Effects of roughage concentration in steam-flaked corn-based diets containing wet distillers grains with solubles on feedlot cattle performance, carcass characteristics, and in vitro fermentation

Two studies were conducted to evaluate effects of wet distillers grains with solubles (WDG) and dietary concentration of alfalfa hay (AH) on performance of finishing beef cattle and in vitro fermentation. In both studies, 7 treatments were arranged in a 2 × 3 + 1 factorial; factors were dietary concentrations (DM basis) of WDG (15 or 30%) and AH (7.5, 10, or 12.5%) plus a non-WDG control diet that contained 10% AH. In Exp. 1, 224 beef steers were used in a randomized complete block (initial BW 342 kg ± 9.03) finishing trial. No WDG × AH interactions were observed (P > 0.12). There were no differences among treatments in final shrunk BW or ADG (P > 0.15), and DMI did not differ with WDG concentration for the overall feeding period (P = 0.38). Increasing dietary AH concentration tended (P < 0.079) to linearly increase DMI, and linearly decreased (P < 0.05) G:F and calculated dietary NE(m) and NE(g) concentrations. Carcasses from cattle fed 15% WDG had greater yield grades (P = 0.014), with tendencies for greater 12th-rib fat (P = 0.054) and marbling score (P = 0.053) than those from cattle fed 30% WDG. There were no differences among treatments (P > 0.15) in HCW, dressing percent, LM area, KPH, proportions of cattle grading USDA Choice, and incidence of liver abscesses. In Exp. 2, ruminal fluid was collected from 2 ruminally cannulated Jersey steers adapted to a 60% concentrate diet to evaluate in vitro gas production kinetics, H(2)S production, IVDMD, and VFA. Relative to the control substrate, including WDG in substrates increased (P < 0.01) H(2)S production and decreased total gas production (P = 0.01) and rate of gas production (P = 0.03). Increasing substrate WDG from 15 to 30% increased (P < 0.05) H(2)S production and decreased (P < 0.001) total gas production, with a tendency (P = 0.073) to decrease IVDMD and fractional rate of gas production (P = 0.063). Treatments did not significantly affect (P > 0.09) molar proportions or total concentration of VFA. Results indicate that including 15 or 30% WDG in steam-flaked corn-based diets did not result in major changes in feedlot performance or carcass characteristics, but increasing AH concentration from 7.5 to 12.5% in diets containing WDG decreased G:F. Including WDG in substrates decreased rate and extent of gas production and increased H(2)S production. Changes in various measures of in vitro fermentation associated with AH concentrations were not large.     

Effects of supplemental zinc concentration and source on performance, carcass characteristics, and serum values in finishing beef steers

Three studies were conducted to examine the effects of zinc concentration or source in diets of finishing beef steers. In Exp. 1, 108 (British x Continental) beef steers were supplemented with concentrations of added zinc (as ZnSO4) at 20, 100, or 200 mg/kg of dietary DM. No differences (P > 0.10) were noted among treatments for ADG or gain:feed for the 112-d finishing period. However, a linear (P < 0.10) decrease was noted in daily DMI with increasing zinc concentrations for the overall finishing period. No differences (P > 0.10) were noted in hot carcass weight; dressing percentage; longissimus muscle area; percentage of kidney, pelvic, and heart fat; or marbling score. There were, however, quadratic increases in s.c. fat thickness (P < 0.05) and yield grade (P < 0.01) with added zinc. In Exp. 2, 12 beef steers were used to examine effects of added dietary zinc on serum concentrations of cholesterol and fatty acid profiles. No differences (P > 0.10) were observed in cholesterol or fatty acids among the supplemental zinc levels. In Exp. 3, 84 Brangus- and Angus-sired steers were fed a steam-flaked corn-based diet containing 30 mg of supplemental zinc per kilogram of dietary DM from one of the following sources: 1) ZnSO4, 2) Zn amino acid complex, or 3) a zinc polysaccharide complex. No differences (P > 0.10) were noted for the overall 126-d trial for ADG, DMI, or gain:feed ratio. Percentage kidney, pelvic, and heart fat was increased (P < 0.10) in steers supplemented with ZnSO4 vs the average of Zn amino acid and Zn polysaccharide complexes. However, s.c. fat thickness was greater (P < 0.10) in steers supplemented with Zn amino acid and Zn polysaccharide complexes vs ZnSO4. Serum zinc concentration did not differ (P > 0.10) among zinc sources. Supplemental zinc concentration in finishing diets did not seem to influence feedlot performance and had a minimal impact on carcass quality. Either the organic or inorganic source can be included in finishing diets without affecting feedlot performance.     

