Effects of twenty percent corn wet distillers grains plus solubles in steam-flaked and dry-rolled corn-based finishing diets on heifer performance, carcass characteristics, and manure characteristics

Two hundred sixty-four crossbred heifers (initial BW = 354 kg ± 0.5) were used to determine effects of corn processing method and wet distillers grains plus solubles (WDGS) inclusion in finishing diets on animal performance, carcass characteristics, and manure characteristics. The study was conducted as a randomized complete block with a 2 × 2 factorial arrangement of treatments. Dietary treatments included steam-flaked corn (SFC)- and dry-rolled corn (DRC)-based finishing diets containing 0 or 20% WDGS (0SFC, 20SFC, 0DRC, and 20DRC, respectively). Heifers averaged 154 d on feed and were marketed in 3 groups. There were no interactions between corn processing method and WDGS detected (P ≥ 0.29) for any performance or carcass response variables. Heifers fed diets containing WDGS tended to have greater final BW (P = 0.10) and increased G:F (P = 0.08) compared with heifers fed diets without WDGS. Heifers fed SFC-based diets consumed 7% less feed (P < 0.01) and were 9% more efficient (P < 0.01) than heifers fed DRC-based diets. Carcass characteristics were not affected by corn processing method or WDGS inclusion (P ≥ 0.16). Intakes of OM, N, P, and K were greater (P ≤ 0.05) for heifers fed DRC-based diets than those fed SFC-based diets, which resulted in greater net accumulation of the nutrients in the manure (P ≤ 0.04). Heifers fed diets containing WDGS had greater (P < 0.01) intakes of N, P, and K than heifers fed diets without WDGS. As a result, a greater net accumulation of P and K (P ≤ 0.03) and N (P = 0.10) were present in the manure from cattle fed diets containing WDGS compared with those fed diets without WDGS. There was no interaction (P ≥ 0.16) between corn processing and WDGS on N volatilization losses. Nitrogen volatilization losses from manure (expressed as a percentage of intake and g·heifer(-1)·d(-1)) were greater (P < 0.01) for heifers fed SFC-based diets than heifers fed DRC-based diets. Feeding DRC-based finishing diets to heifers resulted in increased manure production and nutrient excretion and decreased N volatilization. Both corn processing method and WDGS inclusion affected animal performance and manure characteristics.     

Combinations of alfalfa hay and wet corn gluten feed in limit-fed growing diets for beef cattle

Two experiments were conducted to evaluate the effects of alfalfa hay (AH) and wet corn gluten feed (WCGF) combinations on ADG and gain efficiency of cattle limit-fed growing diets. In Exp. 1, crossbred beef steers (n = 220; initial BW = 262 kg) were limit-fed diets consisting of steam-flaked corn and 40% WCGF (DM basis) with 0, 10, or 20% ground AH (0AH, 10AH, and 20AH, respectively). A fourth diet containing 20% ground AH and steam-flaked corn served as a control. All diets were fed once daily at 1.8% of BW (DM basis). Growing period ADG, gain efficiency, and dietary NE calculated from performance data decreased linearly (P < 0.01) with addition of AH to diets containing WCGF. Rate of DMI increased linearly (P < 0.05) with AH addition to diets containing WCGF. Following the growing period, steers were finished on a common diet offered ad libitum. Gain efficiencies during the finishing period were higher (P < 0.05) for steers fed the 20AH diet than for steers fed the control diet. In Exp. 2, crossbred beef heifers (n = 339; initial BW = 277 kg) were limit-fed diets containing steam-flaked corn with 10, 20, or 30% ground AH and 0, 40, or 68% WCGF in a 3 x 3 factorial arrangement, fed once daily at 1.6% of BW (DM basis). An AH x WCGF interaction occurred (P < 0.05) for growing period ADG and gain efficiency. Increasing AH or WCGF decreased cattle ADG, gain efficiency, and dietary NE with the exception of heifers fed 30AH/40WCGF, which had ADG that did not differ (P > 0.10) from that of heifers fed 20AH/0WCGF or 30AH/0WCGF, and which had greater gain efficiencies (P < 0.05) than heifers fed 30AH/0WCGF. Rate of DMI increased linearly (P < 0.01) with increasing AH and decreased linearly (P < 0.01) with increasing WCGF. Heifers were finished on diets containing 33% WCGF with 0 or 0.5% added urea (DM basis) offered ad libitum. Increasing WCGF in growing diets tended (linear, P < 0.10) to increase finishing ADG and gain efficiency, whereas increasing AH decreased (linear, P < 0.05) kidney, pelvic, and heart fat, and the percentage of carcasses grading USDA Prime. Urea tended to increase ADG (P < 0.10), but decreased (P < 0.04) the percentage of carcasses grading USDA Choice. Results suggest that the value of WCGF relative to steam-flaked corn in limit-fed growing diets might be improved in diets containing 30% AH relative to diets containing 10 or 20% AH.     

