Dell M. Allen

Effects of zilpaterol hydrochloride feeding duration and postmortem aging on Warner-Bratzler shear force of three muscles from beef steers and heifers

To determine the effects of zilpaterol hydrochloride (ZH; 6.8 g/t on 90% DM basis) feeding duration (0, 20, 30, and 40 d) on Warner-Bratzler shear force (WBSF) of longissimus lumborum (LL), triceps brachii (TB), and gluteus medius (GM) muscles, beef from feeding trials was collected and shipped to participating universities. Animals were slaughtered at commercial processing facilities across the United States. Strip loin, shoulder clod, and top sirloin butt subprimals (IMPS 180, 114, and 184, respectively) were obtained from a portion of USDA Choice and Select grade carcasses for WBSF using standardized procedures and equipment. Feeding ZH increased (P < 0.001) LL WBSF values of USDA Choice and Select steaks. A significant linear contrast existed for both quality grades, indicating increased WBSF values were associated with longer feeding durations. Increased postmortem aging decreased LL WBSF of control and treated steaks. Postmortem aging from 7 to 21 d decreased LL WBSF values by 17.6 and 16.4% for USDA Choice and Select steaks, respectively. The percentage of LL steaks from ZH-supplemented cattle with a WBSF value <4.5 kg was significantly less than control steaks for both quality grades. Postmortem aging from 7 to 21 d postmortem increased (P < 0.001) the percentage of LL Choice and Select steaks with WBSF <4.5 kg for all ZH feeding durations. Feeding ZH for 20, 30, or 40 d increased (P < 0.01) WBSF of USDA Choice TB and GM steaks compared with 0-d controls. Feeding ZH for 0, 20, and 40 d had a similar effect on WBSF of USDA Select GM steaks, and produced lesser values than steaks from cattle fed ZH for 30 d. Feeding ZH for 20, 30, and 40 d had no effect on WBSF values of USDA Select TB steaks. However, the 20-, 30-, and 40-d duration produced WBSF values greater (P < 0.05) than control (0 d) TB steaks. Postmortem aging decreased (P < 0.05) WBSF of USDA Choice and Select TB and GM steaks, but the percentage improvement in WBSF attributed to aging was less than observed for LL steaks. The results of this study indicate feeding ZH increased (P < 0.001) WBSF of LL, TB, and GM. The ZH feeding also decreased (P < 0.01) the percentage of steaks with WBSF <4.5 kg regardless of US quality grade, whereas postmortem aging increased (P < 0.01) the percentage of US Choice and Select steaks with WBSF <4.5 kg. Finally, postmortem aging reduced (P < 0.05) WBSF of steaks from ZH-supplemented beef cattle.

Zilpaterol hydrochloride supplementation has no effect on the shelf life of ground beef.

The objective of this study was to determine the effect of feeding zilpaterol hydrochloride (ZH) on the shelf life and stability of ground beef. Beef knuckles and plates were obtained from USDA Select beef heifer carcasses from control (CON) animals or those supplemented with ZH (8.33 mg/kg of dietary DM basis) for the last 20 d of the finishing period. Subprimals were coarsely ground and blended to produce an 80% lean product. The mixture was vacuum-stuffed into chubs and placed in dark storage at 2 to 4°C for 7, 14, or 21 d before fine grinding. Each week, the finely ground samples were packaged on expanded polystyrene trays overwrapped with polyvinyl chloride film and placed in refrigerated retail cases (0 to 2°C) under continuous fluorescent lighting to simulate retail display. Samples were subjected to a variety of analyses at different time intervals (h) during simulated display, including composition analysis, thiobarbituric acid-reacting substance analysis (TBA), sensory color, instrumental color, and aerobic plate count. Data analysis revealed trained sensory color and discoloration scores were similar between CON and ZH-treated samples. Instrumental L* and b* values for CON and ZH-treated samples did not differ (P = 0.13 and 0.19, respectively). Instrumental a* values declined (P < 0.05) over the display period for CON and ZH ground beef. However, a* values for ZH ground beef stored for 7 d were greater (P < 0.05) than CON values at 18 through 72 h of display. There was a treatment × storage day interaction (P < 0.001) for TBA values with ZH having smaller TBA values than CON after 7 d of dark storage. There was no difference (P = 0.21) in aerobic plate count between ZH and CON ground beef samples. Overall, ground beef from cattle supplemented with ZH was equal to or better than CON for sensory color and discoloration, instrumental color, and stability variables, including TBA reactive substances and aerobic plate counts.