Effects of fibre digestibility and level of roughage on performance and rumen fermentation of finishing beef cattle

Tropical Animal Health and Production - The objective was to evaluate effects of neutral detergent fibre (NDF) digestibility and level of fresh sugarcane on intake, body fatness, carcass...     

Effects of days on feed,roughage sources and inclusion levels of grain in concentrate on finishing performance and carcass characteristics in cull beef cows

An experiment was conducted with 16 Japanese Black cows to determine the effects of different days on feed (89, 208, 271 and 341 days), inclusion levels of grain in concentrate (60% vs. 40%; dry matter (DM) basis) and roughage sources (hay vs. rice straw) on finishing performance. Additional four cows were slaughtered at 0 days on feed to obtain non‐fed carcass data. Maximum carcass weights were observed in cows fed for 271 days; an increase in carcass weight of only 14 kg was shown from 208 days to 271 days. The marbling score increased (P < 0.05) with days on feed. The percentage of fat in the subprimal rib linearly increased (P < 0.05) with days on feed. The percentage of lean meat was higher (P < 0.05) for cows fed rice straw than for cows fed hay as a roughage source. Increasing the days on feed decreased (P < 0.05) the yellowness of the fat. The effects of the inclusion levels of grain in concentrate on the finishing performance of cows were lower than the other two factors. In conclusion, feeding improves carcass values, but feeding over 208 days is an inefficient system of production in cows.     

Effects of grain type, roughage level and monensin level on finishing cattle performance

Interactions among grain type (grain sorghum, corn or wheat), roughage level and monensin level were studied in four feedlot trials using pen-fed crossbred yearling cattle. In Trial 1, cattle fed high-moisture corn (HMC) were more efficient (.1537 vs .1406 for gain/feed; P less than .01) than cattle fed dry-rolled grain sorghum (DRGS). As level (0, 3, 6, 9%) of dietary roughage was increased, feed efficiency (gain/feed) decreased (.1566, .1461, .1479, .1382; linear, P less than .01). In Trial 2, a grain type (DRGS; dry-rolled corn, DRC; dry-rolled wheat, DRW) x roughage level interaction was observed for daily gain and feed efficiency. Feed efficiency (gain/feed) was decreased when roughage was added to diets containing DRC (.1608 vs .1750) or DRGS (.1674 vs .1465), but not to the diet containing DRW (.1664 vs .1607). In trial 3, a grain type x roughage level x monensin level interaction (P less than .08) was observed for feed efficiency. The addition of 27.5 mg of monensin per kilogram of the 0% roughage-DRC diet tended to improve feed efficiency (.1633 vs .1531), but the addition of monensin to the 7.5% roughage-DRC diet tended to depress feed efficiency (.1476 vs .1575). The addition of either roughage (.1493 vs .1420) or monensin (.1500 vs .1413) to the DRW diet improved feed efficiency. In Trial 4, cattle fed a combination of 75% DRW and 25% DRC were more efficient (.1618 vs .1591; P less than .06) than cattle fed DRC. As level of roughage (0, 3.75, 7.5%) increased, feed efficiency decreased linearly (.1645, .1599, .1569; P less than .0001). Monensin had no effect on feed efficiency. The value of feeding roughage and monensin was variable both across grain types and within similar grain types.     

