Warner-Bratzler Shear Values Research Articles

Tenderness variation among loin steaks from A and C maturity carcasses of heifers similar in chronological age.

Fifty-two Angus x Gelbvieh rotationally crossed virgin, ovariectomized, or single-calf heifers were slaughtered after 100 d on a high-concentrate diet. Heifers from each treatment were approximately 31, 33, or 35 mo of age, and they produced 31 A, 5 B, and 16 C maturity carcasses. Because of the small number, B maturity carcasses were not included in this study. Number of A maturity carcasses decreased as age increased. No differences (P > .05) in slaughter weight, total weight gain, dressing percentage, longissimus muscle area, or kidney fat percentage existed between carcass maturity groups, but C maturity heifers had 3.56 mm more fat (P < .01) over the longissimus muscle than A maturity heifers. Marbling scores of slight79 and small0 for A and C maturity carcasses, respectively, did not differ (P > .05). The A and C maturity heifers had similar amounts of collagen and hydroxylysyl-pyridinium crosslinks in metacarpal bone cortex and in longissimus muscle. Neither means for panel tenderness nor Warner-Bratzler shear values differed (P > .05) between maturity groups. Coefficients of variation for tenderness were slightly higher in steaks from C maturity carcasses, but CV for shear values between A and C maturity groups were similar. Because inconsistent meat tenderness is a recognized problem in the beef industry, more research on tenderness variability within maturity and marbling groups is needed. This information, in addition to pooled SEM and differences between means, should aid in finding ways to reduce beef tenderness variability.

Texture Evaluations of Cooked, Diced Broiler Breast Samples by Sensory and Mechanical Methods

The texture of cooked chicken breast is usually determined on intact pieces or strips that are representative of the muscle. Researchers emphasize the importance of uniformity of sample size and orientation of fibers to the shearing blades to ensure consistent data from instruments such as shear devices. For sensory evaluations, sample pieces of chicken breasts presented to panelists are often sized as single 2-cm2 or several 1-cm2 pieces. In this study, two sensory and two mechanical procedures were evaluated for efficacy in discerning texture differences in 1-cm2 pieces of cooked chicken. Three postmortem deboning times (2, 6, and 24 h) provided a texture quality spectrum. Sensory characteristics were evaluated by descriptive analysis-trained panel (DA-TP) and by category scales-untrained panel (CS-UP). Twenty-gram breast portions of 1-cm2 pieces were evaluated using a multi-blade Allo-Kramer (AK) shear blade. Warner-Bratzler (WB) shear values of intact 1.9-cm-wide strips were also recorded. Discriminant analysis classification based on CS-UP gave higher error rates (probabilities of misclassification) than classification based on DA-TP. The CS-UP error rates were 0.36 (tender) and 0.65 (juiciness). The error rate of classification by DA-TP was 0.21. Error rates for classification by mechanical devices were 0.30 for WB and 0.21 for AK. Sample size is a consideration in texture evaluation protocols. Smaller sample pieces appear to mask differences in initial chew characteristics and in juiciness that are due to deboning time.

Effect of Stunning Time and Polyphosphates on Quality of Cooked Chicken Breast Meat

The objective of this research was to determine effects of stunning duration and polyphosphates on color, pH, and texture of chicken breast meat. Sixty broiler chickens were electrically stunned for 2 to 10 s in 2-s intervals and then slaughtered. Left and right Pectoralis major muscles were excised 1 h post-mortem. The left muscles (treated) were treated with a sodium tripolyphosphate salt solution, and the right muscles (controls) were treated with a salt solution alone. All muscles were cooked to an endpoint temperature of 72 C in a 95 C water bath. Measurements of muscle pH were taken on the meat 1 h post-mortem, after treating, and after cooking. Color values and Warner-Bratzler shear values were evaluated on each cooked meat sample.As stunning time increased, pH increased at 1 h post-mortem but treating with either of the solutions eliminated this trend. Muscle pH also increased upon cooking except in the polyphosphate-treated muscles, because the latter muscles achieved maximum pH prior to cooking. Stunning had no apparent effect on color values of the cooked meat; however, polyphosphate treatment resulted in meat that was darker and less red than controls. Longer stunning times resulted in greater shear values but polyphosphates did not affect Warner-Bratzler results. Taken together, these data suggest that processing variables that affect muscle pH also affect quality attributes.

Effects of blast chilling and postmortem calcium chloride injection on tenderness of pork longissimus muscle.