Moisture enhancement and blade tenderization effects on the shear force and palatability of strip loin steaks from beef cattle fed zilpaterol hydrochloride

Two trials investigated zilpaterol hydrochloride (ZH) feeding duration, enhancement, blade tenderization, and postmortem aging effect on Warner-Bratzler shear force (WBSF; trial 1) and consumer sensory ratings (trial 2). For trial 1, USDA Select beef strip loins were obtained from carcasses of beef steers fed ZH (6.8 g/t on 90% DM) the last 0, 20, 30, or 40 d of the feeding period. One-half of each strip loin was enhanced (110%) with a brine solution, whereas the remaining portion was not enhanced. Both pieces were portioned into steaks, which were aged 7, 14, or 21 d for WBSF analysis. For trial 2, paired USDA Select beef strip loins were obtained from carcasses of beef steers fed ZH the last 0 or 20 d of feeding. Paired strip loins were fabricated into 4 pieces and assigned to control, moisture enhanced, blade tenderized, and blade tenderized + moisture enhanced treatments. Strip loin pieces were then portioned into steaks that were aged 14 or 21 d postmortem. Consumers panelists (n = 458) indicated their like or dislike of tenderness, juiciness, flavor, and overall like of each sample using 8-point, verbally anchored scales, as well as tenderness and overall acceptability. With exception of 20 d ZH-treated steaks, results from trial 1 indicate WBSF values decreased (P < 0.05) with enhancement. Among enhanced steaks, steaks from cattle fed ZH for 20, 30, and 40 d had greater (P < 0.05) WBSF values than controls. Among nonenhanced steaks, 20 d ZH-treated steaks had WBSF values similar to 0, 30, and 40 d ZH-treated steaks, whereas 30 and 40 d ZH-treated steaks had greater (P < 0.05) WBSF values than controls. Postmortem aging for 21 d improved (P < 0.05) WBSF values for all ZH durations when compared with 7-d aging treatments. Results from trial 2 indicate ZH feeding for 20 d had no effect on flavor scores, decreased tenderness scores (P < 0.05), and tended (P < 0.10) to decrease juiciness and overall like scores when compared with controls for steaks aged 14 d. After 21 d aging, steaks from 20 d ZH-fed cattle had reduced (P < 0.05) tenderness, juiciness, and overall like scores and tended (P < 0.10) to have decreased flavor scores when compared with controls. These results indicate enhancement improved WBSF, but was not sufficient to overcome the detrimental effect of ZH feeding duration on WBSF until steaks were aged for 21 d postmortem. Consumer scores indicate 20 d ZH feeding had no effect on overall acceptability, but decreased tenderness and tenderness acceptability scores when compared with controls.

Effects of zilpaterol hydrochloride feeding duration on beef and calf-fed Holstein strip loin steak color

