Effect of vitamin D, zilpaterol hydrochloride supplementation, and postmortem aging on shear force measurements of three muscles in finishing beef steers.

Vitamin D (D3) supplementation may be used to increase tenderness in beef from cattle fed zilpaterol hydrochloride (ZH). The study was arranged as a 2 × 2 factorial with fixed effects of ZH (no ZH or ZH fed at 8.3 mg/kg DM for 20 d with a 3-d withdrawal) and D3 (no D3 or 500,000 IU D3·steer·d for 10 d prior to harvest). Cattle ( = 466) were harvested in 2 blocks on the basis of BW with subsequent collection of carcass data. Full loins and inside rounds ( = 144 of each subprimal) were collected for fabrication of 5 steaks from the longissimus lumborum (LL), gluteus medius (GM), and semimembranosus (SM), which were aged for 7, 14, 21, 28, or 35 d. Warner-Bratzler shear force (WBSF) was used to evaluate mechanical tenderness of LL, GM, and SM steaks at all aging periods. Slice shear force (SSF) analysis was conducted on only 14- and 21-d LL steaks. No interactions ( > 0.05) between ZH and D3 occurred throughout the entire study. Supplementing ZH resulted in increased HCW ( < 0.01), larger LM area ( < 0.01), and improved calculated yield grades ( < 0.01) with decreases in fat thickness ( = 0.02) and marbling scores ( = 0.05). Supplementation with D3 increased calculated yield grade ( < 0.01) and decreased ( = 0.01) rib eye area. Feeding ZH increased ( ≤ 0.05) WBSF of LL steaks at each postmortem age interval, whereas D3 had no effect ( > 0.05) on WBSF or SSF of LL steaks. Like for WBSF, ZH supplementation increased SSF values at 14 and 21 d postmortem ( < 0.01) compared with those for non-ZH steaks. There was an interaction between ZH and postmortem age ( < 0.01) for WBSF of LL steaks. At 7 d LL steaks from ZH steers sheared over 0.6 kg greater than non-ZH steaks; however, by 21 d this difference was reduced to an average of 0.2 kg. Differences in distribution between LL steaks below 3.0 kg from non-ZH and ZH-fed cattle were also notable ( ≤ 0.05) through 21 d of aging. At 35 d postmortem a high proportion of LL steaks (68.5%) from ZH-fed steers required less than 3.0 kg to shear. Supplementation with ZH and D3 had no impact ( > 0.05) on WBSF values of GM steaks. Feeding ZH did not alter WBSF of SM steaks, but at 28 d D3 increased ( = 0.04) WBSF values. Shear force in ZH steaks was not effectively reduced by feeding D3 for 10 d to steers prior to harvest. Aging, however, was an effective method of reducing initially greater shear force values in LL steaks and, to a lesser degree, GM steaks from ZH-fed cattle.

Comparative effects of beta-adrenergic agonist supplementation on the yield and quality attributes of selected subprimals from calf-fed Holstein steers.

Mechanical portioning tests were performed on beef rib, strip loin, tenderloin, and top sirloin subprimals obtained from calf-fed Holstein steers to characterize the influence of zilpaterol hydrochloride (ZH), ractopamine hydrochloride (RH), or no ß-adrenergic agonist (ßAA; CON) on subprimal and steak yield. In addition, ßAA effects on tenderness, composition, and raw and cooked color of steaks from the aforementioned strip loin subprimals were characterized. At 14 to 15 d (ribs, tenderloins, and top sirloin) or 16 d (strip loin) postmortem, subprimals were portioned into steaks using a mechanical portioning machine. The appropriate variables were measured before and after portioning to determine ßAA influence on trimmed and untrimmed subprimal weight, subprimal length (rib only), steak weight and yield, and steak thickness (rib only). Steaks obtained from the strip loin subprimals were subjected to analysis of raw instrument color (L*, a*, b*), proximate composition, and pH. In addition, strip steaks were aged (16 or 23 d) before analysis of cooked internal color, Warner-Bratzler shear force (WBSF), and slice shear force (SSF). Briefly, ZH supplementation increased (P < 0.01) the weight of all subprimals when compared to CON. Furthermore, subprimals from CON animals consistently had fewer and lighter steaks (P ≤ 0.04) than subprimals from ZH-fed steers. Additionally, raw steaks from ZH cattle were a less vivid red (lower a* and saturation index values; P < 0.01) when compared to CON and RH steaks, which did not differ (P > 0.05). There was no interaction between ßAA treatment and postmortem aging length for WBSF or SSF (P > 0.10). However, CON steaks (3.25 kg) had lower WBSF values (P < 0.05) than ZH or RH steaks (3.68 and 3.67 kg, respectively). Regardless, aging for 23 d vs. 16 d resulted in decreased WBSF and SSF (P < 0.01) for all ßAA treatments. Although differences were numerically small, evaluations indicated the internal cooked surfaces of ZH and RH steaks were less red (P < 0.05) than CON steaks. Overall, these data reemphasize increased subprimal weights due to ßAA supplementation, particularly ZH. However, the data are not indicative of increased steak yield due to ßAA supplementation. Furthermore, the data demonstrate ßAA supplementation increases the shear force of calf-fed Holstein strip steaks regardless of postmortem aging period. However, no differences in shear force between the ßAA treatments (ZH or RH) were noted.

Comparative effects of zilpaterol hydrochloride and ractopamine hydrochloride on live performance and carcass characteristics of calf-fed Holstein steers.