Wet distillers grains plus solubles concentration in steam-flaked-corn-based diets: Effects on feedlot cattle performance, carcass characteristics, nutrient digestibility, and ruminal fermentation characteristics

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 × 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.     

Effects of roughage source and concentration on intake and performance by finishing heifers

Three experiments were conducted to evaluate the effects of roughage source and concentration on intake and performance by finishing heifers. In Exp. 1, 12 medium-framed beef heifers (average BW = 389 kg) were used in three simultaneous 4 x 4 Latin square intake trials to evaluate the effects of dietary NDF supply from alfalfa hay, sudan hay, wheat straw, or cottonseed hulls fed in each Latin square at 5, 10, or 15% of dietary DM. Within each roughage concentration, roughage NDF accounted for the majority of variation in NEg intake/kg of BW0.75 among the roughage sources. Averaged across roughage concentrations, NEg intake/kg of BW0.75 tended to be greater (P < 0.10) when heifers were fed cottonseed hulls, sudan hay, or wheat straw than when they were fed alfalfa. In Exp. 2, six medium-framed beef heifers (average BW = 273 kg) were used in a 3 x 3 Latin square design to determine whether diets containing 10% (DM basis) alfalfa, cottonseed hulls, or sudan silage differed in eating rate. Average DM eating rates did not differ (P > 0.10) among roughage sources, which we interpreted to suggest that 90% concentrate diets containing alfalfa, cottonseed hulls, and sudan silage do not differ in the amount of chewing required during eating. In Exp. 3, 105 medium-framed beef heifers (average BW = 275 kg) were used in a 140-d finishing trial to evaluate three methods of dietary roughage exchange. Alfalfa at 12.5% of the dietary DM (ALF12.5) was used as a standard, and cottonseed hulls and sudan silage were each fed at three different levels: exchanged with ALF12.5 on an equal percentage DM basis, an equal NDF basis, or an equal NDF basis, where only NDF from particles larger than 2.36 mm (retained NDF) were considered to contribute to the NDF. No differences (P > 0.10) in ADG, DMI, gain:feed ratio, or NEg intake/kg of BW0.75 were detected between alfalfa and cottonseed hulls exchanged on an equal NDF basis. For sudan silage, exchanging with ALF12.5 on an equal retained NDF basis resulted in no differences (P > 0.10) in ADG, DMI, or NEg intake/kg of BW0.75. These data provide a preliminary indication that depending on the roughage sources evaluated, roughage NDF content and(or) roughage NDF from particles larger than 2.36 mm might provide a useful index of roughage value in high-concentrate finishing diets.     

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.     

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.     

Effects of a dietary Aspergillus oryzae extract containing alpha-amylase activity on performance and carcass characteristics of finishing beef cattle

Three experiments were conducted to examine the effects of an Aspergillus oryzae extract containing alpha-amylase activity on performance and carcass characteristics of finishing beef cattle. In Exp. 1, 120 crossbred steers were used in a randomized complete block design to evaluate the effects of roughage source (alfalfa hay vs. cottonseed hulls) and supplemental alpha-amylase at 950 dextrinizing units (DU)/kg of DM. Significant roughage source x alpha-amylase interactions (P < 0.05) were observed for performance. In steers fed cottonseed hulls, supplemental alpha-amylase increased ADG through d 28 and 112 and tended (P < 0.15) to increase ADG in all other periods. The increases in ADG were related to increased DMI and efficiency of gain during the initial 28-d period but were primarily related to increased DMI as the feeding period progressed. Supplemental alpha-amylase increased (P = 0.02) the LM area across both roughage sources. In Exp. 2, 96 crossbred heifers were used in a randomized complete block design with a 2 x 3 factorial arrangement of treatments to evaluate the effects of corn processing (dry cracked vs. high moisture) and supplemental alpha-amylase concentration (0, 580, or 1,160 DU/kg of DM). Alpha-amylase supplementation increased DMI (P = 0.05) and ADG (P = 0.03) during the initial 28 d on feed and carcass-adjusted ADG (P = 0.04) across corn processing methods. Longissimus muscle area was greatest (quadratic effect, P = 0.04), and yield grade was least (quadratic effect, P = 0.02) in heifers fed 580 DU of alpha-amylase/kg of DM across corn processing methods. In Exp. 3, 56 crossbred steers were used in a randomized complete block design to evaluate the effects of supplemental alpha-amylase (930 DU/kg of DM) on performance when DMI was restricted to yield a programmed ADG. Alpha-amylase supplementation did not affect performance when DMI was restricted. We conclude that dietary alpha-amylase supplementation of finishing beef diets may result in increased ADG through increased DMI under certain dietary conditions and that further research is warranted to explain its mode of action and interactions with dietary ingredients.     

