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1.
Retail cutting tests were conducted on subprimals from cattle fed zilpaterol hydrochloride (ZH) to determine if the improved carcass composition and red meat yield resulting from ZH feeding would translate into increased retail yields of ready-to-cook products. As part of a 3-phase study, selection of carcasses from Holstein steers was done once (fall 2008), followed by the collection of carcasses from beef-type steers on 2 separate occasions (beef study I: summer 2009; beef study II: spring 2010). Each of the 3 groups of steers was assigned previously to 1 of 2 treatments, treated (fed 8.3 mg/kg of ZH for 20 d) or control (not fed ZH). All steers were slaughtered and carcasses were fabricated in commercial beef-processing establishments. Only those carcasses grading USDA Choice or higher were used. Five subprimals were used for both the calf-fed Holstein study (n = 546 subprimals) and beef study I (n = 576 subprimals): beef chuck, chuck roll; beef chuck, shoulder clod; beef round, sirloin tip (knuckle), peeled; beef round, top round; and beef round, outside round (flat). Seven subprimals were used in beef study II (n = 138 subprimals): beef chuck, chuck roll; beef round, sirloin tip (knuckle), peeled; beef round, top round; beef round, eye of round; beef loin, strip loin, boneless; beef loin, top sirloin butt, boneless; and beef loin, tenderloin. A simulated retail market environment was created, and 3 retail meat merchandisers prepared retail cuts from each subprimal so salable yields and processing times could be obtained. Differences in salable yields were found for the calf-fed Holstein steer chuck rolls (96.54% for ZH vs. 95.71% for control; P = 0.0045) and calf-fed Holstein steer top rounds (91.30% for ZH vs. 90.18% for control; P = 0.0469). However, other than heavier subprimals and an increased number of retail cuts obtained, total salable yields measured on a percentage basis and processing times were mostly unaffected by ZH. Cutability advantages of feeding ZH are achieved primarily in the carcass-to-subprimal conversion rather than in the subprimal-to-retail conversion.  相似文献   

2.
Fifty-six retail stores representing 15 retail chains and 14 foodservice facilities in eight U.S. cities were sampled to determine the tenderness of beef steaks at retail and foodservice levels based on Warner-Bratzler shear (WBS) values and consumer evaluation panels. Retail consumer panels were conducted at five universities. Each retail and foodservice steak was evaluated using 10-point scales. Steaks were divided into the following quality groups for statistical analysis: Prime, Top Choice, Choice, Select, and Lean or No Roll. Quality group had no effect on WBS values of retail clod, chuck roll, top round, bottom round, eye of round, top loin, top sirloin, or ribeye steaks but did (P < .05) affect values for the T-bone/porterhouse. The percentages of retail top round, eye of round, and bottom round steaks with a WBS force > 3.9 kg were 39.6, 55.9, and 68.0, respectively. Foodservice ribeye, top loin, and top sirloin steaks had WBS values less than 3.4 kg for all quality groups, with Prime ribeye steaks having lower (P < .05) WBS values than ribeyes from the other quality groups. With the exception of the retail ribeye steak, quality group did not affect consumer sensory ratings of retail and foodservice steaks. Average postfabrication aging times were 32 d for foodservice subprimals and 19 d for retail cut subprimals. These data indicate that improvements in the tenderness of retail cuts from the round are needed. Finally, quality group had little or no effect on consumer sensory evaluations and WBS values of retail and foodservice steaks used in this study.  相似文献   