Effects of dried full-fat corn germ and vitamin E on growth performance and carcass characteristics of finishing cattle

Two experiments were conducted to evaluate dried full-fat corn germ (GERM) as a supplemental fat source in cattle finishing diets. In Exp. 1, 24 pens totaling 358 crossbred beef steers with an initial BW of 319 kg were allowed ad libitum access to diets containing dry-rolled corn, 35% wet corn gluten feed, and 0, 5, 10, or 15% GERM on a DM basis. Increasing GERM decreased (linear; P < 0.02) DMI and increased (quadratic; P < 0.02) ADG. Steers fed 10% GERM had the greatest ADG (quadratic; P < 0.02) and G:F (quadratic; P < 0.05). The addition of GERM increased (linear; P < 0.05) fat thickness, KPH, and the percentage of USDA Yield Grade 4 carcasses (quadratic; P < 0.03), with steers fed 15% GERM having the greatest percentage of USDA Yield Grade 4 carcasses. In Exp. 2, 48 pens totaling 888 crossbred beef heifers with an initial BW of 380 kg were allowed ad libitum access to diets containing steam-flaked corn, 35% wet corn gluten feed, and either no added fat (control), 4% tallow (TALLOW), or 10 or 15% GERM on a DM basis, with or without 224 IU of added vitamin E/kg of diet DM. No fat x vitamin E (P > or = 0.08) interactions were detected. Fat addition, regardless of source, decreased (P < 0.01) DMI, marbling score, and the number of carcasses grading USDA Choice. Among heifers fed finishing diets containing TALLOW or 10% GERM, supplemental fat source did not affect DMI (P = 0.76), ADG (P = 0.54), G:F (P = 0.62), or carcass characteristics (P > or = 0.06). Increasing GERM decreased DMI (linear; P < 0.01) and ADG (quadratic; P < 0.02), with ADG by heifers fed 10% GERM slightly greater than those fed control but least for heifers fed 15% GERM. Increasing GERM improved (quadratic; P < 0.03) G:F of heifers, with heifers fed 10% GERM having the greatest G:F. Increasing GERM decreased HCW (linear; P < 0.02), marbling score (linear; P < 0.01), and the percentage of carcasses grading USDA Choice (linear; P < 0.01). The addition of vitamin E increased (P < 0.04) the percentage of carcasses grading USDA Select and decreased (P < 0.01) the percentage of carcasses grading USDA Standard. These data suggest that GERM can serve as a supplemental fat source in cattle finishing diets, and that the effect of vitamin E did not depend on source or concentration of supplemental fat.     

Effects of corn processing method and dietary inclusion of wet distillers grains with solubles on energy metabolism, carbon-nitrogen balance, and methane emissions of cattle

The growing ethanol industry in the Southern Great Plains has increased the use of wet distillers grains with solubles (WDGS) in beef cattle (Bos taurus) finishing diets. Few studies have used steam-flaked corn (Zea mays L.; SFC)-based diets to evaluate the effects of WDGS in finishing cattle diets, and a reliable estimate of the net energy value of WDGS has yet to be determined. Effects of corn processing method and WDGS on energy metabolism, C and N balance, and enteric methane (CH(4)) production were evaluated in a short-term study using 8 Jersey steers and respiration calorimetry chambers. A 2 by 2 factorial arrangement of treatments was used in a Latin square design. The 4 treatment combinations consisted of: i) SFC-based diet with 0% WDGS (SFC-0); ii) SFC-based diet with 30% WDGS (SFC-30); iii) dry-rolled corn (DRC)-based diet with 0% WDGS (DRC-0); and iv) DRC-based diet with 30% WDGS (DRC-30). Diets were balanced for degradable intake protein (DIP) and ether extract (EE) by the addition of cottonseed (Gossypium hirsutum L.) meal and yellow grease. As a proportion of GE, grain processing method did not affect (P ≥ 0.12) fecal, digestible, urinary, and ME, or heat production. Steers consuming SFC-based diets produced less (P < 0.04) CH(4) than steers consuming DRC-based diets. Retained energy tended to be greater (P = 0.09) for cattle consuming SFC- than DRC-based diets. Inclusion of WDGS did not affect (P ≥ 0.17) fecal, digestible, urinary, metabolizable, and retained energy, or heat production as a proportion of GE. Furthermore, neither inclusion of WDGS or grain processing method affected (P ≥ 0.17) daily CO(2) production. Due in part to greater N intake, cattle consuming diets containing 30% WDGS excreted more (P = 0.01) total N and excreted a greater (P < 0.01) quantity of N in the urine. From these results, we conclude that cattle consuming SFC-based diets produce less CH(4) and retain more energy than cattle fed DRC-based diets; however, dietary inclusion of WDGS at 30% seems to have little effect on CH(4) production and energy metabolism when diets are balanced for DIP and EE. Cattle excrete a greater amount of C when fed DRC compared with SFC-based diets, and dietary inclusion of 30% WDGS increases urinary N excretion. Finally, we determined the NE(g) values for WDGS were 1.66 and 1.65 Mcal/kg in a SFC or DRC-based diet, respectively, when WDGS replaced 30% of our control (SFC-0 and DRC-0) diets.     