Two studies using beef and calf-fed Holstein cattle were conducted to determine the effect of zilpaterol hydrochloride (ZH) supplementation on the color of strip loin steaks packaged in traditional and modified-atmosphere packaging. Select (USDA) strip loins were obtained from the carcasses of beef (n = 118) or calf-fed Holstein (n = 132) cattle fed ZH (6.8 g/ton on a 90% DM basis) for the last 0, 20, 30, or 40 d of feeding. One portion of the strip loin was moisture enhanced, cut into steaks, and packaged in an atmosphere containing 80% oxygen and 20% carbon dioxide. The remaining portion of the strip loin was vacuum-packaged until further processing. At 14 d postmortem, the vacuum-packaged loins were portioned and packaged in traditional retail packaging. Traditionally packaged and modified-atmosphere-packaged steaks were then placed in retail cases at -1 to 3 degrees C for 5 d and evaluated by both trained and consumer panelists. Instrumental color values and purge loss were also recorded. Zilpaterol hydrochloride duration had no effect on the color and purchase intention scores of consumer panelists for beef and calf-fed Holstein strip loin steaks. Zilpaterol hydrochloride feeding duration had no effect on the color or discoloration scores of trained panelists for enhanced, modified-atmosphere-packaged beef strip steaks. Traditionally packaged beef steaks from cattle treated with ZH for 20 d had more desirable (P < 0.05) lean color scores than steaks from cattle not treated with ZH on d 2, 3, and 4 of display and had similar discoloration scores on d 1, 2, and 3 of display. The color scores of trained panelists for enhanced calf-fed Holstein steaks were more desirable (P < 0.05) for steaks from cattle not treated with ZH than for steaks from cattle treated with ZH for 20 d on d 1, 2, 3, and 4 of display. However, the discoloration scores of trained panelists for enhanced and modified-atmosphere-packaged calf-fed Holstein steaks were similar for steaks from cattle treated with ZH for 0 and 20 d on d 1, 2, and 3 of display. The scores of trained panelists indicated that traditionally packaged steaks from calf-fed Holsteins treated with ZH for 0 d had a darker lean color (P < 0.05) than steaks from ZH-treated cattle on d 1 of display, whereas the lean color scores for ZH treatments of all durations were similar on d 4 of display. The scores of trained panelists indicated that ZH treatment had no effect on the discoloration of traditionally packaged, nonenhanced strip steaks from calf-fed Holsteins. Therefore, feeding ZH to beef or calf-fed Holstein steers had no detrimental effect on the lean color or color stability of strip loin steaks subjected to enhancement, packaged in modified-atmosphere or traditional packaging, and displayed under simulated retail conditions.

Predicting red meat yields in carcasses from beef-type and calf-fed Holstein steers using the United States Department of Agriculture calculated yield grade.

Analyses were conducted to evaluate the ability of the USDA yield grade equation to detect differences in subprimal yield of beef-type steers and calf-fed Holstein steers that had been fed zilpaterol hydrochloride (ZH; Intervet Inc., Millsboro, DE) as well as those that had not been fed ZH. Beef-type steer (n = 801) and calf-fed Holstein steer (n = 235) carcasses were fabricated into subprimal cuts and trim. Simple correlations between calculated yield grades and total red meat yields ranged from -0.56 to -0.62 for beef-type steers. Reliable correlations from calf-fed Holstein steers were unobtainable; the probability of a type I error met or exceeded 0.39. Linear models were developed for the beef-type steers to predict total red meat yield based on calculated USDA yield grade within each ZH duration. At an average calculated USDA yield grade of 2.9, beef-type steer carcasses that had not been fed ZH had an estimated 69.4% red meat yield, whereas those fed ZH had an estimated 70.7% red meat yield. These results indicate that feeding ZH increased red meat yield by 1.3% at a constant calculated yield grade. However, these data also suggest that the calculated USDA yield grade score is a poor and variable estimator (adjusted R(2) of 0.31 to 0.38) of total red meat yield of beef-type steer carcasses, regardless of ZH feeding. Moreover, no relationship existed (adjusted R(2) of 0.00 to 0.01) for calf-fed Holstein steer carcasses, suggesting the USDA yield grade is not a valid estimate of calf-fed Holstein red meat yield.