3.
An in-home beef study evaluated consumer ratings of clod steaks (n = 1,264) as influenced by USDA quality grade (Top Choice, Low Choice, High Select, and Low Select), city (Chicago and Philadelphia), consumer segment (Beef Loyals, who are heavy consumers of beef; Budget Rotators, who are cost-driven and split meat consumption between beef and chicken; and Variety Rotators, who have higher incomes and education and split their meat consumption among beef, poultry, and other foods), degree of doneness, and cooking method. Consumers evaluated each steak for Overall Like, Tenderness, Juiciness, Flavor Like, and Flavor Amount using 10-point scales. Grilling was the predominant cooking method used, and steaks were cooked to medium-well and greater degrees of doneness. Interactions existed involving the consumer-controlled factors of degree of doneness and(or) cooking method for all consumer-evaluated traits for the clod steak (P < 0.05). USDA grade did not affect any consumer evaluation traits or Warner-Bratzler shear force values (P > 0.05). One significant main effect, segment (P = 0.006), and one significant interaction, cooking method x city (P = 0.0407), existed for Overall Like ratings. Consumers in the Beef Loyals segment rated clod steaks higher in Overall Like than the other segments. Consumers in Chicago tended to give more uniform Overall Like ratings to clod steaks cooked by various methods; however, consumers in Philadelphia gave among the highest ratings to clod steaks that were fried and among the lowest to those that were grilled. Additionally, although clod steaks that were fried were given generally high ratings by consumers in Philadelphia, consumers in Chicago rated clod steaks cooked in this manner significantly lower than those in Philadelphia. Conversely, consumers in Chicago rated clod steaks that were grilled significantly higher than consumers in Philadelphia. Correlation and stepwise regression analyses indicated that Flavor Like was driving customer satisfaction of the clod steak. Flavor Like was the sensory trait most highly correlated to Overall Like, followed by Tenderness, Flavor Amount, and Juiciness. Flavor Like was the first variable to enter into the stepwise regression equation for predicting Overall Like, followed by Tenderness and Flavor Amount. For the clod steak, it is likely that preparation techniques that improve flavor without reducing tenderness positively affect customer satisfaction.  相似文献   

4.
Beef carcasses (n = 150) of A-maturity were selected randomly to determine baseline shear force and sensory panel ratings, assess variation in tenderness, and evaluate mean value differences between Certified Angus Beef (CAB), commodity Choice, and Select steaks. Three steaks were removed from the triceps brachii (TB), longissimus lumborum (LL), gluteus medius (GM), semimembranosus (SM), biceps femoris (BF), and quadriceps femoris complex (QF), and assigned to Warner-Bratzler shear (WBSF) and sensory panel analyses. As anticipated, marbling score and measured percentage of i.m. fat were greatest (P < 0.05) for CAB, intermediate (P < 0.05) for Choice, and least (P < 0.05) for Select carcasses. A muscle x quality level interaction (P < 0.05) was observed for WBSF values and sensory panel tenderness ratings. The TB, LL, GM, and BF steaks from CAB carcasses had lower (P < 0.05) WBSF than Select steaks from the same muscles. Even though WBSF values did not differ (P > 0.05) between CAB and Choice QF and TB steaks, the LL and GM steaks from CAB carcasses were more tender (P < 0.05) than Choice-grade LL and GM steaks. The TB from Select carcasses had higher (P < 0.05) WBSF values than TB steaks from CAB or Choice carcasses, but sensory panel ratings indicated that quality level showed little consistency among the GM, SM, BF, and QF. Trained sensory panelists rated CAB LL steaks more tender (P < 0.05) than LL steaks from Choice and Select carcasses, and Choice LL steaks were evaluated as more (P < 0.05) tender than those from Select carcasses. These results demonstrate that the influence of marbling on tenderness was more evident in muscles of middle meats than in end cuts, particularly in muscles of the round.  相似文献   

