Effects of ractopamine hydrochloride on the growth performance and carcass characteristics of heavy-weight finishing pigs sent for slaughter using a 3-phase marketing strategy.

A total of 2,158 crossbred pigs was used to evaluate the effects of feeding 7.4 mg/kg ractopamine hydrochloride (RAC) on the growth performance and carcass characteristics of heavy-weight finishing pigs sent to slaughter using a 3-phase marketing strategy. The study was performed from 121.0 ± 4.28 kg to 144.5 ± 4.73 BW using a randomized complete block design (blocking factor was d of start on test) with 2 treatments (0 vs. 7.4 mg/kg RAC). Pigs were housed in a commercial wean-to-finish facility in groups of approximately 25 (44 groups/treatment), with ad libitum access to feed and water throughout the study, and pen weights of pigs were recorded at the start (d 0), and on d 7, 21, and 35 of study. Pigs were sent for slaughter according to the following marketing strategy: 1) after 7 d on RAC, the heaviest 16% of each pen was sent for slaughter (Phase 1), 2) after 21 d on RAC, the next 40% of each pen was sent for slaughter (Phase 2), and 3) after 35 d on RAC, the remaining 44% of each pen was sent for slaughter (Phase 3). Pigs were selected for slaughter by visual appraisal and shipped to a commercial facility where standard carcass measurements (HCW, LM depth, and backfat depth) were measured. Overall, feeding RAC increased (P < 0.001) ADG (18.8%) and G:F (23.7%) compared to the control, but lowered (P < 0.001) ADFI (3.3%). In addition, feeding RAC increased (P < 0.001) HCW (3.9 kg), carcass yield (0.7% units), LM depth (5.0%), and predicted lean content (1.0% units), and reduced backfat depth (6.3% lower) compared to controls. With each subsequent phase of marketing, the magnitude of improvements in response to feeding RAC decreased for ADG (43.1, 20.9, and -3.1% for Phase 1, 2, and 3, respectively) and G:F (37.5, 25.8, and 6.4% for Phase 1, 2, and 3, respectively); however, improvements in HCW (1.6, 4.5, and 4.2 kg for Phase 1, 2, and 3, respectively), carcass yield (0.2, 0.6, and 0.9% units for Phase 1, 2, and 3, respectively), LM depth (2.3, 5.7, and 5.2% for Phase 1, 2, and 3, respectively), and predicted lean content (0.2, 1.0, and 1.3% units for Phase 1, 2, and 3, respectively) generally increased from feeding RAC. These results suggest that while improvements in growth performance from feeding RAC will generally decline after 21 d of feeding, improvements in carcass traits, particularly carcass yield and lean content, will continue with feeding RAC until d 35.

Effects of dietary ractopamine hydrochloride and zilpaterol hydrochloride supplementation on performance, carcass traits, and carcass cutability in beef steers.

British × Continental steers (initial BW = 484.6 kg) were fed at a commercial feed yard to evaluate the effects of ß-agonists on live performance, carcass characteristics, and carcass subprimal yield. Weights and ultrasonic measurements were used to allocate steers to pens (n = 40) divided equally into 4 blocks, with 2 treatment replicates per block. Pens were randomly assigned to 1 of 5 treatments: control; ractopamine-HCl (RH) fed at 200 or 300 mg • steer(-1) • d(-1), or 400 mg • steer(-1) • d(-1) top dress for the final 30 d of feeding; or zilpaterol-HCl (ZH) fed at 7.5 mg/kg beginning 23 d before slaughter with a 3-d withdrawal period. Steers were harvested by block at a commercial facility over 4 wk. Carcass based performance measures were calculated using initial pen weights and actual DMI. From each pen, eight carcasses that were within ± 13.6 kg of the mean pen HCW were selected such that two carcasses were within each of the following four Yield Grade (YG) ranges: YG ≤ 2.8; 2.9-3.2; 3.3-3.5; YG > 3.5. Carcasses were fabricated by plant personnel to determine subprimal yield. Steers fed ZH had higher carcass-based ADG and carcass-based G:F compared with all other treatments (P < 0.05). Carcass-based ADG and carcass-based G:F were higher in RH treatments compared with controls (P < 0.05). Steers fed ZH had higher dressing percentages (1.0 to 1.6%) and larger LM area (4.3 to 6.7 cm(2)) than all other treatments (P < 0.05). Use of RH 400 and ZH increased HCW 6.3 and 11.1 kg, respectively compared with controls (P < 0.05). Compared with controls, RH 300 and ZH decreased marbling score and the frequency of carcasses qualifying for upper 2/3 Choice premiums (P < 0.05). Beta-agonists increased subprimal yield from the round and loin; however, blade meat was the only cut from the rib or chuck affected by ß-agonists. Results from this study indicated improvements in performance and carcass traits as a result of ß-agonist use; however, differences between ZH, RH 400, and RH 300 treatments were minimal for carcass traits and cutability. Increases in saleable yield following ß-agonist use were not uniformly distributed across the four major primals and the majority of weight gain occurred in the lower priced cuts of the round and chuck. Increased response of the lower priced cuts to ß-agonists could have economic implications to packers.