Two studies were conducted to evaluate the effects of blast chilling of carcasses and injection with calcium chloride (CaCl2) at 24 h postmortem on Warner-Bratzler shear values (WBS) and moisture losses of pork longissimus muscles (LM). In a preliminary study, Exp. 1 was conducted to determine whether the injection procedure using 100% water had an influence on WBS of pork LM. Injecting pork LM with water at 24 h postmortem had no effect on WBS (P = .64). In Exp. 2, 27 carcass sides were assigned to 1) blast chilling for 1 h at 25 degrees C and then chilling for 23 h at 1 degree C or 2) standard chilling for 24 h at 1 degree C. At 24 h postmortem, the LM was removed from each side and divided into anterior (AL) and posterior (PL) halves. For each LM, the CaCl2 treatment was assigned randomly to either the AL or PL. Those receiving CaCl2 were injected with a .3 M solution at 10% by weight. Muscles then were stored for 3 d at 1 degree C before 2.54-cm chops were removed, cooked to an internal temperature of 70 degrees C, and allowed to cool for 2 h, then six 1.27-cm cores were taken and sheared. No differences (P > .05) in purge or cooking loss were observed, but rapid chilling reduced (P < .05) the combination of purge and cooking loss without influencing WBS (P = .77). The injection of CaCl2 at 24 h postmortem lowered (P < .05) WBS of pork LM muscle. Therefore, the tenderness of pork can be enhanced by injection of CaCl2.

The influence of genotype, sex, and dietary lysine on pork subprimal cut yields and carcass quality of pigs fed to either 104 or 127 kilograms.

One hundred twenty pigs (initially 44 kg BW) were used to determine the effects of genotype, sex, and dietary lysine on subprimal cut yields and carcass quality. Within genotype (high or medium potential for lean tissue gain), barrows and gilts were fed separately either a .90 or .70% lysine diet until the mean weight of each pen of three pigs reached 104 kg. Then one pig was removed and dietary lysine for the remaining two pigs was decreased to .75 or .55%, respectively. At both 104 and 127 kg BW, carcasses from high-lean genotype (HLG) pigs and gilts had (P < .01) higher percentages of boneless closely trimmed ham, loin, and shoulder than carcasses from medium-lean genotype (MLG) pigs and barrows, respectively. At 104 kg BW HunterLab values indicated (P < .01) that HLG longissimus muscle (LM) was redder, more yellow, and more intense in color than MLG LM. The LM from HLG gilts had (P < .05) higher Warner-Bratzler shear values (less tender) than LM from HLG barrows and MLG pigs at 104 kg BW. At 127 kg BW, HLG LM was visually firmer (P < .05) and more reddish-pink (P < .01); had HunterLab values (P < .01) that indicated a darker, redder color; had less moisture exudate (P < .05), thaw loss (P < .01), and percentage of lipid (P < .01); and had a higher pH (P < .05) than MLG LM. Barrow LM had more marbling (P < .05), a higher percentage of lipid (P < .01), less moisture exudate (P < .05), and less thaw loss (P < .01) than LM from gilts. The LM from HLG barrows had higher (P < .05) Warner-Bratzler shear values than the LM from HLG gilts and MLG pigs at 127 kg BW. Overall, the dietary regimens used in this trial resulted in minimal differences in either carcass quality or cutability. The production option of feeding HLG gilts to 127 kg can be used to optimize carcass cutability and quality traits.

Effect of beef tenderness on consumer satisfaction with steaks consumed in the home and restaurant.

Loin steaks were eaten by 67 consumers over a 15-wk period (n = 739 consumer observations) to determine the consumer acceptability of beef tenderness in the home and a "white table cloth" restaurant. Steaks were rated for tenderness, juiciness, flavor, and overall palatability on an 8-point scale. The acceptability levels for tenderness were established based on Warner-Bratzler shear (WBS) force values, tenderness ratings, and a chisquare analysis of the judgment of tenderness and overall acceptability by the same consumers in both the home and restaurant. Results based only on observations from consumers in Lubbock, TX indicated that the beef industry should target production of beef steaks that have a Warner-Bratzler shear force value of 4.1 kg or less to ensure high levels (98%) of consumer acceptability. Results suggest that an acceptable level of beef tenderness for consumers can be determined and WBS values can be used as criteria for determining which steaks will be considered acceptably tender to consumers before distribution to retail outlets. The beef industry needs to conduct a nationwide research study to determine whether the results from this study will apply to all U.S. beef consumers.