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7.
An audit of supermarkets in eight U.S. cities was conducted to characterize retail beef loin steaks with respect to grade, postfabrication aging, and tenderness and to provide an interim measure of progress in industry efforts to improve retail beef tenderness. Top sirloin steaks (n = 819) and strip loin steaks (n = 827 paired steaks) were purchased at retail markets in Atlanta, Chicago, Denver, Houston, Philadelphia, Phoenix, San Francisco, and Seattle and shipped to Colorado State University for measurement of shear force (both cut types) and evaluation by a trained sensory panel (strip loins only). Approximately 80% of the steaks originated from beef plants in Kansas, Texas, Nebraska, and Colorado. Postfabrication aging periods ranged from 2 to 87 d (mean = 20.8 d) for top sirloin steaks and from 2 to 91 d (mean = 19.2 d) for strip loin steaks, although most top sirloin (85%) and strip loin (91%) steaks were available for purchase 7 to 35 d after fabrication. The mix of quality grades was similar for both cuts: 60% Select, 31% "commodity" Choice, 6 to 7% "Certified" Choice, and 2 to 3% Prime. Shear force averaged 3.46 kg (SD = .74) for top sirloins and 3.05 kg (SD = .95) for strip loins; 75% of both steak types had shear force values between 2 and 4 kg. Postfabrication periods shorter than 7 d were associated with reduced (P < .05) tenderness, especially for top sirloin steaks. Higher quality grades were associated with greater (P < .05) tenderness (Prime > Choice > Select) for both cuts. Based on panel tenderness ratings, the approximate odds of obtaining a "slightly tough" or tougher strip loin steak at a retail supermarket were: 0 for Prime, 1 in 10 for "Certified" Choice, 1 in 5 for "commodity" Choice, and 1 in 4 for Select. Audit results suggest that tenderness characteristics of loin steaks have not changed materially since the National Beef Tenderness Survey was conducted in 1991 and that two primary focal points of the beef industry's efforts to improve tenderness should be 1) to prevent short-aged (< 7 d postfabrication) product from reaching consumers and 2) to identify methods for enhancing tenderness of Select and "commodity" Choice beef.  相似文献   

8.
Inactive myostatin (one or two copies) results in increased muscularity, increased yield of closely trimmed retail product, reduced fat content, increased lean growth efficiency, reduced quality grade, increased birth weight, and increased dystocia. Even though one or two copies of inactive myostatin reduces quality grade or marbling compared to zero copies, there is no decrease in meat tenderness. It may be possible to use mating systems to make the most of the advantages of inactive myostatin while minimizing the disadvantages. The objective of this study was to develop a method to compare mating systems among genotypes at the myostatin locus. Economic variables that influence the profitability of alternative mating systems are prices per unit of retail product for USDA quality grades Standard, Select, and Choice; cost of an assisted calving; and cost of genotyping. Because of variation in both economic variables and biological parameters, a single mating system is not expected to universally maximize profit. We identified seven mating systems that each yield maximum profit for different combinations of values for biological parameters and economic variables. Use of inactive myostatin was profitable as long as the price for Select was at least 80% of the Choice price and the price for Standard at least 60%. As the price for Select and Standard increase up to the Choice price, mating systems that produce a higher proportion of inactive myostatin alleles become more profitable. Profitable use of inactive myostatin depends either on retaining ownership of beef until it is fabricated into retail product or the development of specialty markets that place greater value on lean yield and less on marbling, unlike conventional U. S. markets.  相似文献   

9.
The preferential sites of infection of Cysticercus bovis were evaluated in the skeletal muscle and entrails of 25 cattle that were experimentally infected with Taenia saginata (2 × 104 eggs). Two other animals were not inoculated (control). Ninety days after inoculation, all the cattle were euthanized. The carcasses were deboned and dissected into 26 anatomical sections (masseter muscles, brain, tongue, esophagus, heart, diaphragm, lungs, liver, kidneys, spleen, top sirloin butt, bottom sirloin butt, outside round, top (inside) round, transversus abdominus, top sirloin cap, strip loin, full tenderloin, eye of round, knuckle, shoulder clod, foreshank, shank, chuck, back ribs, and tail muscles). The dissected tissues were sliced into 5 mm sections. From the 25 cattle, 9258 C. bovis (cysticerci) were recovered; 75.02% (6946) of these were recovered from skeletal muscles and 24.98% (2312) from the entrails. A high parasitism level was found in the shoulder clod (12.55%), heart (11.02%), liver (9.48%), masseter muscles (8.51%), chuck (8.25%), strip loin and full tenderloin (7.26%), knuckle (6.63%), and back ribs (5.53%), totaling 69.23% (5738) of all of the detected cysticerci. On the other hand, there was a low C. bovis parasitism level in the brain, spleen, tail muscles, kidneys, esophagus, and diaphragm, representing just 3.9% of the total number of cysticerci. Given these results, we conclude that specific skeletal musculature regions, such as the shoulder blade, chuck, strip loin and full tenderloin, knuckle, back ribs and top round, which are not officially examined in many countries, are effective sites to efficiently screen C. bovis infection. To date, these regions have not been considered as preferential sites of C. bovis infection. Based on our work, however, these regions deserve greater attention from health inspectors because they contained a greater number of Cysticercus than the other regions of carcasses that are parasitized by T. saginata larvae.  相似文献   

