Biomedical subjects

T L Wheeler

Publications and source records attributed to T L Wheeler.

At least 55 records · Page 3Linked to original sources

PubMed1999

The extent of proteolysis is independent of sarcomere length in lamb longissimus and psoas major.

The objective of this experiment was to determine the effect of sarcomere length on postmortem proteolysis and meat tenderness. Eighteen Dorset market-weight sheep were slaughtered conventionally. The longissimus thoracis et lumborum and psoas major from each carcass were either left intact on the carcass (control), which was chilled at 0 degrees C, or excised from the carcass and chilled in an ice slurry (0 degrees C). At 24 h, control muscles were excised, and all muscles were cut into sections and assigned to 1 or 10 d of postmortem storage at 2 degrees C. Sarcomere length was shorter (P < .01), as intended, in the shortened relative to the control treatment and in longissimus relative to psoas major (1.36 vs 1.69 microm, raw longissimus; 1.45 vs 3.03 microm, raw psoas major). Sarcomere length was not affected (P > .05) by aging time. Western blot analysis of troponin-T and desmin indicated no effect (P > .05) of the shortened treatment compared to the control on the extent of proteolysis. Regardless of aging time or treatment, troponin-T was more degraded (P < .01) in longissimus than in psoas major (38.1 vs 23.5%) and desmin tended to be more degraded (P = .08) in longissimus than in psoas major (50.4 vs 35.1%). Regardless of muscle or treatment, aging 10 d compared to 1 d increased degradation of troponin-T (46.3 vs 15.3%) and desmin (69.3 vs 16.1%). Warner-Bratzler shear force was greater (P < .01) in the shortened treatment than in control (6.9 vs 3.8 kg), greater (P < .01) in longissimus than in the psoas major (6.5 vs 4.2 kg), and greater (P < .01) with 1 d than with 10 d of aging time (6.1 vs 4.6 kg). A muscle x aging time interaction (P < .05) indicated shear force declined more in longissimus than in psoas major during aging. We conclude that sarcomere length did not affect the extent of proteolysis. However, sarcomere length may have an indirect effect on tenderization during aging due to its effect on initial tenderness.

Animals↗

PubMed1998

Coupling of image analysis and tenderness classification to simultaneously evaluate carcass cutability, longissimus area, subprimal cut weights, and tenderness of beef.

The present experiment was conducted to determine whether image analysis of the 12th-rib cross-section used for tenderness classification could accurately predict carcass cutability, longissimus area, and subprimal cut weights. The right side of crossbred steer and heifer carcasses (n=66) was fabricated, and the yield of totally trimmed retail product was determined. Following procedures that we have described for tenderness classification, a 2.54-cm-thick steak was removed from the 12th-rib region of the left side of each carcass, and image analysis was conducted using off-the-shelf technology. Image analysis accounted for more of the variation in retail product yield (RPYD; 89 vs 77%) and retail product weight (95 vs 90%) than did calculated yield grade. Also, image analysis accurately predicted longissimus area (R2=.88). For most subprimals, the combination of image analysis-predicted RPYD and hot carcass weight (HCW) accounted for more of the variation in subprimal weight than did the combination of calculated yield grade and HCW. Whereas HCW, by itself, accounted for only 30 to 34% of the variation in weights of round cuts, the combination of image analysis-predicted RPYD and HCW accounted for 78 to 82% of the variation in weights of round cuts. Hot carcass weight, the combination of calculated yield grade and HCW, and the combination of image analysis-predicted RPYD and HCW accounted for 54, 83, and 91% of the variation in the weight of 80% lean trimmings. Thus, image analysis could be used by the beef industry to more accurately predict individual subprimal weights. In turn, that information and appropriate price extensions could be used to more accurately estimate carcass value. Thus, image analysis could be used by the beef industry in combination with tenderness classification to accurately characterize beef carcasses for cutability and tenderness. These tools should help facilitate the development of value-based marketing systems.

Adipose Tissue↗

PubMed1998

Cooking and palatability traits of beef longissimus steaks cooked with a belt grill or an open hearth electric broiler.

