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Forty-five market weight hogs were conventionally slaughtered, carcasses split, left sides electrically stimulated (ES) and right sides not ES (NES). The first group of 30 carcasses (Group 1) was divided into six subgroups of five carcasses each, and sides were assigned to one of three chilling methods (BLAST = 3 h at −34 C, then 21 h at 2 C; CONV = 2 h at 2 C; BRINE = 3 h under a −5 C brine shower, then 21 h at 2 C). Group 2 consisted of 15 carcasses, divided into three subgroups of five carcasses each, and paired sides were assigned to BLAST, CONV, or BRINE chill. Electrical stimulation did not affect temperature decline of the leg or loin. Chilling method did produce differences in temperature decline. Extrapolation of the data indicated that fabrication procedures could begin at 9.5, 11 and 14.5 h postmortem for BLAST, BRINE and CONV, respectively; whereas optimal temperature for extending shelf-life would be reached at 12, 20 and 24 h postmortem for the respective chill methods. Electrical stimulation did not affect muscle color or firmness of the loin or shoulder, nor muscle separation of the shoulder; however, ES did affect muscle color (paler), firmness (softer) and separation (more extensive) of the legs. More rapid chilling (BLAST or BRINE) increased muscle color scores for legs. The BLAST method improved (over BRINE and CONV) the firmness of all cuts and decreased the separation of the shoulder and leg. Where interactions of stimulation × chilling were not evident, only the flavor desirability and overall palatability of cured biceps muscles were affected by stimulation, with ES having lower (P<.05) ratings than NES. Interactions of stimulation × chilling method and differences that were observed are discussed.

Yearling and long-yearling steers (n = 471) were fed identical finishing diets for 100, 130 or 160 d at a commercial feedlot. The cattle were slaughtered, carcasses were evaluated by a USDA grader and rib steaks were cooked and used for sensory panel evaluation. Marbling had a low, but positive, relationship to all of the palatability traits of beef; more than 90% of the steaks with “slight” or higher degrees of marbling were “desirable” in overall tenderness, flavor desirability and overall palatability. The relationships between subcutaneous fat thickness and the organoleptic properties of beef were neither linear nor additive; fat thickness levels of 7.6 to 10.2 mm provided relatively high assurance of “desirable” palatability. Compared to marbling, fat thickness was ineffective as a predictor of cooked beef palatability and, therefore, would appear to be an unsuitable substitute for marbling. However, marbling, used in combination with a minimum subcutaneous fat thickness constraint of 7.62 mm for carcasses with a “slight” amount of marbling, facilitated more equitable stratification of carcasses according to their expected palatability than did marbling alone.

Three-hundred and fifty-nine pork carcasses varying widely in muscling fatness were selected from two commercial packing plants. Measurements were made of carcass length, fat depth (3/4 measure-10th rib), longissimusmuscle area, average backfat thickness, USDA muscling score and carcass weight. These independent variables were considered to be easily obtainable on the ribbed (between the 10th and 11th ribs) but otherwise intact carcass. The four lean cuts were sequentially fabricated and processed into separable lean, fat and bone. Multiple regression equations were developed to predict percentage of lean in the four lean cuts (L4LC) and to predict muscle to bone ratio in the four lean cuts (M:B). Results indicated that: (1) M:B differed widely among pork carcasses (from 2.89 to 5.49) and was distributed normally; (2) M:B was important in predicting L4LC in a population of carcasses ranging in backfat from 2.29 to 3.28 cm but did not add significantly to predictive accuracy in a population of carcasses with a backfat range of 2.29 to 5.33 cm; (3) the best two-variable equation for predicting L4LC included fat depth and longissimusmuscle area (R2= .87), and the best three-variable equation for predicting L4LC included M:B, fat depth and longissimusmuscle area (R2=.89); (4) the best two-variable equation for predicting M:B included longissimusmuscle area and USDA muscling score (R2=.54), and the best three-variable equation for predicting M:B included longissimusmuscle area, USDA muscling score and carcass length (R2= .55); (5) USDA muscling scores and longissimusmuscle area were significantly associated with M:B (r = .64 and .69, respectively); (6) no prediction equation could account for more than 60% of the observed variability in M:B, and (7) the addition of actual M:B to fat depth and longissimusmuscle area increased the accuracy of estimating L4LC by only 2%, suggesting that the value of estimated M:B probably would not be sufficient to warrant its inclusion in prediction equations for estimating leanness of ribbed carcasses.