Effects of ractopamine hydrochloride and zilpaterol hydrochloride supplementation on longissimus muscle shear force and sensory attributes of beef steers.

Effect of ractopamine hydrochloride (RH) and zilpaterol hydrochloride (ZH) on LM shear force and sensory attributes was determined using pens (n = 40) British × Continental crossbred steers randomly allocated to one of the following treatments: control; RH fed at 200 (RH 200) or 300 mg • steer(-1) • d(-1) (RH 300), or 400 mg • steer(-1) • d(-1) (RH 400) top-dressed for the final 30 d of feeding; or ZH fed at 7.5 mg/kg, beginning 23 d before slaughter with a 3-d withdrawal. Two replicates (pens) per treatment were represented in four blocks. Eighteen carcasses per pen were randomly selected and one 5-cm LM sample was removed from both carcass sides to be used for shear force and sensory evaluation. Samples were aged for 14 d, frozen at -28.8 °C, and cut into 2.5-cm steaks. All steaks were cooked to an internal temperature of 71.1 °C before being evaluated for Warner-Bratzler shear force (WBSF), slice shear force (SSF), or being fed to trained sensory panelists. Increasing dose and potency of ß-agonist increased WBSF by 4 to 17% and SSF by 5 to 24% (P < 0.05). Steaks from steers fed ZH had higher WBSF and SSF values compared with all other treatments (P < 0.05), whereas steaks from controls and steers fed RH 200 were not different (P > 0.05). Probability of steaks failing to meet shear force standards to be certified tender (WBSF <4.4 kg, SSF < 20 kg) was increased from an initial probability of <0.06 in steaks from steers in the control treatment to 0.10 to 0.20 in steers fed RH 400 or ZH (P < 0.05). No difference was detected in panel ratings for overall tenderness of steaks from steers fed RH 200 compared with controls (P > 0.05). Steaks from steers fed RH 300 and RH 400 were comparable for all sensory attributes; however, both RH 300 and RH 400 were rated lower for overall tenderness than controls (P < 0.05). Panelists failed to detect differences in overall tenderness of steaks from steers fed RH 400 and ZH (P < 0.05). Panelists detected no difference in flavor profile or juiciness among treatments (P > 0.05). Results from this study indicated ß-agonists negatively affected beef tenderness and these effects may be more noticeable in steers supplemented with ZH and higher doses of RH.

Toxic effect of chemotherapy dosing using actual body weight in obese versus normal-weight patients: a systematic review and meta-analysis.

BACKGROUND: Many oncologists reduce chemotherapy doses in obese patients due to fear of excess toxic effect from very large weight-based calculations. While recent guidelines advise against this practice, quantitative summarization of the supporting evidence is not available. MATERIALS AND METHODS: We systematically identified studies that compared toxic effect or survival outcomes between obese and normal-weight adults receiving chemotherapy dosed by actual body weight (ABW). We pooled odds ratios (OR) and 95% confidence intervals (CI) using random-effects models. RESULTS: Of 5490 records screened, 12 studies representing 9314 relevant patients met inclusion criteria. The large majority of reported toxic effect and survival outcomes did not statistically differ between obese and normal-weight subjects. Exceptions included five studies in which one or more toxic effect or survival outcomes statistically favored obese patients, and one study that statistically favored normal-weight patients. Pooling usable data, rates of toxic effects were similar or lower in obese patients (grade 3/4 hematologic toxic effect: OR 0.73, CI 0.55-0.98, 4 studies; grade 3/4 nonhematologic toxic effect: OR 0.98, CI 0.76-1.26, 3 subgroups; any grade 3/4 toxic effect: OR 0.75, CI 0.65-0.87, three studies). CONCLUSIONS: Obese patients receiving chemotherapy based on ABW experience similar or lower rates of toxic effects compared with normal-weight patients, and survival outcomes do not differ.