10.
Beef carcasses (129 steers and 80 heifers) differing in weight, muscling, fatness and marbling score were selected to represent the full spectrum of USDA yield grades; one side was fabricated into boneless primal cuts. Primals were trimmed of all external fat and intermuscular (seam) fat and all components were weighed. Regression equations were developed to predict the percentage of seam fat on an external fat-free primal basis using USDA yield grade (YG), marbling score and a squared function of YG as the independent variables. YG (.77) and marbling score (.67) were highly correlated to seam fat. Heifers tended to have a higher predicted percentage of seam fat than did steers across all YG. Primals from USDA Choice carcasses had approximately 1.0 percentage point more predicted seam fat than did USDA Select primals at the same YG and sex-class. The YG 2.5 heifers had similar proportions of predicted seam fat from primals as YG 3.5 steers, but YG 3.5 heifers tended to have more seam fat than YG 4.5 steers. The same trend was noted between YG 4.5 heifers and YG 5.5 steers, indicating a sex-related deposition of seam fat in fed cattle.  相似文献   

11.
The objective of this research was to evaluate the consumer-controlled factors of cooking method and degree of doneness on Top Choice, Low Choice, High Select, and Low Select top round steaks. The in-home product test was conducted in Chicago, Houston, Philadelphia, and San Francisco. Consumers (n = 2,212) evaluated each top round steak for overall like (OLIKE), tenderness (TEND), juiciness (JUIC), flavor desirability (DFLAV), and flavor intensity (IFLAV) using 23-point hedonic scales. Stir-frying, braising, and simmering and stewing consistently produced higher consumer attribute ratings. There were clear OLIKE rating differences (P = .0001) for top round steaks among the four cities. The highest ratings were given by consumers in Houston, and the lowest ratings were given by consumers in Philadelphia (P < .05). There were two interactions for OLIKE: USDA quality grade x degree of doneness (P = .002) and degree of doneness x cooking method (P = .02). Higher ratings generally were given to steaks cooked to medium rare or less or to very well degrees of doneness. Stir-frying, braising, and simmering and stewing were preferred at lower degrees of doneness. Customer satisfaction with the top round steak is very dependent on how it is cooked and by whom it is consumed.  相似文献   

12.
Experimental economic procedures were used to measure the effects of changes in marbling score and Warner-Bratzler shear force (WBSF) value on consumer purchasing behavior and willingness to pay for beef strip loin steaks (n = 541). Consumers were more likely to bid on a steak during the experimental auction if the steak had a high marbling score or low WBSF value. Averaging across all consumers in the study (n = 489), the predicted odds that consumers would submit a nonzero bid were favorable for steaks with a marbling score greater than Modest(50) or a WBSF value less than 3.9 kg. Bid prices for steaks were analyzed with respect to changes in steak marbling score, WBSF value, quality grade marketing category classification (Select, Low Choice, Premium Choice, and Prime), and WBSF marketing category classification (very tender, 5.40 kg). The percentage of bids that were zero was highest (P < 0.05) for Select steaks, intermediate (P < 0.05) for Low Choice steaks, and lower (P <0.05) for Premium Choice or Prime steaks. Steaks in the very tender category had the lowest (P < 0.05) percentage of zero bids, and steaks in the slightly tough and very tough categories had the highest (P < 0.05) percentage of zero bids submitted from "buyers" in the auction. Premium Choice and Prime steaks were valued higher (P < 0.05) than Select steaks by consumers. On average, Premium Choice steaks received a 0.89 dollars/kg premium, and Prime steaks received a 2.47 dollars/kg premium over the mean bid price for Select steaks. Predicted mean bid prices for steaks decreased by 1.02 dollars/kg for each 1 kg increase in WBSF value. On average, steaks in the very tender marketing category received a higher (P < 0.05) bid price than the bid price for steaks in the slightly tender, slightly tough, and very tough categories (+0.83 dollars/kg, +2.09 dollars/kg, and +2.55 dollars/kg, respectively). Mean bid prices for steaks from the slightly tough and very tough categories did not differ (P = 0.184). Compared with the mean bid price for steaks in the slightly tender category, steaks from the slightly tough and very tough categories were discounted (P < 0.05) by 1.26 dollars/kg and 1.72 dollars/kg, respectively. Results suggest that marbling score and WBSF influence both the probability that consumers will purchase and the price they are willing to pay for strip loin steaks.  相似文献   