Holstein steers (n = 2,275) were assigned to 1 of 3 treatments: 1) a control diet containing no ß-agonists, 2) a diet that contained zilpaterol hydrochloride (ZH; 8.3 mg/kg [100% DM basis]) for 20 d with a 3-d withdrawal period before harvest, and 3) a diet that contained ractopamine hydrochloride (RH; 30.1 mg/kg [100% DM basis]) for 28 d before harvest. No differences (P ≥ 0.18) were detected between treatments for initial BW, BW at d 28, or DMI. Final BW, BW gain for the last 28 d, total BW gain, ADG for the last 28 d, and overall ADG were greater (P < 0.05) for steers fed ZH or RH than for steers fed the control diet. Additionally, G:F for the last 28 d and G:F for the entire trial was increased (P < 0.02) for steers fed ZH (0.147, 0.147) or RH (0.153, 0.151) compared to steers fed the control diet (0.134, 0.143), respectively. Steers fed ZH or RH had HCW that were 15.5 and 8.2 kg heavier (P ≤ 0.01) and LM areas that were 7.1 and 2.3 cm(2) larger (P < 0.01) than control cattle. Steers fed ZH also had dressed carcass yields that were 1.3% to 1.5% greater and USDA calculated yield grades that were decreased 0.16 to 0.23 units compared to RH and control steers. No differences (P ≥ 0.39) were found between treatments for marbling score, fat thickness, and percentage KPH. Steers fed ZH had an increased (P ≤ 0.04) percentage of yield grade 1 and 2 carcasses (15.1, 55.0) and a reduced (P ≤ 0.02) percentage of yield grade 3 carcasses (27.1) compared with those fed RH (10.5, 49.1, 36.1) or the control diet (9.0, 47.4, 36.4), respectively. Additionally, ZH-fed steers had a decreased (P ≤ 0.04) percentage of yield grade 4 and 5 carcasses (2.8) compared with steers fed the control diet (6.9). Steers fed ZH had an increased (P ≤ 0.01) percentage of USDA Select grading carcass (31.0%) and a decreased (P ≤ 0.01) percentage of USDA Choice grading carcasses (65.0%) compared with steers fed RH (25.8%, 70.2%) and no ß-agonist (24.8%, 72.0%), respectively. Feeding either ß-agonist to calf-fed Holstein steers increased live performance through increased BW, BW gain, and ADG. Furthermore, supplementing calf-fed Holstein steers with ZH provides greater improvements in HCW, LM area, and yield grade components, with a slight decrease in quality grade when compared to calf-fed Holstein steers supplemented with RH.

Comparative effects of supplementing beef steers with zilpaterol hydrochloride, ractopamine hydrochloride, or no beta agonist on strip loin composition, raw and cooked color properties, shear force, and consumer assessment of steaks aged for fourteen or twenty-one days postmortem.

Beef steers (n = 1,914) were assigned to 1 of 3 ß-adrenergic agonist (ßAA) supplementation treatments-zilpaterol hydrochloride (ZH; 8.3 mg/kg of DM for 20 d with 3-d withdrawal), ractopamine hydrochloride (RH; 308 mg·head(-1)·d(-1) for 28 d), or no ßAA (CON)-to determine the effects on consumer eating quality. Strip loins (n = 1,101; CON = 400, RH = 355, and ZH = 346) were obtained and fabricated into 2.5-cm-thick steaks for proximate, Warner-Bratzler shear force (WBSF), slice shear force (SSF), and consumer analyses; steaks were aged until 14 or 21 d postmortem. Fat and moisture contents were not affected by ßAA supplementation (P > 0.05), but strip steaks from steers fed ZH had more protein (P < 0.01) than those from steers fed CON or RH, which were similar. An interaction between ßAA and aging was observed (P < 0.01) for WBSF but not SSF. Within steaks aged 14 d, ZH steaks required the most force to shear, RH steaks were intermediate, and CON steaks had the lowest WBSF values; however, RH steaks had a stronger response to aging than CON or ZH steaks, resulting in the lowest WBSF values at 21 d. Slice shear force values were greater (P < 0.01) in steaks from steers fed ZH than in steaks from steers fed CON or RH, which did not differ. Following shear force analyses, steaks within 2 SD of each treatment mean for WBSF were selected randomly for consumer assessment of eating quality. Consumer testing (n = 400; 200/postmortem aging period) was arranged in a 3 × 3 factorial representing 3 quality grades (Select, Low Choice, and Premium Choice) and 3 treatments (ZH, RH, and CON). In steaks aged 14 d, ßAA supplementation affected (P < 0.01) tenderness, flavor, and overall liking and tenderness acceptability, resulting in lower consumer scores for ZH than CON and RH; however, juiciness, flavor, and overall acceptability were similar (P > 0.05). In steaks aged 21 d, feeding ßAA influenced (P < 0.01) only tenderness and juiciness scores. Despite these differences, ßAA did not affect (P > 0.05) acceptability. Quality grade impacted (P < 0.01) all traits and acceptability in steaks aged 14 and 21 d. In 14-d steaks, Premium Choice typically was scored higher than Low Choice or Select; however, consumers rated 21-d Low Choice and Premium Choice similarly-both receiving greater scores than Select. Consumers detected several differences in eating quality at 14 d because of ßAA supplementation. Increasing aging from 14 to 21 d mitigated differences in shear force and tenderness scores because of feeding ZH, so that tenderness and overall acceptability were similar between ZH, RH, and CON.

Effects of postmortem calcium chloride injection on meat palatability traits of strip loin steaks from cattle supplemented with or without zilpaterol hydrochloride.