Physical, chemical, and histological characteristics of 18 lamb muscles.

Muscles (n=18) were dissected from each side of 20 lamb carcasses to characterize physical, chemical, and histological traits. Muscles from the right sides were used to measure color values, expressible moisture, pH, total collagen content, and sarcomere length. Muscles from the left sides were aged for 7d and used to determine Warner-Bratzler shear (WBS) force values. The M. adductor and M. semimembranosus had the darkest colored lean (lowest L(∗) values), whereas the M. latissimus dorsi and M. tensor fasciae latae had the lightest colored lean (highest L(∗) values). The M. triceps brachii, M. pectoralis profundus, and M. latissimus dorsi had among the lowest numerical expressible moistures whereas the M. adductor and the M. longissimus lumborum had among the highest. The M. infraspinatus was found to have the highest collagen content (9.0mg/g) and the M. psoas major had the longest sarcomere length (3.1µm). Of the muscles sampled, the M. serratus ventralis had one the lowest WBS values (21.8N) and the M. semimembranosus the highest (42.6N). On average, the largest muscles identified were the M. gluteobiceps, M. gluteus medius, M. longissimus lumborum, M. longissimus thoracis, and M. semimembranosus, which would likely be suitable in terms of physical dimensions for used in a variety of individual muscle applications. Other muscles, however, such as the M. teres major and M. tensor fasciae latae, may be too small in size and dimension to be used for individual application.

In-home consumer evaluations of individual muscles from beef rounds subjected to tenderization treatments.

In-home evaluations of the M. vastus lateralis, M. rectus femoris, M. semimembranosus, and M. adductor (n=266) muscles that were either blade tenderized, enhanced with a salt and phosphate solution, or served as a control (no tenderization or enhancement treatment) were conducted. Consumers (n=261) cooked these steaks and were asked to document cooking method and degree of doneness, and provide palatability ratings for each steak. Enhancing round muscles with a salt and phosphate solution improved most palatability traits compared to blade tenderized or control steaks. For M. semimembranosus and M. vastus lateralis, the enhanced steaks received higher (P<0.05) ratings for all palatability traits. Cooking method and degree of doneness had little influence on consumer palatability ratings, and where differences occurred, they were muscle specific. This may allow limited recommendations for the most appropriate cooking method and degree of doneness for specific beef round muscles.

Benchmarking value in the pork supply chain: Characterization of US pork in the retail marketplace.

Retail pork from eight US cities was obtained for quality and palatability evaluations. Boneless pork loin chops were classified into one of three quality categories - "high," "average," or "low" - with higher quality chops possessing more desirable color, marbling, juiciness, and shear force characteristics than lower quality chops. Loin chops that were enhanced (injected with solution to improve juiciness and/or tenderness) had higher (P<0.05) pH, less purge and cook loss, and higher palatability ratings compared to non-enhanced chops. Hams compared by their protein fat free (PFF) classifications showed that ham and water product received the highest (P<0.05) ratings for juiciness and tenderness, and ham with natural juices received the highest (P<0.05) texture, ham flavor intensity, and smoke flavor ratings. Bacon was compared by price/brand categories; however, the highest priced, national branded bacon (US$12.03/kg) was similar (P>0.05) for most quality and all palatability traits to the lowest priced, national branded bacon (US$6.47/kg) and the store branded bacon (US$8.30/kg) even though retail prices differed widely. Overall, there were tremendous ranges in values for these products indicating that retail pork is quite variable and that efforts to improve the quality and consistency of it must continue.

Benchmarking value in the pork supply chain: Processing and consumer characteristics of hams manufactured from different quality raw materials.