13.
Slaughter steers and heifers (n = 345) were selected representing the following cattle types: English steers and heifers, Exotic steers and heifers, less than 50% Bos indicus steers and heifers, greater than or equal to 50% Bos indicus steers, and Holstein steers. Thirty sides representing 30 carcasses from each cattle type were fabricated into boneless subprimals and trimmed to three fat-trim levels: 2.54, 1.27, and .64 cm. Yields of cuts to each trim level were used to calculate values for each carcass component. Live values were calculated after slaughter and fabrication costs and drop credits were considered. Values were calculated for U.S. Choice and U.S. Select grades and the weighted average value accounting for the Choice/Select mix for each cattle type. At a constant quality level, fatter cattle types were more valuable at the 2.54 cm of fat-trim level. As fat was trimmed, the leaner cattle types became more valuable and the fatter types became less valuable. Cattle types with higher percentages of Choice carcasses were more valuable at the 2.54 cm of fat-trim level, but when subprimals were trimmed to .64 cm, the lower-grading carcasses became closer in value due to cutability advantages.  相似文献   

14.
The objective of this study was to determine the optimal postmortem aging period and nutrient composition for Beef Value Cuts of the round. Forty USDA Select and 40 Premium USDA Choice beef carcasses were selected from a commercial beef packing plant in Colorado over a 12-wk period. The bottom and inside rounds were collected from both sides of each carcass for further fabrication into the following muscles: adductor, gastrocnemius, gracilis, pectineus, and superficial digital flexor. Each pair of muscles was cut into 7 steaks and randomly assigned to 1 of the following aging periods: 2, 4, 6, 10, 14, 21, and 28 d, and placed in refrigerated storage (2°C, never frozen). Upon completion of the designated aging period, steaks were removed from storage, cooked to a peak internal temperature of 72°C, and evaluated using Warner-Bratzler shear force (WBSF). A 2-way interaction was detected (P < 0.05) between individual muscle and postmortem aging period. The WBSF of all muscles except the superficial digital flexor decreased with increased time of postmortem aging. Quality grade did not affect (P > 0.05) WBSF values for the adductor, gastrocnemius, pectineus, and superficial digital flexor muscles. Exponential decay models were used to predict the change in WBSF from 2 to 28 d postmortem (aging response). The adductor, gastrocnemius, Select gracilis, Premium Choice gracilis, and pectineus required 21, 14, 23, 23, and 25 d, respectively, to complete the majority of the aging response. To determine the nutrient composition of the adductor, gastrocnemius, gracilis, pectineus, semimembranosus, and superficial digital flexor, bottom and inside rounds were collected from 10 USDA Select and 10 Premium USDA Choice carcasses and fabricated into the respective muscles, cut into 2.54-cm cubes, frozen (-20°C), and then homogenized. The adductor, gracilis, pectineus, semimembranosus, and superficial digital flexor were analyzed for DM, moisture, CP, and ash percentages. All muscles were evaluated for total lipid, fatty acid, and cholesterol composition. When quality grades were combined, all muscles fell into the extra lean or lean categories specified by USDA guidelines. Results of this study illustrate the potential for Beef Value Cuts of the round to be sold in food service operations and retail stores with marketing emphasis being placed on the exceptional leanness and acceptable tenderness of these cuts.  相似文献   

