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1.
The hypothesis of this experiment was that increasing dietary fat through the use of whole oilseeds and altering the dietary ratio of PUFA:saturated fatty acids would alter carcass composition of finishing steers. Seventy-two steers (443.6 +/- 1.0 kg) were fed for 76 d one of four dietary treatments: a corn/ soybean meal-based diet (NOFAT); two diets containing 16% (DM basis) whole raw soybeans; and a corn/soybean meal-based diet containing choice white grease (CWG) equal to the fat addition supplied by the soybeans. Soybeans used in the diets were either a standard variety (NORM-SB) or a variety high in oleic acid content (HO-SB). The fatty acid profile of diets differed (P < 0.05) in the degree of saturation and content of palmitic, stearic, oleic, linoleic, and linolenic acids. There were no differences in ADG (1.73 kg/d), hot carcass weight (347 kg), longissimus muscle area (79.4 cm2), yield grade (3.31), or percentage of boneless retail cuts (48.8%). Contrasts revealed differences (P < 0.05) in G:F and marbling score with the addition of fat (0.126 vs. 0.137 and 4.66 vs. 4.91, respectively, for NOFAT vs. fat). The addition of fat tended (P < 0.10) to increase backfat, and feeding NORM-SB increased (P < 0.01) dressing percent compared with the HO-SB treatment. Loin samples taken from steers fed NOFAT, NORM-SB, and HO-SB did not differ in alpha-tocopherol content. Loins from the CWG treatment tended (P < 0.10) to have lower alpha-tocopherol content than did the soybean treatments (0.79 vs. 0.99 ppm, respectively). From main-effects analysis, HO-SB loin samples had the highest (F3,8 = 32.91; P < 0.01) concentration of gamma-tocopherol (0.33 ppm); this resulted in differences (P < 0.05) in gamma-tocopherol when comparing all contrasts. When comparing loin samples from NORM-SB-fed steers with those from HO-SB-fed steers, NORM-SB samples had a greater (P < 0.05) percentage oflinoleic acid and PUFA and a lower (P < 0.05) percentage of oleic acid and monounsaturated fatty acids. Furthermore, loin samples from soybean-fed steers tended (P < 0.10) to have a greater concentration of conjugated linoleic acid than samples from CWG-fed steers. These data suggest that the source of added dietary fat may affect overall carcass composition. Furthermore, dietary addition of soybeans or CWG can improve feed efficiency and marbling, whereas the addition of whole raw soybeans compared with CWG may increase unsaturation and total vitamin E content of beef.  相似文献   

2.
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.  相似文献   

3.
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.  相似文献   

4.
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.  相似文献   

5.
Three digestion experiments and one growth experiment were conducted to determine site, extent and ruminal rate of forage digestion and rate and efficiency of gain by cattle offered alfalfa haylage supplemented with corn or dry corn gluten feed (CGF). In Exp. 1, eight steers were fed alfalfa haylage-based diets with substitution of corn for 0, 20, 40 or 60% of haylage in a 4 X 4 latin square. Increasing dietary corn substitution increased (P less than .05) OM, NDF and ADF digestion by steers but decreased (P less than .05) rate of in situ alfalfa DM digestion. In Exp. 2, five heifers were fed alfalfa haylage-based diets with increasing dietary levels of CGF in a 5 X 5 latin square. Increasing dietary CGF increased (P less than .05) OM, NDF and ADF digestion by heifers. In Exp. 3 and 4, cattle were fed alfalfa haylage-based diets containing either 20 or 60% corn or CGF. In Exp. 3, supplementation increased (P less than .05) OM and NDF digestion but level X supplement source interaction (P less than .05) occurred, with added CGF increasing OM and NDF digestion more than added corn. In Exp. 4, supplementation improved (P less than .05) DM intake, daily gain and feed efficiency. Dry matter intake and daily gain were greater (P less than .05) for 60% supplementation than for 20% supplementation. Overall, whereas increasing the level of dietary supplement increased (P less than .05) OM, NDF and ADF digestion, only corn addition decreased (P less than .05) rate of in situ alfalfa DM digestion. Daily gains and feed efficiencies were similar in cattle fed either corn or CGF with alfalfa haylage.  相似文献   

