Effects of 20% corn wet distiller’s grains plus solubles in steam-flaked and dry-rolled corn based diets

35% CORN WET DISTILLER’S GRAINS PLUS SOLUBLES IN STEAM-FLAKED AND DRY-ROLLED
CORN BASED DIETS: EFFECTS ON ANIMAL PERFORMANCE
J. C. MacDonald1,2 K. H. Jenkins1, E. K. Buttrey3, J. B. Lewis1, S. B. Smith4, R. K. Miller4, T. E. Lawrence2, F. T. 1Texas AgriLife Research, Amarillo, 2West Texas A&M University, Canyon, 3Texas AgriLife Extension, Amarillo, Department of Animal Science, College Station, 5USDA-ARS, Bushland Fifty-four individually fed crossbred steers were fed dry-rolled corn (DRC) and steam-flaked corn (SFC) based diets with and without 35% wet distiller’s grains plus solubles (WDGS) derived from corn to determine impacts of corn processing method and WDGS inclusion on animal performance and carcass characteristics. No interactions were detected for corn processing method and WDGS inclusion (P ≥ 0.19). Steers fed SFC-based diets consumed less feed (P < 0.01) and were more efficiency (P < 0.01) compared to steer consuming DRC-based diets. Steers consuming diets containing 35% WDGS were more efficiency (P = 0.03) and produced carcasses with lower percent KPH fat (P = 0.02) and loins with smaller LM area (P < 0.01). Serial ultrasound measurements indicate cattle consuming diets with WDGS deposit intramuscular fat at a reduced rate late in the feeding period. These data indicate that WDGS have energy values similar to SFC, but may impact carcass characteristics. Introduction
The availability of distillers grains (DGs) will increase rapidly as the ethanol industry continues to expand. Current projections suggest that ethanol production will reach 15 billion gallons annually by 2022. This level of ethanol production could result in an annual production of approximately 40 million tons (DM basis) of DGs. The US slaughters approximately 27 million fed cattle (steers and heifers) per year (USDA, 2008). Assuming cattle consume an average of 25 lbs of DM per day and are on feed for an average of 150 days, the US produces approximately 50 million tons of finished feed for feedlot cattle (DM basis). Although the feedyard industry will not utilize all of the DGs, it is likely that DGs may be included in the diets of many of the fed cattle in the US in the future based on availability and increased demand for corn. Experimental Procedures
Eighty pre-conditioned steer calves (542 lb) were purchased from a single ranch to determine effects of corn processing method and WDGS inclusion on animal performance and carcass characteristics. Breed makeup of the steers was ¼ Hereford and ¾ Angus. Fifty-four steers of uniform weight and mild disposition were selected from the pool and trained in the Calan gate system. The experiment was designed as a randomized incomplete block with treatments arranged in a 2X2 factorial. Factors included inclusion or absence of WDGS derived from fermentation of corn in the finishing diet of steers with corn processed by steam flaking (Bushel weight = 27 lb/bu) or dry rolling. Upon trial initiation, steers (678 ± 18 lb) were weighed for three consecutive d after being limit-fed (1.8% BW) a common receiving diet for 5-d to minimize variation in gut fill. They were then stepped up onto their experimental finishing diets (Table 1) in 21-d in three steps containing 40%, 30%, and 20% alfalfa hay. Finishing diets were formulated to contain a minimum of 13.5% CP with a positive degradable intake protein balance. Diets were also formulated to contain 0.70% Ca and 6.0% ether extract thereby attempting to equilibrate fat across diets. All diets contained 10% alfalfa hay as a roughage source and 0.70% supplement which provided trace minerals, vitamins, monensin, and tylosin (Elanco Animal Health; Greenfield, IN) at levels common with industry standards. Steers were initially implanted with 14 mg estradiol and 200 mg progesterone (Synovex S®; Fort Dodge Animal Health, Fort Dodge IA) at trial initiation, and terminally implanted with 16 mg estradiol and 80 mg trenbolone acetate (Revlor IS®; Intervet Inc., Millsboro, DE) on d 84. Ingredient samples were collected weekly for dry ingredients and thrice weekly for wet ingredients (WDGS and SFC) for DM determination. DM was determined in a 60°C oven for 24-h. Weekly samples were composited by month and ground. Monthly samples were then composited to encompass the duration of the study. Steers were weighed every 28-d and received ultrasound scans for 12th rib fat thickness and marbling every 56-d to characterize growth and changes in body composition. All steers were harvested at one time when the mean 12th rib fat thickness reached 0.50 in. Steers were harvested at a commercial abattoir and carcass data collected by the West Texas A&M University Cattlemen’s Carcass Data Service. Individual animal identification was preserved and one loin per animal purchased for