129 1Corresponding author: greg.penner@usask.ca Received September 1, 2019. Accepted October 18, 2019. Use of barley or corn silage when fed with barley, corn, or a blend of barley and corn on growth performance, nutrient utilization, and carcass characteristics of finishing beef cattle Jordan A. Johnson,† Brittney D. Sutherland,† John J. McKinnon,† Tim A. McAllister‡ and Gregory B. Penner†,1 †Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada; and ‡Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada;  ABSTRACT:  The objective of this study was to evaluate the effects of the source of silage, cereal grain, and their interaction on growth perform- ance, digestibility, and carcass characteristics of finishing beef cattle. Using a completely random- ized design within an 89-d finishing study, 288 steers were randomly assigned to 1 of 24 pens (12 steers/pen) with average steer body weight (BW) within a pen of 464  kg ± 1.7  kg (mean ± SD). Diets were arranged in a 2 × 3 factorial with corn silage (CS) or barley silage (BS) included at 8% (dry matter [DM] basis). Within each silage source, diets contained dry-rolled barley grain (BG; 86% of DM), dry-rolled corn grain (CG; 85% of DM), or an equal blend of BG and CG (BCG; 85% of DM). Total tract digestibility of nutrients was estimated from fecal samples using near-infra- red spectroscopy. Data were analyzed with pen as the experimental unit using the Mixed Model of SAS with the fixed effects of silage, grain, and the two-way interaction. Carcass and fecal kernel data were analyzed using GLIMMIX utilizing the same model. There were no interactions de- tected between silage and grain source. Feeding CG increased (P  <  0.01) DM intake by 0.8 and 0.6  kg/d relative to BG and BCG, respectively. Gain-to-feed ratio was greater (P = 0.04) for BG (0.172 kg/kg) than CG (0.162 kg/kg) but did not differ from BCG (0.165  kg/kg). Furthermore, average daily gain (2.07  kg/d) and final body weight did not differ among treatments (P ≥ 0.25). Hot carcass weight (HCW) was 6.2  kg greater (372.2 vs. 366.0  kg; P  <  0.01) and dressing per- centage was 0.57 percentage units greater (59.53 vs. 58.96 %; P = 0.04) for steers fed CS than BS, respectively. There was no effect of dietary treat- ment on the severity of liver abscesses (P ≥ 0.20) with 72.0% of carcasses having clear livers, 24.4% with minor liver abscesses, and 3.6% with se- vere liver abscesses. Digestibility of DM, organic matter, crude protein, neutral detergent fiber, and starch were greater for BG (P < 0.01) than CG or BCG. As expected, grain source affected the ap- pearance of grain kernels in the feces (P ≤ 0.04). Feeding CS silage increased the appearance of fractured corn kernels (P = 0.04), while feeding BS increased fiber appearance in the feces (P = 0.02). Current results indicate that when dry rolled, feed- ing BG resulted in improved performance and di- gestibility compared with CG and BCG. Even at low inclusion levels (8% of DM), CS resulted in improved carcass characteristics relative to BS. Key words: barley, carcass quality, corn, finishing, grain, silage © The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Transl. Anim. Sci. 2020.4:129–140 doi: 10.1093/tas/txz168 D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 mailto:greg.penner@usask.ca?subject= http://creativecommons.org/licenses/by-nc/4.0/ 130 Johnson et al. Translate basic science to industry innovation INTRODUCTION Western Canadian feedlots have predominantly relied on the use of barley silage (BS) and barley grain (BG) as feed ingredients for finishing diets. However, the recent development of short-season corn hybrids offers a yield advantage for producers relative to BS (Baron et  al., 2014; Lardner et  al., 2017). Although corn silage (CS) typically has greater starch and lesser protein content than BS, the amount of dietary energy contributed by silage is relatively small in finishing diets. At such low levels of inclusion (<10% dry matter [DM] basis), forage in finishing diets is more likely to provide value as a source of effective fiber rather than as a source of energy. When processed similarly, starch and pro- tein from barley is degraded more rapidly and to a greater extent in the rumen than corn grain (CG; Herrera-Saldana et  al., 1990). Due to the rapid fermentation of dry-rolled BG, the risk of ruminal acidosis is perceived to be greater than with dry-rolled CG, a response that can have a negative impact on average daily gain (ADG) and gain-to-feed ratio (G:F; Castillo-Lopez et  al., 2014). Several studies have demonstrated that combining grain sources with differing rates of degradable carbohydrate fractions may im- prove the efficiency and growth performance of finishing cattle (Kreikemeier et  al., 1987; Stock et  al., 1987b). That being said, there are cur- rently no studies that compare barley and corn and limited studies that have evaluated short-sea- son CS. Additionally, while previous studies have evaluated the use of either barley- or corn-based diets for finishing cattle (Beauchemin et al., 1997), they have not examined the interactions between cereal silage and cereal grain sources. We hypothesized that due to the differing con- centrations of starch and the expected differences for starch and protein degradability in CG and BG, diets containing blended grains will result in im- proved digestibility, growth performance, and feed efficiency compared with single grain diets, with little effect of silage source. MATERIALS AND METHODS The use of steers and the procedures used were preapproved by the University of Saskatchewan Animal Research Ethics Board (protocol 20100021)  according to the guidelines of the Canadian Council on Animal Care (Ottawa, ON, Canada). Silage Production and Cereal Grain Processing Corn (P7213R, 2050 CHU, DuPont Pioneer, Mississauga, ON) was seeded for silage at a rate of 79,072 plants/ha on May 27, 2016 with 76.2-cm row spacing. Anhydrous ammonia was applied to de- liver 72.1 kg of N/ha and 4.03 MT of fertilizer was applied containing 36.3% N and 12.1% P.  