Data on performance and carcass characteristics of progeny from 13 Hereford bulls were obtained. Weaning data consisted of records on 80 steer progeny; postweaning data were obtained on 70 steer progeny. Comparisons were made between progeny sired by five bulls imported from England and progeny sired by eight bulls of domestic breeding. In addition, for the domestic bulls, comparisons were made among progeny groups sired by bulls selected on the basis of either performance data or visual appraisal. There were no significant differences in adjusted weaning weight, weaning weight per day of age or conformation score between the various sire groups. Progeny sired by imported bulls had significantly more pigmentation around the eyes than did progeny from domestic bulls. After a 168-day feeding period, progeny from bulls selected on the basis of visual appraisal had lower daily gains, lower weights per day of age and lower adjusted 440-day weights than progeny from bulls selected on the basis of performance data. Progeny sired by imported bulls had heavier slaughter and carcass weights per day of age than progeny sired by domestic bulls, primarily because of the lower performance of progeny from domestic sires selected on the basis of visual appraisal alone. Origin of sire had no effect on factors associated with USDA yield or quality grade. Carcasses from the various progeny groups were similar in composition, except that progeny from domestic sires had significantly higher percentages of trimmed bone-in round, loin, rib and chuck than progeny from imported sires. Percentage of edible portion and ratios of edible portion to fat or bone were similar for all sire groups. Progeny from all sire groups produced carcasses that were desirable in cutability and palatability. These data suggest that it is difficult to obtain cattle within a breed which are distinctly different in carcass traits when they are managed and fed alike.

The heat-induced gel strength in suspensions of two types of plasma protein isolates and egg albumen were compared to investigate the use of bovine blood plasma in food systems as a replacement for egg albumen and other proteins. A viscosity index, based on a counter-flow back-extrusion model, was used to measure gel strength. The optimum pH for gel formation was 7.0 for phosphated and nonphosphated plasma protein suspensions and 9.0 for egg albumen. The protein gel strengths were compared at 8% protein concentrations and at their respective pH optima. The gel strength of heated bovine plasma protein suspensions was greater (P<.01) than that of egg albumen, indicating that blood plasma exhibited a binding ability superior to that of egg albumen. The addition of controlled low levels of sodium and calcium increased (P<.05) the binding ability of both plasma protein isolates, while egg albumen showed no changes (P>.05). Greater concentrations substantially decreased (P< .01) the gel strength in both types of heated plasma protein suspensions and egg albumen, revealing that all three protein types exhibited an ionic strength dependency.

Mature cows (n = 95) were slaughtered and assigned to one of three treatment groups: (1) electrical stimulation (ES) of unsplit carcasses, before evisceration, (2) ES, after splitting, of sides, and (3) untreated (not ES) control carcasses or sides. Electrical stimulation consisted of either 150 volts or 550 volts for 1 (16 impulses) min or for 2 (32 impulses) minutes. Carcasses were ribbed at 24 hr postmortem and USDA quality grade factors, lean-color score and “heat-ring” incidence were evaluated. Sections of longissimusmuscle (10 to 11th ribs) were used for shear force determinations. Electrical stimulation, irrespective of carcass form, ES voltage or ES duration, improved (P<.05) lean-maturity score, improved (P<.05) lean-color score and decreased (P<.05) shear force value when treated (ES) carcasses and steaks were compared to control (not ES) carcasses and steaks. Use of 550 volts, irrespective of carcass form or ES duration, improved (P<.05) lean-color score and decreased (P<.05) “heat-ring” incidence compared to the use of 150 volts; advantages for 550 vs150 volts were more evident for carcasses (P<.05 differences in lean-color score and shear force value) than for sides (no significant differences). Stimulation for 2 min, rather than for 1 min, did not affect (P>.05) carcass characteristics or shear force value at either voltage (150 or 550 volts). ES can be performed on mature beef carcasses with expectations in terms of improved quality and increased tenderness proportionately similar to those achieved in electrical stimulation of young beef carcasses.