further analyses. Data were analyzed using the Mixed procedures of SAS (SAS Inst. Inc., Cary, NC) with pen considered to be a random effect. Data were analyzed by ANOVA as an unbalanced randomized incomplete block design with individual steer as the experimental unit and pen as the block. The unbalanced design was necessary because there were six pens with nine gates per pen available. The model included WDGS inclusion, corn processing method, and their interaction. If the F-test was significant was significant for the interaction of WDGS inclusion and corn processing method (P < 0.05), simple means were separated using a T-test. For responses measured across time, a repeated measures statement was added. Covariance patterns were selected by their reduction of Akaike’s criterion relative to the unstructured pattern (Littell et al., 2002). Liner, quadratic, and cubic terms were added to the model to determine the response to time. Slope and intercepts were separated as suggested by Littell et al. (2002). Results and Discussion
The study required to be an unbalanced design because the facility had only 54 Calan gates available (six pens with nine gates per pen). However, one steer stopped consuming feed after the trial was initiated and was removed from the study and one loin was not retained at the abattoir. Therefore, for live animal response variables and carcass characteristics, sample size = 13, 14, 14, 12 for SFC + 0% WDGS, DRC + 0% WDGS, SFC + 35% WDGS, and DRC + 35% WDGS, respectively, and for response variables measured in the loin, sample size = 12, 14, 14, 12 for SFC + 0% WDGS, DRC + 0% WDGS, SFC + 35% WDGS, and DRC + 35% WDGS, respectively. Therefore, SE estimates are provided parenthetically following treatment means in the tables. Chemical analysis of diet ingredients. The chemical analysis of ingredients suggests both the SFC and DRC had higher than expected CP concentrations and lower than expected ether extract concentrations (Table 1). Additionally, the SFC had slightly greater ether extract and lesser CP compared to DRC. From an energetic intake standpoint, this may have put the DRC diets at a slight disadvantage. The lower than expected ether extract content of the DRC and SFC also resulted in diets containing WDGS to have slightly greater ether extract contents even though we attempted to equilibrate fat. Additionally, the WDGS had lower Ca than expected which resulted in reduced Ca levels in diets containing WDGS. However, the Ca:P ratio was still greater than 1 for the WDGS diets leading us to believe there were no negative impacts of the lower Ca levels in the WDGS diets. Animal performance. There were no differences in final BW or ADG calculated from an actual live animal (final BW measured live and shrunk 4%) or carcass adjusted (final BW calculated as HCW/0.63) weight basis (P > 0.25; Table 2). Steam-flaking corn resulted in lesser DMI and improved feed efficiency compared to DRC in diets with and without WDGS (P < 0.01). Additionally, while the addition of 35% WDGS did not significantly impact DMI or ADG (P > 0.26) slight shifts in these variables resulted in significant improvements in F:G (P = 0.03) due to the inclusion of WDGS. It is well documented that steam-flaking increases the energy availability of cereal grains resulting in improved feed efficiency from reduced DMI, improved ADG, or both (Zinn et al., 2002). The current data set suggests SFC resulted in a 13.3% improvement in feed efficiency over DRC in diets without WDGS. These observations are consistent with previous observations comparing SFC and DRC. The current data set also suggests an improvement in feed efficiency from feeding 35% WDGS. Vander Pol et al. (2006) fed 0% to 50% WDGS in DRC-based diets and found optimal inclusion to be approximately 40% based on greatest feed efficiency. Similarly, Corrigan et al. (2007) fed 0% to 40% WDGS in diets utilizing three corn processing methods and saw a linear increase in G:F when adding WDGS to DRC-based diets but no change in G:F when adding WDGS to SFC based diets. The observations of Corrigan et al. (2007) suggest WDGS has an energy value similar to SFC. Conversely, Depenbusch et al. (2008) observed reduced feed efficiency when feeding 25% corn WDGS in SFC-based diets and suggested that the relative response to WDGS in SFC-based diets may be lesser compared to DRC-based diets because of the energetic differences associated with these two corn processing methods. Our data are unique in that the inclusion of WDGS improved feed efficiency in both DRC- and SFC-based diets. The NEm and NEg of the DRC and SFC were determined from the NRC (1996) equations and cattle performance while the replacement method was used to determine the energy values of the WDGS (Table 4). The SFC was 116% the energy value of the DRC while the WDGS was 103% the energy value of SFC and 124% the value of