The objective of this experiment was to compare the effects of belt grill and Open Hearth electric broiler cookery on palatability and cooking traits of longissimus steaks. The longissimus thoracis from carcasses of grain-fed steers or heifers was used. Duplicate measurements were made for Warner-Bratzler shear force at 3 and at 14 d after slaughter (n = 180) and trained sensory evaluation at 14 d after slaughter (n = 91) using both cooking methods. Belt grill-cooked samples had lower (P<.01) percentage of cooking losses (21.5 vs 25.8%) and higher (P<.01) shear force values (4.6 vs 4.3 kg) than electric broiler-cooked samples. Repeatability of duplicate measurements was higher for cooking losses (.58 vs .23) and shear force values (.85 vs .64) for belt grill than for electric broiler cooked samples. Belt grilled steaks had lower (P<.01) cooking losses (20.2 vs 29.8%); higher (P<.01) tenderness (7.0 vs 6.7) and juiciness (6.0 vs 5.1); and lower (P<.02) connective tissue amount (7.7 vs 7.8), beef flavor intensity (5.0 vs 5.1), and off-flavor (3.2 vs 3.3) ratings than steaks cooked with the electric broiler. Belt grill cooking increased the repeatability of duplicate sensory measurements for tenderness (.87 vs .71), connective tissue amount (.66 vs .30), and juiciness (.51 vs .08) ratings, and cooking losses (.63 vs .18) compared with cooking with the electric broiler. Belt grill cooking increased the precision for measurements of cooking, Warner-Bratzler shear force, and palatability traits of beef longissimus thoracis.

Animals↗

PubMed1998

Effect of prerigor freezing and postrigor calcium chloride injection on the tenderness of callipyge longissimus.

The effect of rapid prerigor freezing and postrigor freezing and postrigor calcium chloride injection on the tenderness of callipyge longissimus was studied. Ewe and wether lambs (n = 49; 1/2 Dorset x 1/2 Romanov) were grain-fed and slaughtered at approximately 250 d of age. Based on leg conformation scores, 23 of the carcasses had the callipyge phenotype. Within each phenotype, approximately one-half of the carcasses were chilled conventionally (24 h at -2 degrees C). At approximately 17 min postmortem, the remaining carcasses were submersed in liquid nitrogen for 15 min and then held at -2 degrees C for 4 d. At 1 d postmortem for carcasses chilled conventionally and at 4 d postmortem for carcasses frozen in liquid nitrogen, the longissimus muscles from both sides were removed. The longissimus from one side of each carcass was vacuum-packaged and aged (1 degrees C) conventionally for 7 or 14 d. The remaining muscles were injected with a 2.22% solution of food-grade calcium chloride at 5% by weight, vacuum-packaged, and aged as above. Liquid nitrogen freezing was effective in limiting sarcomere shortening (1.99 vs 1.63 microm; P < .05). Warner-Bratzler shear force values of callipyge longissimus were 222 and 232% of that of normal longissimus after 7 and 14 d postmortem, respectively (P < .001). Also, trained panel tenderness rating was decreased by 49.4% in untreated callipyge longissimus after 14 d postmortem. Liquid nitrogen, calcium chloride injection and their combination did not affect d-14 longissimus shear force and sensory tenderness for normal lambs because untreated muscles were already tender. Liquid nitrogen freezing improved the shear force and sensory tenderness rating of callipyge longissimus by 30 and 86.2% after 14 d postmortem, respectively. Calcium chloride injection improved the shear force and sensory tenderness of callipyge longissimus by 36.7 and 86.2% after 14 d postmortem, respectively (P < .001). The most effective treatment for mitigating the callipyge effect on tenderness was the combination (freezing and calcium chloride injection) treatment, which improved the shear force and sensory tenderness by 51.2 and 124.2% after 14 d postmortem, respectively (P < .001). We conclude that either treatment can effectively mitigate the negative effect of callipyge phenotype on longissimus tenderness. Callipyge lamb carcasses subjected to the combination of prerigor liquid nitrogen freezing, postrigor calcium chloride injection, and 14 d postmortem storage had tenderness similar (P > .05) to that of normal, untreated carcasses after 14 d of postmortem storage.

Animals↗

PubMed1997

Effect of postmortem injection time and postinjection aging time on the calcium-activated tenderization process in beef.