Breed type and sex effects on carcass traits, composition and tenderness of young goats

Seventy-five goats of three breed groups (Florida native (FN), Nubian × Florida native (NF), Spanish × Florida native (SF)) and three sex classes (female, intact male, castrate) were used to study factors affecting carcass and meat characteristics. Goats were fed predominantly a forage diet and slaughtered at the Meat Science Laboratory, Gainesville, FL. NF crosses had the heaviest slaughter and carcass weights when compared to the other breed types. Dressing percentage and individual dress-off items were not affected by breed. Breed type had very little effect on carcass quality and yield indicators. Carcasses from FN goats had higher percentages of fat and lower percentages of bone than did NF or SF carcasses. Breed type did not affect percentage fat-free lean in the side or fat-free lean to bone ratio. Breed type had no effect on Warner-Bratzler shear (WBS) values for muscles from the leg and loin. In contrast, female goats had lower percentages of feet, pelt, liver, heart and kidney when compared to the other sex classes. Male carcasses had softer flank firmness, less marbling but lighter lean color scores than did castrate or female carcasses. Male carcasses had less actual and adjusted fat opposite the ribeye and less estimated kidney and pelvic fat. Sides from male goats had less fat and more fat-free lean than did castrate or female carcasses. Castrates had the lowest fat-free lean to bone ratio of the three sex classes. WBS values from female carcasses indicated more tender muscles than from castrate or intact male carcasses. This study suggested that sex class had a greater influence on carcass characteristics than did breed type.

Carcass and meat quality of second-cross cryptorchid lambs grazed on chicory (Cichorium intybus) or lucerne (Medicago sativa)

The meat quality of cross-bred cryptorchid lambs (6 months old) that had been grazed on chicory (Cichorium intybus; n = 20) or lucerne (Medicago sativa; n = 20) for 8 weeks preslaughter was studied. Unfasted preslaughter liveweight (range 42.5-51.5 kg) was not affected (P&gt;0.05) by treatment. There was no difference (P&gt;0.05) between groups for age at slaughter, hot carcass weight, or measures of fatness GR and Fat C (fat depth over longissimus thoracis et lumborum) when adjusted to a common carcass weight of 21.9 kg. Lucerne-fed lambs were, however, significantly (P&lt;0.05) fatter at the 5th rib. There was no significant (P&gt;0.05) difference between groups for pH, colour values (where L* indicates relative lightness, a* relative redness, b* relative yellowness), Warner-Bratzler shear values, or cooking loss. There was no significant (P&gt;0.05) difference between groups for mean fat colour score or for the distribution of the scores. The b* values for subcutaneous fat tended (P = 0.06) to be greater for lucerne-fed lambs. A comparison of the mean values for aroma and flavour of the longissimus thoracis et lumborum showed no significant (P&gt;0.05) difference between groups and no difference in overall acceptability. Finishing lambs on the chicory cultivar used in this experiment did not adversely affect meat quality and did not result in fatter carcasses than lucerne-fed lambs.

Injection-site lesions: incidence, tissue histology, collagen concentration, and muscle tenderness in beef rounds.

The national incidence and extent of injection-site lesions in the muscles of the round were determined via audits conducted at retail stores and in purveying establishments. Two additional experiments were conducted to examine the subsequent effects of pharmaceutical administration on tissue histology, soluble and insoluble collagen concentration, and muscle tenderness in beef bottom-rounds. Injection-site lesion incidence in beef round cuts audited at retail (n = 3,538) and in steak-cutting facilities (n = 15,464) was 8.45 and 10.04%, respectively, with an average lesion-trim of 314.7 and 191.59 g, respectively, in these two studies. Lesion classification revealed that 93.20 and 99.91% of lesions reported for the retail and purveyor audits, respectively, were chronologically aged lesions. Overall, 19,002 round cuts were examined, and injection-site lesion incidence (nationally) was 9.74%, whereas lesion-trim averaged 211.8 g. Warner-Bratzler shear measurements taken near lesions and in areas 7.62 cm from the lesions were higher (P < .001) for lesioned, than for control bottom-round steaks. Warner-Bratzler shear values for lesion cores were 3.5 times greater than those in paired control (non-affected) steaks. Concentrations of insoluble and soluble collagen were much higher (P < .001) at the site of the lesion center in lesion-afflicted vs control steaks. Histological determinations of the relative proportions of muscle, connective tissue and fat to a distance of 5.08 cm from the site of the lesion center confirmed that severe disruption of muscle tissue constituents and architecture had occurred. Injection-site lesions occur at an unacceptable frequency in the muscles of the round, and severe tissue changes accompany these lesions that can dramatically affect tenderness of those cuts.