Feeder steers (n=471) were fed for 100, 130 or 160 days, then slaughtered, and carcass grade data were collected. A wholesale rib was removed from each carcass, vacuum packaged, and aged for 12 to 14 days, and steaks were obtained, Palatability of the steaks generally increased as marbling score increased; however, the differences in palatability associated with each successive increase in marbling score were not always directionally consistent, nor were they always statistically significant. Steaks from the highest grading (by thirds of grades) carcasses (high Choice and average Choice) were (P<.05) more juicy, more flavorful and more desirable in overall palatability than were steaks from the lowest grading (by thirds of grades) carcasses (low Good and high Standard); however, steaks from low Choice, high Good and average Good carcasses did not differ in ratings for juiciness, tenderness or overall palatability. When steaks from carcasses of different grades (by full grades) were compared, grade was not associated with differences in palatability. Increased time on feed was associated with increased carcass maturity, increased fat deposition, decreased (higher numerical) yield grade and increased percentage of carcasses grading Choice. Increased feeding time from 100 days to 160 days had a beneficial effect on flavor desirability but did not significantly affect juiciness, tenderness or overall palatability. These data suggest that knowledge of feeding history might be a useful adjunct to — or substitute for — USDA quality grade for predicting beef palatability.

Marbling, color, firmness and muscle structure scores were assigned to 403 wholesale pork loins. Multiple regression equations that combined quality scores assigned to the muscle surfaces at the 10th rib, blade end or sirloin end accounted for 31.9%, 22.2% or 21.0%, respectively, of the observed variability in overall palatability scores. Quality scores were grouped to create five levels each of marbling, color and firmness. Response surface techniques were used to identify combinations of factor levels (scores for marbling, color and firmness) which would yield maximum response in the dependent variable (overall palatability score) and to assign loins to “Superior”, “Acceptable” or “Inferior” palatability groups. Stratification systems based on quality indicator scores assigned at the 10th rib, blade end or sirloin end correctly assigned 53, 47 and 46% of the loins to the appropriate palatability group (Superior, Acceptable or Inferior). Fresh pork loins can be segmented into expected palatability groups by use of quality indicator scores assessed at the sirloin end of the wholesale loin (commercial grading application) or at the 10th rib (carcass contests, breed certification programs) with approximately 50% success.

Goats (n = 95) of known history were used to study palatability attributes of loin, sirloin and leg samples as related to differences in age and quality level (essentially fatness). Quality level within an age class was much less important than age at slaughter in determining palatability of cooked meat, however, quality level did not differ greatly among goats of the same slaughter age despite attempts to ensure differences in fatness (and thereby differences in carcass quality) via management practices. Fatness did not vary enough between goats of similar age to facilitate its use in segmenting product into expected palatability groups. Age at slaughter can be used to segment goat carcasses into expected palatability groups. Yearling Angora goats produced chops and roasts which were (P<.05) juicier and more tender than those from young goats; 6-month-old Spanish goats produced chops and roasts that were (P<.05) more tender than those from more youthful or more mature goats in a majority of such comparisons. Aged Spanish goats yielded meat which was decidedly inferior in palatability to that from more youthful goats. Spanish and Angora goats that were slaughtered at 3 to 5 months of age yielded meat that was tough; since this toughness may have been created by effects of chilling on light-weight, thinly-finished carcasses, changes in age/weight at slaughter or in processing conditions could alleviate this problem.

Fifty light-weight (300 to 375 kg) heifers were slaughtered, split longitudinally and randomly selected sides were electrically stimulated (machine setting=100 volts, 5 amps, 50 to 60 cycles per second; producing a 440 volt potential difference between electrodes) within 1 hr post-exsanguination. Treatment groups for paired sides included 0 vs25, 0 vs50, 0 vs75, 25 vs50, and 50 vs75 electrical impulses per side. When significant differences in carcass traits, tenderness and overall palatability were observed between control and treated sides, advantages were always in favor of electrically stimulated sides. The most consistent improvements elicited by electrical stimulation were in USDA lean maturity score (more youthful), muscle color (brighter), incidence of “heat-ring” (less frequent; less severe), shear force (more tender) and sensory panel ratings (more tender; less organoleptically-detectable connective tissue; more desirable overall palatability). Use of 75, rather than 25 or 50, impulses slightly reduced the incidence and severity of “heat-ring”; however, there was very little evidence that use of more than 25 impulses would materially enhance the response in palatability achieved via electrical stimulation.