Impact of fresh ham quality on finished ham product characteristics was evaluated. Bone-in hams destined for spiral-sliced ham manufacturing were sorted into two pH groups before processing: pH⩽5.5 and pH⩾5.6. For boneless hams, raw materials were sorted into groups with different levels of pale, soft, and exudative (PSE) product before manufacturing into sliced vacuum packaged hams: "Low PSE" (⩽5% PSE muscle), "Intermediate PSE" (20-30% PSE muscle) or "High PSE" (40-60% PSE muscle). Few differences were observed between the pH⩽5.5 and pH⩾5.6 groups in objective color measures and drip loss in bone-in spiral-sliced hams stored under refrigeration, however, after frozen storage, hams from the pH⩽5.5 group had lower L*- and a*-values and had much higher drip loss than those from the pH⩾5.6 group. Processing yields for bone-in spiral-sliced hams were similar through cooking and chilling, however, the pH⩾5.6 group had higher yields after slicing. For boneless hams, defects occurred at a greater frequency in hams formulated with a greater percentage of PSE raw materials than those with lower amounts of PSE. Differences in objective color measures and purge were minimal over the duration of storage time, but hams formulated with greater percentages of PSE raw materials were lighter in appearance and had less redness. Consumers gave lower color responses for hams formulated with "High PSE" amounts, but did not differentiate between hams manufactured with lower quantities of PSE muscle. However, when consumers directly compared packages of ham, there was distinct discrimination against hams manufactured with greater amounts of PSE. Purchase intent showed that consumers favored ham manufactured from fresh ham muscles containing low quantities of PSE tissue. Further research is needed to determine the optimal ratio of allowable PSE product in formulation that enables processors to maximize consumer appeal with the economic realities of sorting out PSE pork.

Benchmarking value in the pork supply chain: Processing characteristics and consumer evaluations of pork bellies of different thicknesses when manufactured into bacon.

Impact of belly thickness on processing yields and consumer evaluations of finished bacon products was measured. Before processing through a commercial facility, pork bellies (n=96 per group) were sorted into three target thickness groups: "thin" (approximately 2.0cm); "average" (approximately 2.5cm); "thick" (approximately 3.0cm). Processing yields at various production points were recorded and samples from each thickness group were evaluated by consumers for palatability characteristics and visual appearance. Bacon manufactured using "thick" bellies had the highest processing yields through the smoking and cooking phase. "Thin" bellies had the lowest slicing yields and generated the highest percentage of less valuable "#2 slices" (slice profile less than 1.9cm at any point) and "ends and pieces." Consumers found that bacon manufactured from "average" thickness bellies did not have deficiencies in palatability characteristics, but bacon manufactured from "thin" bellies lacked crispiness and bacon manufactured from "thick" bellies lacked flavor. Consumers found the lean-to-fat ratio and the visual appearance of bacon from "thick" bellies was less appealing than bacon from "thin" and "thick" bellies. Moreover, consumers showed much stronger purchase intent for bacon from "thin" and "average" bellies. Belly thickness impacted processing yield and consumer palatability evaluations of bacon. Producers need to minimize production of "thin" bellies because of reduced processing yields and "thick" bellies because of reduced consumer appeal.

Biochemical and physical factors affecting discoloration characteristics of 19 bovine muscles.

Steaks from muscles (n=19 from nine beef carcasses) were evaluated over the course of retail display (0-, 1-, 2-, 3-, 4- or 5-d) for objective measures of discoloration (metmyoglobin, oxymyoglobin, L*-, a*-, and b*-values), reducing ability (metmyoglobin reductase activity (MRA), resistance to induced metmyoglobin formation (RIMF), and nitric oxide metmyoglobin reducing ability (NORA)), oxygen consumption rate (OCR), oxygen penetration depth, myoglobin content, oxidative rancidity, and pH. Muscles were grouped according to objective color measures of discoloration. M. longissimus lumborum, M. longissimus thoracis, M. semitendinosus, and M. tensor fasciae latae were grouped as "high" color stability muscles, M. semimembranosus, M. rectus femoris, and M. vastus lateralis were grouped as "moderate" color stability muscles, M. trapezius, M. gluteus medius, and M. latissimus dorsi were grouped as "intermediate" color stability muscles, M. triceps brachi - long head, M. biceps femoris, M. pectoralis profundus, M. adductor, M. triceps brachi - lateral head, and M. serratus ventralis were grouped as "low" color stability muscles, and M. supraspinatus, M. infraspinatus, and M. psoas major were grouped as "very low" color stability muscles. Generally, muscles of high color stability had high RIMF, nitric oxide reducing ability, and oxygen penetration depth and possessed low OCRs, myoglobin content, and oxidative rancidity. In contrast, muscles of low color stability had high MRA, OCRs, myoglobin content, and oxidative rancidity and low RIMF, NORA, and oxygen penetration depth. Data indicate that discoloration differences between muscles are related to the amount of reducing activity relative to the OCR.