Effects of dry, wet, and rehydrated corn bran and corn processing method in beef finishing diets

Two finishing trials were conducted to determine the effects of adding different types of corn bran, a component of corn gluten feed, on cattle performance. In Trial 1, 60 English crossbred yearling steers (283 +/- 6.7 kg) were used in a completely randomized design with four dietary treatments. Treatments were diets with no corn bran, dry corn bran (86% DM), wet corn bran (37% DM), and rehydrated dry bran (37% DM). Bran was fed at 40% of dietary DM. All finishing diets had (DM basis) 9% corn steep liquor with distillers solubles, 7.5% alfalfa hay, 3% tallow, and 5% supplement. Gain efficiency and ADG were greater (P < 0.01) for cattle fed no corn bran compared with all treatments containing corn bran; however, no differences were detected across corn bran types. In Trial 2, 340 English crossbred yearling steers (354 +/- 0.6 kg) were used in a randomized block design with treatments assigned based on a 2 x 4 + 2 factorial arrangement (four pens per treatment). One factor was the corn processing method used (dry-rolled corn, DRC; or steam-flaked corn, SFC). The other factor was corn bran type: dry (90% DM), wet (40% DM), or dry bran rehydrated to 40 or 60% DM. Bran was fed at 30% of dietary DM, replacing either DRC or SFC. Two control diets (DRC and SFC) were fed with no added bran. All finishing diets contained (DM basis) 10% corn steep liquor with distiller's solubles, 3.5% alfalfa hay, 3.5% sorghum silage, and 5% supplement. Corn bran type did not affect DMI (P = 0.61), ADG (P = 0.53), or G:F (P = 0.10). Dry matter intake was greater (P < 0.01) by steers fed bran compared with those fed no bran, and was greater by steers fed DRC than by steers fed SFC (P < 0.01). Interactions occurred (P < 0.01) between grain source and bran inclusion for ADG and G:F. The ADG by steers fed the SFC diet without bran was greater (P < 0.01) than by steers fed SFC diets with bran, whereas the ADG by steers fed DRC diets with or without bran was similar. Daily gain was 15.2% greater (P < 0.01) by steers fed SFC without bran than by steers fed DRC without bran. Gain efficiency was 16.9% greater (P < 0.01) for steers fed SFC without bran compared with steers fed DRC without bran. In DRC and SFC diets, feeding bran decreased (P < 0.01) G:F by 5.2 and 13.8%, respectively. The moisture content of corn bran had no effect on finishing steer performance, and drying corn bran did not affect its energy value in finishing cattle diets.     

Performance and digestibility characteristics of finishing diets containing distillers grains, composites of corn processing coproducts, or supplemental corn oil

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.     

Corn distillers grains with solubles derived from a traditional or partial fractionation process: Growth performance and carcass characteristics of finishing feedlot heifers

Six hundred ten crossbred-yearling heifers (347 +/- 5 kg of initial BW) were obtained and used in a randomized complete-block design finishing study. Finishing diets were based on steam-flaked corn and ground alfalfa hay. The control (CONT) treatment contained no distillers grains with solubles (DGS), the second diet was formulated to contained 13% (DM basis) dried corn DGS derived from a traditional dry-grind ethanol process (TRAD), and the third diet was formulated to contained 13% (DM basis) dried corn DGS derived from a partial fractionation dry-grind process (FRAC). Dry matter intake, ADG, and gain efficiency were not different (P >/= 0.48) for yearling heifers fed CONT when compared with heifers fed DGS. Heifers fed TRAD consumed more (P = 0.01) feed than heifers fed FRAC. However, ADG and feed efficiency were not different (P >/= 0.07) for heifers fed DGS. Moderate inclusion levels of DGS in finishing flaked corn diets yielded satisfactory performance. Growth performance was not different for heifers fed DGS originating from either ethanol processing method.     

Factors influencing characteristics of steam-flaked corn and utilization by finishing cattle

Three experiments were conducted to identify factors influencing steam-flaked corn (SFC) characteristics and feeding value. In Exp. 1, corn samples (n = 108) were tempered for 2 h using 6, 10, or 14% moisture containing 0 or 0.67 mL of surfactant/L. Samples were steamed for 20 or 40 min and flaked to 360, 335, or 310 g/L. Treatments were arranged in a 3 x 2 x 2 x 3 factorial. No interactions existed in Exp. 1. Increasing tempering moisture linearly (P < 0.001) increased corn moisture after tempering, steaming, and flaking; however, SFC moisture was not increased (quadratic; P < 0.001) greatly by applying more than 10% water during tempering. The surfactant, steam time, and flake density had no effect (P = 0.16 to 0.93) on corn moisture after tempering, steaming, or flaking, but adding a surfactant during tempering decreased (P = 0.05) moisture loss after flaking. Starch availability was unaffected (P = 0.31 to 0.84) by tempering moisture concentration, tempering with a surfactant, or steam time but was increased (linear; P < 0.01) by decreasing flake density. Flake durability was increased by increasing tempering moisture (linear; P < 0.001), tempering with a surfactant (P = 0.04), increasing steam time (P < 0.001), and decreasing flake density (linear; P = 0.02). In Exp. 2, 89 heifers (initial BW = 350 kg) were fed 75% SFC-based diets for 108 d to determine the effects of SFC particle size on performance and carcass traits. Treatments were SFC that was mixed for 0 (4,667 microm) or 15 min (3,330 microm) before addition of other ingredients. Heifers fed 3,330-microm SFC tended (P = 0.13) to eat less DM, but ADG and G:F did not differ (P = 0.58 to 0.65) between treatments. Carcass traits did not differ, except that heifers fed 3,330-microm SFC had less (P = 0.008) KPH. In Exp. 3, 96 heifers (initial BW = 389 kg) were fed for 82 d diets containing 73% SFC that was either 18 or 36% moisture. Heifers fed 36% moisture SFC ate less DM (P = 0.02) and gained slower (P = 0.05) than heifers fed 18% moisture SFC, but G:F did not differ (P = 0.93) with SFC moisture. Heifers fed 36% moisture SFC were fatter at the 12th rib (P = 0.009), but all other carcass traits did not differ. Methods that increase moisture of SFC improved durability, but extreme moisture levels negatively affected cattle performance. Flake particle size did not affect cattle performance. Flake density is the major factor affecting starch availability in SFC.     