Liquid Herbicide (R/T 540, Monsanto Canada, Winnipeg, MB) was applied June 6 at 0.82 L/ha and June 20 at 1.66 L/ha. Corn heat units (CHU) were calculated for each day using historical weather data obtained from the Saskatoon RCS weather station according to the following calculation: Daily CHU = [ 1.8 (Tmin − 4.4) + 3.3 (Tmax − 10) −0.084 (Tmax − 10)2 ] 2 Corn silage was harvested after 1,940 CHU using a kernel processor (2-mm roller gap) and at a theor- etical chop length of 0.95 cm on August 30 at 32% whole-plant DM. Silage was treated with an in- oculant (Biomax 5, Chr. Hansen Inc., Milwaukee, WI) at a rate of 1.0 × 1011 lactic acid bacteria colo- ny-forming units (CFU) per tonne during ensiling. The barley variety used for silage production was CDC Copeland (SeCan, Kanata, ON). Barley was seeded at 108  kg/ha on May 19, 2016. Prior to seeding, the seed was treated with a fungicide (Rancona Pinnacle, Arysta Lifescience Canada Inc., Guelph, ON) at a rate of 325 mL/100 kg of seed. Anhydrous ammonia was applied to deliver 64.56 kg of N/ha along with 1.36 MT of 12-40-0 10 S 1 Zn (MicroEssentials SZ, The Mosaic Company, Plymouth, MN). Curtail M Herbicide (Dow AgroSciences LLC, Indianapolis, IN) was selectively applied to the field on June 6 at a rate of 1.98 L/ha and a combination of 0.99 L each of Buctril M Emulsifiable Selective Weedkiller (Bayer CropScience Inc., Calgary, AB) and Bison 400L (ADAMA Agricultural Solutions Canada Ltd., Winnipeg, MB) were applied on June 14, 2016. Barley silage harvest occurred between July 27 and 30 at the soft dough stage to target a DM of ~35%. Silage was harvested with a theoretical chop length of 0.95 cm and was treated with an inoculant (Biomax 5, Chr. Hansen Inc., Milwaukee, WI) at a rate of 1.0  × 1011 lactic acid bacteria CFU/tonne during ensiling. Cereal grains were obtained from a commer- cial feed mill (Canadian Feed Research Centre, North Battleford, SK) and barley was dry rolled to an average processing index (PI) of 66%. Corn was D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 131Grain and silage inclusion for finishing Translate basic science to industry innovation processed to ensure that 5% of the sample (wt/wt basis) would pass through a 1-mm sieve. This pro- cessing resulted in a PI of 83.0%. Chemical com- positions of the silage and grain sources used for the duration of the finishing study are presented in Table 1. Steer Management, Experimental Design, and Dietary Treatments A total of 288 commercial crossbred steers were purchased from a local auction market and used in a previous study until reaching a mean body weight (BW) of 465 ± 28 kg. One day before the start of the study, steers were implanted with 120 mg of tren- bolone acetate and 24 mg of estradiol (Revalor-S, Merck Animal Health, Madison, NJ). Steers were stratified by BW into 1 of 24 pens (12 steers/pen) with the average BW of each pen being 464 kg ± 1.7 kg (mean ± SD). Pens were then randomly as- signed to one of six treatments (described below) in a completely randomized design. Steers were housed in pens measuring 12 × 24 m with a 3.3-m high windbreak (20 cm/m porosity) fence along the back of each pen. Dietary treatments were arranged in a 2 × 3 fac- torial with silage source: CS or BS included at 8% (DM basis; Table 2) and cereal grain source: dry- rolled BG (86% of DM); dry-rolled CG (85% of DM); or an equal blend of BG and CG (BCG; 85% of DM). Steers were gradually transitioned to their respective finishing diet over 24 d (Table 3). All diets were formulated to be similar in crude protein (CP) and to have the same forage inclusion and mineral and vitamin concentrations. The mineral supple- ment contained monensin (Elanco Animal Health, Greenfield, IN) to target a final dietary concentra- tion of 33  mg/kg. Steers were fed once daily be- tween 0830 and 1100 hours with the amount of feed delivered targeted to achieve ad libitum intake while also minimizing residual feed. Growth Performance and DM Intake Measurements obtained during the dietary transition period were included when calculating overall performance. The BW of individual steers was measured on two consecutive days at the start and end of the study and the average BW was calcu- lated to determine initial and final BW. Throughout the study, steers were weighed every 2 weeks with BW data used to calculate ADG by regressing BW with the day of study. On weigh days, cattle BW measurements were initiated at 0830 hours and feeding was delayed to reduce the effect of gut fill on BW. Feed bunks were also cleaned and the re- sidual feed was weighed and sampled to determine DM concentration. The difference in weight be- tween the amount of DM offered and the quantity of DM refused was used to determine the biweekly pen DM intake (DMI). These values were then used to determine the average DMI per steer rep- resented as kilograms per day by dividing the bi- weekly pen DMI by the number of steers per pen and by the number of days between consecutive measurements. On the same days as BW measurement, repre- sentative samples of BS, BG, CS, CG, urea, lime- stone, mineral and vitamin pellet, and canola meal were collected. All samples of feed ingredients, as well as samples of refusals, were dried in a forced- air oven at 55 °C for 72 h for DM determination. The DM content of each ingredient was used to ensure that the as fed ingredient inclusion achieved dietary formulation specifications. Dried feed in- gredient samples were then composited by month (n = 3) on an equal weight basis. Concentrate sam- ples (CG, BG, mineral pellet, and