Influence of feeding vitamin D(3) and aging on the tenderness of four lamb muscles.

In Trial 1, rams (n=26) were fed different levels (0, 250,000, 500,000 or 750,000 IU) of vitamin D(3) for 4 days to determine the most effective dose to increase blood calcium concentrations. Trial 2 consisted of feeding feedlot lambs (n=40) different levels (0 or 750,000 IU) of vitamin D(3) for 14 days to determine if vitamin D(3) could improve the tenderness of lamb muscles. Lambs were slaughtered and the M. longissimus lumborum, M. biceps femoris, M. semitendinosus, and M. semimembranosus were removed after chilling, cut into chops, and assigned to an aging period (5, 10 or 15 days) for Warner-Bratzler shear force (WBS) determination. In Trial 1, feed intake and weight gain were lower for rams supplemented with 500,000 IU of vitamin D(3) compared to all other groups. Blood calcium concentrations were not different between groups, although the 750,000 IU group tended (P<0.10) to have higher blood calcium concentrations on day 5 of the trial compared to controls. In Trial 2, blood calcium concentrations were not different between the treated and control groups, however, treated lambs had higher (P<0.01) calcium concentrations in both the liver and kidneys. Control chops from the M. longissimus lumborum had lower (P<0.05) WBS values than chops from vitamin D(3) fed lambs, but no other muscles were affected by vitamin D(3) feeding. An interaction between treatment and aging was observed for the M. biceps femoris, with chops from vitamin D(3) fed lambs having lower WBS values at 5 days aging, but chops from control lambs having lower WBS values at 15 days aging. WBS values decreased for the M. longissimus lumborum, M. semitendinosus, and M. semimembranosus with increasing aging time. Vitamin D(3) supplementation was not an effective means of improving the tenderness characteristics of lamb muscles.

Methods to increase tenderness of individual muscles from beef rounds when cooked with dry or moist heat.

Muscles (n=9) from beef rounds (n=40) were subjected to one of the four tenderization strategies: control, blade tenderization, enzymatic tenderization or salt/phosphate injection. Treated muscles were aged, cut into steaks, cooked using one of the two cooking methods (dry-heat or moist-heat), and Warner-Bratzler shear (WBS) force values were determined. For dry-heat cookery, injection with a salt and phosphate solution resulted in the lowest WBS values, however, WBS values for blade tenderization and enzymatic tenderization were comparable in the M. adductor, M. vastus lateralis, M. rectus femoris, and M. semimembranosus (cranial and caudal aspects). The M. gluteobiceps (cranial and caudal aspects, and ischiatic head) and M. semitendinosus showed little improvement in WBS values with any of the tenderization treatments. For moist-heat cookery, only the M. rectus femoris and M. semimembranosus, caudal aspect, showed significant decreases in WBS values, and those improvements were only associated with salt and phosphate injection and enzymatic tenderization. Within each cooking method and tenderization treatment, the M. rectus femoris, M. semimembranosus, cranial aspect had the lowest WBS values, whereas the M. gluteobiceps, ischiatic head and M. semimembranosus typically had the highest WBS values. All tenderization strategies increased the frequency of muscles being rated as "very tender" (WBS<31.4 N) and "tender" (31.4 N

Comparison of clam-shell cookers and electric broilers and their effects on cooking traits and repeatability of Warner-Bratzler shear force values.