Evaluation of sulfur content of dried distillers grains with solubles in finishing diets based on steam-flaked corn or dry-rolled corn

Crossbred yearling steers (n=80; 406 ± 2.7 kg of BW) were used to evaluate the effects of S concentration in dried distillers grains with solubles (DDGS) on growth performance, carcass characteristics, and ruminal concentrations of CH(4) and H(2)S in finishing steers fed diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC) and containing 30% DDGS (DM basis) with moderate S (0.42% S, MS) or high S (0.65% S, HS). Treatments consisted of SFC diets containing MS (SFC-MS), SFC diets containing HS (SFC-HS), DRC diets containing MS (DRC-MS), or DRC diets containing HS (DRC-HS). High S was achieved by adding H(2)SO(4) to DDGS. Ruminal gas samples were analyzed for concentrations of H(2)S and CH(4). Steers were fed once daily in quantities that resulted in traces of residual feed in the bunk the following day for 140 d. No interactions (P ≥ 0.15) between dietary S concentration and grain processing were observed with respect to growth performance or carcass characteristics. Steers fed HS diets had 8.9% less DMI (P < 0.001) and 12.9% less ADG (P=0.006) than steers fed diets with MS, but S concentration had no effect on G:F (P=0.25). Cattle fed HS yielded 4.3% lighter HCW (P = 0.006) and had 16.2% less KPH (P=0.009) than steers fed MS. Steers fed HS had decreased (P=0.04) yield grades compared with steers fed MS. No differences were observed among treatments with respect to dressing percentage, liver abscesses, 12th-rib fat thickness, LM area, or USDA quality grades (P ≥ 0.18). Steers fed SFC had less DMI (P < 0.001) than steers fed DRC. Grain processing had no effect (P > 0.05) on G:F or carcass characteristics. Cattle fed HS had greater (P < 0.001) ruminal concentrations of H(2)S than cattle fed MS. Hydrogen sulfide concentration was inversely related (P ≤ 0.01) to ADG (r=-0.58) and DMI (r=-0.67) in cattle fed SFC, and to DMI (r=-0.40) in cattle fed DRC. Feeding DDGS that are high in dietary S may decrease the DMI of beef steers and compromise the growth performance and carcass characteristics of feedlot cattle.     

Effects of feeding whole cottonseed and cottonseed products on performance and carcass characteristics of finishing beef cattle

Three experiments were conducted to determine the effects of whole cottonseed or cottonseed products on performance and carcass characteristics of beef cattle. In Exp. 1, 120 beef steers (initial BW = 381 +/- 31.7 kg) were fed steam-flaked corn-based finishing diets with 10% (DM basis) basal roughage, and whole cottonseed or individual cottonseed components (cottonseed hulls, meal, and oil). Over the entire feeding period, ADG did not differ (P = 0.95), but DMI increased (P = 0.07) and G:F decreased (P = 0.06) for steers fed the cottonseed diets compared with the control diet. Dressing percent (P = 0.02) and marbling scores (P = 0.02) of carcasses from steers fed the cottonseed diets were less than for steers fed the control diet. In Exp. 2, 150 beef steers (initial BW = 364 +/- 9.9 kg) were used to determine the effects of whole cottonseed or pelleted cottonseed (PCS) on performance and carcass characteristics. Cattle were fed steam-flaked corn-based finishing diets in which whole cottonseed or PCS replaced all of the dietary roughage, supplemental fat, and supplemental natural protein of the control diet. Over the entire feeding period, steers fed the cottonseed diets had lower (P = 0.04) DMI and greater (P < 0.01) G:F than steers fed the control diet. Carcass characteristics did not differ (P = 0.16 to 0.96) among dietary treatments. In Exp. 3, 150 beef heifers (initial BW = 331 +/- 17.1 kg) were used to determine the effects of PCS or delinted, whole cottonseed (DLCS) on performance and carcass characteristics. Heifers were fed rolled corn-based finishing diets in which cottonseed replaced the dietary roughage, supplemental fat, and all or part of the supplemental natural protein of the control diet. Over the entire feeding period, ADG, DMI, and G:F of heifers fed the control diet did not differ (P = 0.19 to 0.80) from those of the cottonseed diets; however, heifers fed the diets containing PCS had greater ADG (P = 0.03) and G:F (P = 0.09) than heifers fed diets containing DLCS. Carcass characteristics of heifers fed the control diet did not differ (P > or = 0.28) from those fed the cottonseed diets. Heifers fed the diets containing PCS had greater (P < or = 0.03) HCW, dressing percent, and LM area than those fed DLCS. Based on our results, whole cottonseed, or products derived from processing whole cottonseed, can replace feedstuffs commonly used in beef cattle finishing diets with no adverse effects on animal performance or carcass characteristics.     