6.
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.  相似文献   

7.
One thousand twenty steers and heifers were used in six feeding trials to examine the influence of laidlomycin propionate on feedlot performance and to determine the most efficacious dietary concentrations of that ionophore. Cattle were fed diets ranging in energy content from 1.08 to 1.49 Mcal NEg/kg of DM. Laidlomycin propionate improved rate of gain and feed conversion in both steers and heifers. Improvements in performance were not evident when laidlomycin propionate was fed at only 3 mg/kg. However, both average daily gain and feed conversion were improved by laidlomycin propionate within the range of 6 to 12 mg/kg of DM (P less than .001). Feed consumption was not substantially affected by inclusion of laidlomycin propionate in the diet. Improvements in ADG and feed conversion were greater on lower-energy diets than on higher-energy diets, but both these performance characteristics were improved regardless of the type of diet fed. Average daily gain was maximized with laidlomycin propionate at 6 mg/kg, whereas improvements in feed conversion were sustained through 12 mg/kg. Carcasses of cattle fed diets containing 6 to 12 mg/kg of laidlomycin propionate weighed 7.3 kg more (P less than .001) than carcasses of cattle fed the control diets. Yield grade and quality grade were not affected by laidlomycin propionate (P greater than .05).  相似文献   

8.
A metabolism study and two feedlot trials were conducted to evaluate urea supplementation of peanut skin (PS) diets and ammoniation of PS as methods of reducing detrimental effects of tannins in PS on nutrient digestibility and performance of beef cattle. Tannin content of PS was reduced by 42% after ammoniation. Digestibility coefficients for dry matter, crude protein, nitrogen free extract, energy and total digestible nutrients were higher (P less than .05) for the control diet without PS compared with urea-supplemented PS (UPS) and ammoniated PS (APS) diets. Ether extract digestibility was higher (P less than .05) for UPS and APS diets compared with the control diet. Fecal N was higher (P less than .05) and N retention was lower (P less than .05) in steers fed UPS and APS diets compared with controls, which suggested that in UPS and APS diets dietary protein was being complexed with tannins and excreted. Steers fed the APS diet had lower (P less than .05) plasma urea nitrogen compared with control and UPS diets at 2, 4 and 6 h post-feeding. Eighteen heifers were fed control, UPS and APS diets individually for 84 d, resulting in similar (P less than .05) feedlot performance and carcass traits for heifers on all dietary treatments. Rumen fluid propionic acid levels were similar for control and APS heifers and somewhat lower (P greater than .05) for UPS heifers at 3 and 6 h post-feeding on d 62 of the trial. The experimental diets were fed to 54 steers (360 kg initial wt) ad libitum. After 98 d on dietary treatments average daily gains (ADG), final weights, carcass weights and carcass quality grades were not different (P greater than .05) for control and APS steers. Live weight and ADG were lower (P less than .05) for UPS steers on d 98 compared with control and APS steers, and UPS steers continued in the feedlot through d 147. After 98 d on control or APS diets 72.2% of the beef carcasses produced on each diet graded USDA Choice, and 100% of the carcasses of steers fed UPS graded USDA Choice after 147 d. A urea-supplemented PS diet or a diet containing ammoniated PS was ineffective in improving digestibility and N retention of PS diets when limit-fed to steers. However, ad libitum feeding of an ammoniated PS diet was effective in overcoming detrimental effects of tannins on feedlot performance of heifers and steers.  相似文献   