Calcium chloride concentration, injection time, and aging period effects on tenderness, sensory, and retail color attributes of loin steaks from mature cows

Calcium chloride (CaCl2) injection effects on retail color changes and sensory traits of loin steaks from mature cows were studied. Left side strip loins (SL) of 10 carcasses were divided into three portions within .5 h postmortem. One was a control, and the other portions were injected with either 150 mM or 200 mM CaCl2. At 24 h postmortem, the chilled, right side SL was removed and the same treatments applied. Steaks from each treatment were evaluated for color changes during 5 d of retail display. Treatments were also divided into 7-d or 14-d aging periods. Warner-Bratzler shear (WBS) values and sensory evaluations of juiciness, tenderness, flavor intensity, flavor description, and overall palatability were obtained on all treatments. Concentration of CaCl2 had no effect on measures of color. However, injection at 24 h reduced colorimeter L values and visual color scores on d 1 and 2 of retail display and increased discoloration scores on d 3 (P < .05) compared with injection at .5 h. All steaks had greater than 40% discoloration when measured beyond d 3. Steaks aged 14 d exhibited significantly lower WBS values than steaks aged 7 d (P < .05). Injections of CaCl2 increased scores for juiciness, tenderness, and overall palatability, and aging improved tenderness, flavor intensity, flavor description, and overall palatability (P < .05). Cuts injected at 24 h had 8.3% and 8.8% higher yields than cuts injected at .5 h or controls, respectively (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of postmortem injection of calcium chloride on tenderness of pork longissimus muscle (1994)

Twenty-seven pork carcass sides were assigned randomly to either blast chilling for 1 h at -13°F followed by 23 h chill at 34°F or a standard chill at 34°F for 24 h. At 24 h postmortem, the longissimus muscle from the center loin region was removed and divided into anterior and posterior halves. Halves were assigned randomly to either calcium-chloride (CaCI2) injection or non-injected controls. Those receiving CaCl2 were injected with a .3 molar solution at 10% pump by weight. Muscles then were stored for 3 d at 34OF before 1-in chops were removed, cooked to an internal temperature of 160°F, and allowed to cool for 2 h before six .5 in cores were sheared. The Warner-Bratzler Shear (WBS) values were lower (more tender) for the CaCl2-injected loins than controls. Blast chilling decreased the combined purge and cooking losses compared to standard chilling. A second trial was conducted to determine the influence of only a 10% water injection on WBS and cooking loss. Five loins were divided into anterior and posterior halves and assigned randomly to either water injection or noninjected controls. Water injection did not influence either WBS or cooking loss values. In conclusion, 24 h postmortem injection of CaCl2 enhances the tenderness of pork longissimus muscle.; Swine Day, Manhattan, KS, November 17, 1994

Observations on some chemical and physical characteristics of buffalo meat

Proximate composition, sarcoplasmic and myofibrillar protein fractions of buffalo meat were similar to those of beef. Buffalo meat was also rich in lysine. Meat from young animals had a lower collagen content than that from old ones. As the temperature of holding the carcasses was increased, the rate of pH fall was faster. Meat from stressed animals showed a higher ultimate pH. Percentage of cooking loss and thermal shrinkage was higher in muscles of old animals than in young ones, which probably reflected the poor condition of the older animals. Meat cooked by pressure cooking showed lower Warner-Bratzler shear values as compared with meat cooked in boiling water.

Interaction of Porcine Somatotropin Administration to Growing Pigs and Frozen Storage of Carcass on Lipids and Quality Characteristics of Roasts

The purpose of this study was to evaluate the effect of porcine somatotropin (pST) treatment on the lipid content and fatty acid profile of cooked pork roasts and to determine if differences were exacerbated by extended frozen storage. Pigs were injected with 3 mg porcine somatotropin (pST) or a placebo daily. At slaughter, roasts were cut from the second to tenth ribs, frozen (−20°C) for 2.5 weeks or 4 months, then cooked and evaluated. Roasts from pST-treated pigs had a lower content of lipids than did the placebo-treated pigs, with the saturated fatty acids decreasing about 40%. They also demonstrated greater Warner-Bratzler shear values. Cholesterol content of the roasts stored frozen for 4 months decreased slightly. Four-month storage slightly decreased cooking time, cooking losses, and expressible moisture index and increased moisture, typical flavor, and juiciness of the roasts. These data suggest that pST treatment altered fat favorably when viewed in light of current dietary recommendations but had less effect on meat quality than did extended frozen storage.