An experiment was conducted to determine the effects of zilpaterol hydrochloride mM supplementation (ZH; 8.3 mg/kg on a DM basis for 20 d) and calcium chloride injection [CaCl(2), 200 at 5% (wt/wt) at 72 h postmortem] on palatability traits of beef (Bos taurus) strip loin steaks. Select (USDA) strip loins were obtained from control (no ZH = 19) and ZH-supplemented carcasses (n = 20). Right and left sides were selected alternatively to serve as a control (no INJ) or CaCl(2)-injected (INJ) and stored at 4°C. Before injecting the subprimals (72 h postmortem), 2 steaks were cut for proximate, sarcomere length, and myofibrillar fragmentation index (MFI) analyses. At 7 d postmortem each strip loin was portioned into steaks, vacuum packaged, and aged for the appropriate period for Warner-Bratzler shear force (WBSF; 7, 14, 21, and 28 d postmortem), trained sensory analysis (14 and 21 d postmortem), purge loss (7 d), and MFI (3, 7, 14, 21, and 28 d postmortem). Results indicated steaks from both ZH supplementation and INJ had reduced WBSF values as days of postmortem aging increased. The WBSF values of ZH steaks were greater (P < 0.05) than no ZH steaks at each postmortem aging period. The INJ steaks had lower WBSF values (P < 0.05) than non-injected steaks. A greater percentage (91 vs. 71%) of steaks had WBSF values < 4.6 kg from steers with no ZH supplementation at 7 d postmortem, but the percentage did not differ (P > 0.05) due to ZH at 14, 21, or 28 d or due to INJ at any aging period. Trained panelists rated tenderness less in ZH steaks than steaks with no ZH at 14 d and 21 d. However, INJ improved (P < 0.05) the tenderness ratings and flavor intensity of the trained panelists, compared with their non-injected cohorts at 21 d. Zilpaterol hydrochloride supplementation reduced (P < 0.05) MFI values, but INJ resulted in greater (P < 0.05) MFI values compared with no INJ. Subprimals from ZH and INJ showed greater purge loss (P < 0.05). Although no interactions were found with ZH and CaCl(2), injecting USDA Select strip loins from ZH-fed cattle can help reduce the normal WBSF variation as it does in steaks from non-ZH-fed cattle.

Dietary zilpaterol hydrochloride. II. Carcass composition and meat palatability of beef cattle.

Experiments were conducted at 3 US locations (California, Idaho, and Texas) to determine the effects of dietary zilpaterol hydrochloride and duration of zilpaterol feeding on carcass composition and beef palatability. At each site, 160 steers and 160 heifers were stratified within sex by initial BW (study d -1) and assigned randomly within BW strata to 1 of 4 treatments in a randomized complete block design (4 blocks/treatment for each sex). The 4 treatments were arranged in a 2 (no zilpaterol vs. zilpaterol) x 2 (20- or 40-d duration of zilpaterol feeding) factorial. When included in the diet, zilpaterol was supplemented at 8.3 mg/kg (DM basis). Each pen consisted of 10 animals. After slaughter 2 carcasses per pen (n=64 per trial site) were selected. The entire right side of the selected carcasses was collected for dissection and chemical analysis of the soft tissue. Additionally, the left strip loin was collected for Warner-Bratzler shear force determinations and aged to 28 d postmortem. Sensory analysis was conducted on the Idaho trial site samples only. All data were pooled for analyses. Feeding zilpaterol hydrochloride increased carcass muscle deposition (P<0.01) of both steer and heifer carcasses. However, carcass percentage fat of steers and heifers was not affected (P>0.11) by the zilpaterol treatment. In heifer carcasses, carcass moisture percentage was increased (P=0.04) and bone percentage was decreased (P=0.02), whereas in steer carcasses, carcass moisture and bone percentage were not affected (P>0.10). In heifer carcasses, carcass ash percentage was not affected (P=0.61) by zilpaterol, whereas in steer carcasses, carcass ash percentage tended (P=0.07) to be increased. The protein-to-bone ratio was increased (P<0.001) by zilpaterol hydrochloride treatment in both steers and heifers, whereas the protein-to-fat ratio was not affected (P=0.10). Cooking loss of the LM was not affected (P=0.41) by zilpaterol treatment of steers or heifers. However, LM Warner-Bratzler shear force was increased (P=0.003) on average (3.3 vs. 4.0 kg) due to zilpaterol hydrochloride treatment of both steers and heifers. In both steers and heifers, LM sensory panel scores of overall juiciness (6.2 vs. 6.0), tenderness (6.2 vs. 6.0), and flavor intensity (6.2 vs. 6.0) tended (P=0.06) to be decreased in cattle supplemented with zilpaterol. Zilpaterol hydrochloride is a repartitioning agent that seems to affect carcass composition primarily through protein deposition. However, zilpaterol treatment can adversely affect tenderness and other palatability traits.

Effects of feeding zilpaterol hydrochloride with and without monensin and tylosin on carcass cutability and meat palatability of beef steers.

An experiment was conducted using 200 beef carcasses to evaluate the effects of feeding zilpaterol hydrochloride with or without monensin and tylosin on carcass cutability and meat sensory variables. The experiment was conducted using a randomized complete block design with treatments arranged as a 2 (no zilpaterol vs. zilpaterol) x 2 (monensin and tylosin withdrawn vs. monensin and tylosin fed) factorial. Cattle (n=3,757) were fed zilpaterol hydrochloride, a beta(2)-adrenergic agonist, for 30 d at the end of the finishing period and withdrawn from zilpaterol hydrochloride for the last 5 d on feed. Five carcasses (weighing between 305 and 421 kg and free of slaughter defects) were selected from each of 40 feedlot treatment pens. Strip loins from the left sides were collected for sensory analysis and Warner-Bratzler shear force (WBSF) testing, and the rib was collected for 9th, 10th, 11th-rib dissections. A subsample of 3 carcass right sides per pen was fabricated into boneless subprimals according to Institutional Meat Purchase Specifications. Carcasses from zilpaterol-fed steers had greater (P or= 0.26). For the main effect of monensin and tylosin, withdrawal of monensin and tylosin decreased (P=0.01) consumer juiciness scores, although other yield and compositional measurements were not affected (P >or= 0.07). Zilpaterol is a strong repartitioning agent that increases meat yield through increased protein and decreased fat deposition.