One hundred Santa Gertrudis steer calves were used in a study of 10 management systems for producing beef. Growth stimulants were not used. Steers were slaughtered as calves, yearlings, long-yearlings and 2-year-olds after periods on grass alone, grain on grass, or in dry-lot Steers fed grain reached slaughter weight and grade 100 to 230 days sooner, were higher in USOA quality grade, dressed higher and yielded lower percentages of primal cuts than steers finished on forage management systems. Steers grown on grass and then fed concentrates for 98 days before slaughter produced much more protein than did steers grain-fed 125 or 255 days after weaning, or steers which were grazed or fed grain on grass as either long-yearlings or 2-year-olds. The best management system to conserve grain and yet produce an adequate supply of high quality beef would incorporate maximum growth and frame development on forages followed by short-term (100 to 120 days) drylot feeding. Management practices of this nature would allow maximum protein production and greater assurance of acceptable palatability with only small losses in cutability. Steers from grass or grain on grass were approximately 6 months older if slaughtered at comparable weight and grade than those fed in drylot after grazing and were lower and more variable in palatability.

Ribs, knuckles and blade chucks were vacuum packaged via a chamber heat seal (CHS) system or a nozzle clip seal (NCS) system and were stored at 1 C for 7, 14, 21, 35 or 42 days. Three observers evaluated each of the 295 primal cuts for surface discoloration, appearance of fat covering and incidence of off-odor. Total psychrotrophic microbial counts were obtained on randomly selected samples at each storage interval. Steaks derived from each primal cut were used for retail display and sensory evaluation. The primary visual difference observed between packaging systems was the higher vacuum score attained by use of the CHS system. Cuts stored in different packaging systems did not differ (P<.05) with regard to evaporative or purge loss. With increased storage time, weight loss increased and retail caselife was reduced for cuts packaged in both systems. Primal cuts stored in leaker packages for 21 days had higher microbial counts, lower scores for appearance of primal cuts and greater trim losses (1.2% for intact packages vs4.8% for leaker packages). Differences between packaging systems in package leaker rates appear to be of greater economic significance than differences due to degree of vacuum or other variables involved with intact packages.

Single sides from each of 27 steer and 21 cow carcasses were placed in a 0 to 2 C holding cooler 1 hr post-exsanguination. Counterpart sides from each carcass were placed in a 14 to 19 C cooler for 12, 16 or 20 hr (nine steer and seven cow sides per time interval) and then moved to the 0 to 2 C cooler for the remainder of a 48-hr storage period. At 48 hr postmortem, steaks from steer and cow sides held at 14 to 19 C for 20 hr were significantly more tender than those from normally chilled sides. Panel tenderness ratings for steaks removed 7 days postmortem revealed that steaks from sides stored for 12 hr at 14 to 19 C were more tender than those from control sides. Steaks from mature (cow) carcasses exhibited a greater tenderness response to temperature treatments than did steaks from the youthful (steer) carcasses. The sarcomere lengths of myofibrils from cow carcasses were significantly greater for sides held at a higher temperature for 20 hours. Bacterial counts at the termination of the 48-hr storage period were not significantly (P<.05) different between control and treated sides. Pre-rigor storage at elevated temperatures enhanced the visual appearance of subsequent steaks from steer and cow carcasses. In 115 of 120 comparisons (P<.05 in 40 comparisons) steaks from treated sides displayed numerically higher ratings than steaks from control sides for muscle color, consumer acceptability and discoloration during 5 days of retail display.

A total of 403 butcher hog carcasses were selected from two commercial firms or from the Meats Laboratory at Texas A&M University. These carcasses, chosen to vary widely in muscling and fatness, were cut and trimmed according to procedures developed by U.S.D.A. and Texas A&M University personnel. Among measures of fatness, fat depth over the longissimusmuscle (10th or last rib) was most closely associated with yields of lean cuts and total lean. Neither length nor weight of carcass was associated with more than 10% of the variability in cutting yields. Among measures of muscling, loin eye area (longissimusmuscle area at the 10th or last rib) and lumbar lean depth were most highly correlated with percentages of trimmed four lean cuts (.64, .66 and .49, respectively). Some advantage in accuracy of lean yield estimation was noted in favor of the use of overall U.S.D.A. muscling scores as compared to either of the ham evaluations (rear or stifle views). Unadjusted and subjectively adjusted (by use of other visual indices of carcass fatness) backfat thickness measures were not different for predicting percentages of regular trimmed four lean cuts (−.88 and −.89). An equation combining measures of average backfat thickness, carcass length and U.S.D.A. muscling score (overall evaluation) was associated with 83.4% of the observed variability in percentage of regular trimmed four lean cuts. A change of .25 cm (.1 in) in average backfat thickness was equivalent to a change of one full U.S.D.A. muscling score in its effect on percentage yields of regular trimmed four lean cuts. Fat depth over the longissimusmuscle at the 10th rib, in combination with carcass length and longissimusarea at the 10th rib most accurately predicted percentages of total separable muscle from the four lean cuts (R2× 100 = 89.5%).