DRC. Carcass characteristics. Dietary treatment had no effect on fat thickness, HCW, or dressing percent (P ≥ 0.27; Table 2). The inclusion of WDGS resulted in a concomitant reduction in % KPH (P = 0.02) and LM area (P < 0.01) which resulted in no difference in calculated USDA yield grade (P ≥ 0.39). Zinn et al. (1997) reported a linear decline in LM area as dietary sulfur concentrations increased from 0.15% to 0.25%. Conversely, Loneragan et al. (2001) reported a linear increase in LM area with increasing water sulfur intake. Thus the reason for the reduction of LM area in the current study is unclear. The sulfur concentration of diets containing WDGS was 0.34% compared to 0.12% for diets containing no WDGS (Table 1). However, reduced KPH % has not been reported in studies investigating sulfur intake (Loneragan et al., 2001; Zinn et al., 1997) or dietary WDGS inclusion (Depenbusch et al., 2008), however, the % KPH is not consistently reported. There was a tendency for an interaction between WDGS inclusion and corn processing method on marbling score (P = 0.10). This interaction would suggest that cattle fed SFC without WDGS had greater marbling and other dietary treatments were not different. However, analysis of ultrasound estimated marbling scores collected at the initiation of the study suggested steers assigned to the SFC without WDGS treatments also had greater marbling at the time the study began (P < 0.03; data not shown). Therefore, initial marbling score was used as covariate in the analysis of marbling score and differences in marbling score became non-significant (P ≥ 0.22). Serial ultrasound estimates of marbling score suggest greater s.c. and i.m. fat accretion in cattle fed SFC- compared to DRC-based diets (Figures 1 and 2). This is consistent with greater energy intake in steers fed more intensely processing corn. Conversely, dietary inclusion of 35% WDGS resulted in similar s.c. fat accretion (Figure 3), but decreased i.m. fat accretion, especially late in the feeding period (Figure 4) compared to steers fed diets without WDGS. A major objective of this study was to determine if WDGS influenced marbling. Given the variation in marbling scores among individuals, even when genetic variation is minimized, it is not surprising that we did not observe a difference in marbling of carcasses. However, serial ultrasound reduces individual variation because the same steer is measured multiple times. This technique provided evidence that the inclusion of WDGS may reduce marbling. Implications
Steers fed WDGS were more efficient that steers fed control diets, although the numeric improvement was more pronounced in DRC-based diets than in SFC-based diets. The energetic value of WDGS was 124% the value of DRC and 103% the value of SFC. Steers fed WDGS might also be expected to produce carcasses with reduced % KPH fat and smaller LM areas. Additionally the accretion of intramuscular fat may diminish late in the finishing period in steers fed WDGS. Acknowledgements
This research was supported, in part, by beef and veal producers and importers through their $1-per-head checkoff and was produced for the Cattlemen’s Beef Board and state beef councils by the National Cattlemen’s Beef Association. Further funding was provided by the Texas Beef Council and through a cooperative agreement between the USDA-ARS and Texas AgriLife Research. The mention of trade or manufacturer names is made for information only and does not imply an endorsement, recommendation, or exclusion by USDA-ARS or Texas AgriLife Research. The authors acknowledge Intervet Inc. for donating pharmaceutical product used in this research. Literature Cited
Corrigan, M.E., G.E. Erickson, T.J. Klopfenstein, K.J. Vander Pol, M.A. Greenquist, M.K. Lubbe.2007. Effects of corn processing and wet distiller’s grains inclusion level in finishing diets. NE Beef Report MP90. Depenbusch, B.E., J.S. Drouillard, E.R. Loe, J.J. Higgins, M.E. Corrigan and M.J. Quinn. 2008. Efficacy of monensin and tylosin in finishing diets based on steam-flaked corn with and without corn wet distiller's grains with solubles. J. Anim. Sci. doi:10.2527/jas.2007-0017. availabl. Accessed May 20, 2008. Loneragan, G. H., J. J. Wagner, D. H. Gould, F. B. Garry, and M. A. Thoren. 