canola meal) were ground using a Retch ZM 200 grinder (Haan, Germany) to pass through a 1-mm screen, while silage samples were ground through a 1-mm screen using a hammer mill (Christie-Norris Laboratory Mill, Christie-Norris Ltd, Chelmsford, UK). All dried and ground feed samples were submitted for chemical analysis to Cumberland Valley Analytical Services (Waynesboro, PA) for determination of DM, organic matter (OM), CP, neutral detergent Table 1. Chemical composition of silage and grain sources used for the duration of the study Ingredient Barley silage Barley grain Corn silage Corn grain Chemical composition, % DM* DM, % 40.54 ± 3.40 90.15 ± 0.36 35.38 ± 2.33 89.44 ± 1.27 OM 93.92 ± 0.53 97.88 ± 0.16 95.13 ± 0.11 98.38 ± 0.13 CP 10.90 ± 0.56 11.77 ± 0.25 9.57 ± 0.15 8.57 ± 0.21 Starch 22.47 ± 1.55 58.80 ± 1.66 30.17 ± 0.81 71.36 ± 1.33 ADF 27.57 ± 1.55 6.80 ± 0.40 26.00 ± 0.35 3.93 ± 0.25 NDF 44.90 ± 2.36 19.63 ± 2.08 42.70 ± 0.72 10.27 ± 0.38 Ether extract 2.91 ± 0.13 2.18 ± 0.10 2.93 ± 0.02 4.22 ± 0.42 Ca 0.31 ± 0.06 0.06 ± 0.01 0.25 ± 0.01 0.02 ± 0.01 P 0.26 ± 0.02 0.35 ± 0.02 0.26 ± 0.01 0.32 ± 0.02 NEm, Mcal/kg† 1.52 ± 0.07 1.94 ± 0.02 1.61 ± 0.02 2.14 ± 0.02 NEg, Mcal/kg† 0.93 ± 0.07 1.30 ± 0.02 1.01 ± 0.02 1.46 ± 0.02 *Chemical composition is expressed as means ± SD (n = 3). †Net energy values were calculated from feed samples using the NRC (2001) equations. D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 132 Johnson et al. Translate basic science to industry innovation fiber (NDF), acid detergent fiber (ADF), starch, ether extract, calcium, and phosphorus concen- trations. For silage, DM was determined using a modified procedure that combined a partial DM adapted from Goering and Van Soest (1970), fol- lowed by heating samples to 105  ºC for 3  h ac- cording to method 2.1.4 (Shreve et al., 2006). For all other feeds, DM was determined by drying sam- ples at 135 ºC using AOAC (2000) method 930.15. Ash was determined using AOAC (2000) method 942.05 with the modification of using 1.5-g sample weight with a 4-h ashing time, followed by hot weighing. Ash content was used to determine the OM concentration by subtracting ash from 100%. Crude protein was determined using AOAC (2000) method 990.03 using a LECO FP-528 Nitrogen Combustion Analyzer (LECO, St. Joseph, MI). Neutral detergent fiber was determined using the method of Van Soest et al. (1991) including α-am- ylase and sodium sulfite, and ADF was deter- mined using AOAC (2000) method 973.18, both with the modification that Whatman 934-AH (GE Healthcare Life Sciences, Chicago, IL) glass 1.5- um microfiber filters were used in place of a fritted glass crucible. Starch concentration was deter- mined with correction for free glucose as described by Hall (2009). Ether extract was determined ac- cording to AOAC (2000) method 2003.05 using the Tecator Soxtec System HT 1043 Extraction unit (Tectator, Foss, Eden Prairie, MN). Calcium and phosphorus content were determined according to AOAC (2000) method 985.01 with the modification that a 0.35-g sample was ashed for 1 h at 535 ºC, di- gested in open crucibles for 25 min in 15% nitric acid on a hotplate, diluted to 50 mL, and analyzed on axial view using a Perkin Elmer 5300 DV ICP (Perkin Elmer, Shelton, CT). Finally, the net energy values (NE) of feed were calculated using National Research Council (NRC, 2001) equations. At the end of the study (89 d on feed), steers were transported to a federally inspected abat- toir (Cargill Meat Solutions, High River, AB). Hot carcass weight, back-fat thickness, and rib eye area were measured between the 12th and 13th ribs. The Canadian Beef Grading Agency yield and quality grades, as well as marbling score, were determined using the Computer Vision Grading System (VBG 2000 e+v Table 2. Ingredients and chemical composition of diets used during the finishing period Barley silage Corn silage Barley grain Corn grain Blend Barley grain Corn grain Blend Ingredient, % DM Barley silage 8.00 8.00 8.00 — — — Corn silage — — — 8.00 8.00 8.00 Barley grain 85.94 — 42.72 85.86 — 42.69 Corn grain — 84.96 42.72 — 84.89 42.69 Urea — 0.98 0.50 0.08 1.06 0.57 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 Limestone 0.50 0.50 0.50 0.50 0.50 0.50 Chemical composition, % DM† DM, % 82.2 ± 1.07 81.7 ± 0.83 82.0 ± 0.81 80.0 ± 0.95 79.9 ± 1.65 80.1 ± 1.28 OM 95.6 ± 0.10 96.0 ± 0.16 95.8 ± 0.03 95.7 ± 0.14 96.1 ± 0.11 95.9 ± 0.02 CP 11.5 ± 0.17 11.3 ± 0.18 11.5 ± 0.14 11.6 ± 0.21 11.4 ± 0.20 11.5 ± 0.17 NDF 21.6 ± 1.57 13.5 ± 0.50 17.5 ± 0.53 21.4 ± 1.82 13.3 ± 0.26 17.3 ± 0.78 ADF 8.4 ± 0.44 5.9 ± 0.34 7.1 ± 0.31 8.3 ± 0.33 5.8 ± 0.24 7.0 ± 0.16 Starch 54.2 ± 1.43 64.5 ± 1.17 59.3 ± 0.27 54.7 ± 1.35 65.1 ± 1.23 59.9 ± 0.15 Ether extract 2.3 ± 0.08 4.0 ± 0.35 3.2 ± 0.22 2.3 ± 0.09 4.0 ± 0.36 3.2 ± 0.23 Ca 0.86 ± 0.03 0.83 ± 0.03 0.84 ± 0.03 0.86 ± 0.03 0.82 ± 0.02 0.84 ± 0.03 P 0.35 ± 0.02 0.32 ± 0.02 0.34 ± 0.01 0.35 ± 0.02 0.32 ± 0.02 0.34 ± 0.01 NEm, Mcal/kg‡ 1.85 2.00 1.93 1.86 2.00 1.93 NEg, Mcal/kg‡ 1.23 1.35 1.29 1.23 1.36 1.30 *The mineral pellet supplement was mixed with ground barley grain for pelleting at a ratio of 78:21 (DM basis), respectively. On DM basis, the mineral supplement (excluding the barley grain) contained 9.2% of calcium, 0.32% of phosphorus, 1.64% sodium, 0.28% of magnesium, 0.60% of potassium, 0.12% of sulfur, 4.9 mg/kg of cobalt, 185 mg/kg of copper, 16.6 mg/kg of iodine, 84 mg/kg of iron, 500 mg/kg of manganese, 2 mg/kg of selenium, 558 mg/kg of zinc, 40,000 IU/kg of vitamin A, 5,000 IU/kg of vitamin D3, and 600 IU/kg of vitamin E. The final supplement contained 510 mg/kg of monensin (Elanco Animal Health, Greenfield, IN) on a DM basis. †Chemical composition is expressed as means ± SD (n = 3). ‡Net energy values were calculated from feed samples using the NRC (2001) equations. D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 133Grain and silage inclusion for finishing Translate basic science to industry innovation Technology GmbH, Oranienburg, Germany). Liver scores were determined using the Elanco Liver Check System (Elanco Animal Health, Greenfield, IN). Carcass-adjusted final BW was calculated for each pen as the average hot carcass weight divided by the corresponding average pen dressing percentage. ADG and G:F were then adjusted on a carcass Table 3. Ingredient composition of transition diets used to transition steers to their respective finishing diets over 24 d, each step was 4 d in duration with the final diet being fed on day 25 Ingredient, % DM Stage of transition Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Final BS–BG Barley silage 55.00 45.00 35.00 25.00 18.00 12.00 8.00 Barley grain 31.44 44.44 55.44 65.94 73.94 80.94 85.94 Canola meal 8.00 5.00 4.00 3.00 2.00 1.00 0.00 Limestone 0.00 0.00 0.00 0.50 0.50 0.50 0.50 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 5.56 BS–CG Barley silage 55.00 45.00 35.00 25.00 18.00 12.00 8.00 Corn grain 30.97 42.94 54.74 65.74 73.94 80.96 84.96 Canola meal 8.00 6.00 4.00 3.00 2.00 0.00 0.00 Urea 0.47 0.50 0.70 0.70 0.80 0.98 0.98 Limestone 0.00 0.00 0.00 0.00 0.50 0.50 0.50 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 5.56 BS–BCG Barley silage 55.00 45.00 35.00 25.00 18.00 12.00 8.00 Barley grain 15.61 22.07 27.57 33.22 37.22 40.72 42.72 Corn grain 15.61 22.07 27.57 33.22 37.22 40.72 42.72 Canola meal 8.00 5.00 4.00 2.00 1.00 0.00 0.00 Urea 0.22 0.30 0.30 0.50 0.50 0.50 0.50 Limestone 0.00 0.00 0.00 0.50 0.50 0.50 0.50 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 5.56 CS–BG Corn silage 55.00 45.00 35.00 25.00 18.00 12.00 8.00 Barley grain 31.17 44.24 55.29 65.84 73.86 80.86 85.86 Canola meal 8.00 5.00 4.00 3.00 2.00 1.00 0.00 Urea 0.27 0.20 0.15 0.10 0.08 0.08 0.08 Limestone 0.00 0.00 0.00 0.50 0.50 0.50 0.50 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 5.56 CS–CG Corn silage 55.00 45.00 35.00 25.00 18.00 12.00 8.00 Corn grain 30.72 42.72 54.64 65.54 72.94 79.94 84.89 Canola meal 8.00 6.00 4.00 3.00 2.00 1.00 0.00 Urea 0.72 0.72 0.08 0.90 1.00 1.00 1.05 Limestone 0.00 0.00 0.00 0.00 0.50 0.50 0.50 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 5.56 CS–BCG Corn silage 55.00 45.00 35.00 25.00 18.00 12.00 8.00 Barley grain 15.47 21.97 27.47 32.72 36.72 40.22 42.69 Corn grain 15.47 21.97 27.47 32.72 36.72 40.22 42.68 Canola meal 8.00 5.00 4.00 3.00 2.00 1.00 0.00 Urea 0.50 0.50 0.50 0.50 0.50 0.50 0.57 Limestone 0.00 0.00 0.00 0.50 0.50 0.50 0.50 Mineral pellet* 5.56 5.56 5.56 5.56 5.56 5.56 5.56 *The mineral pellet supplement was mixed with barley grain for pelleting at a DM basis ratio of 78:21, respectively. On DM basis, the mineral supplement (excluding the barley grain) contained 9.2% of calcium, 0.32% of phosphorus, 1.64% sodium, 0.28% of magnesium, 0.60% of potas- sium, 0.12% of sulfur, 4.9 mg/kg of cobalt, 185 mg/kg of copper, 16.6 mg/kg of iodine, 84 mg/kg of iron, 500 mg/kg of manganese, 2 mg/kg of selenium, 558 mg/kg of zinc, 40,000 IU/kg of vitamin A, 5,000 IU/kg of vitamin D3, and 600 IU/kg of vitamin E. The final supplement contained 510 mg/kg of monensin (Elanco Animal Health, Greenfield, IN) on a DM basis. D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 134 Johnson et al. Translate basic science to industry innovation basis. Net energy values for maintenance (NEm) and gain (NEg) were calculated based on animal per- formance as described by Zinn et al. (2002). The re- tained energy (RE) for large framed yearling calves was used (RE =  [0.0437BW0.75] × ADG1.097; NRC, 1984) where BW was the shrunk (4% shrink) mid- test weight. Net energy of gain was determined from NEm according to Zinn and Shen (1998) using the equation: NEg = NEm × 0.877 – 0.41. Near-Infrared Estimated Digestibility and Fecal Composition On day 51 of the study, fecal samples were col- lected from each pen. Approximately 1 L of fresh feces were collected from pats produced by at least four steers in each pen while avoiding contamination with bedding or soil from the pen floor (Jancewicz et  al., 2016a). The total number of fecal pats col- lected per pen was recorded. Composited fecal samples were thoroughly mixed and a 250-mL sub- sample was weighed, diluted in 250 mL of tap water, and screened using a 1.18-mm screen. The sample was continuously rinsed with tap water until only solid material remained. The residue was then dried for 24 h at 55 °C and sorted according to grain type (corn or barley) and fibrous portions. Material re- tained on the screen was further sorted into whole, fractured grain kernels, and fiber. The weight of the sorted fractions was then used to estimate the source and amount of grain kernels in the feces. The remaining composite sample of feces was dried in a forced-air oven at 55 °C to a constant weight and then ground to pass through a 1-mm screen using a Retsch ZM 200 grinder (Haan, Germany). Ground fecal samples were analyzed using near-infrared (NIR) spectroscopy to estimate ap- parent total tract digestibility using previously developed calibration equations as described by Jancewicz et al. (2016b). For each pen, quartz ring cups were evenly filled and packed with the dried and ground fecal samples and scanned in duplicate using two repacks with the second scan utilizing a separate subsample from the original sample. Samples were scanned using a SpectraStar Near- Infrared analyzer 2400 RTW (Unity Scientific, Brookfield, CT). Spectral information was col- lected at wavelengths between 1,200 and 2,400 nm in 1-nm increments. Statistical Analysis Data were analyzed with pen as the experi- mental unit in a completely randomized design using the mixed model of SAS (SAS version 9.4; SAS Institute, Inc. Cary, NC) with the fixed