9.
The objective of this study was to determine if dietary cation-anion balance (DCAB) affects the concentration of S that can be tolerated by growing and finishing cattle without adversely affecting performance. Angus cross and Bradford steers (n=114; average initial BW=252.8 kg) were blocked by BW and breed, and randomly assigned within a block to treatment. The design was a 3 × 2 factorial arrangement of treatments with S (from NH(4)SO(4)) supplemented at 0, 0.15, or 0.30% of DM, and NaHCO(3) added at 0 or 1.0% of DM. Each treatment consisted of 3 pens containing 5 steers and 1 pen containing 4 steers. Steers were used in an 84-d growing study followed by a finishing study. A corn silage-based diet was fed during the growing study and a corn-based diet was fed during the finishing study. Steers were not randomized between experiments. The analyzed concentrations of S in the growing diets were 0.12, 0.30, and 0.46%, whereas the analyzed concentrations of S in the finishing diets were 0.13, 0.31, and 0.46% for treatments supplemented with 0, 0.15, and 0.30% S, respectively. Increasing DCAB by approximately 15 mEq/100 g of DM, by the addition of NaHCO(3,) did not affect (P > 0.36) performance during the growing or finishing studies. During the growing study DMI was not affected (P=0.29) by dietary S. Steers fed diets containing 0.30% S had greater ADG (P=0.02) and G:F (P=0.01) than those receiving 0.46% S, but similar (P > 0.36) performance to steers fed 0.12% S. During the finishing study, steers fed diets containing 0.46% S had less ADG than steers fed 0.13 (P=0.004) or 0.31% S (P=0.07), whereas ADG did not differ (P=0.18) among steers fed 0.13 and 0.31% S. Steers fed diets containing 0.31 (P=0.01) or 0.46% S (P=0.001) had less DMI than controls, but G:F was not affected (P=0.52) by S during the finishing study. Carcass characteristics did not differ (P > 0.18) among steers fed diets containing 0.13 and 0.31% S. Steers receiving diets containing 0.46% S had decreased HCW (P=0.001), quality (P=0.02), and yield grades (P=0.04) than steers receiving 0.13% S. Plasma Cu concentrations on d 101 of the finishing phase and liver Cu concentrations at slaughter were greater (P ≤ 0.05) in control steers compared with those fed diets containing 0.31 or 0.46% S. This study indicates that steers fed growing diets can tolerate up to 0.46% S with minimum effects on performance. Finishing steers tolerated diets containing 0.31% S without adverse affects on ADG or G:F. However, 0.46% S greatly decreased ADG and DMI, and increasing DCAB did not prevent these depressions.  相似文献   

10.
Thirty-six Angus x Hereford heifers (365 +/- 60 kg) were used to determine the effects of supplemental dietary lipid sources on fatty acid composition of i.m., perianal (p.a.), and s.c. lipid depots. Lipid was supplied to diets as either corn oil or a rumen-protected conjugated linoleic acid (CLA) salt for two specific treatment periods of either the final 32 or 60 d on feed. Following an initial 56-d feeding period, heifers were fed one of three dietary treatments (DM basis): 1) basal diet containing 88% concentrate and 12% grass hay (CON), 2) basal diet plus 4% corn oil (OIL), or 3) basal diet plus 2% rumen-protected CLA salt (RPCLA) containing 31% CLA. The trans-10, cis-12 CLA concentration was greatest (P < 0.05) for heifers fed RPCLA and OIL diets and least (P < 0.05) for CON, regardless of time on dietary treatment. Heifers fed supplemental RPCLA had greater (P < 0.05) total CLA content than either CON- or OIL-fed heifers. Adipose tissue concentration of trans-11 vaccenic acid (TVA) was less (P < 0.05) for CON than OIL or RPCLA, which did not differ (P > 0.05). Percentages of C18:1 trans-10 were least (P < 0.05) in i.m. lipid compared with p.a. and s.c., which did not differ (P > 0.05). Following 60 d of lipid supplementation, heifers fed OIL and RPCLA had lower (P < 0.05) concentrations of oleic acid and total monounsaturated fatty acids (MUFA) compared with CON. The ratio of cis-9, trans-11 CLA:TVA was higher (P < 0.05) for heifers fed 60 vs. 32 d, but did not differ (P > 0.05) between adipose depots. Feeding OIL increased (P < 0.05) adipose concentration of C18:2 fatty acid, whereas feeding RPCLA increased (P < 0.05) total CLA isomers by 22%. Intramuscular lipid contained the lowest (P < 0.05) percentage of cis-9, trans-11 CLA, total CLA, C18:1 cis-9, C18:1 trans-10, and TVA. Total CLA and cis-9, trans-11 CLA isomers were increased (P < 0.05) in p.a. and s.c. adipose depots, whereas i.m. adipose tissue contained increased (P < 0.05) amounts of total PUFA. Results from this study indicate that short-term lipid supplementation to feedlot cattle can increase adipose tissue CLA concentrations, but only marginally (8.3 to 17.5%). Moreover, observed decreases in oleic acid and total MUFA concentrations of adipose tissues from heifers fed rumen-protected CLA or corn oil suggest that lipid supplementation may decrease delta9 desaturase activity in adipose tissues, which in turn would lower the conversion of TVA to cis-9, trans-11 CLA isomer.  相似文献   