The objectives of this study were to determine 1) the effectiveness of calcium chloride when injected later than 2 d postmortem, 2) the effect of extended postinjection aging time, and 3) the tenderness response curve in calcium chloride-treated beef. In Exp. 1, the longissimus thoracis et lumborum was injected on either d 2 or 14 postmortem with 5% by weight of a 200 mM calcium chloride solution. Samples were aged (1 degree C) either 7 or 35 d after injection. The uninjected control longissimus from the contralateral side was aged for 9, 21, 37, or 49 d. In Exp. 2, the longissimus thoracis et lumborum was injected on d 2 postmortem with 5% by weight of a 200 m x M calcium chloride solution then sampled for shear force on d 1, 2, 6, 8, 12, and 14 after injection. Calcium chloride injection, regardless of injection time or postinjection aging time, had higher (P < .05) sensory tenderness rating than control with the same total aging time (5.2, 5.5, 5.8, and 6.1 vs 4.3, 4.8, 5.1, and 5.3, respectively). Calcium chloride injection at d 14 reduced shear force (.7 kg) and increased tenderness rating (.7 units) as effectively (P > .05) as injection at d 2 (1.2 kg and .8 units, respectively). Calcium chloride-injected steaks had higher (P < .05) juiciness ratings than control steaks. Postrigor calcium chloride injection reduced (P < .05) shear force within 1 d after injection and resulted in more tender meat through 14 d after injection. Extended postinjection aging (35 d) had little effect on color display stability. Calcium activated tenderization can be applied as late as 14 d postmortem and will reduce the occurrence of tough meat if aging is limited.

Animals↗

PubMed1997

Consumer evaluation of beef of known categories of tenderness.

A study was conducted to determine consumer perceptions of beef top loin steaks of known shear force and to evaluate how buying trends were modified by the tenderness and price variations of these steaks. Strip loins were cut into a 2.54-cm-thick steaks, and the center steak from each strip loin was used to determine Warner-Bratzler shear force. The remaining steaks were placed into one of the following shear force categories based on that shear force and color-coded accordingly: 1) 2.27 to 3.58 kg (Red); 2) 4.08 to 5.40 kg (White); and 3) 5.90 to 7.21 kg (Blue). Randomly recruited consumers were allowed to evaluate steaks and then purchase steaks based on their findings. A $1.10/kg price difference was placed between each category. Results of the analysis indicated that consumers were able to differentiate between the three categories of tenderness (P < .05). In addition, consumers gave higher (P < .05) juiciness and flavor ratings to Red steaks than to Blue steaks. Overall satisfaction was higher (P < .05) for Red steaks than for the other two categories of steaks. The following percentages of steaks were purchased: 1) Red, 94.6%; 2) White, 3.6%; and 3) Blue, 1.8%. These results suggest that consumers could discern between categories of tenderness and were willing to pay a premium for improved tenderness.

Animals↗

PubMed1997

Effects of somatotropin and salbutamol in three genotypes of finishing barrows: growth, carcass, and calorimeter criteria.

We evaluated the combined use of 0 or 4 mg/d of recombinant porcine somatotropin (pST) and 0 or 2.75 ppm salbutamol in three genotypes of growing barrows (139 d old) differing in lean and lipid accretion potential. Treatments were in a 2 x 2 x 3 factorial arrangement, and the three genotypes tested were Meishan (M, n = 32, 49 kg), Duroc x White composite (D x Wc, n = 31, 62 kg), and Meishan x White composite (M x Wc, n = 31, 64 kg) pigs. Growth performance was evaluated over 28 d for individual pigs, and 20-h feed-deprived heat production was measured before slaughter (d 34). Daily pST injection increased ADG (+70 g/d) and reduced ADFI (-.61 kg/d) across genotypes (P < .05). Salbutamol increased (P < .05) ADG in M x Wc pigs (+146 g/d) but not in M pigs (-60 g/d) or D x Wc (+80 g/d) pigs. However, M pigs had the lowest ADG and ADFI, and M x Wc pigs not treated with salbutamol grew slower than D x Wc pigs (P < .05). Carcass protein and moisture accretion were additively (P < .05) increased by pST and salbutamol for D x Wc and M x Wc pigs. Meishan pigs had increased carcass protein and moisture accretion from pST, whereas only moisture accretion was increased by salbutamol (P < .05). The longissimus muscle area and semitendinosus weight increased as the percentage of M in the genotype decreased (P < .05), and both were increased by pST or salbutamol treatment (P < .001). Leaf fat was decreased more (P < .05) in M pigs than in D x Wc or M x Wc pigs with pST injection. The similar magnitude of leaf fat reduction between D x Wc and M x Wc pigs resulted in a mean genotype difference (P < .05), and salbutamol decreased leaf fat across genotypes. Oxygen consumption and heat production were increased by pST in M pigs more than in the crossbred genotypes, but CO2 production was reduced by similar magnitudes across genotypes, and salbutamol only tended to reduce CO2 production in D x Wc pigs. In general, these data indicate that pST and salbutamol result in additive increases in carcass lean composition; however, growth rate, carcass accretion, and various organ weights may vary among genotypes with salbutamol and pST treatment.