Spoilage and safety characteristics of ground beef packaged in traditional and modified atmosphere packages.

Two separate studies, one with pathogen-inoculated product and one with noninoculated product, were conducted to determine the safety and spoilage characteristics of modified atmosphere packaging (MAP) and traditional packaging of ground beef patties. Ground beef patties were allotted to five packaging treatments (i) control (foam tray with film overwrap; traditional), (ii) high-oxygen MAP (80% 02, 20% CO2), (iii) high-oxygen MAP with added rosemary extract, (iv) low-oxygen carbon monoxide MAP (0.4% CO, 30% CO2, 69.6% N2), and (v) low-oxygen carbon monoxide MAP with added rosemary extract. Beef patties were evaluated for changes over time (0, 1, 3, 5, 7, 14, and 21 days) during lighted display. Results indicated low-oxygen carbon monoxide gas flush had a stabilizing effect on meat color after the formation of carboxymyoglobin and was effective for preventing the development of surface discoloration. Consumers indicated that beef patties packaged in atmospheres containing carbon monoxide were more likely to smell fresh at 7, 14, and 21 days of display, but the majority would probably not consume these products after 14 days of display because of their odor. MAP suppressed the growth of psychrophilic aerobic bacteria when compared with control packages. Generally, control packages had significantly higher total aerobic bacteria and Lactobacillus counts than did modified atmosphere packages. In the inoculated ground beef (approximately 10(5) CFU/g) in MAP, Escherichia coli O157 populations ranged from 4.51 to 4.73 log CFU/g with no differences among the various packages, but the total E. coli O157:H7 in the ground beef in the control packages was significantly higher at 5.61 log CFU/g after 21 days of storage. On days 14 and 21, the total Salmonella in the ground beef in control packages was at 5.29 and 5.27 log CFU/g, respectively, which was significantly higher than counts in the modified atmosphere packages (3.99 to 4.31 log CFU/g on day 14 and 3.76 to 4.02 log CFU/g on day 21). Data from these studies indicate that MAP suppresses pathogen growth compared with controls and that spoilage characteristics developed in MAP packages.

Tasco supplementation: effects on carcass characteristics, sensory attributes, and retail display shelf-life.

Two hundred crossbred cattle (Bos indicus x Bos taurus) were supplemented with 2% Tasco (Ascophyllum nodosum) in a commercial finishing facility to evaluate marbling score, USDA quality grade, sensory traits, and retail display shelf life. Treatment animals (n = 100) received a steam-rolled corn (Zea mays)-based diet containing 2% Tasco meal (DM basis), for 14 d beginning at d 45 of the finishing period and again 14 d before slaughter. Control animals (n = 100) received a steam-rolled corn (Zea mays)-based diet without Tasco at identical feeding periods. Carcasses from Tasco-fed cattle exhibited greater marbling scores (P = 0.003) than controls. There were no treatment effects (P > 0.05) on sensory, shear, or purge attributes of striploin or inside round steaks with the exception of inside round steaks from Tasco animals having a greater initial tenderness (P = 0.03) and lower off-flavor score (P = 0.002) than control steaks. The LM samples from Tasco-fed cattle had a greater percentage of ether extractable fat (P = 0.001) and lower percentage of protein (P = 0.001) than controls. Inside round samples from treated animals exhibited a greater percentage of moisture (P = 0.03) than control steaks. Visual lean color of striploin steaks was not affected by Tasco supplementation (P = 0.26); however, steaks from Tasco-treated animals were more uniform and had less discoloration and browning than those from controls (P = 0.005, 0.04, and 0.05, respectively). Inside round visual scores and instrument values reflected similar treatment responses (P < 0.05), with a majority of the effects on muscle redness (CIE a*, hue angle) and measures of discoloration. Tasco steaks were generally more red and less discolored during extended postmortem aging and retail exposure (P < 0.05). The results from this study indicate that short-term supplementation of 2% Tasco meal in feedlot cattle increases carcass quality and prolonged retail shelf life.

Effect of supplemental vitamin D3 concentration on concentrations of calcium, phosphorus, and magnesium relative to protein in subcellular components of the longissimus and the distribution of calcium within longissimus muscle of beef steers.

The effect of supplementing diets with various levels of vitamin D3 to provide 0, 0.5, 1, and 5 million IU/(steer x d) for 8 d before slaughter on the mineral content and localization of Ca in LM and muscle fragments was studied during the postmortem aging process. Twelve feedlot steers of three biological types were given access to the four levels of vitamin D for 8 d before slaughter. Differential centrifugation techniques were used to determine the concentrations of minerals relative to protein in different muscle fragments on d 3 and 21 postmortem. Electron microscopy visualization of bound Ca indicated that vitamin D3 mobilized Ca from the sarcoplasmic reticulum and transverse tubule system into the myofibrils. Bound Ca was concentrated near the Z-line at the A-band/I-band juncture within the sarcomere. Supplementing steers with 1 and 5 million IU/(steer x d) of vitamin D3 increased (P < 0.05) Ca, P, and Mg concentrations per unit of protein in the cytosol. Soluble cytosolic Ca concentrations were greater (P < 0.05) on d 21 than on d 3 postmortem only when steers were supplemented with 5 million IU/d. Concentrations of Ca, P, and Mg in isolated tissues were increased (P < 0.05) in nuclei and myofibrilar proteins by supplementing steers with 1 and 5 million IU/ (steer x d) of vitamin D3. All supplemental vitamin D3 treatments also increased (P < 0.001) Mg concentrations in the cytosol, regardless of aging treatment, and increased Mg concentrations (P < 0.04) within the mitochondria at d 3 postmortem. Thus, supplementation of feedlot steers with vitamin D3 at levels of 0.5 to 5 million IU/(steer x d) increased Ca concentrations within respiring muscle, resulting in increased bound tissue Ca concentrations. When the respiring muscle was converted to meat, the increased bound tissue Ca resulting from vitamin D3 treatment released Ca concentrations into the cytosol during aging (P < 0.05). Results of this study indicate that vitamin D3 supplementation increased total cytosolic Ca, P, and Mg concentrations in meat.