Feeding zilpaterol hydrochloride to calf-fed Holsteins has minimal effects on semimembranosus steak color

To determine the effects of feeding zilpaterol hydrochloride (ZH) for 0, 20, 30, or 40 d (ZH0, ZH20, ZH30, ZH40) on semimembranosus (SM) steak color and color stability in 3 packaging systems, SM subprimals were removed from 60 calf-fed Holstein steers 24 h postmortem. A 7.62-cm-thick portion was removed from each subprimal and stored (2 degrees C) for 21 d; then two 2.54-cm-thick steaks were cut, overwrapped with polyvinyl chloride (PVC) film, and assigned to 0 or 3 d of display. Remaining portions of the subprimals were vacuum packaged for 10 d and then enhanced (10% with a solution containing 0.3% sodium chloride, 0.35% phosphate, and 0.05% rosemary extract), cut into steaks, packaged in high-oxygen (HO-MAP) or carbon monoxide (CO-MAP) modified atmosphere packaging (MAP), and assigned to 0, 3, or 5 d (HO-MAP) or 0 or 9 d (CO-MAP) of display. Panelists evaluated the deep and superficial portions of SM steaks for initial color, display color, discoloration, pH, L*, a*, b*, hue angle, and saturation indices. Feeding duration did not affect (P > 0.05) initial color scores of steaks in PVC. Steaks displayed in PVC from ZH20 or ZH30 diets were slightly brighter and less discolored than the ZH40 treatment. For enhanced steaks in HO-MAP, ZH20 steaks were darker on d 5 (P < 0.05) and more discolored (P < 0.05) on d 3 through 5 than all other diet treatments. For enhanced steaks from steers fed ZH40 and in CO-MAP, the deep and superficial SM tended (P > 0.05) to have improved display color compared with other dietary regimens; however, steaks in CO-MAP from all feeding durations had less than 20% metmyoglobin through d 9 of display. Overall, feeding ZH20 might result in steaks with slightly less color stability when packaged in HO-MAP; however, feeding ZH20 or ZH30 to calf-fed Holstein steers will yield steaks that have equal to or more desirable color traits when packaged in PVC or CO-MAP. Regardless of ZH feeding regimen, HO-MAP and CO-MAP extended the color life of the SM. The CO-MAP system minimized color differences between the superficial and deep portions of the SM muscle and extended total case life compared with traditional and HO-MAP packaging.

Effects of zilpaterol hydrochloride feeding duration on crossbred beef semimembranosus steak color in aerobic or modified atmosphere packaging.

The objective of this research was to determine the effects of feeding zilpaterol hydrochloride (ZH) for 0, 20, 30, or 40 d before slaughter (ZH0, ZH20, ZH30, or ZH40, respectively) on semimembranosus (SM) color development and stability. A 7.62-cm-thick portion was removed from 60 beef steer SM subprimals and stored (2 degrees C) for 21 d; then two 2.54-cm-thick steaks were cut, overwrapped with polyvinyl chloride (PVC) film, and assigned to 0 or 3 d of display. Remaining portions of the subprimals were stored in a vacuum for 10 d and then enhanced 10% to a meat concentration of 0.3% sodium chloride, 0.35% phosphate, and 0.05% rosemary extract. Steaks were packaged in a high-oxygen (HO-MAP) or carbon monoxide (CO-MAP) modified atmosphere and assigned to 0, 3, or 5 d (HO-MAP) or 0 or 9 d (CO-MAP) of display. The deep (DSM) and superficial (SSM) portions of steaks were evaluated for initial color, display color, discoloration, pH, L*, a*, b*, hue angle, and saturation indices. For steaks in PVC, no differences (P > 0.05) occurred in initial or discoloration color scores because of ZH feeding duration. The enhanced SSM steaks from ZH20 in PVC were brighter red (P < 0.05) than SSM steaks from ZH40 in PVC. The DSM in PVC had less (P < 0.05) pH and paler (P < 0.05) color than the SSM. Display color scores for the DSM of PVC steaks were brighter red (P < 0.05) than the SSM initially (d 0 and 1), but the DSM discolored faster (P < 0.05) than the SSM on d 1 to 3. The SM steaks from steers fed ZH20 or ZH30 were slightly brighter and less discolored during display in PVC than the ZH40 diet. For enhanced steaks in HO-MAP, the DSM of ZH20 and ZH30 diets displayed 4 d and the DSM of ZH20 displayed 5 d was a brighter (P < 0.05) red than the DSM from ZH40. At display d 1 and 5, the SSM of ZH20 steaks in HO-MAP was a brighter (P < 0.05) red than SSM steaks from ZH40. The SSM of ZH40 HO-MAP steaks was darker (P < 0.05) red on d 3 than the SSM from other diets. For enhanced steaks in CO-MAP, ZH30 steaks were brighter (P < 0.05) red than ZH0 or ZH40 steaks on d 0 and 9 of display. Steaks in CO-MAP from all feeding durations were less than 20% discolored through d 9. The DSM was lighter (P < 0.05) than the SSM on d 0 for steaks packaged in HO-MAP and CO-MAP. Feeding cattle ZH for 20 or 30 d will yield steaks with color characteristics equal to or better than steaks from control cattle, whereas feeding ZH for 40 d will likely produce less desirable meat color traits.