ef- fect of silage source, grain source, and the two- way interaction. Yield grades, quality grades, liver scores, and marbling scores were analyzed using the GLIMMIX procedure of SAS (SAS version 9.4, SAS Institute, Inc. 2002)  with a binominal error structure and logit data transformation. Following analysis, means and SEM were reverse transformed for presentation. For grain kernels isolated from feces, data were analyzed using the mixed model of SAS (SAS ver- sion 9.4; SAS Institute, Inc. Cary, NC) with the fixed effect of silage source, grain source, and the two-way interaction. When data were not normally distributed, the GLIMMIX procedure of SAS (SAS version 9.4; SAS Institute, Inc. Cary, NC) was used with a logit link function and binominal distribu- tion. For variables where all observations within a treatment were not possible (e.g., the appearance of corn in feces from steers fed diets only containing barley), the individual treatment was excluded from analysis for that specific variable and kernel appearance was denoted as not present (NP). For all analyses, when the P value for grain type or the interaction was <0.05, means were separated using the Tukey’s test. RESULTS Growth Performance and Carcass Characteristics No interactions between silage source and cereal grain source were observed and as such, the main effects of grain and silage source are pre- sented and discussed. Unshrunk initial BW and final BW and carcass-adjusted final BW were not affected by cereal silage or cereal grain source (P ≥ 0.20; Table 4). Feeding CG increased (P < 0.01) DMI by 0.8 and 0.6 kg/d relative to BG and BCG, respectively, but ADG, whether reported on a live weight basis or carcass-adjusted basis did not differ among grain source. As a result, G:F was greater (P = 0.04) for BG (0.172 kg/kg) than CG (0.162  kg/kg) but did not differ from BCG (0.165 kg/kg). Adjusted G:F was also greatest for BG, intermediate but not different for BCG, and least for CG (P = 0.02). Silage source did not af- fect DMI, ADG, carcass-adjusted ADG, or G:F. Hot carcass weight was 6.2 kg greater (P < 0.01) and dressing percentage was 0.57 percentage units greater (P = 0.04) for steers fed CS than BS, re- spectively. Grain source did not affect hot carcass weight or dressing percentage. D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 135Grain and silage inclusion for finishing Translate basic science to industry innovation There was no effect of silage or cereal grain source on back-fat thickness, ribeye area, yield grades, or quality grades. For marbling scores, the percentage of carcasses grading small was greater for BS relative to CS (61.6 vs. 44.5%; P = 0.01), while CS had a greater percentage of carcasses grading slight relative to BS (42.3 vs. 29.9%; P  =  0.04). There were no differences in the severity of liver ab- scesses among steers fed differing silage or cereal grain sources (P ≥ 0.20) with 72.0% of carcasses having no evidence of abscesses, 24.4% with minor liver abscesses, and 3.6% with severe liver abscesses. The NEm and NEg, calculated based on steer per- formance, were greater for BG compared with CG Table 4. Effect of cereal silage source (8% of DM) and cereal grain source (86% of DM) on DMI, BW, ADG, G:F, and carcass characteristics for finishing steers (12 steers/pen with 4 pens/treatment) Barley silage Corn silage SEM* P value Barley Corn Blend Barley Corn Blend Silage Grain S × G† Initial BW, kg 464 464 464 464 466 464 0.80 0.30 0.20 0.30 Final BW, kg 648 647 645 654 651 649 4.93 0.25 0.71 0.99 Adjusted final BW, kg‡ 622 621 619 628 625 623 4.78 0.27 0.71 0.99 DMI, kg/d 12.1b 12.8a 12.3b 12.3b 13.2a 12.4b 0.22 0.23 <0.01 0.79 ADG, kg/d 2.05 2.05 2.04 2.13 2.10 2.05 0.05 0.25 0.60 0.70 Carcass-adjusted ADG, kg/d‡ 1.99 1.97 1.95 2.05 2.00 1.99 0.06 0.37 0.69 0.94 G:F, kg/kg 0.170a 0.163b 0.165ab 0.173a 0.160b 0.165ab 0.004 1.00 0.04 0.79 Carcass-adjusted G:F, kg/kg‡ 0.164a 0.154b 0.158ab 0.167a 0.152b 0.161ab 0.004 0.82 0.02 0.77 Hot carcass, kg 365 368 365 372 375 370 2.05 <0.01 0.17 0.85 Dressing, % 58.7 59.2 59.0 59.2 60.0 59.4 0.31 0.04 0.14 0.80 Back fat, cm 1.09 1.12 1.19 1.14 1.19 1.12 0.06 0.57 0.76 0.37 Rib eye area, cm2 88.98 87.80 88.68 91.55 89.93 91.53 0.57 0.05 0.56 0.94 Yield grade, %** CBGA 1 47.9 47.9 37.5 50.0 34.0 40.8 7.2 0.63 0.36 0.42 CBGA 2 47.9 37.5 45.8 29.2 53.2 40.8 7.3 0.62 0.61 0.08 CBGA 3 4.2 12.5 16.7 18.8 12.8 18.4 5.6 0.13 0.30 0.24 Quality grade, %** CBGA AAA 79.2 83.3 75.0 75.0 78.7 67.4 6.7 0.30 0.30 0.98 CBGA AA 20.8 14.6 25.0 22.9 21.3 32.7 6.7 0.28 0.22 0.89 CBGA A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.00 1.00 1.00 CBGA B 0.0 2.1 0.0 2.1 0.0 0.0 2.1 1.00 1.00 1.00 Marbling score, %†† Moderate 2.1 0.0 0.0 0.0 4.3 2.0 2.9 0.99 1.00 1.00 Modest 6.2 4.2 14.6 6.3 12.8 14.3 5.1 0.38 0.15 0.46 Small 54.2 72.9 56.2 45.8 48.9 38.8 7.3 0.01 0.16 0.52 Slight 37.5 22.9 29.2 47.9 34.0 44.9 7.2 0.04 0.15 0.91 Trace 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.00 1.00 1.00 Liver score‡‡ Clear 68.0 73.3 76.6 79.2 71.7 63.0 7.1 0.85 0.85 0.20 Minor 32.0 22.2 19.1 20.8 28.3 23.9 6.6 0.98 0.74 0.34 Severe 0.0 4.4 4.3 0.0 0.0 13.0 5.0 0.99 1.00 1.00 NEm, Mcal/kg*** 1.98a 1.89b 1.92ab 2.00a 1.86b 1.96ab 0.03 0.87 <0.01 0.68 NEg, Mcal/kg*** 1.33a 1.24b 1.28ab 1.34a 1.22b 1.30ab 0.03 0.89 <0.01 0.73 a,b,cValues within a row with uncommon letters differ among grain sources (P < 0.05). *Greatest SEM was reported. †S × G = silage by grain interaction. ‡Adjusted final BW was calculated for each pen as hot carcass weight divided by the corresponding average pen dressing percent. Carcass- adjusted ADG was calculated the adjusted BW and was used to determine G:F. **Percent of total according to Canadian Beef Grading Agency (CBGA). ††Percent of total according to U.S. Department of Agriculture (USDA) where 600–699 = moderate; 500–599 = modest; 400–499 =  small; 300–399 = slight; and 200–299 = trace. ‡‡According to Elanco Liver Check System (Elanco Animal Health, Greenfield, IN). ***Net energy values calculated based on animal performance for the finishing period as described by Zinn et al. (2002) and Zinn and Shen (1998) D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 136 Johnson et al. Translate basic science to industry innovation but not different from BCG (P < 0.01) and did not differ among silage sources. Estimated Total Tract Digestibility and Fecal Composition There was no effect of silage source on pre- dicted total tract digestibility of DM, OM, CP, NDF, or ADF digestibility (P ≥ 0.24; Table 5). However, predicted starch digestibility was greater (87.1 vs. 85.8%; P = 0.02) for BS than CS. Digestibility of DM and CP was greater for BG relative to CG or BCG (P < 0.01). Organic matter, NDF, and starch, digestibility were greatest for BG, intermediate for BCG, and the least for CG (P < 0.01). In general, fecal starch concentrations were high, but fecal starch content was greatest for CG, least for BG, and intermediate for BCG (P  <  0.01). Predicted gross energy (GE) digest- ibility was greatest (P  <  0.01) for BG relative to other grain sources and not affected by silage source. More (P < 0.01) whole barley kernels appeared in the feces of cattle fed BG, intermediate for BCG, and the least for CG (Table 6). More fractured barley kernels were present in the feces of cattle fed BG (P  =  0.04). Whole corn kernels in feces were not affected by diet, but more fractured kernels were observed for CS than BS (P = 0.04). Likewise, fractured corn kernels were most common in feces from cattle fed CG, intermediate for BCG, and least for BG (P < 0.01), and greater for CS than BS (P = 0.04). Fibrous (nonkernel) content in feces was greater for BG, intermediate for BCG, and least for Table 5. Effect of cereal silage (8% of DM) and cereal grain source (86% of DM) on apparent total tract digestibility in steers during the finishing period using NIR calibrations (Jancewicz et al., 2016b) on feces collected on day 51 of the study. Barley silage Corn silage SEM P values Barley Corn Blend Barley Corn Blend Silage Grain S × G* Digestibility, % DM basis DM 84.4a 77.2b 78.0b 83.0a 78.0b 79.5b 0.75 0.63 <0.01 0.17 OM 85.7a 74.0c 76.1b 83.3a 74.2c 77.3b 0.77 0.60 <0.01 0.08 CP 73.2a 67.6b 67.1b 72.7a 66.4b 67.5b 0.87 0.57 <0.01 0.68 NDF 61.5a 52.0c 56.4b 59.8a 52.0c 56.3b 0.61 0.24 <0.01 0.31 ADF 30.3a 28.1b 26.3ab 29.9a 26.1b 29.3ab 1.08 0.84 0.03 0.10 Starch 92.5a 83.0c 85.9b 90.1a 82.3c 85.0b 0.63 0.02 <0.01 0.33 Fecal starch, % DM 14.5c 32.4a 26.0b 15.8c 32.3a 28.0b 1.35 0.33 <0.01 0.72 GE digestibility, % 88.4a 81.6b 83.2b 89.0a 84.1b 84.8b 1.16 0.12 <0.01 0.71 a,b,c Values within a row with uncommon letters differ significantly among grain sources (P < 0.05). *S × G = silage by grain interaction. Table 6. Effects of cereal silage (8% of DM) and cereal grain source (86% of DM) on the composition of solids retained on a 1.18-mm sieve after wet screening a 250-mL subsampled fecal composite collected from pen floors on day 51 of the study Barley silage Corn silage P values Barley Corn Blend Barley Corn Blend SEM* Silage Grain S × G† Wet fecal weight, g/250mL 240.2b 259.6a 245.1b 243.9b 259.1a 246.7b 4.33 0.65 <0.01 0.89 Total solids retained, g‡‡ 17.4c 43.1a 35.2b 20.6c 44.5a 35.8b 1.95 0.29 <0.01 0.81 Whole barley, % retained 21.11a 1.30c 9.61b 21.30a NP 7.33b 0.71 0.13 <0.01 0.07 Fractured barley, % retained 1.69a 0.19b 1.57b 6.20a NP 1.48b 0.48 0.10 0.04 0.08 Whole corn, % retained NP 0.71 0.72 0.48 1.37 1.42 0.40 0.08 0.14 0.96 Fractured corn, % retained NP 66.65a 42.36b 2.69c 70.43a 51.02b 2.78 0.04 <0.01 0.40 Fiber, % retained 77.20a 31.17c 44.73b 68.48a 28.20c 38.75b 2.70 0.02 <0.01 0.58 NP = Not present. Data were not included in statistical analysis as there was no supply of the specific grain source and fecal analysis confirmed that none were present. a,b,cValues within a row with uncommon letters differ significantly among grain sources (P < 0.05). *Greatest SEM was reported. †S × G = silage by grain interaction. ‡Total weight of dry solid material that was retained on a 1.18-mm sieve after rinsing a 250-mL fecal sample under tap water. D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 137Grain and silage inclusion for finishing Translate basic science to industry innovation CG diets (P < 0.01), and greater for BS than CS (P = 0.02). DISCUSSION We hypothesized that diets containing a blend of CG and BG would have greater digestibility, growth performance, and feed efficiency compared to single grain diets. The dietary treatments in the current study were formulated to deliver similar CP concentrations while comparing the effects of dif- fering grain and silage sources fed at similar levels of dietary DM. To achieve this, silage and grain in- clusion were held constant, with the exception that urea was used as a substitute for the cereal grain to maintain isonitrogenous diets. As a result of differ- ences in starch content between CG and BG, the diet starch content was numerically greatest for CG diets, intermediate for BCG diets, and least for BG diets. Starch content was allowed to change with grain source as ingredient substitution approaches are common in industry and that cereal grain inclu- sion rates rather than dietary starch were reported to be considerations of feedlot nutritional consult- ants in the United States (Samuelson et al., 2016). That said, it should be acknowledged that in add- ition to starch source, starch concentration may af- fect the responses observed. Though not examined when feeding a combin- ation of dry-rolled CG and dry-rolled BG, several studies have demonstrated synergistic effects on growth performance and feed