Clam-shell (CS) type cookers were investigated as an alternative cookery method for objective tenderness evaluations of beef strip loin steaks. This study was conducted in two phases: Phase I determined the most effective clam-shell cooking temperature setting (Low, Medium or High) and Phase II compared the repeatabilities of cooking traits and Warner-Bratzler shear (WBS) values from steaks cooked on electric broilers (EB) to steaks cooked on CS. Data from Phase I showed that cooking time was reduced (P<0.05) substantially for steaks cooked on CS with the shortest cooking times associated with the highest temperature settings. EB steaks had higher cooking losses compared with CS steaks (P<0.05), while the CS-Low temperature setting yielded the lowest cooking losses. WBS values did not differ except for steaks cooked on the CS-Medium setting, which were lower (P<0.05) than EB and CS-Low cooked steaks. CS-High setting was determined to be the optimum temperature setting for CS cooking because it required the least amount of time to cook and produced WBS values that were not different from steaks cooked on EB. Therefore, repeatability of cooking traits and WBS values of CS-High and EB were investigated in Phase II. Data from Phase II showed similar trends for cooking traits and WBS values between CS and EB cooked steaks as were observed in Phase I. Repeatabilities for WBS values were higher for steaks cooked on CS (R=0.86) compared with EB (R=0.41). The CS method appears to be an acceptable alternative to EB for cooking steaks used in meat tenderness research.

Interrelationships of breed type, USDA quality grade, cooking method, and degree of doneness on consumer evaluations of beef in Dallas and San Antonio, Texas, USA.

The objective of this research was to evaluate the consumer controlled factors of cooking method and degree of doneness on top loin steaks from different USDA quality grades (Low Choice, High Select or Low Select) and breed-types (English, Continental European Cross or Brahman Cross). In addition, cities within the same region were evaluated for differences in consumer controlled factors and palatability responses. The in-home product test was conducted in Dallas and San Antonio, Texas, USA. Consumers (n=173) evaluated steaks for overall like (OSAT), tenderness (TEND), juiciness (JUIC), and flavor (FLAV) using 23-point hedonic scales. Respondents in Dallas cooked their steaks to higher degrees of doneness than did those in San Antonio. Outdoor grilling was the most frequently used method of cookery for steaks in both cities. Generally, consumers in San Antonio gave higher palatability ratings to Choice steaks and Dallas consumers gave higher ratings to Select steaks. The interactions of city×cooking method, breed-type×cooking method, and degree of doneness×cooking method were significant for all palatability attributes. In addition, the interaction of cooking method×quality grade was significant for TEND, JUIC, and FLAV. Warner-Bratzler shear (WBS) force was determined on a steak from each strip loin. Steaks from Continental European Cross cattle and Low Choice carcasses had the lowest WBS values. Differences in consumer preparation of beef top loin steaks present very unique challenges for the beef industry. Consumer information programs may serve a valuable role in connecting consumer perceptions with the preparation techniques needed to consistently achieve satisfaction.

Retail yields from beef chuck and round subprimals from two grade groups when merchandised as single muscle cuts.

Beef subprimals from two different grade groups were obtained from two beef processors to assist in updating the Beef Computer Assisted Retail Decision Support (CARDS) program with new fabrication styles. The grade groups consisted of Top Choice (containing subprimals from carcasses with a Modest or Moderate degree of marbling) and Select (containing subprimals from carcasses with a Slight degree of marbling). Subprimals (shoulder clod; top blade, roast; arm roast; knuckle, peeled; outside round, flat) were separated into individual muscles and fabricated into retail cuts by professional retail meat cutters. Mean retail cutting yields and labor requirements were calculated from observed weights (kilograms) and processing times (seconds). Data were analyzed to determine means and standard errors of percentage yield and processing times for subprimals in each grade group, and comparisons were made between grade groups. Generally, there were few differences in processing times between Top Choice and Select subprimals, and the trimming phase required the most time to complete for each subprimal. Differences (P < 0.05) were observed in saleable yield between Top Choice and Select subprimals for the shoulder clod (Top Choice = 73.89%; Select = 78.49%), top blade, roast (Top Choice = 84.36%; Select = 86.70%), and outside round, flat (Top Choice = 85.99%; Select = 91.34%). Trimmable fat differed (P < 0.05) between Top Choice and Select subprimals: shoulder clod (Top Choice = 25.30%; Select = 20.85%), top blade, roast (Top Choice = 14.88%; Select = 12.59%), arm roast (Top Choice = 8.35%; Select = 7.47%), knuckle (Top Choice = 5.72%; Select = 2.73%), and outside round, flat (Top Choice = 13.82%; Select = 7.26%). Most of the differences in saleable yields were related to less trimmable fat for Select subprimals, which also required less trimming time than Top Choice subprimals. These data will serve to update the Beef CARDS program and will provide retailers and foodservice operators with third-party cutting yield and time allocation information.

Warner-Bratzler shear evaluations of 40 bovine muscles.

