DDGS results in altered lipid digestibility. Our results are similar to Jolly-Breithaupt et al. (2015) in that feeding the lower oil DDGS resulted in lower total tract lipid digestibility which could suggest that lower oil DDGS has lipids that are not as digestible as the lipids in the higher oil DDGS. Additionally, in our study, we found that there was an increase in lipid intake in the moderate- vs. the low-oil DDGS but no differences were found in fecal lipid output which indicates that the animal is utilizing more of the lipid from the moderate-oil DDGS than the low-oil DDGS which supports the theory that the lipids in the lower oil concentration products may not be as digestible. This theory needs to be studied further to know the full effects and implications that can be associated with feeding an ethanol coproduct with lower oil concentrations, especially as in our companion study (Rodenhuis et al. 2017), feeding the same diets, we observed no differences in growth performance or carcass characteristics between steers fed diets containing low-oil DDGS vs. moderate-oil DDGS. It should be pointed out that NDF and ADF concentrations were greater and starch concentrations lesser in the moderate-oil compared to the low-oil ddgs which could potentially influence the responses observed in this experiment. Although it is unlikely that other nutrient differences between the DDGS sources tested in this experiment largely affected the observed results, our results also have practical significance as the sources of the DDGS are major suppliers of DDGS to feedlots both in the USA and in Canada. In conclusion, utilizing barley, as compared to corn, in finishing diets increased total tract starch digestibility, which could result in increased energy available to the animal and potentially 11

13 Page 12 of 18 improve growth performance. Also, decreasing the oil concentration of DDGS had no effect on site of digestion or total tract digestibility of DM, OM, CP, or starch of the diets. Therefore, utilizing low-oil DDGS in place of moderate-oil DDGS in finishing diets may not affect digestibility of nutrients, other than lipids, of finishing cattle diets. Acknowledgements The authors would like to thank the North Dakota Corn Utilization Council for partial funding of the project and the employees at the Animal Nutrition and Physiology Center and the Nutrition Laboratory in the Department of Animal Sciences for their assistance. References Anderson, V.L., Ilse, B.R., and Wiederholt, R Effects of increasing levels of distillers grains in barley-based diets on growing and finishing feedlot performance, carcass traits, and nutrients in manure. Prof. Anim. Sci. 27: AOAC Official Methods of Analysis, Arlington, VA. Broderick, G.A., and Kang, J.H Automated simultaneous determination of ammonia and total amino acids in ruminal fluid and in vitro media. J.Dairy Sci. 63: Ceconi, I., Ruiz-Moreno, M., DiCostanzo, A., and Crawford, G.I Effect of low-fat dried distillers grains inclusion in finishing diets on finishing cattle total-tract digestibility and ruminal fermentation parameters. J. Anim. Sci. 91(E-Suppl. 2): 692. Fenton, T.W., and Fenton, M An improved procedure for the determination of chromic oxide in feed and feces. Can.J.Anim.Sci. 59: Ferraretto, L.F., Crump, P.M., and Shaver, R.D Effect of cereal grain type and corn grain harvesting and processing methods on intake, digestion, and milk production by dairy cows through a meta-analysis. J.Dairy Sci. 96: Folch, J., Lees, M., and Stanley, G A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226: Gozho, G.N., and Mutsvangwa, T Influence of carbohydrate source on ruminal fermentation characteristics, performance, and microbial protein synthesis in dairy cows. J.Dairy Sci. 91: Herrera-Saldana, R., and Huber, J.T Influence of varying protein and starch degradabilities on performance of lactating cows. J.Dairy Sci. 72:

14 Page 13 of 18 Jenkins, T.C Lipid metabolism in the rumen. J.Dairy Sci. 76: Jolly-Breithaupt, M.L., Schreck, A.L., Harding, J.L., MacDonald, J.C., Klopfenstein, T.J., and Erickson, G.E Nutrient digestibility and ruminal ph of finishing diets containing dry milling byproducts with and without oil extraction. In Nebraska Beef Cattle Report. Agricultural Research Division, University of Nebraska Extension, Institute of Agriculture and Natural Resources, University of Nebraska Lincoln. pp Klopfenstein, T.J., Erickson, G.E., and Bremer, V.R BOARD-INVITED REVIEW: Use of distillers by-products in the beef cattle feeding industry. J.Anim.Sci. 86: Merchen, N.R Digestion, absorption and excretion in ruminants. In The Ruminant Animal - Digestive Physiology and Nutrition. Edited by D.C. Church. Prentice-Hall, Englewood Cliffs, NJ. p NRC Nutrient Requirements of Beef Cattle. National Academy Press, Washington, DC. Owens, F.N., Secrist, D.S., Hill, W.J., and Gill, D.R The effect of grain source and grain processing on performance of feedlot cattle: a review. J.Anim.Sci. 75: Robertson, J.B., and Van Soest, P.J The detergent system of analysis and its application to human foods. In The Analysis of Dietary Fiber. Edited by W.P.T. James and O. Theander. Marcell Dekker, New York. pp Rodenhuis, M.A., Keomanivong, F.E., Gaspers, J.J., Gilbery, T.C., Underdahl, S.R., Bauer, M.L., Anderson, V.L., Engel, C.L., and Swanson, K.C Influence of grain source and dried corn distillers grains plus solubles oil concentration on finishing cattle performance and feeding behavior. Can. J. of Anim. Sci. 97: Tothi, R., Lund, P., Weisbjerg, M., and Hvelplund, T Effect of expander processing on fractional rate of maize and barley starch degradation in the rumen of dairy cows estimated using rumen evacuation and in situ techniques. Anim. Feed Sci. Technol. 104: Zinn, R., and Owens, F A rapid procedure for purine measurement and its use for estimating net ruminal protein-synthesis. Can. J. Anim. Sci. 66: Zinn, R.A Influence of level and source of dietary fat on its comparative feeding value in finishing diets for steers: feedlot cattle growth and performance. J.Anim. Sci. 67:

15 Page 14 of 18 Table 1. Analyzed nutrient concentration of DDGS a (DM basis). Dietary Component, % of DM Low-Oil DDGS Moderate- Oil DDGS Crude protein, % of DM Neutral detergent fibre, % of DM Acid detergent fibre, % of DM Ether extract, % of DM Calcium, % of DM Phosphorus, % of DM Starch, % of DM a Corn distillers grains with solubles (Low-Oil DDGS, 4.5% ether extract; moderate-oil DDGS; 7.9% ether extract). 14

16 Page 15 of 18 Table 2. Dietary composition and analysis. Dietary composition, % of DM Low-Oil DDGS Corn Moderate- Oil DDGS Treatment a Low-Oil DDGS Barley Moderate- Oil DDGS Rolled corn Rolled barley DDGS Corn silage Limestone Urea Salt Vitamin premix b Mineral premix c Rumensin d Tylan e Fine-ground corn Chromium oxide Analysis f, % of DM Organic matter Crude protein Starch Neutral detergent fibre Acid detergent fibre Lipids Calcium Phosphorus a Treatments contained rolled-corn or rolled-barley and dried corn distillers grains with solubles (low-oil DDGS, 4.5% ether extract; moderate-oil dried corn distillers grains with solubles, 7.9% ether extract). b Contained 48,510 kiiu/kg vitamin A and 4,630.5 kiu/kg vitamin D. c Contained 3.62% Ca, 2.56% Cu,16% Zn, 6.5% Fe, 4.0% Mn, mg/kg I, and 250 mg/kg Co. d Contained g monensin/kg premix. e Contained 88.2 g tylosin/kg premix. f Average from weekly samples. 15

17 Page 16 of 18 Table 3. Effects of grain source and oil level of dried distillers grains plus solubles on OM intake and digestibility. Treatment a Low-Oil DDGS Rolled Corn Rolled Barley P-value Moderate- Low-Oil Oil DDGS DDGS Moderate- Oil DDGS SEM b Grain DDGS Grain*DDGS Item OM Intake, kg/d Duodenal flow, kg/d Feed Microbial Total Ruminal disappearance, kg/d Fecal output, kg/d Digestibility Apparent ruminal, % of intake True ruminal, % of intake Intestinal, % of intake Intestinal, % of entering duodenum Total tract, % of intake a Treatments contained rolled-corn or rolled-barley and dried corn distillers grains with solubles (low-oil DDGS, 4.5% ether extract; moderate-oil dried corn distillers grains with solubles, 7.9% ether extract). b Standard error of the mean (n = 7). 16

18 Page 17 of 18 Table 4. Effects of grain source and oil level of dried distillers grains plus solubles on CP intake and digestibility. Treatment a Rolled Corn Rolled Barley P-value Item Low-Oil DDGS Moderate- Oil DDGS Low-Oil DDGS Moderate- Oil DDGS SEM b Grain DDGS Grain*DDGS Intake, kg/d Duodenal flow, kg/d Feed Microbial Total Ruminal disappearance, kg/d Fecal output, kg/d Digestibility Apparent ruminal, % of intake True ruminal, % of intake Intestinal, % of intake Intestinal, % of entering duodenum Total tract, % of intake Microbial efficiency, g microbial N/kg of OM truly fermented a Treatments contained rolled-corn or rolled-barley and dried corn distillers grains with solubles (low-oil DDGS, 4.5% ether extract; moderate-oil dried corn distillers grains with solubles, 7.9% ether extract). b Standard error of the mean (n = 7). 17

19 Page 18 of 18 Table 5. Effects of grain source and oil level of dried distillers grains plus solubles on starch and lipid intake and digestibility. Treatment a Rolled Corn Rolled Barley P-value Moderate- Low-Oil Oil DDGS DDGS Low-Oil DDGS Moderate- Oil DDGS SEM b Grain DDGS Grain*DDGS Item Starch Intake, kg/d Duodenal flow, kg/d Ruminal disappearance, kg/d Fecal output, kg/d Digestibility Apparent ruminal, % of intake Intestinal, % of intake Intestinal, % of entering duodenum Total tract, % of intake Lipid Intake, kg/d <0.001 < Duodenal flow, kg/d Ruminal disappearance, kg/d Fecal output, kg/d Digestibility Apparent ruminal, % of intake Intestinal, % of intake Intestinal, % of entering duodenum Total tract, % of intake < a Treatments contained rolled-corn or rolled-barley and dried corn distillers grains with solubles (low-oil DDGS, 4.5% ether extract; moderate-oil dried corn distillers grains with solubles, 7.9% ether extract). b Standard error of the mean (n = 7). 18