Scores were assigned for marbling, color, firmness and structure of muscle surfaces at the blade end, 10th rib, last rib, fifth lumbar vertebra and sirloin end of 403 wholesale pork loins. Chops from a section of the loin between the 10th and last ribs were cooked to an internal temperature of 75 C and rated by a trained six-member sensory evaluation panel. Quality scores at the five anatomical locations as well as chemical and physical measurements from the longissimusmuscle were related to cooking losses and palatability attributes. Marbling, color, firmness and muscle structure, evaluated at all five loin interfaces, were related (P<.01) to ratings for juiciness and overall satisfaction. Multiple regression equations combining the four quality scores at the blade end, 10th rib and sirloin end, respectively, accounted for .5, 19.7, 8.1 and 15.6; 1.8, 28.2, 12.0 and 24.1; 2.0, 23.6, 9.2 and 15.5% of the variability in ratings for flavor, juiciness, tenderness and overall satisfaction, respectively. Stratification according to marbling, color or muscle structure segmented loins into groups which differed significantly in juiciness, tenderness, overall satisfaction and cooking loss percentages, but did not identify loins which differed significantly in flavor intensity. Marbling, color and/or structure scores assigned at the blade or sirloin end of the loin (if industry practice necessitates grading at one end or the other) can be used to segment wholesale pork loins into quality groups for grade identification purposes.

Consumer preference studies involving 1,186 grocery shoppers and a 21-member laboratory panel revealed that the most desirable bacon in fresh appearance, cooked appearance and palatability contained more than 40% muscle and had “good” distribution of muscle and fat. Bacon with less than 30% muscle (irrespective of distribution) was less desirable in fresh and cooked appearance, was less satisfactory in palatability and sustained greater cooking shrinkage than bacon with more than 30% muscle. Lighter weight (4.1 to 5.0 kg) bellies had higher lean to fat ratios than heavier weight (5.0 to 5.9 kg) bellies and yielded much higher proportions of desirable bacon slices. Bellies which were “out of proportion”, “scribed” or “flank biased” did not yield lower proportions of desirable slices than did bellies which were free of these defects. Within belly weight groups, increases in weight and length were associated with lower lean to fat ratios and lower percentages of desirable bacon slices. In-plant classification, after slicing, appears more feasible than physical measurements of green or pressed bellies for identifying differences in bacon leanness.

The red meat industry has undergone significant change during recent decades. Mechanization has resulted in high-efficiency, high-volume cattle slaughter-dressing facilities. Livestock composition has changed in response to various pressures, reflected in changed grading standards. Temperature conditioning and electrical stimulation have been applied to reduce muscle cold shortening. Mechanical tenderization has been improved. Plant-source proteolytic enzymes applied to cuts and introduced to the circulatory systems have improved tenderness. Vacuum packaging has changed the distribution of fresh beef and lamb. Distribution of frozen meat cuts has been shown to be technologically feasible. Least-cost sausage formulation using computer programs has been proven practical. Phosphates improving cooking yields have made possible such accepted products as the water-added ham. Ascorbates and erythorbates have facilitated rapid curing and color stability. Tumblers and massagers allow the reassembly of dissected muscles into single-entity products minus components to which consumers object. Mechanical separation of meat from bone has salvaged much meat formerly lost to human use. The established safety of nitrites and nitrates in meat curing has been questioned. Widespread concern about saturated fats and cholesterol has been expressed. Caloric contribution of dietary fats has become a health issue. Future trends will include consumer marketplace expression of a preference for reduced fat, which will be reflected in further grade standard changes. The subjective component of grading will be reduced with electronic and other technology. Post-slaughter technology will further modify natural characteristics in response to consumer preference. Additives to improve safety and sensory characteristics of meat products will continue to be challenged by consumers, whether the technologies are new or traditional.