Ascophyllum nodosum supplementation: a preharvest intervention for reducing Escherichia coli O157:H7 and Salmonella spp. in feedlot steers.

Ascophyllum nodosum (Tasco-14) decreased the prevalence of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in animals fed prior to harvest. Tasco-14 was supplemented on a 2% dry matter basis 14 days prior to harvest to determine its effects on EHEC and Salmonella spp. prevalence. Two hundred mixed crossbred steers and heifers (Bos indicus x Bos taurus), in a large commercial finishing facility, served as experimental units. Treatment (TRT, n = 100) animals received a steam-rolled corn-based diet containing 2% Tasco-14 on a dry matter basis, and control (CON, n = 100) animals received only the steam-rolled corn-based diet. Hide swabs and fecal samples were obtained for EHEC and Salmonella spp. evaluations. Animals were sampled 1 day prior to (d - 1) the feeding of Tasco-14 and immediately following exsanguinations. The prevalence of EHEC O157 on hide swabs and in fecal samples (P = 0.0001 and P < 0.0001, respectively) and the prevalence of EHEC O157:H7 on hide swabs and in fecal samples (P < 0.0001 and P < 0.0001, respectively) was reduced by 33 and 36% from d - 1 levels on TRT hide swabs and by 9 and 11% in TRT fecal samples. The prevalence of EHEC O157 and EHEC O157:H7 was reduced by 33 and 36% from d - 1 levels on TRT hide swabs and by 9 and 11% in TRT fecal samples. The prevalence of Salmonella spp. on hide swabs did not change for TRT animals (P = 0.64). CON animals showed an increase in Salmonella spp. prevalence (P < 0.0001) from d - 1 feeding levels on hide swabs. The prevalence of Salmonella spp. increased in both TRT and CON fecal samples when compared to d - 1 levels (P = 0.002). However, TRT samples exhibited a lower (P < 0.05) postfeeding prevalence of Salmonella spp. in fecal samples than did CON samples. Results from this study indicate that 2% Tasco-14 supplementation in feedlot cattle diets reduces EHEC O157 and EHEC O157:H7 prevalence on hide swabs and in fecal samples and may suppress increases in Salmonella spp.

Effects of biological type of beef steers on vitamin D, calcium, and phosphorus status.

Feedlot steers (n = 36) from three biological types (Bos indicus, Bos taurus-Continental, and Bos taurus-English) were used to determine the Ca, P, and vitamin D3 status of feedlot cattle. The USDA yield and quality grade traits were measured at slaughter, and the concentrations of vitamin D3 (VITD) and the metabolites 25-hydroxyvitamin D3 (25-OH D) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2 D) were determined in LM, liver, kidney, and plasma. Plasma and muscle Ca and P concentrations also were determined. Biological type of cattle affected a number of carcass traits. Carcasses from Bos taurus-English cattle had more marbling, resulting in higher quality grades (P < 0.05). Carcasses from Bos taurus-Continental cattle had lower calculated yield grades (P < 0.05) than did carcasses from cattle in the other biological types. In general, differences in carcass traits resulting from biological type were consistent with other reports. Plasma and LM Ca and P concentrations were not affected (P = 0.06) by biological type of cattle, indicating that Ca and P homeostasis is a conserved trait across the different types of cattle. Plasma VITD and 25-OH D concentrations were not affected (P = 0.41) by biological type, whereas plasma 1,25-(OH)2 D concentration was lower (P < 0.05) in Bos taurus-English cattle than in Bos taurus-Continental and Bos indicus cattle. Liver VITD and 25-OH D were not affected by biological type (P = 0.76), but liver 1,25-(OH)2 D concentration was greater (P < 0.05) in Bos indicus cattle than in Bos taurus-Continental cattle. Kidney vitamin D metabolite concentrations were not affected by biological type of cattle (P = 0.21). Muscle VITD concentration was greater (P < 0.05) in Bos taurus-English cattle than in the other two biological types, and muscle 25-OH D concentrations were greater (P < 0.05) in Bos taurus-English cattle than in Bos indicus cattle. Muscle 1,25-(OH)2 D concentration was less (P < 0.05) in the Bos taurus-Continental cattle than in the other two biological types. Cooking eliminated vitamin D metabolite differences among the biological types. Our results suggest that Bos indicus cattle had greater 1,25-(OH)2 D (the biologically active form) in tissues, and greater 1,25-(OH)2 D plasma concentrations than Bos taurus cattle. Thus, the need for VITD supplementation and optimal levels of Ca and P in feedlot diets might differ between Bos indicus and Bos taurus cattle.

Supplemental vitamin D3 concentration and biological type of beef steers. I. Feedlot performance and carcass traits.