Performance and carcass traits of finishing heifers fed crude glycerin

Crossbred heifers (n = 373; 421.6 kg +/- 28.9) were fed finishing diets containing 0, 2, 4, 8, 12, or 16% crude glycerin (DM basis). Diets consisted of steam-flaked corn with 6% alfalfa hay and 1.2% urea and provided 300 mg of monensin, 90 mg of tylosin, and 0.5 mg of melengestrol acetate per animal daily. Cattle were stratified by BW and allocated randomly, within strata, to concrete-surfaced feedlot pens each containing 6 to 7 heifers, with 9 pens per dietary treatment. Cattle were transitioned from the control diet to diets containing increasing proportions of glycerin over a period of 10 d. Cattle had ad libitum access to feed, and diets were delivered once daily throughout the 85-d trial period. As the concentration of glycerin increased, DMI decreased linearly (P < 0.001). Heifers fed 0, 2, 4, 8, 12, and 16% glycerin had ADG of 1.19, 1.34, 1.29, 1.25, 1.17, and 1.03 kg, respectively (linear, P = 0.013; quadratic, P = 0.010). Feeding glycerin had a quadratic effect on G:F, and G:F was optimal when glycerin was fed at 2% of the diet (quadratic, P = 0.046). Glycerin increased the final BW by 12.7, 8.1, and 5.3 kg when fed at 2, 4, and 8% of the diet, respectively, but reduced the final BW by 1.9 and 14.3 kg when included at 12 and 16% of the diet (linear, P = 0.009; quadratic, P = 0.006). Similarly, HCW increased by 8.1, 5.1, and 3.3 kg when glycerin was fed at 2, 4, and 8% of the diet, respectively, but were 1.2 and 9.1 kg less than controls when glycerin was fed at 12 and 16%, respectively (linear, P = 0.009; quadratic, P = 0.006). Longissimus muscle area decreased linearly as glycerin concentrations increased (P < 0.013). Feeding glycerin resulted in linear decreases in subcutaneous fat over the 12th rib and marbling scores (P = 0.045). Glycerin tended to decrease the percentage of cattle grading USDA Choice (P = 0.084) and increase the percentage of cattle grading USDA Select. Adding glycerin to cattle-finishing diets improved BW gain and feed efficiency, particularly when added at concentrations of 8% or less on a DM basis.     

Effects of feeding wet corn distillers grains with solubles with or without monensin and tylosin on the prevalence and antimicrobial susceptibilities of fecal foodborne pathogenic and commensal bacteria in feedlot cattle

Distillers grains, a coproduct of ethanol production from cereal grains, are composed principally of the bran, protein, and germ fractions and are commonly supplemented in ruminant diets. The objective of this study was to assess the effect of feeding wet distillers grains with solubles (WDGS) and monensin and tylosin on the prevalence and antimicrobial susceptibilities of fecal foodborne and commensal bacteria in feedlot cattle. Cattle were fed 0 or 25% WDGS in steam-flaked corn-based diets with the addition of no antimicrobials, monensin, or monensin and tylosin. Fecal samples were collected from each animal (n = 370) on d 122 and 136 of the 150-d finishing period and cultured for Escherichia coli O157. Fecal samples were also pooled by pen (n = 54) and cultured for E. coli O157, Salmonella, commensal E. coli, and Enterococcus species. Antimicrobial resistance was assessed by determining antimicrobial susceptibilities of pen bacterial isolates and quantifying antimicrobial resistance genes in fecal samples by real-time PCR. Individual animal prevalence of E. coli O157 in feces collected from cattle fed WDGS was greater (P < 0.001) compared with cattle not fed WDGS on d 122 but not on d 136. There were no treatment effects on the prevalence of E. coli O157 or Salmonella spp. in pooled fecal samples. Antimicrobial susceptibility results showed Enterococcus isolates from cattle fed monensin or monensin and tylosin had greater levels of resistance toward macrolides (P = 0.01). There was no effect of diet or antimicrobials on concentrations of 2 antimicrobial resistance genes, ermB or tetM, in fecal samples. Results from this study indicate that WDGS may have an effect on the prevalence of E. coli O157 and the concentration of selected antimicrobial resistance genes, but does not appear to affect antimicrobial susceptibility patterns in Enterococcus and generic E. coli isolates.     

The effects of ractopamine-hydrogen chloride (Optaflexx) on performance, carcass characteristics, and meat quality of finishing feedlot heifers

Two experiments were conducted at the Kansas State University Beef Cattle Research Center to determine the effects of ractopamine-HCl (Optaflexx) on growth performance, carcass characteristics, and meat quality of finishing feedlot heifers. In Exp. 1, heifers implanted with Revalor-H (n = 302, initial BW = 479 kg) were fed steam-flaked corn diets with 0 (control) or 200 mg of ractopamine-HCl (OPT) per heifer daily for 28 d before slaughter. Average daily gain and DMI were not different between treatments (P > 0.17); however, OPT cattle tended to have a greater G:F (P = 0.06). Treatments did not differ with respect to final BW, HCW, dressing percentage, USDA yield grade, USDA quality grade, marbling score, LM area, KPH, Warner-Bratzler shear force, weight loss during cooking, or L*, a*, or b* colorimetric values during a 7-d retail display or purge loss from loin steaks during retail display (P > 0.19). In Exp. 2, nonimplanted crossbred heifers (n = 281, BW = 451 +/- 2 kg) were fed finishing diets based on steam-flaked corn. A control diet (no ractopamine) was compared with diets providing 200 mg of OPT per heifer daily for periods of 28 or 42 d (200 x 28 and 200 x 42, respectively), 300 mg/d for 28 d (300 x 28), and a step-up regimen consisting of 14 d at 100 mg, followed by 14 d at 200 mg, and the final 14 d at 300 mg of OPT (step-up). Feeding OPT had no effect on carcass weight gain among treatments (P = 0.18). The efficiency of carcass gain was 34 and 35% greater (P = 0.06) for the 200 x 42 and step-up groups compared with control, respectively. Feeding OPT at 300 mg for 28 d reduced DMI compared with the control, 200 x 28, and 200 x 42 (P < 0.05) groups. Administration of OPT had no effect on marbling score, yield grade, LM area, KPH, or percentages of carcasses grading USDA Choice (P > 0.10). Feeding ractopamine-HCl (Optaflexx) to finishing heifers generally improved the efficiency of carcass gain with minimal effect on carcass characteristics. These effects were most pronounced in heifers fed ractopamine for 42 d.     