15.
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.  相似文献   

16.
One hundred thirty-eight consumers evaluated steaks from the complexus (CX), infraspinatus (IF), serratus ventralis (SV), supraspinatus (SS), and triceps brachii (TB) from the wholesale beef chuck; the deep pectoral (DP) from the wholesale brisket; and the longissimus thoracis (LT) from the wholesale rib. The LT was used as a reference for comparison to the other muscles. Ten USDA Choice and ten USDA Select boneless boxed beef subprimals were used for each muscle. Subprimals were aged 14 d from box date, frozen, and cut into 2.5-cm-thick steaks. Consumers rated the IF highest (P < 0.05) for overall like, tenderness, juiciness, and flavor, and assigned it the highest (P < 0.05) price/0.45 kg. The TB also was rated higher (P < 0.05) than the LT for overall like, tenderness, juiciness, flavor, and price/0.45 kg. The SV and CX were rated as being similar (P < 0.05) to the LT for overall like, tenderness, juiciness, flavor, and price/0.45 kg. Consumers rated the SS lower (P < 0.05) than the LT for tenderness, juiciness, flavor, and price. The DP was rated as the toughest, driest, and blandest (P < 0.05), resulting in assignment of the lowest (P < 0.05) price/0.45 kg. Differences in palatability ratings due to quality grade were found for several muscles; USDA Choice SV and SS were rated higher (P < 0.05) for overall like, tenderness, and juiciness than USDA Select SV and SS. For the IF, USDA Choice was rated higher (P < 0.05) for tenderness and juiciness than USDA Select. The USDA Choice TB was rated higher (P < 0.05) for juiciness, and the USDA Choice DP was rated higher (P < 0.05) for overall like, than their USDA Select counterparts. Tenderness, juiciness, and flavor ratings were correlated with overall like ratings (r = 0.84, 0.77, and 0.76, respectively) and with price (r = 0.73, 0.70, and 0.68, respectively). These results indicate the IF, TB, SV, and CX were acceptable, whereas and the SS and DP were unacceptable as steaks.  相似文献   

17.
Serial ultrasound estimates of backfat thickness and marbling score were obtained on two groups of steers fed high-energy rations for averages of 166 and 148 d. These measurements were used to develop mathematical models that described the changes in those two attributes as functions of days on feed. An exponential model best described the increase in backfat thickness, and the rate coefficients were .0117 and .0096 for the two groups (doubling times = 59 and 72 d, respectively). A modified power function was better than either a linear or exponential model for describing the development of marbling. In this model, marbling increased very slowly, approximately one degree every 100 d, in the interval from low Select to low Choice but then increased at faster rates as initial marbling scores became higher. Ultrasound backfat measures could be used to predict days to reach a target carcass backfat level with an average error of 30 d or less when backfat thickness averaged more than 3 mm at evaluation. Projections from measurements taken when cattle were started on feed were not accurate from one group, which averaged only 1.7 mm backfat at that time. Projections of carcass marbling improved as evaluation date neared slaughter date. Projections from the initial evaluation date allowed tentative categorization of candidates for Choice or not Choice but were only 64% accurate. Projections from evaluations made later in the feeding period exceeded 75% accuracy in distinguishing Choice from Select. Only small relationships (r2 = .07 or .16) existed between carcass backfat thickness and marbling score. Results indicate that ultrasound estimates of backfat and marbling made during the feeding period can be used to predict carcass merit at slaughter.  相似文献   