Because of the Ca dependency of the calpains, oral supplementation of vitamin D3 (VITD) can increase the Ca content of muscle to activate the calpains and improve tenderness. Feedlot steers (n = 142) were arranged in a 4 x 3 factorial arrangement consisting of four levels of VITD (0, 0.5, 1, and 5 million IU/[steer x d]) for eight consecutive days antemortem using three biological types (Bos indicus, Bos taurus-Continental, and Bos taurus-English). Feedlot performance factors of ADG, DMI, and G:F were measured, and carcass quality, yield, and color data were collected. Plasma Ca and P concentrations were measured during d 4 to 6 of supplementation and at exsanguination, and carcass pH and temperature were measured in the LM at 3 and 24 h postmortem. Vitamin D3 treatment at 5 million IU/(steer x d) decreased ADG (P < 0.05) over the supplementation and feed intake for the last 2 d of feeding compared with untreated control steers. Likewise, G:F was decreased (P = 0.03) in steers supplemented with 5 million IU/d compared with controls. Overall, there was a linear decrease (P < 0.01) in ADG and G:F as a result of VITD supplementation. Plasma concentrations of Ca and P were increased (P < 0.05) by VITD concentrations of 1 and 5 million IU/(steer x d). All VITD treatments increased (P < 0.05) LM temperature at 3 h postmortem and pH at 24 h postmortem. Vitamin D3 treatments did not affect (P = 0.07) any other carcass measurements, including USDA yield and quality grade; thus, any improvements in meat tenderness as a result of VITD supplementation can be made without adversely affecting economically important carcass factors. Biological type of cattle did not interact with VITD treatment for any carcass or feedlot performance trait. Although feeding 5 million IU/(steer x d) of VITD for eight consecutive days had negative effects on performance, supplementing VITD at 0.5 million IU/ (steer x d) did not significantly alter feedlot performance.

Supplemental vitamin D3 concentration and biological type of steers. II. Tenderness, quality, and residues of beef.

Vitamin D3 was orally supplemented to determine the supplemental dose that improved beef tenderness in different cattle breed types. Feedlot steers (n = 142) were arranged in a 4 x 3 factorial arrangement consisting of four levels of supplemental vitamin D3 (0, 0.5, 1, and 5 million IU/steer daily) administered for eight consecutive days antemortem using three biological types (Bos indicus, Bos Taurus-Continental, and Bos Taurus-English). Warner-Bratzler shear force (WBSF) was measured at 3, 7, 10, 14, and 21 d postmortem, and trained sensory analysis was conducted at 7 d postmortem on LM, semimembranosus, gluteus medius, and supraspinatus steaks. Concentrations of vitamin D3 and the metabolites 25-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 were determined in the LM, liver, kidney, and plasma. Biological type of cattle did not interact (P > 0.10) with vitamin D3 supplementation for sensory or tenderness traits, suggesting that feeding vitamin D3 for 8 d before slaughter affected the different biological types of cattle similarly. Supplementing steers with 0.5, 1, or 5 million IU/(steer(d) decreased (P < 0.05) LM WBSF at 7, 10, 14, and 21 d postmortem compared with controls, and vitamin D3 treatments of 0.5, 1, and 5 million IU decreased (P < 0.05) semimembranosus WBSF at 3, 7, and 14 d postmortem. In general, vitamin D3-induced improvements in WBSF were most consistent and intense in LM steaks. Sensory panel tenderness was improved (P < 0.05) by all vitamin D3 treatments in LM steaks. Sensory traits ofjuiciness, flavor, connective tissue, and off-flavor were not (P > 0.05) affected by vitamin D3 treatments. All vitamin D3 treatments decreased micro-calpain activity and increased muscle Ca concentrations (P < 0.05). Vitamin D3 concentrations were increased (P < 0.05) by supplementation in all tissues tested (liver, kidney, LM, and plasma); however, cooking steaks to 71 degrees C decreased (P < 0.05) treatment residue effects. The vitamin D metabolite 1,25-dihydroxyvitamin D3 was increased (P < 0.05) only in plasma samples as a result of the vitamin D3 treatments. These results indicate that supplementation with vitamin D3 at 0.5 million IU/steer daily for eight consecutive days before slaughter improved tenderness in steaks from different subprimal cuts by affecting muscle Ca concentrations, micro-calpain activities, and muscle proteolysis, with only a small effect on tissue residues of vitamin D3.

Effect of vitamin D3 supplementation level on the postmortem tenderization of beef from steers.