Effects of 2-hydroxy-4-(methylthio)-butanoic acid on performance and carcass characteristics of finishing beef cattle and on fermentation in continuous culture

Three experiments were conducted to evaluate the effects of feeding 2-hydroxy-4- (methylthio)-butanoic acid (HMTBA) on performance and carcass characteristics of feedlot cattle and on microbial fermentation in a continuous-culture system. In Exp. 1, 160 crossbred steers (initial BW = 385 +/- 10.3 kg) were assigned to 4 treatments consisting of control (0% HMTBA) or 3 diets containing HMTBA (0.069, 0.137, and 0.204%; DM basis) in a randomized complete block design. As the percent of HMTBA increased in the diet, final BW (P = 0.069), final BW adjusted to a constant dressing percent (P = 0.063), and overall ADG (P = 0.099) tended to decrease linearly. Overall DMI decreased linearly (P < or = 0.006) with increasing HMTBA dose. No differences (P > or = 0.10) were noted for carcass characteristics, except for a tendency (P = 0.078) for a linear increase in the percentage of cattle grading USDA Choice with increasing HMTBA dose. In Exp. 2, 80 crossbred steers (initial BW = 450 +/- 17 kg) in a randomized complete block design were assigned to a control (0% HMTBA) diet or to a diet in which the concentrations of HMTBA were gradually increased from 0.036 to 0.212% of DM over a 50-d period. The HMTBA-containing diet tended to decrease DMI (P = 0.132), but G:F (P = 0.319) for the overall feeding period, carcass measurements, and USDA quality grade (P > or = 0.149) did not differ between treatments. In Exp. 3, continuous culture fermenters (n = 5/treatment) were used to determine the effects of HMTBA (control vs. 0.24% HMTBA) on microbial fermentation. No differences (P > or = 0.31) were detected between treatments in ruminal OM digestibility, microbial N synthesis, pH, ammonia, molar proportions of VFA, or effluent concentration of selected long-chain fatty acids. These results suggest that HMTBA decreased DMI by feedlot steers fed a steam-flaked corn-based diet in a dose-dependent manner; however, gradually increasing the dose over time seemed to moderate effects on DMI. No major changes in microbial fermentation in continuous culture were observed with HMTBA at 0.24% of dietary DM, suggesting effects of HMTBA on DMI were not likely associated with changes in ruminal digestion or fermentation.     

Effects of crude protein concentration and degradability on performance, carcass characteristics, and serum urea nitrogen concentrations in finishing beef steers