Growth and slaughter characteristics of ram and wether lambs implanted with zeranol

Forty-nine Columbia ram and wether lambs born in April 1990 and 46 born in April 1991 were studied to determine the effects of zeranol implants on growth, difficulty of pelt removal, and carcass characteristics. Implanting ram and wether lambs once (1990) or twice (1991) with 12 mg of zeranol did not change live weight or ADG but gain/feed decreased (P < .05) in ram lambs slaughtered at approximately 50 kg. Testes weight was reduced approximately 50% by implanting. Two implants reduced (P < .05) the force needed to pull the pelt from the hind legs of ram lambs, but implanting tended to increase the force required to pull the pelt from wether lambs. Data for pelt weight, force required to pull the pelt, percentage of the carcass in the shoulder or splenius muscle, and Warner-Bratzler shear values showed that zeranol implants resulted in ram lambs becoming more like wethers and wether lambs becoming more like rams. Implanting with zeranol did not affect closure of the metacarpal growth plate in ram or in wether lambs. Difficulty of pelt removal can be reduced by implanting ram lambs with 12 mg of zeranol at approximately 114 d of age and reimplanting zeranol 28 d later.

Quadratic relationship between early-post-mortem glycolytic rate and beef tenderness

Post-mortem (PM) glycolytic rate in beef M. longissimus thoracis et lumborum (LTL) was controlled by applying low-voltage electrical stimulation (ES) for 1 min at different stages along the slaughter line. The ES treatments were as follows: (1) No electrical stimulation (NES); (2) 75 V to one side of the carcass immediately after splitting; (3) 20–40 V during exsanguination; (4) 75 V either during or following exsanguination. The study utilized 40 bulls and 40 steers. Loin steaks were aged in vacuum pouches 2, 4, 8 and 16 days PM. Quadratic equations utilizing pH at 3 h (pH 3) gave the best estimate of Warner-Bratzler (WB) shear force for 2, 4, 8 and 16 day steaks. The rate of glycolysis is the primary determinant of LTL tenderness in this study. Temperature may only be important through its influence on early PM glycolytic rate. Optimum tenderness was produced by stimulating carcasses or sides to produce a pH 3 of 6·0. ES application to the carcass either just before or after splitting (treatment 2) produced more desirable and consistent pH 3 responses than either NES or ES during exsanguination. Aging has a differential effect whereby the WB shear values from tougher (leaner bulls) 2 day steaks improve to a greater degree, so they are not different from more tender (fatter steers) steaks by 16 day PM.

Titin content of beef in relation to tenderness

Steaks obtained from the longissimus dorsi muscle of 24 crossbred steers were subjected to four treatments (unaged raw, aged raw, unaged cooked, aged cooked) and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Titin migrated primarily as a single protein band in unaged raw samples (48 h post mortem), as a doublet in aged (16 days) raw samples, and as a triplet in unaged and aged cooked samples. Total titin band density remained constant among steaks that varied widely in Warner-Bratzler shear value, suggesting that beef steaks varying in tenderness contain the same amount of titin. It is concluded that titin content, as determined by gel electrophoresis, does not distinguish ‘tough’ from ‘tender’ beef.

The influence of high temperature, type of muscle and electrical stimulation on the course of rigor, ageing and tenderness of beef muscles

The course of rigor mortis (rigor), ageing and tenderness has been evaluated for three beef muscles; M. biceps femoris (BF), M. semimembranosus (SM) and M. semitendinosus (ST), when entering rigor at constant temperatures of 15 and 37°C respectively, with and without electrical stimulation (ES/NS) (85 V, 14 Hz and 32 s). The course of post-mortem changes has been registered by isometric tension, by shortening of unrestrained muscle strips and by following the pH decline and the changes in metabolites, such as ATP and CP. Ageing at +4°C was recorded by measuring Warner-Bratzler (W-B) shear values 2, 8 and 15 days post mortem. On the last occasion, the sensory properties of the cooked meat were also evaluated. Maximum shortening and isometric tension were higher at 37°C as compared to 15°C, whereas ES did not reduce rigor shortening. A high correlation between maximum shortening and the ATP-level at the onset of the shortening rapid phase was found ( r = 0·77 ∗∗∗), which could explain the greater shortening obtained at 37°C compared to 15°C. Rigor shortening is an important phenomenon governing meat tenderness as tenderness is highly affected by rigor temperature but not by ES. This was the case for muscles SM and ST but not for BF muscle. Even though tenderness was measured after ageing (15 days post mortem), shortening during rigor seems to be more important for toughness when rigor mortis occurs at 37°C than any suggested tenderizing effect due to increased proteolysis in this temperature region.

