Three experiments evaluated the lipids in distillers grains plus solubles compared with corn or other sources of lipid in finishing diets. Experiment 1 utilized 60 individually fed yearling heifers ...(349 ± 34 kg of BW) fed treatments consisting of 0, 20, or 40% (DM basis) wet distillers grains plus solubles (WDGS), or 0, 2.5, or 5.0% (DM basis) corn oil in a finishing diet based on high-moisture corn (HMC) and dry-rolled corn. Cattle fed 20 and 40% WDGS had greater (P < 0.10) G:F than cattle fed 0% WDGS. Cattle fed the 5.0% corn oil had less overall performance than cattle fed the other diets. Results from Exp. 1 indicated that adding fat from WDGS improves performance, whereas supplementing 5.0% corn oil depressed G:F, suggesting that the fat within WDGS is different than corn oil. Experiment 2 used 234 yearling steers (352 ± 16 kg of BW) fed 1 of 5 treatments consisting of 20 or 40% (DM basis) dry distillers grains plus solubles, 1.3 or 2.6% (DM basis) tallow, or HMC. All diets contained 20% (DM basis) wet corn gluten feed as a method of controlling acidosis. No differences between treatments for any performance variables were observed in Exp. 2. The dry distillers grains plus solubles may be similar to tallow and HMC in finishing diets containing 20% wet corn gluten feed. Experiment 3 used 5 Holstein steers equipped with ruminal and duodenal cannulas in a 5 x 5 Latin square design. Treatments were a 40% WDGS diet, 2 composites, one consisting of corn bran and corn gluten meal; and one consisting of corn bran, corn gluten meal, and corn oil; and 2 dry-rolled corn-based diets supplemented with corn oil or not. Cattle fed the WDGS diet had numerically less rumen pH compared with cattle fed other treatments. Cattle fed WDGS had greater (P < 0.10) molar proportions of propionate, decreased (P < 0.10) acetate:propionate ratios, greater (P < 0.10) total tract fat digestion, and a greater (P < 0.10) proportion of unsaturated fatty acids reaching the duodenum than cattle fed other treatments. Therefore, the greater energy value of WDGS compared with corn may be due to more propionate production, greater fat digestibility, and more unsaturated fatty acids reaching the duodenum.
A feedlot (Exp. 1) experiment was conducted to evaluate the effects of an essential oil mixture (EOM), experimental essential oil mixture (EXP), tylosin, and monensin (MON) on performance, carcass ...characteristics, and liver abscesses. A metabolism experiment (Exp. 2) was conducted to evaluate the effects of EOM, EXP, and MON on ruminal fermentation and digestibility in finishing steers. In Exp. 1, 468 yearling steers (398 ± 34 kg initial BW) were used in 50 pens (10 pens/treatment) and received their respective dietary treatments for 115 d. Five dietary treatments were compared in Exp. 1: 1) control, no additives (CON); 2) EOM, 1.0 g/steer daily; 3) EXP, 1.0 g/steer daily; 4) EOM, 1.0 g/steer daily plus tylosin, 90 mg/steer daily (EOM+T); and 5) monensin, 300 mg/steer daily plus tylosin, 90 mg/steer daily (MON+T). Compared with CON, steers fed MON+T had decreased DMI (P < 0.01), and steers fed EOM+T and MON+T had improved G:F (P less-than or equal to 0.02). Average daily gain was not different among treatments (P > 0.58). There was a trend (P = 0.09) for a treatment effect on 12th-rib fat thickness, which resulted in a significant increase in calculated yield grade for the EOM+T treatment. No other carcass characteristics were affected by treatment (P greater-than-or-equal 0.10). Prevalence of total liver abscesses was reduced for steers fed tylosin compared with no tylosin (P < 0.05). In Exp. 2, 8 ruminally fistulated steers (399 ± 49 kg initial BW) were assigned randomly to 1 of 4 treatments in a replicated 4 x 4 Latin square designed experiment. Treatments were 1) CON, 2) EOM, 3) EXP, and 4) MON with feeding rates similar to Exp. 1. There were no differences in DMI, OM intake, and apparent total tract DM or OM digestibilities among treatments (P > 0.30). Feed intake patterns were similar among feed additive treatments (P > 0.13). Total VFA (P = 0.10) and acetate (P = 0.06) concentrations tended to be affected by treatment with EOM numerically greater than CON. Average ruminal pH ranged from 5.59 to 5.72 and did not differ among treatments. Addition of a EOM or monensin to a diet containing tylosin improves G:F, but little difference was observed in metabolism or digestibility.