11.
Twelve ruminally cannulated crossbred Angus steers were used to evaluate ruminal fermentation characteristics and diet digestibility when 30% (DM) corn dried distillers grains with solubles (DDGS) containing 0.42 or 0.65% (DM) of dietary S was incorporated into finishing diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC). The study was a replicated, balanced randomized incomplete block design with a 2 × 2 factorial arrangement of treatments. Factors consisted of dietary S concentration (0.42 and 0.65% of DM; 0.42S and 0.65S, respectively) and grain processing method (SFC or DRC). The 0.65S concentration was achieved by adding H(2)SO(4) to DDGS before mixing rations. Steers were assigned randomly to diets and individual, slatted-floor pens, and fed once daily for ad libitum intake. Two 15-d experimental periods were used, each consisting of a 12-d diet adaptation phase and a 3-d sample collection phase. Samples were collected at 2-h intervals postfeeding during the collection phase. Ruminal pH was measured immediately after sampling, and concentrations of ruminal ammonia and VFA were determined. Fecal samples were composited by steer within period and used to determine apparent total tract digestibilities of DM, OM, NDF, CP, starch, and ether extract. Feeding 0.65S tended (P = 0.08) to decrease DMI but resulted in greater apparent total tract digestibilities of DM (P = 0.04) and ether extract (P = 0.03). Ruminal pH increased (P < 0.05) in steers fed 0.65S diets, which may be attributable, in part, to decreased (P = 0.05) VFA concentrations and greater (P < 0.01) ruminal ammonia concentrations when 0.65S was fed, compared with feeding 0.42S. These effects were more exaggerated in steers fed DRC (interaction, P < 0.01), compared with steers fed SFC. Steers fed DRC-0.65S had greater (P < 0.01) acetate concentration than steers fed DRC-0.42S, but acetate concentration was not affected by S concentration when SFC was fed. Propionate concentration was decreased (P < 0.01) in steers fed SFC-0.65S compared with steers fed SFC-0.42S, but dietary S concentration had no effect on propionate concentration when DRC was fed. Butyrate concentration was less (P < 0.01) in steers fed 0.65S diets than in steers fed 0.42S. Lactate concentrations tended (P = 0.06) to decrease in steers fed 0.65S diets. Feeding DDGS with increased S concentration may decrease feed intake and ruminal VFA concentration but increase ruminal ammonia concentration.  相似文献   