Effects of wet corn gluten feed and roughage levels on performance, carcass characteristics, and feeding behavior of feedlot cattle

Two experiments were conducted to evaluate the effects of feeding different levels of wet corn gluten feed (WCGF) and dietary roughage on performance, carcass characteristics, and feeding behavior of feedlot cattle fed diets based on steam-flaked corn (SFC). In Exp. 1, crossbred steers (n = 200; BW = 314 kg) were fed 4 dietary treatments (DM basis): a standard SFC-based diet containing 9% roughage (CON) and 3 SFC-based diets containing 40% WCGF, with either 9, 4.5, or 0% roughage. A linear (P = 0.04) increase in final BW and DMI (P < 0.01) was observed in diets containing WCGF as dietary roughage increased. Steers fed WCGF and higher levels of roughage had greater (P = 0.01) ADG than steers fed lower levels of roughage. Steers fed the CON diet had lower (P = 0.04) daily DMI and greater (P = 0.03) G:F than those fed WCGF. Most carcass characteristics of steers fed CON did not differ (P > 0.10) from those of steers fed WCGF. Based on feed disappearance and visual scan data, consumption rate did not differ (P > 0.10) among treatments; however, feeding intensity (animals present at the bunk after feeding) was greater for steers fed CON (P < 0.01) than for steers fed WCGF. In Exp. 2, yearling crossbred steers (n = 1,983; BW = 339 kg) were fed 4 dietary treatments (DM basis): a standard SFC-based control diet that contained 9% roughage (CON) and 3 SFC-based diets containing either 20% WCGF and 9% roughage or 40% WCGF with 9 or 4.5% roughage. Steers fed the CON diet tended to have lower final BW (P = 0.14), ADG (P = 0.01), and DMI (P < 0.01) than steers fed diets containing WCGF. Steers fed the 20% WCGF diet had greater (P = 0.08) G:F than steers fed the 40% WCGF diets. With 40% WCGF, increasing roughage from 4.5 to 9% decreased (P < 0.01) G:F and increased (P = 0.06) DMI. Gain efficiency was improved (P < 0.01) for steers fed CON vs. those fed diets containing WCGF, whereas HCW (P = 0.02) and dressing percentage (P < 0.01) were greater for steers fed WCGF. Percentage of cattle grading USDA Choice was greater (P = 0.02) for cattle fed WCGF. Results suggest that replacing SFC with up to 40% WCGF increased ADG and decreased G:F when 4.5 to 9.0% roughage was supplied. More CON steers were present at the feed bunk during the first hour after feeding than WCGF steers, suggesting that including WCGF at 40% of the diet affected feeding behavior.     

Intake restriction strategies and sources of energy and protein during the growing period affect nutrient disappearance, feedlot performance, and carcass characteristics of crossbred heifers.

Two trials were conducted to evaluate intake restriction, energy, and protein source on the performance and carcass merit of heifers limit-fed corn gluten feed. Trial 1 crossbred heifers (n = 140) were allotted to ad libitum wet corn gluten feed (WCGF)-hay, ad libitum WCGF-corn, WCGF-corn continuously limit-fed to achieve a gain of 1.1 kg/d or WCGF-corn fed in the following sequence: 70% of ad libitum for 20 d, ad libitum for 20 d, and 2 d common intake during the 84-d growing period. One-half of these restricted-refed heifers received a rumen-undegraded protein supplement, and the other half received a rumen degraded protein supplement. Heifers were fed a common finishing diet ad libitum subsequent to the growing period. Heifers offered ad libitum WCGF-hay and WCGF-corn were slaughtered at a common compositional fat end point. Heifers limit-fed WCGF-corn were slaughtered at the same time as heifers offered ad libitum WCGF-corn, regardless of subcutaneous fat cover. Limit-feeding WCGF-corn diets to growing heifers reduced ADG (P < or = 0.01) but did not compromise feed efficiency. Method of intake restriction, continuous or ad libitum-interrupted, and supplemental protein source did not affect combined growing-finishing performance. However, when fed for a common length of time, the average of the limit-fed heifers had lighter carcass weights (P < or = 0.01) and lower (P = 0.04) marbling scores. Heifers offered ad libitum WCGF-hay gained slower (P < or = 0.01) and less efficiently (P < or = 0.01) than heifers offered WCGF-corn. Trial 2 crossbred heifers (n = 222) were allotted to dry corn gluten feed (DCGF)-corn ad libitum or restricted to 80% of ad libitum for 42, 84, or 126 d; or ad libitum corn silage or DCGF-corn silage at 80% of ad libitum for 84 d. Feed efficiency (P = 0.07) and ADG (P = 0.08) tended to behave quadratically, being poorer for heifers limit-fed for 126 d during the growing period. Heifers limit-fed DCGF-corn gained more efficiently (P = 0.05) than heifers grown on ad libitum corn silage. Limit-feeding CGF-corn to growing beef heifers can be used to achieve moderate rates of gain without compromising feed efficiency. However, limit-feeding during the growing period may result in lighter weight carcasses with lower quality grades if not fed to the same fat end point as heifers grown with free access to concentrate.     