18.
One hundred beef carcasses were selected to represent the mix of cattle slaughtered across the United States. Selection criteria included breed type (60% British/continental European, 20% Bos indicus, and 20% dairy carcasses), sex class (beef and Bos indicus: 67% steers, 33% heifers; dairy: 100% steers), USDA quality grade (4% Prime, 53% Choice, and 43% Select), USDA yield grade (10% YG 1, 43% YG 2, 40% YG 3, and 7% YG 4), and carcass weight (steers: 272.2 to 385.6 kg, heifers: 226.8 to 340.2 kg). One side of each carcass was fabricated into boneless subprimals and minor cuts following Institutional Meat Purchase Specifications. After fabrication, subprimals were trimmed progressively of fat in .64-cm increments beginning with a maximum of 2.54 cm and ending with .64 cm. Linear regression models were developed for each individual cut, including fabrication byproduct items (bone, fat trim) to estimate the percentage yield of those cuts reported by USDA Market News. Strip loin, top sirloin butt, and gooseneck rounds from heifers tended to have a higher percentage yield at the same USDA yield grade than the same cuts from steers, possibly resulting from increased fat deposition on heifers. Percentage of fat trimmed from dairy steers was 2 to 3% lower than that from other sex-class/carcass types; however, due to increased percentage of bone and less muscle, dairy steers were lower-yielding. Fat trimmed from carcasses ranged from 7.9 to 15.6% as the maximum trim level decreased from 2.54 to .64 cm.  相似文献   

19.
Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as carcass adjusted 12th-rib fat thickness. After collection of USDA carcass grade data, one side of each carcass was fabricated into boneless primals, subprimals, and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the knuckle, tri-tip, and tenderloin, which were trimmed of all fat. Forced four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at the three fat trim levels as influenced by sex class, frame size, muscle score, and adjusted 12th-rib fat thickness. Independent variables that had the most influence on percentage yield of primals and boneless subprimals were adjusted 12th-rib fat thickness and sex class. Within the same phenotypic group, percentage of trimmable fat increased by 2.32% as 12th-rib fat thickness increased by .75 cm. Estimated percentage yield of the major subprimals from the loin and round tended to be higher or relatively equal for heifer carcasses at all trim levels compared with those subprimals from steer carcasses. Holding frame size, sex class, and fat thickness constant, there was a higher percentage yield of chuck roll, rib eye roll, and strip loin for carcasses from thick-muscled cattle than for those from average- and thin-muscled cattle. Frame size had little effect on percentage yield of boneless subprimals.  相似文献   

20.
Top sirloin butts (n = 162) were used to investigate the influence of quality classification, aging period, blade tenderization passes, and endpoint cooking temperature on the tenderness of gluteus medius steaks. Top sirloin butts (gluteus medius) from Select (SEL), Choice (CHO), and Certified Angus Beef (CAB) carcasses were obtained, aged for 7, 14, or 21 d, and either not tenderized or blade tenderized one or two times. Three steaks from each top sirloin butt were randomly selected and assigned to a final endpoint cooking temperature of 65.5, 71.0, or 76.6 degrees C. Cooking characteristics and Warner-Bratzler shear force (WBSF) were analyzed as a split-plot with a 3 x 3 x 3 factorial treatment structure of quality classification, aging period, and tenderization passes in the whole plot and endpoint cooking temperature in the subplot. Sensory panel data for CHO steaks cooked to 70 degrees C were analyzed with a 3 x 3 factorial treatment structure of aging period and tenderization passes. Thawing loss was greater (P < 0.05) for steaks aged 7 d than those aged 21 d. Cooking loss was greater (P < 0.05) for steaks aged for 14 and 21 d than those aged 7 d, and increased (P < 0.05) with each increasing endpoint temperature. Each increase in aging period resulted in lower (P < 0.05) WBSF values. In addition, steaks blade tenderized two times had lower (P < 0.05) WBSF values than steaks blade tenderized once or not at all. Within each quality classification, WBSF values increased (P < 0.05) as endpoint cooking temperature increased. When cooked to 71 or 76.6 degrees C, CHO and CAB steaks had lower (P < 0.05) WBSF than SEL steaks. Steaks blade tenderized one or two times received higher (P < 0.05) sensory panel ratings for myofibrillar and overall tenderness than steaks not blade tenderized. Connective tissue amount and overall tenderness ratings were higher (P < 0.05) for steaks aged 21 vs. 7 d. Postmortem aging and blade tenderization of gluteus medius steaks can improve tenderness, as measured by WBSF and sensory panel, without decreasing flavor or juiciness. When cooking to higher endpoint temperatures, higher quality classifications should be selected to minimize toughness due to cooking.  相似文献   

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