The objective of this experiment was to determine the effect of different doses of vitamin D3 (VITD) on beef feedlot performance, plasma and muscle Ca2+, tissue residues, and improvement of Warner-Bratzler shear force (WBS) and panel tenderness. A total of 167 steers were fed one of six levels of VITD. The VITD treatments (28 steers/treatment) were 0, 0.5 x 10(6), 1 x 10(6), 2.5 x 10(6), 5 x 10(6), and 7.5 x 10(6) IU/steer daily of VITD fed nine consecutive days before slaughter. Feedlot performance and plasma Ca2+ were measured during the last 21 days on feed. Warner-Bratzler shear force was measured on strip loin and top round steaks at 7, 10, 14, and 21 d postmortem. The VITD treatments of 5 and 7.5 x 10(6) IU/steer daily decreased (P < 0.05) ADG, and VITD supplementation of 2.5, 5, and 7.5 x 10(6) IU/steer daily decreased average dry matter feed intake (P < 0.05) at the end of the feeding trial. Plasma Ca2+ increased linearly with VITD treatment (P < 0.01). Calpastatin and calpain activity were not influenced by treatment (P > 0.05), but muscle Ca2+ was increased (P < 0.05) by VITD treatments of 1, 2.5, 5, and 7.5 10(6) IU/steer daily. Feeding VITD did not influence (P > 0.05) carcass quality or yield traits. Supplementing VITD at levels of 1, 2.5, 5, and 7.5 10(6) IU/steer daily increased (P < 0.05) VITD concentrations in strip loin and liver samples. Cooking liver decreased VITD concentrations 10 to 28%. Vitamin D3 treatments of 0.5 and 7.5 x 10(6) IU/d reduced strip loin steak WBS at d 7 (P < 0.05), but VITD treatments did not decrease strip loin steak WBS at any other time postmortem. The VITD treatments of 0.5, 1, and 5 x 10(6) IU/steer daily decreased top round steak WBS at 7 d, and all VITD treatments decreased 10-d top round steak WBS (P < 0.05). Supplementing steers with 0.5 x 10(6) IU/steer daily of VITD also decreased (P < 0.05) top round steak WBS at 21 d postmortem compared with controls. Sensory tenderness at 7 d postmortem was increased (P < 0.05) by all VITD treatments in top round steaks, yet strip loin tenderness scores were not affected (P > 0.05) by VITD treatment. Treatment with VITD quadratically decreased (P < 0.05) round WBS. Thus, VITD treatment will effectively improve tenderness when cattle tend to be tough and have no impact on cattle that produce tender beef. Feeding steers 0.5 x 10(6) IU of VITD daily for 9 d improved tenderness in two muscles without negatively affecting feedlot performance or tissue residues.

Vitamin-mineral supplementation and accelerated chilling effects on quality of pork from pigs that are monomutant or noncarriers of the halothane gene.

We examined the effects of vitamin and mineral supplementation of the finishing diet on growth and accelerated chilling of carcasses on carcass and muscle traits of halothane gene carrier and noncarrier pigs. Barrows and gilts that were either monomutants (MON, n = 49) or noncarriers (NON, n = 28) of the halothane gene were fed a standard finishing diet until they reached 86 kg. They then were randomly assigned to one of four finishing diets formulated to contain 11 IU/kg vitamin E (0), 311 IU/kg vitamin E plus additional vitamins and minerals (300), 611 IU/kg vitamin E plus additional vitamins and minerals (600), or 911 IU/kg vitamin E plus additional vitamins and minerals (900) until they were slaughtered (118 kg). Alternating carcass sides were assigned either a normal chilling procedure (NC, 4 degrees C for 24 h) or an accelerated chilling procedure (AC, -20 degrees C for 1.5 h and then 4 degrees C for 22.5 h). Supplementing vitamin E in the finishing diet increased (P < 0.05) the concentration of vitamin E in the longissimus muscle. Supplementing vitamin E in the diets of MON pigs did not affect color, firmness, or cooking losses of loins or color and firmness of hams. For the NON genotype, increasing the level of vitamin E in the diet decreased (P < 0.05) the percentage of PSE loins and hams. Color and firmness scores of the gluteus medius and longissimus muscles were improved 0.4 unit (P < 0.005) by AC compared with NC of carcasses. Loin chop juiciness and flavor were improved (P < 0.05) in the MON genotype for AC compared to NC. Accelerated chilling reduced (P < 0.05) the percentage of PSE loins from 38 to 17% and PSE hams from 32 to 10% for the MON genotype, but percentage of PSE was not affected (P > 0.05) by chilling treatment for the NON genotype. No interaction between diet and chill treatments existed for muscle quality traits (P > 0.05). Supplementing finishing diets of NON pigs with at least 600 IU/kg vitamin E, in addition to other vitamins and minerals, or accelerated chilling of MON carcasses can reduce the incidence of PSE pork.

Tasco-Forage: III. Influence of a seaweed extract on performance, monocyte immune cell response, and carcass characteristics in feedlot-finished steers.

Tall fescue (Festuca arundinacea Schreb.) infected with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) causes fescue toxicosis in cattle grazing the forage, but effects of the endophyte were considered to be abated soon after removal of the animals from pastures. Tasco-Forage, a proprietary extract from the brown seaweed Ascophyllum nodosum, is a known source of cytokinins and has increased antioxidant activity in both plants and the animals that graze the forage. Tasco was applied at 0 and 3.4 kg/ha to infected and uninfected tall fescue pastures in Virginia and Mississippi. Forty-eight steers grazed the pastures at each location during each of 2 yr (n = 192) before being transported to Texas for feedlot finishing. On arrival at the feedlot, steers from Tasco-treated pastures had higher (P < 0.01) monocyte phagocytic activity and tended (P < 0.07) to have higher major histocompatibility complex class II expression than steers that grazed the untreated pastures. A depression (P < 0.05) in monocyte immune cell function due to grazing infected fescue was detected throughout the feedlot finishing period but was reversed by Tasco. Rectal temperatures were elevated (P < 0.07) in steers that had grazed the infected tall fescue when they arrived in Texas, but by d 14 no difference was detected. However, by d 28 the temperature effects of infected tall fescue were reversed. Steers that had grazed infected fescue had lower (P < 0.01) rectal temperatures on d 112 of the feedlot period, demonstrating a much longer-lasting effect of the endophyte on thermoregulatory mechanisms than previously thought. Steers that had grazed Tasco-treated pastures had higher (P < 0.01) rectal temperatures on d 56 than steers that had grazed untreated fescue. Steers that had grazed the Tasco-treated pastures had higher marbling scores (P < 0.05) regardless of the endophyte, but no effect of Tasco or endophyte on gain was measured. Our data suggest that Tasco application to tall fescue pastures alleviated some of the negative effects of tall fescue toxicity.