Forty muscles from each of 20 beef carcass sides were used to perform Warner-Bratzler shear (WBS) force determinations for within and among muscle effects. The M. triceps brachii differed (P <0.05) in WBS values between the caput longum and caput laterale, and the M. gluteobiceps differed (P <0.05) in WBS values between the vertebral, cranial, and caudal portions. The M. trapezius did not differ between the pars cervicalis and pars thoracica. Larger muscles were evaluated for location effects within muscles. The M. pectoralis profundus, M. infraspinatus, M. triceps brachii (caput longum), psoas major, and M. semimembranosus all had significant location effects. Muscles were allocated into "very tender," "tender," "intermediate" or "tough" categories. Those muscles considered "very tender" (WBS <3.2 kg) were the diaphragm (outside skirt or wing of diaphragm), M. spinalis, M. infraspinatus, M. iliacus, M. psoas major, M. serratus ventralis, M. biceps brachii, M. obliquus internus abdominis, and M. vastus medius. Muscles considered "tender" (3.2 kg 4.6 kg) were the M. extensor carpi radialis, M. trapezius, M. brachialis, M. pectoralis profundus, and M. flexor digitorum superficialis (hind limb). The diaphragm muscle was the most tender (WBS=2.03 kg), and the M. flexor digitorum superficialis was the toughest (WBS=7.74 kg). Tenderness, as measured by WBS, varied among and within bovine muscles, and knowledge of this variation allows for more appropriate use for specific purposes in the marketplace.

National Beef Quality Audit-2000: survey of targeted cattle and carcass characteristics related to quality, quantity, and value of fed steers and heifers.

The National Beef Quality Audit-2000 was conducted to assess the current status ofthe quality and consistency of U.S. fed steers and heifers. Between May and November 2000, survey teams assessed hide condition (n = 43,415 cattle for color, brands, mud/manure), bruises (n = 43,595 carcasses), offal and carcass condemnation (n = 8,588 cattle), and carcass quality and yield information (n = 9,396 carcasses) in 30 U.S. beef packing plants. Hide colors were black (45.1%), red (31.0%), yellow (8.0%), Holstein (5.7%), gray (4.0%), white (3.2%), brown (1.7%), and brindle (1.3%). Brand frequencies were no (49.3%), one (46.2%), and two or more (4.4%), and brands were located on the butt (36.3%), side (13.7%), and shoulder (3.6%). Most cattle had no (18.0%) or a small amount (55.8%) of mud/manure on their hides, and they had no (77.3%) horns. Most carcasses (53.3%) were not bruised, 30.9% had one bruise, and 15.8% had multiple bruises. Bruise location and incidence were round (14.9%), loin (25.9%), rib (19.4%), chuck (28.2%), and brisket, flank, and plate (11.6%). Condemnation item and incidence were liver (30.3%), lungs (13.8%), tripe (11.6%), heads (6.2%), tongues (7.0%), and carcasses (0.1%). Carcass evaluation revealed these traits and frequencies: steer (67.9%), heifer (31.8%), and bullock (0.3%) sex-classes; dark-cutters (2.3%); A (96.6%), B (2.5%), and C or older (0.9%) overall maturities; and native (90.1%), dairy-type (6.9%), and Bos indicus (3.0%) breed-types. Mean USDA yield grade traits were USDA yield grade (3.0), carcass weight (356.9 kg), adjusted fat thickness (1.2 cm), longissimus muscle area (84.5 cm2), and kidney, pelvic, and heart fat (2.4%). USDA yield grades were Yield Grade 1 (12.2%), Yield Grade 2 (37.4%), Yield Grade 3 (38.6%), Yield Grade 4 (10.4%), and Yield Grade 5 (1.3%). Mean USDA quality grade traits were USDA quality grade (Select85), marbling score (Small23), overall maturity (A66), lean maturity (A65), and skeletal maturity (A67). Marbling score distribution was Slightly Abundant or higher (2.3%), Moderate (4.8%), Modest (13.1%), Small (33.3%), Slight (43.3%), and Traces (3.4%). USDA quality grades were Prime (2.0%), Choice (49.1%), Select (42.3%), Standard (5.6%), and Commercial, Utility, Cutter, and Canner (0.9%). This information will help the beef industry measure progress compared to the past two surveys and will provide a benchmark for future educational and research activities.