12.
An experiment was conducted to determine the effects of dietary Co concentration on performance, carcass traits, and plasma, liver, and ruminal metabolites of steers fed corn- or barley-based diets. Sixty steers, initially averaging 316 kg, were stratified by BW and assigned randomly to treatments in a 2 x 3 factorial arrangement, with factors being a corn- or barley-based diet and supplemental Co added at 0, 0.05, or 0.15 mg/kg of DM. Control corn-and barley-based diets analyzed 0.04 and 0.02 mg of Co/kg of DM, respectively. Steers were fed individually using electronic Ca-lan gate feeders. Cobalt supplementation increased (P < 0.05) DMI and ADG over the total study. From d 85 to finish, Co supplementation increased (P < 0.05) ADG by steers fed corn- but not barley-based diets. The G:F was increased (P < 0.05) by Co supplementation during the first 84 d but not over the entire finishing period. Average daily gain and G:F were greater (P < 0.05) for corn- vs. barley-fed steers. Supplemental Co increased vitamin B12 in plasma and liver (P < 0.05), and plasma vitamin B12 was greater (P < 0.05) in steers fed corn-vs. barley-based diets. Cobalt supplementation increased (P < 0.05) ruminal fluid vitamin B12 on d 84 in steers fed corn- but not barley-based diets. Folate was greater in plasma (P < 0.01) and liver (P < 0.05) of steers fed Co-supplemented diets. Increasing supplemental Co from 0.05 to 0.15 mg of Co/kg of DM increased (P < 0.05) liver folate in steers fed barley- but not corn-based diets. Supplemental Co decreased (P < 0.01) plasma methylmalonic acid concentration in steers. Increasing supplemental Co from 0.05 to 0.15 mg/kg of DM decreased plasma and ruminal succinate concentrations, and steers fed barley-based diets had greater (P < 0.05) plasma and ruminal succinate relative to those fed corn-based diets. Addition of supplemental Co to the basal diets increased (P < 0.01) plasma glucose concentrations of steers, and steers fed corn-based diets had greater plasma glucose than those fed barley-based diets. Steers supplemented with Co had greater ruminal propionate (P < 0.01) and lesser (P < 0.05) ruminal acetate and butyrate proportions than controls. Supplemental Co increased dressing percent (P < 0.10) and HCW (P < 0.01) at slaughter. These results indicate that feeding steers corn- or barley-based diets deficient in Co adversely affects performance and vitamin B12 status.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
Crossbred Angus steers (n = 30) were used to determine whether the conjugated linoleic acid (CLA) content of beef fat could be increased by feeding varying levels of extruded full-fat soybeans as a source of polyunsaturated fatty acids for rumen biohydrogenation. Diets were as follows: 1) control, 2) 12.7% extruded full-fat soybeans (LESB), and 3) 25.6% extruded full-fat soybeans (HE SB). Steers were individually housed and fed the diets for 111 d during the finishing period. Over the experimental period, treatment groups were similar in ADG (1.7 +/- 0.1 kg/d) and had a similar slaughter weight (603 +/- 11.6 kg). Dressing percentage averaged 61.6% and carcass composition averaged 14.3% protein, 30.9% lipid, and 54.8% water. At slaughter, the intramuscular, intermuscular, and subcutaneous fat depots were sampled from the rib longissimus, eye of round, and chuck tender muscles. Across all fat depots, the CLA content differed (P < 0.05), averaging 6.6, 6.7, and 7.7 mg/g of fatty acids for the control, LESB, and HESB diets, respectively. There were significant differences in CLA content between fat depots within a cut, but differences were relatively small and the hierarchy in fat depots was not consistent among cuts. The cis-9, trans-11 isomer was the predominant CLA isomer and its content in fat was related to trans-11 C18:1 content (r = 0.53; P < 0.001). There was substantial individual variation in CLA content and this varied from 2.6 to 17.0 mg/g fatty acids across all treatments and fat depots. Overall, results demonstrated that including extruded full-fat soybeans in the diet of finishing steers increased the CLA content of beef fat. Differences were relatively small and the relationship of this to rumen fermentation and endogenous synthesis of CLA is considered.  相似文献   

17.
The effects of feeding high levels of Mg were evaluated in a 130-d study with 24 steers. Six steers were allotted to each of four diets supplemented with MgO to attain .3, 1.4, 2.5 or 4.7% Mg, DM basis. Chromic oxide was used as digesta marker; fecal grab samples were collected once daily during nine consecutive 10-d periods. Steers fed 2.5 and 4.7% Mg refused some feed during the study, so their respective dietary Mg intakes were 2.4 and 3.7% (DM basis). Severe diarrhea and a lethargic appearance were observed in steers fed the two higher Mg levels. Fecal DM and apparent DM digestibility decreased linearly (P less than .01) with increased dietary Mg. Apparent Mg absorption (g/d) increased linearly (P les than .01) and apparent Ca and P absorption (g/d) decreased linearly (P less than .01) with addition of Mg to the diet. Increasing dietary Mg linearly elevated blood serum and erythrocyte Mg (P less than .01; P less than .05, respectively) and serum inorganic P (P less than .05) and linearly decreased serum Ca (P less than .01). Magnesium concentration in liver, kidney, skeletal muscle and rib-bone and P in skeletal muscle all increased linearly (P less than .05) with dietary Mg. Increasing dietary Mg in the steers caused a progressive degeneration of the stratified squamous epithelium of rumen papillae. A progressively more serious Mg toxicosis condition developed over time in steers fed diets containing 2.4 and 4.7% Mg.  相似文献   