Twelve heifers and 12 steer calves born in the fall were slaughtered at weaning at an average age of 259 days. Before weaning, calves grazed a bermudagrass-ryegrass-arrowleaf clover sward at three levels of forage availability (FA). Average daily gains (ADG) of cows and calves on the low, medium and high FA paddocks were −.25 and .67, −.02 and .76, and .47 and .97 kg (P<.05), respectively. The low, medium and high FA paddocks supported stocking rates of 6.27, 4.52 and 2.72 cow-calf units/ha (P<.05) and calf weaning weights of 236, 251 and 289 kg (P<.05), respectively. Carcasses of calves that had grazed high FA paddocks were fatter (P<.05) than carcasses of calves that had grazed low FA paddocks (5.08 vs1.27 mm over the longissimusmuscle) and their longissimusmuscle areas were more than 18% larger (P<.05). Marbling scores and quality grades of carcasses from calves on high FA paddocks were 33 and 27% higher (P<.05), respectively, than those of calves on low FA paddocks. There were few significant differences in palatability-related traits of loin steaks from carcasses of calves on the three levels of FA. Also, except for juiciness, steaks from 22 grain-fed steers generally received higher (P<.05) taste panel scores and had lower shear force values than did steaks from carcass of any of the three FA groups of calves. Steer carcasses showed higher (P<.05) ADG and weaning weight and larger longissimusmuscle areas than did heifer carcasses, whereas heifer carcasses had greater (P<.05) fat thickness over the longissimusmuscle, more (P<.05) kidney, pelvic and heart (KPH) fat and a higher (P<.05) yield grade number (lower cutability). There were no differences (P>.05) in other carcass characteristics or in any of the palatability-related traits of loin steaks from steers and heifers.

Effects of chloride salts, acid phosphate and electrical stimulation (ES) on processing properties of beef clods were determined. Ten pairs of shoulder clod muscles (right side = ES; left side = not ES) from cattle varying in maturity and live weight and representing both sexes were assigned to the following treatments: control (no additives), 2.5% NaCl, 3.18% KCl, 1.58% CaCl2, 1.35% MgCl2and .5% monocalcium phosphate monohydrate (acid phosphate). Concentrations of chloride salts were selected to have ionic strengths equivalent to that of 2.5% NaCl (.628). Samples treated with monocalcium phosphate and CaCl2exhibited greater expressible moisture loss and moisture loss during cooking and had lower pH values (P<.05) than control samples and samples with 2.5% added NaCl. In contrast, treatment with MgCl2resulted in less expressible moisture loss and moisture loss during cooking than did the control and the NaCl treatments. ES decreased (P<.05) expressible moisture loss when NaCl was used, increased (P<.05) these values when CaCl2was used and had no effect (P>.05) on expressible moisture loss from either control clods or clods treated with KCl, MgCl2or monocalcium phosphate. Although moisture losses during cooking were numerically greater in five of six comparisons (ES versusnot ES), these differences were not significant. ES had no effect (P>.05) on muscle pH values.

Data on 359 pork carcasses were divided into four groups based on ranges in carcass fatness (average backfat thickness). Independent variables included carcass weight (CW), carcass length (CL), average backfat thickness (ABF), USDA muscling score (MS), fat depth 3/4 the lateral length of the longissimusmuscle at the 10th rib (FD), longissimusmuscle area at the 10th rib (LMA) and seam fat scores in the blade (SFB) and sirloin (SFS) ends of the loin. Dependent variables were percentage of lean (PCLN) and kilograms (KGLN) of lean in the four lean cuts. Regression equations were computed to identify the best equations containing two or three independent variables for predicting PCLN and KGLN. All measures of fatness wee negatively correlated with both PCLN and KGLN. When only those variables available from the intact carcass (CW, CL, MS, ABF) were used, the best two-variable equations for predicting PCLN included MS and ABF, while the best equation for predicting KGLN included CW and ABF in two of the four fat ranges. R2values were generally low when only intact carcass measurements were included. When all available variables were included, the best two-variable equation for predicting PCLN was that including LMA and FD. Two-variable equations including CW and FD most accurately predicted KGLN. LMA, FD and SFS combined to give the best three-variable equation for predicting PCLN (coefficient of determination, [CD] = 89.2). The best three-variable equation for predicting KGLN included CW, LMA and FD (CD = 91.8). Findings suggest that the independent variables used in the National Pork Producers Council procedure for estimating muscle in carcasses are the appropriate indices for such estimation across a wide range in fatness of pork carcasses.