Two experiments were conducted at two locations to determine the effects of dietary CP concentration and source on performance, carcass characteristics, and serum urea nitrogen (SUN) concentrations of finishing beef steers. British x Continental steers were blocked by BW (357 +/- 28 and 305 +/- 25 kg initial BW; n = 360 and 225; four and five pens per treatment in Exp. 1 and 2, respectively). Steam-flaked corn-based diets were arranged in a 3 x 3 factorial with three CP concentrations (11.5, 13, or 14.5% of DM) and three sources of supplemental CP (N basis): 100% urea; 50:50 blend of urea and cottonseed meal; or 100% cottonseed meal. Steers in both experiments were initially implanted with Ralgro and reimplanted with Revalor-S on d 56. Performance and carcass data were pooled across locations. Crude protein concentration x source interactions were not observed (P = 0.22 to 0.93) for performance and carcass data. Crude protein concentration affected ADG (P = 0.02) and carcass-adjusted (to a common dressing percent within location) ADG quadratically (P = 0.06). Increasing the concentration of supplemental urea linearly increased carcass-adjusted ADG and G:F (P < 0.05) and carcass-adjusted G:F (P < 0.001). Dry matter intake was not affected (P = 0.93) by either CP concentration or source. Hot carcass weight (HCW; P = 0.02), LM area (P = 0.05), and dressing percent (P = 0.03) increased linearly with increasing urea concentration, whereas increasing CP concentration quadratically affected HCW (P = 0.02), with a maximum at 13% CP. Differences in backfat thickness and yield grade were negligible across treatments. Neither marbling score nor percentage of carcasses grading USDA Choice was affected by CP concentration or source. At all times measured, SUN concentrations increased (P < 0.05) with increasing CP concentration, but effects of CP source were small and variable across time. Results indicate that increasing CP concentrations from 11.5 to 13% slightly increased ADG and carcass-adjusted ADG, whereas increasing the proportion of supplemental urea increased carcass-adjusted ADG, G:F, and carcass-adjusted G:F and increased HCW, LM area, and dressing percent. A CP concentration above 13% seemed detrimental to ADG and HCW. Serum urea N increased over time, with CP concentration having a greater effect than CP source.     

不同粗饲料组合对晋南牛瘤胃体外发酵特性的研究

旨在研究全株玉米青贮(WCS)、小麦秸秆(WS)和苜蓿青贮(AS)不同组合比例对晋南牛瘤胃体外发酵特性的影响,筛选不同饲料组合应用的最适比例.将全株玉米青贮、小麦秸秆、苜蓿青贮以不同比例组合(80:10:10,70:10:20,70:20:10,60:10:30,60:20:10,60:30:10,50:10:40,5...     

Use of dried distillers grains throughout a beef production system: effects on stocker and finishing performance, carcass characteristics, and fatty acid composition of beef

A 2-yr study was conducted using a 3 × 2 factorial arrangement of treatments to evaluate the effects of feeding dried distillers grains throughout a beef production system on performance, carcass characteristics, and fatty acid profile of beef. Factors were wheat pasture supplement [no supplement (CON), dry-rolled corn (DRC), and dried distillers grains (DDG)] fed at 0.5% BW daily and finishing diet [steam-flaked corn based diet containing 0 (SFC) or 35% (35DDG) DDG]. Each year, 60 preconditioned Hereford steers (initial BW = 198 kg ± 3) grazed winter wheat pasture with or without supplement. Body weight gain was 8% greater for steers consuming DDG supplement compared with CON and DRC steers (P < 0.01). After the grazing period, pastures within supplement treatment were randomly assigned to SFC or 35DDG. There was no supplement by finishing diet interaction for any performance or carcass variable of interest (P ≥ 0.41). Previous supplementation on winter wheat affected BW at feedlot entry and adjusted G:F (P ≤ 0.05) but had no effect on finishing ADG or carcass traits (P ≥ 0.12). On a carcass-adjusted basis, steers consuming 35DDG had reduced final BW, ADG, G:F, and total BW gain throughout the system (P ≤ 0.04) compared with SFC. Additionally, steers consuming 35DDG had reduced HCW, dressing percent, and fat thickness (P ≤ 0.03) compared with SFC. There was a supplement by finishing diet interaction (P = 0.02) for 18:0, in which cattle supplemented with DRC and fed the SFC finishing diet had the lowest concentration of 18:0 but DRC supplemented steers fed the 35DDG diet had the greatest concentration. The interaction was not significant (P ≥ 0.18) for other fatty acids. Main effects of supplement and finishing diet affected (P ≤ 0.05) several other fatty acids of interest, particularly 18:2, which is associated with reduced flavor-stability of beef. The use of DDG as a supplement to wheat pasture resulted in greater ADG during wheat grazing and heavier BW at feedlot entry, but final BW was not different from CON or DRC groups. Feeding DDG at 35% DM in steam-flaked corn-based finishing diets reduced ADG, G:F, and HCW, and affected the fatty acid composition of beef.     