efficiency for fin- ishing cattle fed a combination of grain sources that differ in their ruminal fermentability. Stock et  al. (1987a, 1987b) demonstrated, in multiple stud- ies, a positive associative effect of combining high moisture corn with diets comprised of whole CG or dry-rolled sorghum grain, noting an improve- ment in feed efficiency and ADG for blended grain diets. Additionally, Stock et al. (1987b) found that feeding a combination of grain sources improved ruminal and total tract starch digestion, an obser- vation that may partially explain the positive im- pact of this practice on feed efficiency. In another study, Huck et  al. (1998) observed positive asso- ciative effects of feeding steam flaked sorghum in combination with high moisture or dry-rolled corn noting improvements in ADG and G:F. A similar study conducted by Kreikemeier et  al. (1987) in- dicated that with wheat, which had 35% more di- gestible starch than dry-rolled corn, ADG and G:F were improved when wheat was included with corn in finishing diets as compared with when ei- ther grain source was fed alone. For dairy cattle, Khorasani et  al. (2001) demonstrated an increase in milk and milk component yield in primiparous cows fed an equal blend of coarse ground CG and BG relative to individual grain-based diets. Those authors suggested that improvements were due in part to the synchronization of dietary energy and protein with the blended grain diet. As such, there is a large body of support suggesting that there may be potential additive benefits when combining grain sources that have varying rates and extents of starch degradation. However, no additive ef- fects of feeding a blend of cereal grain sources were detected in this study. It is possible that the cereal grain processing method imposed in the current study were inadequate to improve fermentability sufficiently enough to observed additive effects or that differences in the fermentability of the grain sources were small. Effects of Cereal Silage Source Although inclusion rates of silage were low (8% of DM), we observed that CS improved hot carcass weight, and dressing percentage relative to diets with BS. Given the relatively low inclusion rate, these observations are difficult to explain. However, it is possible that numerically greater starch concentra- tion in CS may have contributed to greater quantity of digestible starch supply to the rumen and poten- tially the intestine relative to BS (Table 1). Owens et  al. (1986) estimated that starch digested in the small intestine may provide up to 42% more energy than when fermented in the rumen. While this sug- gestion may provide a potential explanation, given the high fecal starch content in general, and par- ticularly that of CG-fed steers (>30% DM), it could be expected that limits to intestinal starch digestion may have been exceeded (Huntington et al., 2006). Second, fat provided by corn-based diets is gener- ally greater in content and of different composition than that provided by barley which, given its higher energy value relative to carbohydrates, would in- crease energy intake and could relate to carcass quality improvement (Table 1). However, the contri- bution of silage towards energy supply, at such low levels of inclusion is unlikely to stimulate carcass gain, particularly considering that there were no differences in predicted NDF or ADF digestibility among silage sources. The most reasonable explan- ation is that although only numerically greater, that the increase in estimated GE digestibility of CS treatments, as well as the numerically greater starch and NE for CS (Table 1) when compounded over D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 138 Johnson et al. Translate basic science to industry innovation the 89-d finishing study may have increased total energy intake and subsequently resulted in improve- ments for carcass quality. Although not significant, the additional energy intake may have been suffi- cient to result in the improvements in carcass gain observed. Interestingly, when energy density was predicted based on growth performance, no differ- ences were detected and silage source did not affect DMI. However, the equations of Zinn et al. (2002) and Zinn and Shen (1998) use shrunk live BW ra- ther than carcass weight, a potential flaw when using this method in cases where there are differ- ences in HCW. Interestingly, feeding BS increased the appear- ance of whole barley kernels in the feces. When feeding CS, the appearance of whole and fractured corn kernels in the feces was also increased. With finishing diets, it is generally assumed that the ap- pearance of grain in the feces may be an indication of inadequately processed cereal grain. However, despite the fact that CS was harvested using a kernel processor (2-mm gap width) there was still an influ- ence of silage source on kernel appearance in the feces. Previous studies have suggested that kernel processing through a 2-mm gap should be sufficient to optimize starch digestibility in CS (Ferraretto and Shaver (2012). However, such processing con- ditions may not be adequate with finishing diets or with short-season corn varieties. For barley kernel appearance in the feces, it is evident that the ma- jority of whole kernels arise from the grain source as opposed to the silage source, suggesting that not all kernels were adequately damaged during the dry-rolling process despite achieving an adequate processing index. Effects of Cereal Grain Source In the current study, there were no observed benefits in feeding a combination of dry-rolled BG and CG. In fact, feeding BG improved G:F and had greater predicted digestibility compared with CG or BCG. Several studies have been conducted directly comparing dry-rolled BG and CG, although results have been inconsistent with regards