Longissimusand semimembranosusmuscles from 42 forage-fed steers were used to determine singular and combined effects of electrical stimulation (ES), delayed chilling (DC) and pelvic suspension (PS) of sides, cooler aging (CA) of wholesale loins and blade tenderization (BT) of wholesale loins and top rounds on palatability and cooking loss. ES or PS (used singularly) increased (P<.05) tenderness and decreased (P<.05) shear force of loin steaks, compared to steaks from untreated (control) sides or cuts. Maximum tenderization of the longissimusmuscle was achieved by either ES or DC of sides, followed by CA and BT of shortloins. None of the initial tenderization treatments (ES; DC; or PS), used singularly, enhanced the tenderness of the semimembranosusmuscle; however, combined treatments—ES + PS; PS + DC; ES + DC + PS— of sides, and use of BT (in combination with PS; ES + PS; PS + DC; or ES + DC + PS) of the wholesale cut increased (P<.05) tenderness and decreased (P<.05) shear force of top round steaks. Maximum tenderization of the semimembranosusmuscle was achieved by ES + PS + DC of the side followed by BT of the top round. Effects of initial and (or) secondary tenderization techniques were minimal or nonexistent on carcass shrinkage; carcass quality grade factors; firmness, color, moisture content, fat content or water holding capacity of longissimusmuscle; and flavor, juiciness and cooking loss of loin or top round steaks.

A total of 80 beef loin steaks were selected on the basis of tenderness differences from a population of 1,005 steaks from carcasses of known USDA grade (US Choice—A maturity, n=20; US Choice—B maturity, n=10; US Good—A maturity, n=20;US Good—B maturity, n=10; US Commercial—C maturity, n=20). Among steaks from US Choice-—A maturity carcasses, the most tender steaks had (P<.05) more intramuscular fat, less intramuscular moisture, higher water holding capacity and a lower fragmentation index. Among steaks from US Good—A maturity carcasses, the most tender steaks had a lower (P<.05) fragmentation index. Among steaks from US Commercial—C maturity carcasses, those that were most tender had (P<.05) more intramuscular fat, less intramuscular moisture, higher water holding capacity, longer sarcomeres, higher collagen solubility and a lower fragmentation index. Among steaks from the five grade-maturity groups characterized, multiple regression equations containing 17 chemical, physical and histological measurements as independent variables accounted for 62.8 to 96.4% of the variation in shear force values. The independent variables that contributed most in accounting for the observed variability in tenderness were fragmentation index, sarcomere length, intramuscular moisture percentage and soluble collagen percentage. Samples of muscle from two tenderness levels were not different (P>.05) in any of 14 myofibrillar protein fractions.

A field trial was conducted with 200 steers of mixed breeding with a mean initial weight of 351 kilograms. The steers were randomly allotted within three breed type groups into control (C) or protected tallow (PT) treatments. The C steers were offered a diet containing 85% concentrates and 15% corn silage on a dry matter basis. The PT steers received the same diet except a formaldehyde-treated protein protected tallow product (containing 40% tallow) was substituted for grain sorghum at 19% of the total dry matter of the diet. At that level, the PT provided 7.65% added tallow to the diet. Within the C group, 20 steers were fed for 89 days and 78 were fed for 118 days. In the PT group, 76 were fed for 89 days and 20 were fed for 118 days. Feeding the PT product increased (P<.08) average daily gain (ADG), however, increasing the time on feed from 89 to 118 days reduced (P<.002) ADG. The feed required per unit of gain was reduced by PT feeding and was increased by extending the length of time on feed.Adjusted subcutaneous fat thickness, percentage of kidney, pelvic and heart fat and USDA yield grade were increased (P<.01) by either feeding the C group 118 days or by including the PT product in the diet for 89 days. Fat content of the longissimusmuscle was increased (P<.04) by inclusion of the PT product in the diet and was also increased (P<.08) by increasing the time on feed. Feeding the PT product for 89 days produced steers with carcass characteristics quite similar to steers fed the control diet for 118 days.Sensory characteristics of cooked longissimussteaks were unaffected (P<.05) by either time on feed or by the PT product. Increasing the time on feed from 89 to 118 days increased shrinkage (P<.07) and cooking time (P<.02), but had no significant effect on the appearance of doneness.