Effects of increasing crude glycerol and dried distillers grains with solubles on growth performance, carcass characteristics, and carcass fat quality of finishing pigs

This study was conducted to determine the effects of dietary crude glycerol and dried distillers grains with solubles (DDGS) on growing-finishing pig performance, carcass characteristics, and carcass fat quality. We hypothesized that because dietary crude glycerol has been observed to increase carcass SFA, it might ameliorate the negative effects of DDGS on fat quality. The 97-d study was conducted at a commercial swine research facility in southwestern Minnesota with 1,160 barrows (initial BW = 31.0 ± 1.1 kg). Pigs were blocked by initial BW, and pens were randomly allotted to 1 of 6 dietary treatments with 7 replications per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of crude glycerol (0, 2.5, or 5%) and DDGS (0 or 20%). All corn-soybean meal-based diets contained 3% added fat (choice white grease). There were no glycerol × DDGS interactions for any response criteria evaluated. Increasing dietary glycerol did not affect finishing pig growth performance. Adding 20% DDGS to the diet did not affect ADG; however, finishing pigs fed diets with added DDGS had greater (2.47 vs. 2.41 kg/d; P = 0.02) ADFI and poorer (0.39 vs. 0.40; P = 0.01) G:F than pigs not fed DDGS. Feeding increasing dietary glycerol or 20% DDGS did not affect carcass characteristics. For carcass fat quality, feeding 20% DDGS resulted in decreased (P < 0.01) palmitic and oleic acids, total SFA and total MUFA, and increased (P < 0.01) linoleic, total PUFA, total unsaturated fatty acids, and iodine value in jowl fat, belly fat, and backfat. Increasing dietary crude glycerol increased myristic acid (linear, P < 0.05) and MUFA (quadratic, P < 0.05) in jowl fat and increased (quadratic, P < 0.05) oleic acid and MUFA in backfat. In conclusion, feeding 20% DDGS to finishing pigs increased ADFI, reduced G:F, and increased carcass fat iodine value, whereas feeding crude glycerol did not influence growth performance, carcass characteristics, and had a minor influence on fatty acids of carcass fat. Both of these biofuel coproducts can be used in combination without affecting finishing pig performance or carcass traits; however, feeding crude glycerol did not fully mitigate the increased unsaturation of carcass fat observed when feeding DDGS.     

Vitamin E supplementation in beef finishing diets containing 35% wet distillers grains with solubles: feedlot performance and carcass characteristics