to feed intake and growth performance given the reported differ- ences in energy value between these grain sources. Consistent with results in the current study, stud- ies by Boss and Bowman (1996) and Milner et al. (1995) both demonstrated an increase in DMI for steers fed dry-rolled corn compared with barley. Boss and Bowman (1996) also reported that feed ef- ficiency was greater for barley-fed steers compared with those fed dry-rolled corn. In contrast, studies by Mathison and Engstrom (1995) reported that when dry rolled, no effect of grain source (corn vs. barley) was observed on intake or growth perform- ance. Nelson et  al. (2000) reported that steers fed dry-rolled corn were more efficient than those fed dry-rolled barley. The greater DMI and G:F with barley are most likely influenced by the less severe processing of CG and consequently reduced digest- ibility relative to BG. Supporting this, fecal starch for all treatments was high in this study. Jancewicz et  al. (2017) reported a mean fecal starch of 7% when evaluating 282 fecal samples from six feedlots in southern Alberta. Although the study only evalu- ated diets containing BG or a combination of barley and wheat, they observed a quadratic relationship between fecal starch and G:F and a high PI was also correlated with higher fecal starch. Given the high fecal starch and low digestibility for CG in the pre- sent study, these results support that dry-rolling corn is not a processing method sufficient to disrupt the complex starch and protein matrix of CG and sub- sequently improve digestibility (Owens et al., 1997; Zinn et al., 2011). For barley, even with a mean PI of 66.6% in the current study, fecal starch for the BS– BG treatment was still 14.5%, substantially greater than observed by Jancewicz et al. (2017). Although PI was more severe for BG, it is possible that large variability in kernel size may have resulted in a non- uniform processing and that a portion of smaller kernels may have remained unprocessed as further evidenced by whole kernel appearance in feces. Such processing conditions would explain the lower than expected starch digestibility for BG, as well as the higher fecal starch content, given that whole barely has poor digestibility. However, it should be noted that despite high fecal starch, ADG still exceeded 2 kg/d for all treatments. In feedlot diets, DMI is predominantly influenced by metabolic factors (Allen et al., 2009). Net energy values published by National Academies of Sciences, Engineering, and Medicine NASEM (2016) suggest that dry-rolled corn should have a greater energy content than dry-rolled barley (2.17 vs. 2.06 Mcal/kg NEm, respectively). However, when calculated based on growth performance, NE values were greater for BG than CG. The relationship between NE and DMI has been well established such that dietary NEm con- tent can be used to predict DMI (NASEM, 2016). Predictions developed by both NASEM (2016) and Anele et al. (2014) demonstrate that DMI decreases with increasing NEm. As such, it is likely that the lower growth performance, as calculated NEm, as well as the lower digestibility of CG were driving factors behind the greater DMI for CG-fed steers, D ow nloaded from https://academ ic.oup.com /tas/article/4/1/129/5601926 by Biblio Sta R echerches Ste-Foy user on 12 July 2024 139Grain and silage inclusion for finishing Translate basic science to industry innovation despite there being no increase in growth perform- ance. Additionally, the low processing index of CG may explain the low energy utilization. Likewise, greater digestibility of BG diets may have reduced feed intake, the extent to which likely limited a cor- responding improvement in ADG or G:F. Not surprisingly, the appearance of whole barley kernels in the feces was greater for BG diets, while whole and fractured corn kernel appearance were greatest on CG diets. Results suggest that at least for CG, a PI of 83% resulted in a large amount of bypass starch. These results reinforce the importance of adequate grain processing in finishing diets to maximize feed utilization, while also minimizing the risk of digestive upsets such as acidosis that can occur when feeding over pro- cessed grains. Contrary to our hypothesis, feeding a blend of dry-rolled CG and BG showed no benefit with re- spect to growth performance or carcass characteris- tics for finishing beef cattle. Current results indicate that when dry rolled, feeding BG resulted in im- proved growth performance and digestibility com- pared to either CG or BCG. Despite low inclusions levels (8% of DM), feeding CS improved carcass characteristics relative to BS and no interactions were detected between silage and grain sources, indicating there were no observed additive benefits of concurrently feeding BG with CS. ACKNOWLEDGMENTS Funding for this project was provided by the Saskatchewan Barley Development Commission (Saskatoon, SK, Canada), Dupont Pioneer (Johnston, IA), the Saskatchewan Cattlemen’s Association, and the Saskatchewan Ministry of Agriculture and the Canada-Saskatchewan Growing Forward 2 bilat- eral agreement. In-kind support from Cargill Meat Solutions Ltd. is acknowledged through the provision of carcass and liver score data. LITERATURE CITED Allen, M. S., B. J. Bradford, and M. Oba. 2009. Board Invited Review: The hepatic oxidation theory of the control of feed intake and its application to ruminants. J. Anim. Sci. 87:3317–3334. doi:10.2527/jas.2009-1779. Anele,  U.  Y., E.  M.  Domby, and M.  L.  Galyean. 2014. Predicting dry matter intake by growing and finishing beef cattle: evaluation of current methods and equation development. J. Anim. Sci. 92:2660–2667. doi:10.2527/ jas.2014-7557. AOAC. 2000. Official methods of analysis of AOAC International. 17th ed. 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