Comparisons were made of carcasses and palatability traits of 78 steers produced by Hereford dams and sired by Hereford, Angus, Lincoln Red, Brown Swiss, Simmental, Limousin, Maine Aiijou or Charolais bulls. Carcasses from steers sired by bulls of the British breeds (Hereford, Angus and Lincoln Red) were fatter (greater fat thickness; higher fat trim; higher marbling score; more chemical fat in the rib section; lower yield of boneless chuck, rib, loin and round) than carcasses from steers sired by the French breeds (Limousin, Maine Anjou and Charolais). Carcasses from crossbred steers sired by bulls of the French breeds had higher bone trim percentages, more protein in the rib section, lower fat thickness measurements, less chemical and trimmable fat, higher yields of trimmed boneless cuts and lower quality grades than carcasses from steers sired by bulls of the British breeds. Of carcasses from Swiss breed crossbreds, those sired by Brown Swiss tended to be similar in carcass traits to those sired by bulls of the British breeds while those sired by Simmental tended to be similar to those sired by bulls of the French breeds. Taste panel members rated the cooked steaks from all breed groups in the acceptable range for palatability and found no significant differences in tenderness or flavor among breed groups. Differences were observed among breed groups in juiciness and overall satisfaction ratings, however, no distinct pattern was apparent with regard to origin of the respective breeds.

Thirty pairs of carcasses (one forage-finished and one grain-finished of essentially identical USDA quality grade) were obtained. One side of each forage-finished carcass was chilled at conventional cooler temperatures; the other side was chilled at high cooler temperatures. High temperature chilling of forage-finished beef did not affect (P>.05) cooking loss, juiciness, flavor or overall palatability, but significantly decreased shear force requirements and nonsignificantly increased muscle fiber tenderness and amount of organoleptically-detectable connective tissue. Grain-finished beef was (P<.05) more tender, more desirable in flavor and more satisfactory in overall palatability than forage-finished beef. Grain-finished beef had twice as much subcutaneous fat as forage-finished beef, the longest sarcomeres and the lowest shear force values. Forage-finished beef had the least subcutaneous fat and when conventionally chilled had the shortest sarcomeres and the highest shear force values. Increases in fat thickness opposite the longissimusmuscle (at the 12 to 13th rib interface) from 1.27 mm to 8.9 mm were associated with increased tenderness in a manner which suggests that fatter carcasses sustain less shortening of muscle fibers and/or increased enzymatic proteolysis during development of rigor mortis. Relationships between fatness, chilling rate and tenderness did not, however, account for all of the differences in tenderness between grain-finished and forage-finished beef. High temperature chilling of forage-finished beef improved tenderness, but did not make it comparable in tenderness or flavor to grain-finished beef.

Forty cattle, ranging in age from 10 months to 27 years at the time of slaughter, were assigned to one of three groups based on chronological age: group I = 305 to 1,033 days, group II = 1,332 to 2,927 days and group III = 3,635 to 9,828 days. The three age groups did not differ significantly in fat percentage, total collagen content, shear force value or sensory panel ratings for juiciness, tenderness and amount of connective tissue; however, samples from age group III had lower (P<.05) percentages of moisture and soluble collagen than samples from age group I. Increases in actual age were significantly associated with decreases in tenderness (initial tenderness rating, age group III; muscle fiber tenderness rating, age group III; amount of connective tissue rating, age group III and the complete population; shear force value, age group III and the complete population). Increased quantities of total collagen were associated with higher (P<.05) sensory panel ratings for juiciness and lower (P<.05) ratings for tenderness and amount of connective tissue; but total collagen content was not related to actual age of the animal. Percentages of soluble collagen and shear force values were positively associated with chronological age of the animal. Actual age and total collagen content were the most important independent variables in multiple regression equations designed to account for the observed variability in tenderness of the bovine longissimusmuscle. In a selected subsample of the parent population, differences in sarcomere length were related (P<.05) to variations in juiciness, amount and solubility of connective tissue (ratings and chemical measures) and fat percentages. Sarcomere length was not associated with tenderness ratings or shear force values suggesting that this histological trait is not closely related to tenderness differences among animals of widely differing chronological age.