2001. Effects of water sulfate concentration on performance, water intake, and carcass characteristics of feedlot steers. J. Anim. Sci. 79:2941-2948. USDA. 2008. Livestock Slaughter 2007 Summary. Released March 2008. Available at: Vander Pol, K.J., G.E. Erickson, T.J. Klopfenstein, M.A. Greenquist, T. Robb. 2006. Effects of dietary inclusion of wet distiller’s grains on feedlot performance of finishing cattle and energy value relative to corn. NE Beef Cattle Report MP89:51. Zinn, R. A., E. Alvarez, M. Mendez, M. Montano, E. Ramirez, and Y. Shen. 1997. Influence of dietary sulfur level on growth performance and digestive function in feedlot cattle. J. Anim. Sci. 75:1723-1728. Zinn, R. A., F. N. Owens, and R. A. Ware. 2002. Flaking corn: processing mechanics, quality standards, and impacts on energy availability and performance of feedlot cattle. J. Anim. Sci. 80:1145-1156. Table 1. Diet composition of dry rolled corn and steam-flaked corn based diets with and without corn wet distiller’s grains plus solubles. Item 1WDGS = wet distiller’s grains plus solubles. Purchased from Chief Ethanol Fuels, Hastings, NE. Contained 26.8% CP, 11.0% ether extract, 9.7% crude fiber, 23.3% NDF, 0.06% Ca, 0.83% P, 1.16% K, and 0.74% S. 2Corn processing method; SFC = steam-flaked corn; DRC = dry rolled corn. 3Premix, 0.60% units of urea, and 0.70% units of limestone were fed in a pelleted supplement at 2% of diet DM. Additional required urea and limestone were added daily to the diet during mixing. 4Formulated to provide a dietary DM inclusion of 0.30% salt, 60 ppm Fe, 40 ppm 30 ppm Mg, 25 ppm Mn, 10 ppm Cu, 1 ppm I, 0.15 ppm Co, 0.10 ppm Se, 1.5 IU/g vitamin A, 0.15 IU/g vitamin D, 8.81 IU/kg vitamin E, 33 mg/kg monensin, and 8.7 mg/kg tylosin. 5Chemical analysis conducted on all ingredients except yellow grease (assumed to contain 100% ether extract), glycerin (assumed to contain 0% nutrients of interest), urea (assumed to contain 281% CP), and limestone (assumed to contain 38% Ca). Table 2. Effects of corn processing method and dietary wet distiller’s grains plus solubles (WDGS) inclusion on animal performance of steer calves. Item 1Overall treatment F-test; Corn = main effect of corn processing method; WDGS = main effect of dietary WDGS inclusion; Interaction = interaction of corn processing method and dietary WDGS inclusion. Standard errors are provided parenthetically following the treatment mean due to the unbalanced experimental design. 2Corn processing method; SFC = steam-flaked corn; DRC = dry rolled corn. 3Final individual BW measured live and shrunk 4%. 5Final individual BW calculated as individual HCW / 63% (common dressing percent). Table 3. Effects of corn processing method and dietary wet distiller’s grains plus solubles (WDGS) inclusion on carcass characteristics of steer calves. Item 1Overall treatment F-test; Corn = main effect of corn processing method; WDGS = main effect of dietary WDGS inclusion; Interaction = interaction of corn processing method and dietary WDGS inclusion. Standard errors are provided parenthetically following the treatment mean due to the unbalanced experimental design. 2Corn processing method; SFC = steam-flaked corn; DRC = dry rolled corn. 3Final individual BW measured live and shrunk 4%. 4400 = Slight00, 500 = Small00, 600 = Modest00, etc. 5Ultrasound estimated marbling from trial initiation was used as a covariate in the statistical analysis and was significant (P < 0.01). Table 4. Energy density (Mcals NEg/lb) of dry rolled corn (DRC), steam-flaked corn (SFC) and wet distiller’s grains plus solubles (WDGS)1. Ingredient DRC 1Energy densities of ingredients calculated from animal performance relative to the DRC control using the replacement method. 2Energy density of WDGS is 124% value of DRC in DRC-based diets. 3Energy density of SFC is 116% value of DRC. 4Energy density of WDGS is 103% value of SFC in SFC-based diets.
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Figure 1. Effects of corn processing method on ultrasound measured 12th rib fat thickness of steer calves. Slopes for steam-flaked corn (SFC) and dry-rolled corn (DRC) differed (P = 0.02). The SFC slope (dashed line) was quadratic (P < 0.01) whereas the DRC slope was linear (P < 0.01), but not quadratic (P = 0.50). The intercepts for SFC and DRC did not differ (P = 0.32). S 3
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Figure 2. Effects of corn processing method on ultrasound measured marbling scores of steer calves. Slopes for steam-flaked corn (SFC) and dry-rolled corn (DRC) differed (P < 0.01), but were both linear (P < 0.01). The intercepts for SFC and DRC did not differ (P = 0.39). ib Fa
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Figure 3. Effects of dietary wet distiller’s grains plus solubles (WDGS) inclusion on ultrasound measured 12th rib fat thickness of steer calves. Slopes for 0% WDGS (dashed line) and 35% WDGS (solid line) were linear (P < 0.01), but did not differ (P = 0.58). Intercepts did not differ (P = 0.99) S 3
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Figure 4. Effects of dietary wet distiller’s grains plus solubles (WDGS) inclusion on ultrasound measured marbling scores of steer calves. Slopes for 0% WDGS (dashed line) and 35% WDGS (solid line) tended to differ (P = 0.07). The 0% WDGS slope was linear (P < 0.01), but not quadratic (P = 0.19) whereas the 35% WDGS slope was quadratic (P = 0.05). Intercepts tended to differ (P = 0.09).

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