Effect of zilpaterol hydrochloride supplementation of beef steers and calf-fed Holstein steers on the color stability of top sirloin butt steaks.

Top sirloin butt steaks were used to determine the effects on color stability of supplementing zilpaterol hydrochloride (ZH) to beef and calf-fed Holstein steers. This study compared the effects of dietary ZH supplementation for 0, 20, 30, or 40 d on feed. One-half of the top sirloin butts were enhanced and packaged in modified-atmosphere packaging (MAP); the remaining one-half were packaged in polyvinylchloride (PVC) film. Beef steaks packaged with PVC from cattle supplemented for 30 d had a tendency (P = 0.07) to produce a redder (a* = 18.31) steak than the control cattle (a* = 17.00) or cattle supplemented for 40 d (a* = 17.05). In beef steaks, ZH had no effect on subjective visual color (P = 0.15 to 0.27) and discoloration (P = 0.10 to 0.59) of steaks packaged with PVC when stratified by day of display, with the exception of visual color on d 5. Beef steaks under MAP from cattle supplemented for 20 d were redder (a* = 19.50, P < 0.05) than those from cattle supplemented for 30 (a* = 18.07) or 40 d (a* = 17.57), but were similar to the control steaks (a* = 18.68). There was no effect (P > 0.05) of retail display day and day of supplementation on objective or subjective color of calf-fed Holstein steaks packaged with PVC. Dietary supplementation for 20 d produced a greater (P < 0.05) b* value on d 1 of display in MAP-packaged steaks from calf-fed Holsteins. If recommending a period of dietary supplementation, 20 to 30 d would be suggested to result in, on average, the brightest, reddest sirloin butt steaks.

Performance and carcass characteristics of different cattle types

Different cattle types were evaluated for growth, feed efficiency, and carcass and meat traits. Hereford (H), Angus (A), Red Poll (RP), Brown Swiss (BS), Gelbvieh (G), Maine Anjou (MA) and Chianina sires were mated artificially to Angus and Hereford cows to obtain different crossbred (X) cattle types. Two calf crops were born in March, April, and May of 1973, and 1974, and weaned when 200 days old. All male calves (787) were castrated, fed out and slaughtered in a commercial plant. Carcasses were graded in the cooler and the right side was transported to KSU for detailed cutout and meat quality evaluations.

Supplementing feedlot steers and heifers withZilmax increases proportions of strip loin,chuck clod, and top sirloin steaks exceedingWarner-Bratzler shear force thresholds,whereas aging moderates this effect

Introduction Ractopamine hydrochloride (Elanco, Greenfield, IN) and Zilmax (zilpaterol hydrochloride; Intervet/Schering-Plough, Millsboro, DE) are β-adrenergic agonists approved in the United States and several other countries to increase growth rate, improve efficiency of feed utilization, and increase carcass meat yield. Zilmax has been shown to improve feed efficiency by 26% and increase hot carcass weight, longissimus muscle area, and meat yield. However, a few studies have shown that Zilmax significantly increased Warner-Bratzler shear force values (decreased tenderness).