Supplementation of vitamin E has indications for improving cattle health, performance, and retail characteristics when included in grain-based diets. This experiment was conducted to determine performance and carcass characteristics of steers fed diets containing wet distillers grains with solubles (WDGS) and supplemented with vitamin E. Steers of mixed Bos indicus and Bos taurus breeding (n = 199; BW = 363 ± 32 kg) were blocked by BW and assigned to 1 of 4 supplemental vitamin E (VITE) treatments [0 (control), 125, 250, and 500 IU·steer(-1)·d(-1)], which were fed for the last 97 d of the feeding period. Two blocks were on feed 129 d, and 3 blocks were fed for 150 d. Steers were fed a dry-rolled corn-based finishing diet with 35% WDGS (DM basis). Individual BW were measured initially, the initial day of vitamin E supplementation, and the day of slaughter. Carcass weights were collected at slaughter, and carcass data were collected after a 36-h chill. Body weight and ADG were not affected by VITE (P ≥ 0.34). There was a tendency for a linear (P = 0.08) increase in carcass-adjusted BW with increasing VITE. Use of carcass-adjusted final BW resulted in a linear increase (P = 0.04) in ADG with increasing VITE. Pre-vitamin E and vitamin E feeding period DMI were not affected (P ≥ 0.24) by VITE, but there was a tendency (P = 0.08) for a linear increase in overall DMI with increasing VITE. No difference (P ≥ 0.29) occurred in G:F measures using BW gains, but G:F using carcass-adjusted BW gains resulted in a trend (P = 0.11) for G:F to increase linearly with increasing VITE. Hot carcass weights tended (P = 0.08) to increase linearly with increasing dietary vitamin E. Vitamin E supplementation resulted in no effects (P ≥ 0.13) on measured carcass characteristics. Calculated yield grades (YG) were also not affected (P ≥ 0.37). However, the distribution of calculated YG resulted in a quadratic effect (P = 0.02) for YG 3 with the control and 500 VITE being greater than the 2 intermediate amounts. However, the percentage of carcasses grading YG 3 or less were not affected by vitamin E supplementation (P = 0.64). No differences were observed in the distribution of quality grades based on marbling scores (P ≥ 0.57). Data from this study suggest that vitamin E supplemented above basal requirements during the last 97 d of the feeding period in finishing diets containing 35% WDGS results in slight to no effect on animal performance or carcass characteristics.     

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.     

Effects of zilpaterol hydrochloride and days on the finishing diet on feedlot performance, carcass characteristics, and tenderness in beef heifers

British × Continental heifers (n = 3,382; initial BW = 307 kg) were serially slaughtered to determine if increasing days on the finishing diet (DOF) mitigates negative consequences of zilpaterol HCl (ZH) on quality grade and tenderness of beef. A 2 × 3 factorial arrangement of treatments in a completely randomized block design (36 pens; 6 pens/treatment) was used. Zilpaterol HCl (8.33 mg/kg DM) was fed 0 and 20 to 22 d before slaughter plus a 3 to 5 d withdrawal to heifers spending 127, 148, and 167 DOF. Feedlot and carcass performance data were analyzed with pen as the experimental unit. Three hundred sixty carcasses (60 carcasses/treatment) were randomly subsampled, and strip loin steaks were aged for 7, 14, and 21 d for assessment of Warner-Bratzler shear force (WBSF) and slice shear force (SSF) with carcass serving as the experimental unit for analysis. No relevant ZH × DOF interactions were detected (P > 0.05). Feeding ZH during the treatment period increased ADG by 9.5%, G:F by 12.5%, carcass ADG by 33.6%, carcass G:F by 35.9%, carcass ADG:live ADG by 15.6%, HCW by 3.2% (345 vs. 356 kg), dressing percent by 1.5%, and LM area by 6.5% and decreased 12th-rib fat by 5.2% and yield grade (YG) by 0.27 units (P < 0.01). Feeding ZH tended to decrease marbling score (437 vs. 442 units; P = 0.10) and increased WBSF at 7 (4.25 vs. 3.47 kg; P < 0.01), 14 (3.57 vs. 3.05 kg; P < 0.01), and 21 d (3.50 vs. 3.03 kg; P < 0.01). Feeding ZH decreased empty body fat percentage (EBF; 29.7% vs. 30.3%; P < 0.01) and increased 28% EBF adjusted final BW (473.4 vs. 449.8 kg; P < 0.01). Analysis of interactive means indicated that the ZH × 148 DOF group had a similar percentage of USDA Prime, Premium Choice, Low Choice, and YG 1, 2, 3, 4, and 5 carcasses (P > 0.10) and decreased percentage of Select (30.4 vs. 36.6%; P = 0.03) and Standard (0.2 vs. 0.9%; P = 0.05) carcasses compared with the control × 127 DOF group. As a result of ZH shifting body composition, extending the DOF of beef heifers is an effective feeding strategy to equalize carcass grade distributions. This can be accomplished along with sustaining the ZH mediated advantages in feedlot and carcass weight gain.     

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.