Tasco-Forage: IV. Influence of a seaweed extract applied to tall fescue pastures on sensory characteristics, shelf-life, and vitamin E status in feedlot-finished steers.

Tasco-Forage is an Ascophyllum nodosum seaweed-based product that has increased antioxidant activity in both plants and animals. Endophyte (Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin)-infected and uninfected tall fescue (Festuca arundinacea Schreb.) pastures in Virginia and Mississippi during 1997 were treated or not with 3.4 kg Tasco/ha in April and July. There were two replications of each treatment at each location. Forty-eight steers (6/replication) grazed pastures at each location (n = 96) from April to October prior to transportation to Texas Tech, Lubbock, for finishing during a 160-d period in the feedlot. Blood (antemortem) and liver (postmortem) samples were collected. After slaughter and chilling, the left strip loins (IMPS #180) were collected from three randomly selected steers from within each pasture replication (n = 48). Strip loins were vacuum-packaged and stored at 2 degrees C. At postmortem d 7, 14, 21, and 28, strip loins were removed from packaging and fabricated into 2.54-cm steaks. Following each fabrication day postmortem, the strip loins were repackaged and stored at 2 degrees C until the following postmortem time. After the prescribed fabrication, steaks were overwrapped with polyvinyl chloride film, subjected to simulated retail display at 2 degrees C for up to 3 d, and subjective and objective color were evaluated daily by a trained panel. Steaks from Mississippi steers that had grazed Tasco-treated fescue retained higher (P < 0.05) CIE a* color scores throughout retail display. Steaks were more uniform and had less discoloration and less browning (P < 0.05) if they were from steers that had grazed Tasco-treated fescue, and the effect was greatest for steers from Mississippi (location x Tasco interaction; P < 0.05). The endophyte in tall fescue may decrease uniformity and increase lean discoloration and two-toning of beef steaks when removed from vacuum packaging on or beyond d 21 postmortem (endophyte x Tasco x postmortem day interaction: P < 0.05). Vitamin E in liver was increased (P < 0.06) and serum vitamin E was decreased (P < 0.09) in steers that had grazed the treated pastures. These experiments indicated that Tasco applied to tall fescue during the grazing season can improve color stability and extend beef shelf-life, particularly in cattle grazing infected tall fescue. The mode of action of Tasco is not clear, but antioxidants and specific vitamins may be involved.

Retail consumer acceptance of beef tenderized with calcium chloride.

Beef inside round subprimals were injected with a 200 mM calcium chloride (CaCl2) solution at 5% (wt/wt) to determine its effects on beef steak palatability and quality traits. Alternating subprimals from the right and left sides were selected for injection of CaCl2 or not injected to serve as a control. After 7 d of postmortem storage, 2.5-cm-thick steaks were cut from each subprimal for consumer evaluation (n = 478) in a retail setting. Three supermarkets with customers varying widely in income were selected as test sites for measuring consumer perceptions of the treated and control steaks and package labeling acceptance. Supermarket, income level, education, and sex were evaluated for their impact on acceptance of calcium-injected beef. Steak flavor and tenderness both were important in determining beef eating quality; 50% of consumers said tenderness was the most important and 40% said flavor was the most important. Consumers visually preferred CaCl2-treated steaks 71% of the time over the control steaks based on package labeling. The CaCl2 injection improved tenderness, juiciness, flavor desirability, and overall palatability ratings by the consumers for inside round steaks and did not cause any off-flavor problems compared with the controls. Therefore, injecting beef with a solution of 200 mM CaCl2 at 5% (wt/wt) can improve retail consumer evaluations of beef steak tenderness and reduce tenderness variation without detrimental effects on other palatability or quality traits.

Dietary energy source and density: effects of roughage source, roughage equivalent, tallow level, and steer type on feedlot performance and carcass characteristics.

The effects of roughage level (10, 20, or 30% roughage equivalent [RE]), roughage source (alfalfa vs cottonseed hulls), roughage regimen (constant RE vs 2% RE during the mid-finishing period), tallow level (1.2 vs 4.6%), and steer type (British crossbred [BRITX] vs Bos indicus crosses [BRX]) were evaluated in three experiments with a common allotment and several overlapping treatments. Steers (n = 432; initial weight = 326 +/- 26 kg) were divided into three BW blocks and allotted randomly to 72 pens and 24 treatments. Steers were fed steam-flaked, sorghum grain-based finishing diets for 124 to 166 d. Diets with 20% RE decreased gain efficiency and 30% RE diets decreased both gain (linear, P < .07) and efficiency (linear, P < .001) compared with 10% RE diets. Reducing roughage level during the mid-finishing period improved overall gain efficiency 2, 7, and 24% (P > .2, < .05, and < .001, respectively) for the 10, 20, and 30% RE diets, respectively. Steers fed cottonseed hulls consumed more feed (9.6 vs 8.8 kg/d, P < .001) but tended to gain less (1.53 vs 1.58 kg/d, P = .11) than steers fed alfalfa, were leaner, and had fewer carcasses grading Choice (62 vs 77%, P < .05). Feeding 4.6% tallow decreased DMI (P < .05) and improved gain efficiency (P < .05) compared with 1.2% tallow. The BRITX steers consumed more feed (6%, P < .001) but were somewhat less efficient (3.5%, P < .05) than BRX steers. Carcasses from BRITX steers tended to be fatter than carcasses from BRX steers and more of them graded Choice (62 vs 37%, P < .01). Commercial BRX steers did not perform as well as BRITX steers on higher-energy-density diets (4.6% tallow or variable roughage regimen). Knowledge of the genetic background of feeder cattle can be important in the selection of dietary energy density and marketing expectations.