EXTRUSION PROCESSING OF RICE OR CORN FLOUR WITH MECHANICALLY DEBONED TURKEY

Rice flour and yellow or white corn flour were combined at 50, 60 and 70% levels with mechanically deboned turkey and extrusion processed at 104C and 121C. The texture of the extrudates was evaluated by Warner-Bratzler shear (WBS), and flour concentration had more effect on the WBS values than flour type; treatments with 70% flour had significantly greater WBS values. Corn flour treatments and low temperature extrusion resulted in greater TBA values. Proximate composition of extrudates confirmed moisture losses during extrusion and that high temperature processing had mixed results on ether-extractable compounds.

Effect of Calf Management on Carcass Characteristics and Palatability Traits of Veal Calves

Objectives were to explore the feasibility of producing grain-fed veal. Fifteen Holstein bull calves and two Holstein beef cross females were fed milk only or were weaned by 28 d and fed concentrate. Milk-fed calves were reared in painted, metal-sided pens (1.2m × 1.8m) on rubber covered concrete (hosed daily); grain-fed calves were in outdoor movable pens (1.2 × 2.5m). Mean slaughter age was 127 d for both groups. Average birth weight, final BW, and average daily gains were 98, 98, and 97% as much for grain-fed as for milkfed calves. Total 127-d consumption was 1488kg of milk per milk-fed calf, with peak 14-d consumption of 19.9 kg/d, and consumption for grain-fed calves was 103kg of milk and 351kg of concentrate. Blood hemoglobin (10.75 g/dl) did not differ. All calves finished the experiment; scour incidence and medications (48 vs. 0) were much higher with milk feeding. Growth rate (d 28 to 127) was 1.1 kg/d for grain feeding compared with 1.0 kg/d (less than expected) for milk feeding. Hide was not removed until 24h when carcasses were evaluated for USDA grade factors. Milk feeding resulted in lower lean and overall maturity scores; lighter color; more flank fat streaking; greater fat thickness; more kidney, pelvic, and heart fat; lower Warner-Bratzler shear values of loin chops; and higher percentage graded as veal. Composition of longissimus muscle, cooking characteristics, and sensory panel attributes did not differ. Lean maturity and color were not related to shear values or sensory panel evaluations. Total pigment content was correlated positively with flavor intensity.

Effects of implanting ram and wether lambs with zeranol at birth and weaning on palatability and muscle collagen characteristics.

Thirty-five zeranol-implanted (I) and nonimplanted (NI) ram and wether lambs representing four treatments (implanted rams [IR], nonimplanted rams [NIR], implanted wethers [IW], and nonimplanted wethers [NIW]) were evaluated for meat palatability and muscle collagen characteristics. Rib (longissimus muscle, LM) chops from I lambs were juicier (P less than .05) than rib chops from NI lambs. Chops from IR lambs had more (P less than .05) detectable connective tissue and lower myofibrillar and overall tenderness scores than chops from NIR, IW, or NIW lambs. Warner-Bratzler shear (WBS) values tended to be higher (P = .06) for LM chops from rams than for those from wethers, but WBS values for Biceps femoris (BF) chops were similar (P greater than .05) for rams and wethers. Implanting did not affect (P greater than .05) WBS values. Rams had more (P less than .05) LM heat-labile (soluble, SC), nonheat-labile (insoluble, IC), and total collagen (TC) and a higher (P less than .05) percentage of SC (SC/TC) than did wethers. Soluble collagen, TC, and percentage of SC for the BF were higher (P less than .05) and IC tended (P = .09) to be higher in chops from rams than in those from wethers. Implanting did not affect (P greater than .05) collagen amount or solubility. Serum nonprotein hydroxyproline (NPHP) was higher (P less than .05) in rams than in wethers throughout the feeding period and tended (P = .05) to be higher at slaughter. Implanting did not affect (P greater than .05) serum NPHP.(ABSTRACT TRUNCATED AT 250 WORDS)