Two experiments were conducted to determine the effect of corn processing method and corn wet distillers grains plus solubles (WDGS) level on steer performance and metabolism. In Exp. 1, 480 ...crossbred steer calves (314 ± 18 kg of BW) were used in a finishing experiment with a randomized complete block design and a 3 x 4 treatment structure. Diets were based on dry-rolled (DRC), high-moisture (HMC), or steam-flaked corn (SFC) with increasing levels of WDGS (0, 15, 27.5, or 40%; DM basis). A corn processing x WDGS level interaction (P < 0.01) was observed for ADG and G:F. Average daily gain and G:F increased linearly (P < 0.01) in steers fed DRC; ADG increased quadratically (P = 0.04) and G:F increased linearly (P = 0.02) in steers fed HMC; and ADG decreased quadratically (P = 0.02) with no change in G:F (P = 0.52) in steers fed SFC as WDGS increased. In Exp. 2, 7 ruminally fistulated steers (440 ± 41 kg of BW) were used in a 6-period crossover design with 3 x 2 factorial treatment structure. Diets were the same as those fed in Exp. 1, except they contained only 2 levels of WDGS (0 or 40% of diet DM). Total tract starch digestibility was greater (P < 0.01) for steers fed SFC than for steers fed DRC or HMC. Minimum ruminal pH was less (P < 0.01) for steers fed SFC than for steers fed HMC or DRC. Variance of ruminal pH was different among all 3 processing methods with DRC < HMC < SFC (P < 0.10). In situ 22-h DM digestibility of DRC and HMC and starch digestibility of DRC were greater (P < 0.10) in steers fed DRC compared with steers fed HMC or SFC. Steers fed 0% WDGS had less (P less-than or equal to 0.02) intake of DM, OM, NDF, and ether extract compared with steers fed 40% WDGS. Total tract digestibility of DM and OM was greater (P less-than or equal to 0.08) and digestibility of ether extract tended (P = 0.11) to be less for steers fed 0% WDGS compared with steers fed 40% WDGS. Maximum ruminal pH and pH variance were greater (P less-than or equal to 0.08) in steers fed 0% WDGS. A corn processing x WDGS level interaction (P = 0.09) was observed for ruminal acetate to propionate ratio (A:P). Within diets containing 0% WDGS, A:P in steers fed SFC was less (P less-than or equal to 0.08). In diets containing 40% WDGS, A:P was similar between processing methods and not different from the SFC with 0% WDGS. The corn processing x WDGS level interaction observed in the finishing experiment may be due to the decreased ruminal A:P in DRC and HMC diets with 40% WDGS.