Albuterol↗

PubMed1997

Effect of the callipyge phenotype and cooking method on tenderness of several major lamb muscles.

We conducted three experiments to determine the effects of the callipyge phenotype on the tenderness of several major lamb muscles and to determine the effect of method of cookery on the tenderness of callipyge lamb at 7 d postmortem. In Exp. 1, chops from normal (n = 23) and callipyge (n = 16) carcasses were open-hearth-broiled. Warner-Bratzler shear force values of longissimus, gluteus medius, semimembranosus, biceps femoris, semitendinosus, adductor, and quadriceps femoris were 123, 44, 28, 26, 19, 16, and 13% greater, respectively, for callipyge (P < .05). In Exp. 2, muscles from normal (n = 18) and callipyge (n = 18) carcasses were oven-roasted. Shear force of triceps brachii was 11% greater for callipyge (P < .001); however, phenotype did not affect shear force of supraspinatus (P = .87) or psoas major (P = .64). In Exp. 3, a trained sensory panel evaluated leg roasts and open-hearth-broiled leg chops from normal (n = 60) and callipyge lamb carcasses (n = 60). Callipyge chops were less tender than normal chops (P < .05). Regardless of callipyge phenotype, muscles were more (P < .05) tender when roasted; however, the effect of method of cookery on tenderness scores was greater for callipyge muscles than for normal muscles. Callipyge roasts and normal roasts had similar tenderness (P = .58), and callipyge roasts were more tender than normal chops (P < .05). Regardless of cooking method, callipyge samples were less juicy than normal samples (P < .05). These data demonstrate that the callipyge phenotype will likely reduce consumer satisfaction due to reduced tenderness and juiciness; however, reduced tenderness in callipyge leg muscles could be prevented by ovenroasting.

Analysis of Variance↗

PubMed1997

Characterization of different biological types of steers (cycle IV): wholesale, subprimal, and retail product yields.

Carcass cut-out yields of 888 steers obtained from mating Hereford and Angus cows to Hereford or Angus (HA), Charolais (Ch), Gelbvieh (Gb), Pinzgauer (Pz), Shorthorn (Sh), Galloway (Gw), Longhorn (Lh), Nellore (Ne), Piedmontese (Pm), and Salers (Sa) sires were compared. Data were evaluated at constant age (426 d), carcass weight (324 kg), fat thickness (1.2 cm), fat trim percentage (23%), and marbling (Small(00)) end points. Piedmontese-sired steers excelled in total retail product and fat trim percentages at all slaughter end points except at the 23% fat trim end point. At an age end point, percentage of retail product was greater in steers sired by Continental European breeds (Gb, Ch, Sa, Pz; 63.3 to 65.5% at 0 cm trim) than in steers sired by British breeds (Sh, HA; 60.1 to 61.0%). Piedmontese-sired steers, which were expected to carry one copy of a major gene for muscle hypertrophy, had the highest (P < .05) retail product yields at an age end point (69.7%). At an age end point, although carcass weights were significantly heavier (P < .05) for Charolais-sired steers than for Piedmontese-sired steers, lean growth rate, as reflected by totally trimmed retail product at 426 d, was similar (P > .05) for Piedmontese and Charolais-sired steers. Differences among sire breeds were small for retail product percentage at marbling, fat thickness, and fat trim end points. Ranking of sire breeds for age-constant weight of retail product was as follows: Ch, Pm, Gb, Sa, Ne, Pz, HA, Sh, Gw, and Lh. Sire breed differences in wholesale and subprimal cut yields were similar to total retail product differences. Piedmontese-sired steers produced the most muscular, leanest, and highest-yielding carcasses, and HA- and Sh-sired steers produced the fattest, lowest-yielding carcasses.