18.
Ruminally cannulated steers (281 +/- 18 kg) were used to evaluate effects of choline on digestion and metabolism. Four steers were implanted with 24 mg of estradiol and 120 mg of trenbolone acetate, and four steers were not implanted. Cattle were assigned to concurrent 4 x 4 Latin squares. Dietary treatments were a 2 x 2 factorial: 0 or 4% tallow (DM basis) in corn-based diets, and 0 or 5 g/d supplemental choline administered abomasally. Blood collected before and 6 h after the initial choline infusion was used to assess acute responses to choline. Digestibility and blood metabolites were measured after adaptation to choline, as well as after an abomasal dose of 100 g of lipid. Digestibilities of dietary DM (P = 0.29) and of dietary total fatty acids (P = 0.42) were not affected by choline. Apparent digestibilities of C18:0 and C18:1 fatty acids were greater (P < 0.05) when diets contained 4% tallow. Digestibilities of fatty acids in the lipid dose were less than those in the diet, and no biologically important differences in fatty acid disappearance resulted from the treatments. No significant acute responses to choline were detected. After adaptation to choline, no important differences in plasma metabolites occurred in response to choline infusion. Plasma urea was less (P < 0.05) for implanted cattle, reflecting increased deposition of protein. Plasma cholesterol was greater (P < 0.05) for steers fed 4% tallow. Changes in plasma triglycerides in response to an abomasal lipid dose were less (P < 0.05) for steers fed 4% tallow, probably due to greater triglyceride concentrations at the time of lipid dosing. In summary, few responses to abomasally infused choline were observed in either digestion or plasma metabolites.  相似文献   

19.
A feeding trial involving 160 crossbred steers (357 kg) and a metabolism trial involving eight Holstein steers (189 kg) cannulated in the rumen and proximal duodenum were conducted to evaluate the interaction of dietary Mg level (.18 vs .32%, DM basis) and supplemental fat (0% supplemental fat vs 4% tallow [T], yellow grease [YG], or griddle grease [GG]) on growth performance and NE value of the diet. Dietary Mg level did not influence (P > .10) growth performance. Daily weight gain was lower (11%, P < .05) for steers fed GG than for those fed YG. Supplemental fat decreased (5%, P < .10) DMI and increased (P < .05) gain efficiency (7%). There was a fat x Mg level interaction (P < .01) for dietary NE. The increase in dietary NEg with T and YG supplementation was similar (8.6 vs 8.0%) for diets containing .18 and .32% Mg. In contrast, the increase in dietary NEg with GG supplementation was 8.9% with .18% dietary Mg, but the NEg value of the diet did not increase when GG was added to diets with .32% dietary Mg. Dressing percentage was lower (1.5%, P < .1) and retail yield was greater (2.2%, P < .05) for steers fed GG- than for steers fed YG-supplemented diets. Increasing dietary Mg level increased kidney, pelvic, and heart fat (5.5%, P < .05). There was a fat x Mg level interaction (P < .1) for marbling score. With diets containing no supplemental fat, increasing dietary Mg decreased (15.2%) the marbling score, and with diets containing supplemental fat, increasing dietary Mg increased (7.2%) the marbling score. Fat supplementation decreased (P < .01) ruminal and total tract digestion of OM (10 and 3.5%, respectively) and NDF (37 and 17%, respectively). Supplemental fat did not affect (P > .10) Ca digestion but decreased (41.7%, P < .01) apparent Mg digestion. Increasing dietary Mg level increased (77.7%, P < .05) apparent Mg digestion. There were no treatment effects (P > .10) on postruminal fatty acid digestion. Fat supplementation decreased (17.3%, P < .01) the acetate:propionate molar ratio. Total ruminal protozoal counts were increased (12.7%, P < .05) by increasing dietary Mg level and decreased (12.9%, P < .05) by fat supplementation. We conclude that supplemental fats may depress Mg absorption. Increasing dietary magnesium levels beyond current recommendations may increase marbling scores in cattle fed fat-supplemented diets but may not affect growth performance or dietary NE. The NE value of fat is a predictable function of level of fat intake.  相似文献   

20.
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.  相似文献   

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