Two experiments were conducted to determine the effects of wet distillers grain plus solubles (WDG; <15% sorghum grain) concentration in steam-flaked corn (SFC) diets on feedlot performance, carcass ...characteristics, ruminal fermentation, and diet digestibility. In Exp. 1, six hundred crossbred steers (364 ± 35 kg of BW) were used in a randomized complete block design with 8 replications/treatment. Dietary treatments consisted of a dry-rolled corn (DRC) control diet without WDG, a SFC control without WDG, and SFC with 4 WDG concentrations (15, 30, 45, 60% DM basis) replacing SFC, cottonseed meal, urea, and yellow grease. Final BW, ADG, G:F, HCW, and 12th-rib fat depth were greater (P ≤ 0.05) for SFC compared with DRC. Dry matter intake tended (P = 0.06) to be greater for DRC compared with SFC. Final BW, ADG, G:F, HCW, 12th-rib fat depth, and marbling score decreased linearly (P < 0.01) with increasing WDG concentration. In Exp. 2, six ruminally and duodenally cannulated crossbred steers (481 ± 18 kg of BW) were used in a 6 x 6 Latin square design using the same diets as Exp. 1. Ruminal, postruminal, and total tract OM and NDF digestibility were not different (P > 0.14) for DRC compared with SFC. Ruminal and total tract starch digestibility were greater (P < 0.01) for SFC compared with DRC. Dry matter and OM intake were not different (P ≥ 0.43) among WDG treatments. Ruminal and total tract OM digestibility decreased linearly (P < 0.01) with increasing WDG concentration. Intake, ruminal digestibility, and total tract digestibility of NDF increased linearly (P < 0.01) with increasing WDG concentration. Starch intake decreased linearly (P < 0.01) with increasing WDG concentration. Ruminal starch digestibility increased (P = 0.01) with increasing concentration of WDG. Total tract starch digestibility decreased quadratically (P < 0.01) with increasing concentration of WDG. Feeding SFC improved steer performance compared with DRC. The concentration of WDG and corn processing method influences nutrient digestibility and ruminal fermentation. The addition of WDG in SFC-based diets appears to negatively affect animal performance by diluting the energy density of the diet.
Two experiments using 96 steers each were conducted to evaluate the effect of corn wet distillers grains plus solubles (WDGS) concentration on steer performance, N loss, and P mass balance. Feeding ...WDGS as an energy source instead of protein may increase N release into the environment but also the amount of N removed in the manure. Calves (BW = 294 ± 33 kg) were fed 167 d from November to May (WIN), and yearlings (BW = 373 ± 24 kg) were fed 133 d from June to October (SUM). Treatments consisted of 0, 15, and 30% dietary inclusion of WDGS (DM basis) replacing corn (CON, 15WDGS, 30WDGS, respectively). Basal diets consisted of high-moisture and dry-rolled corn fed at a 1:1 ratio, 7.5% alfalfa hay, 5% molasses, and 5% supplement (DM basis). The CON and 15WDGS diets were formulated to meet MP requirements, and 30WDGS exceeded MP requirements. Dry matter intake, ADG, and HCW increased linearly (P < 0.05) with WDGS concentration in the WIN, whereas DMI and ADG increased linearly (P < 0.10) in the SUM. Efficiency of BW gain was not different (P > 0.10) among treatments in either experiment. Nitrogen and P intake increased linearly (P < 0.01) with WDGS concentration in both experiments. Calculated retention of N and P increased linearly (P ≤ 0.05) with WDGS concentration in the WIN but not in the SUM (P > 0.10). Calculated excretion of N and P increased linearly (P < 0.01) with WDGS concentration in both experiments. Amount of N removed in the manure was not different (P = 0.26) among treatments in the WIN but increased linearly (P = 0.05) with WDGS concentration in the SUM. Amount of P and OM removed increased linearly (P ≤ 0.05) with WDGS concentration in both experiments. Amount of N lost (kg/steer) increased linearly (P < 0.05) with WDGS concentration in both experiments. Expressed as a percentage of N excretion, N volatilization rate (amount of N lost divided by N excretion) was not different (P > 0.30) among treatments and averaged 68.3 and 77.0 in the WIN and SUM, respectively. More N volatilized when WDGS were fed, but not all of the additional N excreted was volatilized. Regressing the amount of OM on the pen surface against manure N, 98% of the variability for manure N in the WIN and 92% in the SUM was accounted for. Feeding WDGS increased the total amount of N lost to volatilization; however, not all of the additional N excreted was lost because of an increase in the proportion of manure OM.