Analysis of Variance↗

PubMed1997

Repeatability of tenderness measurements in beef round muscles.

The present experiment was conducted to determine 1) the repeatability of Warner-Bratzler shear force and trained sensory panel tenderness ratings in beef round cuts and 2) the effect of location within beef round cuts on shear force and tenderness ratings. Biceps femoris (BF) and semitendinosus (ST) were obtained from the carcasses of youthful (A-maturity), grain-fed, crossbred steers (n = 25) at 16 d postmortem. Steaks were removed from each muscle for determination of shear force and tenderness rating at each of three locations (A = proximal end, B = center, and C = distal end). Tenderness ratings of triplicate samples were slightly more repeatable than shear force for BF (R = .50 vs .30) and ST (R = .60 vs .56). However, all of those estimates of repeatability were much less than values we have obtained for beef longissimus using similar laboratory procedures (R = .79 to .90). Across both muscles and both methods of assessing tenderness, less than 40% of the total variance was accounted for by animal. The variance of tenderness rating among animals was less for BF (.12) and ST (.09) than values we have obtained for beef longissimus (.60). Location did not affect (P > .05) BF shear force; however, BF tenderness ratings were higher (P < .05) for location A (5.5) than for B (5.0) and C (5.2). Location accounted for a higher percentage of the total variance of ST tenderness rating and ST shear force than did animal. Shear force decreased (P < .05) from the proximal end to the distal end of ST (5.1, 4.6, and 3.9 kg for locations A, B, and C, respectively). Also, ST tenderness ratings were lower for location A (4.8) than for locations B (5.6) and C (5.7). Neither method of measuring tenderness was highly repeatable for BF or ST because there was little animal-to-animal variation in tenderness for these round muscles. Thus, there would be little opportunity for segregating round muscles into tenderness classes.

Analysis of Variance↗

PubMed1997

Tenderness classification of beef: I. Evaluation of beef longissimus shear force at 1 or 2 days postmortem as a predictor of aged beef tenderness.

The present experiments were conducted to evaluate the use of longissimus shear force at 1 or 2 d postmortem as a predictor of beef longissimus shear force at 14 d postmortem. Experiments 1 (n = 400) and 2 (n = 554) included carcasses slaughtered and processed under laboratory and commercial conditions, respectively. A carcass was classified as "tender," "intermediate," or "tough" if its longissimus shear value at 1 or 2 d postmortem was < 6 kg, 6 to 9 kg, or > 9 kg, respectively. For Exp. 1 and 2, large (P < .001) differences existed between each successive tenderness class in mean shear force at 14 d postmortem. Moreover, frequency analysis indicated that tenderness classification accurately (84.8 and 94.8% for Exp. 1 and 2, respectively) predicted whether the sample would have a "low" (< 6 kg) Warner-Bratzler shear (WBS) value at 14 d postmortem. All (100%) of the carcasses in the "tender" class had "low" WBS values at 14 d postmortem, most (81 and 85% for Exp. 1 and 2, respectively) of the carcasses in the "intermediate" class had "low" WBS values at 14 d postmortem, and most (74 and 67% for Exp. 1 and 2, respectively) of the carcasses in the "tough" class did not have "low" WBS values at 14 d postmortem. Although shear force at 2 d postmortem was only moderately correlated (r = .68) with shear force at 14 d postmortem, 68% of the carcasses sampled in Exp. 2 could be guaranteed tender with 100% accuracy based on shear force at 2 d postmortem. Thus, cooked beef longissimus shear force can be measured at 1 or 2 d postmortem and used to predict longissimus tenderness after cooler aging (14 d postmortem) with a relatively high degree of accuracy.