Effects of grain processing and dietary lipid source on performance, carcass characteristics, plasma fatty acids, and sensory properties of steaks from finishing cattle

An experiment was conducted to evaluate the effects of grain processing and lipid addition to finishing diets on cattle performance, carcass characteristics, and meat quality. Eighty Hereford x Angus steers (384 kg +/- 17 kg of BW) were fed diets containing steam-flaked corn (SFC) or dry-rolled corn (DRC) with and without the addition of tallow (SFC/Fat and DRC/Fat) or steam-flaked corn with ground flaxseed (SFC/Flax). Ribeye steaks from steers fed SFC, SFC/Fat, or SFC/ Flax were used to evaluate the effects of fat source on meat quality. Cattle fed SFC and SFC/Fat tended to have greater ADG, G:F, HCW, and USDA yield grade, compared with those fed DRC and DRC/Fat (P < 0.10). Steaks from steers fed SFC/Flax developed a detectable off-flavor (P < 0.05) compared with steaks from steers fed SFC and SFC/Fat, and steaks from steers fed SFC retained desirable color longer than those from steers fed SFC/Flax (P < 0.05). Feeding SFC/Flax increased deposition of alpha-linolenic acid in muscle tissue compared with feeding SFC or SFC/Fat (P < 0.01). Dietary treatment did not cause differences in tenderness, juiciness, or flavor intensity. Ground flaxseed can replace tallow in finishing diets without loss in performance, but flax may affect flavor and color stability of beef. Feeding flaxseed can effectively alter composition of carcass tissues to yield beef that is high in n-3 fatty acids.     

The effects of feeding flaxseed during the receiving period on morbidity, mortality, performance, and carcass characteristics of heifers

Two experiments were conducted at the Kansas State University Beef Cattle Research Center to determine the effects of feeding ground flaxseed (flax) during the receiving period on the growth, health, and subsequent finishing performance of heifers. Crossbred heifers (Exp. 1: n = 363, 214 +/- 1 kg of initial BW; Exp. 2: n = 377, 222 +/- 1 kg of initial BW) were purchased during January and April of 2006. Heifers were fed receiving rations based on steam-flaked corn with 0, 2, 4, or 6% ground flax (DM basis) for 56 d. Following the receiving period, cattle in Exp. 1 and 2 were fed steam-flaked corn-based diets for 150 and 147 d, respectively, and then slaughtered. Heifers were implanted 91 and 109 d before slaughter for Exp. 1 and 2, respectively. In Exp. 1, DMI during the receiving period tended to increase linearly (P = 0.09) with increasing flax in the diet. Average daily gain was 1.46, 1.56, 1.58, and 1.61 kg for heifers fed 0, 2, 4, and 6% flax, respectively (linear, P = 0.03). Final BW in Exp. 1 after the finishing period was increased (linear, P = 0.04) with increasing inclusion of flax in the receiving diets. In Exp. 2, growth performance and mortality during the receiving period were not different among treatments (P > 0.12). During the receiving period in Exp. 2, incidence of the first respiratory treatment tended to be greatest (P = 0.09) for heifers fed 4% flax. During the finishing period, DMI were 8.4, 8.4, 8.0, and 8.1 kg/d for 0, 2, 4, and 6% flax, respectively (linear, P = 0.05). In Exp. 2, LM areas were greatest (quadratic, P = 0.04) for cattle fed 2% flax at receiving. In general, feeding flax during the receiving period may have the potential to improve growth performance; however, performance between experiments was variable, and many factors excluding flax feeding may have contributed to this response.     

Optimal wet corn gluten and protein levels in steam-flaked corn-based finishing diets for steer calves

A feeding trial evaluated the hypothesis that wet corn gluten feed would improve growth performance of cattle fed steam-flaked corn-based finishing diets and supply required degradable intake protein (DIP). The trial used 360 steer calves (initial BW = 288 +/- 11 kg) housed in 36 pens for 166 d in an incomplete 4 x 3 factorial arrangement of treatments. Pens of steers were assigned to treatments according to a completely randomized design (four replicates per treatment combination). Treatments were wet corn gluten feed (0, 20, 30, or 40% of dietary DM) and CP (13.0, 13.7, or 14.4% of dietary DM) via supplemental urea as DIP. The 0% wet corn gluten feed treatment included only the 13.7% CP diet, and the 40% wet corn gluten feed treatment included only the 13.7 and 14.4% CP diets. Final dietary DIP concentration was 9.0% for 0% wet corn gluten feed; 8.7, 9.5, and 10.2% for 20% wet corn gluten feed; 9.0, 9.7, and 10.3% DIP for 30% wet corn gluten feed; and 10.0 and 10.6% for 40% wet corn gluten feed. Hot carcass weight, ADG, DMI, and G:F responded quadratically (P < or = 0.05) to wet corn gluten feed. The 20, 30, and 40% wet corn gluten feed treatments increased ADG by 7, 6, and 3% and increased DMI by 4, 5, and 5%, respectively, relative to the 0% wet corn gluten feed treatment. Feed efficiency was 102, 101, and 98% of the 0% wet corn gluten feed treatment for 20, 30, and 40% wet corn gluten feed, respectively. Hot carcass weight, ADG, and G:F increased linearly (P < or = 0.05) in response to increased DIP. Nonlinear analysis for DIP over the combined 20 and 30% wet corn gluten feed treatments indicated a DIP requirement of 9.6% of DM for ADG and 9.2% of DM for G:F, corresponding to 14.6 and 14.3% CP for 20% wet corn gluten feed and 14.8 and 14.5% CP for 30% wet corn gluten feed, respectively. Fat thickness, marbling, LM area, and USDA yield grade were not affected (P = 0.12 to 0.99) by wet corn gluten feed or CP. These results show that the inclusion rate of wet corn gluten feed for maximizing ADG and G:F in steam-flaked corn-based finishing diets is approximately 20% of DM. The DIP requirement determined in this trial averaged 9.4% of DM.     

Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings

To assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 +/- 14 kg of initial BW) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (WHL), rolled flax (RLD; 1,300 microm), or ground flax (GRD; 700 microm). Heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; DM basis) for 56 d, after which they were adapted to a finishing diet (79% corn, 7% corn silage, 7% alfalfa, 4.75% linseed meal, and 2.25% supplement; DM basis). In WHL, RLD, and GRD, flax replaced all linseed meal and partially replaced corn at 8% of diet DM. All diets provided 0.5 mg of melengestrol acetate, 2,000 IU of vitamin E, and 232 mg of monensin per heifer daily. Cattle were slaughtered by block after 96, 97, and 124 (2 blocks) d on feed. At 24 h postmortem, carcass data were collected, and a portion of the loin was removed, vacuum-packaged, and aged for 14 d. After aging, 2 steaks were removed from each loin for Warner-Bratzler shear force measurement, sensory panel evaluation, and fatty acid analysis (approximately 100 g of muscle was collected). Flax inclusion (WHL, RLD, and GRD vs. control) did not affect DMI (P = 0.79), fat thickness over the 12th rib (P = 0.32), or LM area (P = 0.23). Flax inclusion increased ADG (P = 0.006), G:F (P = 0.006), and USDA yield grade (P = 0.01). Flax processing (RLD and GRD vs. WHL) increased ADG (P = 0.05), G:F (P = 0.08), and apparent dietary NEm and NEg (P = 0.003). Muscle from heifers fed flax had greater phospholipid 18:3n-3 (P < 0.001), 20:5n-3 (P < 0.001), 22:5n-3 (P < 0.001), and 22:6n-3 (P = 0.02) fractions, and greater neutral lipid 18:3n-3 (P < 0.001). Feeding 8% flax to feedlot heifers increased gain and efficiency, and processing flax increased available energy and resulted in increased efficiency of gain. Feeding 8% flax also increased levels of n-3 fatty acids in fresh beef.     

Wet corn gluten feed and alfalfa hay combinations in steam-flaked corn finishing cattle diets

One finishing trial and one digestibility trial were used to evaluate wet corn gluten feed (WCGF) and alfalfa hay (AH) combinations in steam-flaked corn (SFC) finishing diets. In Exp. 1, 631 crossbred heifers (initial BW = 284 +/- 7.9 kg) were fed SFC-based diets containing combinations of WCGF (25, 35, or 45% of diet DM) and AH (2 or 6% of dietary DM) in a 2 x 3 factorial arrangement of treatments. No interactions existed between WCGF and AH for heifer performance. Increasing dietary WCGF linearly decreased gain efficiency (P < 0.01), dietary NEg concentration (P < 0.05), and 12th-rib fat thickness (P = 0.10). Cattle fed 35% WCGF had the lowest occurrence of abscessed livers, resulting in a quadratic response (P < 0.05) as dietary WCGF increased. In Exp. 2, 12 ruminally cannulated Jersey steers (585 kg) were fed SFC-based diets containing combinations of WCGF (25 or 45% of diet DM) and AH (0, 2, or 6% of diet DM) in an incomplete Latin square design with a 2 x 3 factorial arrangement of treatments. Starch intake was lower (P < 0.05), but NDF intake was greater (P < 0.05) as AH and WCGF increased in the diet. Ruminal pH was increased by AH (linear, P < 0.05) and tended (P < 0.07) to increase with WCGF. Feeding 2% AH led to the greatest ruminal NH3 but the lowest total VFA and propionate (quadratic, P < 0.05). Addition of AH to diets containing 25% WCGF increased acetate to a greater extent than addition to diets containing 45% WCGF (AH x WCGF interaction, P < 0.05). Feeding 45% WCGF tended to increase passage rate (P = 0.17) and decrease (P < 0.05) total tract OM digestibility but increase (P < 0.05) in situ degradation of DM from AH and WCGF. Interactions between AH and WCGF existed (P < 0.05) for ruminal fluid volume (quadratic effect of AH x WCGF level), in situ SFC degradation (linear effect of AH x WCGF level), and in situ rate of WCGF DM disappearance (quadratic effect of AH x WCGF level). We conclude that AH levels may be decreased when WCGF is added to SFC diets as 25% or more of the dietary DM.