Phosphorus is an expensive nutrient to supplement, and excess may lead to manure P challenges. Therefore, minimizing dietary P to meet requirements is important. Two experiments were conducted to ...determine the P requirement of finishing cattle (Exp. 1) and to evaluate the effects of feeding different P concentrations on the quantity and route of P excretion (Exp. 2). In Exp. 1, 60 heifers (BW = 278 kg ± 17 kg) were individually fed 1 of 5 dietary P concentrations (0.10, 0.17, 0.24, 0.31, or 0.38% P). Cattle performance, plasma P concentration, bone characteristics, and bone P concentration were used to determine the P requirement. Intake and ADG increased quadratically (P < 0.01) as dietary P increased. Plasma P in heifers receiving the 0.10% treatment was less (P < 0.01) than the other treatments and suggested that these heifers were experiencing a P deficiency. Total ash weight of the phalanx bones increased linearly (P < 0.01) as dietary P increased. In Exp. 2 using a 5 x 5 Latin square design, 5 different diets varying in P concentration (0.12, 0.27, 0.42, 0.30, and 0.36% P) were fed to steers to evaluate route and quantity of P excreted. Steers excreted little (1.78 g/d on average) P in the urine as a percentage of total P excretion. Steers on the 0.12% P diet excreted very little P in urine (0.50 g/d). Excretion of P was less (P < 0.05) for the cattle fed 0.12% P compared with all other treatments. Results from cattle performance, plasma P concentrations, and bone characteristics indicate that the heifers fed 0.10% P were experiencing a deficiency and the P requirement of finishing heifers is between 0.10 and 0.17% P. Dietary P concentrations of 0.10 to 0.17% P resulted in decreased P excretion. Supplementation of mineral P is unnecessary in grain-based feedlot diets because dietary P will greatly exceed the requirements (<0.17%).
In a 3-yr study, corn dried distillers grains plus solubles (DDGS) were evaluated as a substitute for forage and N fertilizer in yearling steers grazing smooth bromegrass. A total of 135 steers (330 ...± 10 kg) were used in a randomized complete block design to measure the effects of DDGS supplementation and N fertilization on animal and pasture performance. Steers were initially stocked at 6.8 animal unit month (AUM)/ha on nonfertilized smooth bromegrass pastures (CONT), at 9.9 AUM/ha on smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT), or at 9.9 AUM/ha on nonfertilized smooth bromegrass pastures with 2.3 kg of DDGS DM supplemented daily (SUPP). Paddock was the experimental unit, with 3 replications per year for 3 yr. Paddocks were strip-grazed and put-and-take cattle were used to maintain similar grazing pressure among treatment paddocks during the 160-d grazing season. In vitro DM disappearance declined quadratically (P < 0.01), whereas CP and standing crop showed cubic responses (P < 0.01) throughout the grazing season. Crude protein was greater (P < 0.05) for FERT compared with CONT and SUPP. Standing crop was 18% greater (P < 0.01) for FERT than CONT and was 10% greater (P < 0.01) than SUPP. Adjusted stocking rates (AUM/ha) were greater (P < 0.01) for FERT and SUPP compared with CONT. Final BW were greater (P < 0.01) for SUPP steers compared with CONT and FERT steers. Similar results were observed for ADG, with SUPP steers gaining more (P < 0.01) compared with CONT and FERT steers. Total BW gain per hectare was increased (P < 0.01) by 53% with FERT and by 105% with SUPP. Feedlot ADG was similar among treatments (P = 0.88), and SUPP steers maintained their BW advantage through the finishing phase. Dried distillers grains can be used to substitute effectively for N fertilizer by increasing the performance of yearling steers grazing smooth bromegrass and increasing stocking rates compared with nonfertilized pastures.
Six experiments were conducted to evaluate dietary cation-anion difference (DCAD) in concentrate diets on urinary pH, feedlot performance, and N mass balance. In Exp. 1, 15 wether lambs (33.5 ± 3.0 ...kg) in five 3 x 3 Latin squares were fed a basal diet of 82.5% dry-rolled corn (DRC), 7.5% alfalfa hay, 5% molasses, and 5% supplement with different proportions of anionic and cationic salts. The DCAD was -45, -24, -16, -8, 0, +8, +16, +24, +32, and +40 mEq per 100 g of DM with the control basal diet (DCAD = +8) included in each square. Urinary pH increased (cubic, P < 0.01) as DCAD increased and DMI increased linearly (P < 0.01) with increasing DCAD. In Exp. 2 and 3, 8 Holstein steers (312 ± 24 kg) were used in 2 consecutive 4 x 4 Latin squares. Steers were fed either the same basal diet as Exp. 1 or a basal diet with 20% wet distillers grains (WDGS) replacing DRC. In Exp. 2, DCAD was adjusted to -2, -12, and -22 mEq per 100 g of DM from the basal diet (DCAD = +8) and DCAD was adjusted in Exp. 3 to -12, -22, and -32 mEq per 100 g of DM from the basal WDGS diet (DCAD = -2). Urinary pH decreased linearly as DCAD decreased (P < 0.01) in both experiments, whereas DMI decreased linearly in Exp. 2 (P = 0.02) but not Exp. 3 (P = 0.96). In Exp. 4, 6 crossbred steers (373 ± 37 kg) were used in a 2-period crossover design. Steers were fed the same basal diet as Exp. 3 with DCAD of -16 (NEG) and +20 (POS) mEq per 100 g of DM. Urinary pH and DMI (P < 0.05) were less for cattle fed the NEG diet compared with POS. In 2 experiments, steers (n = 96 each) were fed NEG or POS as calves (260 ± 22 kg of BW) for 196 d from November to May (Exp. 5) or as yearlings (339 ± 32 kg of BW) for 145 d from June to October (Exp. 6). Final BW, DMI, ADG, and HCW were not different (P > 0.11) among treatments in either experiment. Efficiency of BW gain was increased (P = 0.05) for steers fed NEG compared with POS in Exp. 5 but was not different (P = 0.11) in Exp. 6. Amount of N intake, retention, excretion, and manure N (kg/steer) were not different (P > 0.11) among treatments in either experiment. Manure pH (soil, feces, and urine) was decreased (P < 0.01) in pens fed NEG compared with POS in both experiments. Amount of N lost (kg/steer) was not different (P = 0.44) in Exp. 5, but tended (P = 0.09) to be 10.6% greater for POS compared with NEG in Exp. 6. Urinary pH was decreased by reducing DCAD, but this had minimal effect on N losses in open feedlot pens in these experiments.
In a 3-yr study, 135 crossbred steers (330 ± 10 kg) were used in a randomized complete block design to evaluate corn dried distillers grains plus solubles (DDGS) fed to yearling steers as a ...substitute for forage and N fertilizer and its effect on N use efficiency in yearling steers grazing smooth bromegrass pastures. Steers were initially stocked at 6.8 animal unit months (AUM)/ha on nonfertilized smooth bromegrass pastures (CONT), at 9.9 AUM/ha on smooth bromegrass pastures fertilized with 90 kg of N/ha (FERT), or at 9.9 AUM/ha on nonfertilized smooth bromegrass pastures with 2.3 kg (DM) of DDGS supplemented daily per steer (SUPP). Paddock was the experimental unit, with 3 replications per treatment per year for 3 yr. Paddocks were strip-grazed, and put-and-take cattle were used to maintain similar grazing pressure among treatment paddocks during the 160-d grazing season. Steers consumed less forage (P < 0.01), but total N intake for SUPP was greater (P < 0.01) per steer and per hectare than for FERT, and both were greater (P < 0.01) than for CONT. Nitrogen retention for steers in the SUPP treatment was increased (P < 0.01) by 31% compared with N retention in the CONT and FERT treatments. Nitrogen retention per hectare for SUPP was 30 and 98% greater (P < 0.01) than N retention per hectare for FERT and CONT, respectively. Nitrogen excretion per steer and per hectare were also greater (P < 0.01) for SUPP than FERT, and both were increased (P < 0.01) compared with CONT. Animal N use efficiency was similar (P = 0.29) for steers in the CONT, FERT, and SUPP treatments. However, system-based N use improved (P < 0.01) by 144% for SUPP compared with FERT. The DDGS increased N intake and N excretion in yearling steers. However, because of improvements in BW gain and increases in stocking rate of pastures, DDGS can be a useful tool to increase the efficiency of N use in smooth bromegrass grazing systems.
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