Animals↗

PubMed1997

A comparison of Warner-Bratzler shear force assessment within and among institutions.

Our objective was to compare measurement of Warner-Bratzler shear force of beef longissimus within and among institutions when each institution used its own protocol and when all institutions used a standardized protocol. In Exp. 1, each of five institutions (A, B, C, D, and E) received two adjacent steaks from each of 27 beef strip loins (longissimus lumborum). Warner-Bratzler shear force was measured for both steaks using the procedures normally used at each institution. In Exp. 2, each institution received two adjacent steaks from each of 45 strip loins. Shear force was measured for both steaks using a standardized protocol. In Exp. 1, Warner-Bratzler shear force was highest (P < .05) for A (4.7 kg) and lowest (P < .05) for B (2.9 kg). Repeatability of shear force was highest for A and C (.73 and .72), intermediate for D (.63), and lowest for B and E (.39 and .44). In Exp. 2, Warner-Bratzler shear force was highest (P < .05) for A (5.1 kg) and lowest (P < .05) for E (3.7 kg). Repeatability of shear force was highest for A (.87), intermediate for B, D, and E (.81, .75, and .80), and lowest for C (.67). Shear force values differed within and among institutions due to protocol, execution of the protocol, and instrument variation. Thus, comparisons of Warner-Bratzler shear force data among institutions are currently not valid. However, it is possible for institutions to obtain the same mean shear force value and have high repeatability if a standard protocol is properly executed with calibrated equipment.

Analysis of Variance↗

PubMed1996

Meat toughening does not occur when rigor shortening is prevented.

The objective of this experiment was to test the hypothesis that meat toughening during the first 24 h postmortem results from sarcomere shortening during rigor mortis development. Eleven market-weight lambs were used to measure changes in shear force of clamped longissimus during rigor development. Within 15 min of exsanguination, while attached at both ends, each longissimus was separated from the vertebrae body and clamped between three sets of metal plates to prevent muscle shortening (six clamped sections per lamb). Five of the clamped sections were placed at -1.1 degrees C for 0, 3, 6, 12, or 24 h. After storage at their respective times at -1.1 degrees C, the samples were placed at -30 degrees C for 90 min and then at -5 degrees C for 8 d. The sixth section (168-h section) was stored at -1.1 degrees C for the first 24 h, at 4 degrees C for 144 h, and then treated the same as other sampling times. Sections were sampled for pH, sarcomere length, shear force, and Western blot analyses before and after storage at -5 degrees C. Shear force values were the same (P > .05) from 0 to 24 h (4.5 kg at 0 h to 4.9 kg at 24 h) then declined (P < .05) to 3.3 kg at 168 h postmortem. As evident by lack of statistical difference in the sarcomere lengths, we were successful in holding the muscle length constant. Western blot analyses of nebulin, vinculin, and troponin-T indicated that minimum degradation occurred through 12 h, was slightly increased by 24 h, and was relatively extensive by 168 h postmortem. Although limited proteolysis occurred during storage at -5 degrees C for 8 d, this by itself had no effect on shear force. Results indicate that shear force values do not increase during rigor development when muscle is prevented from shortening; thus, the toughening that occurs during the first 24 h of slaughter is most likely due to sarcomere shortening.

Animals↗

PubMed1996

Effects of a beta-adrenergic agonist (L-644,969) and male sex condition on muscle growth and meat quality of callipyge lambs.

The objective of this study was to determine the effects of dietary administration of a beta-adrenergic agonist (BAA; L-644,969) and male sex condition (ram vs wether) on muscle growth and meat quality of Dorset x Romonov lambs believed to be heterozygous for the callipyge gene. At approximately 17 wk of age, lambs were blocked by weight within each sex condition and randomly assigned to BAA treatment group. The interaction of BAA and male sex condition was not significant for any of the traits measured. Rams had greater initial and final live weights, average daily gain, and hot carcass weight (P < .01). Rams did not differ (P > .05) from wethers with respect to any of the carcass traits, possibly because the wethers were so lean and heavily-muscled that there was little room for improvement. Kidney-pelvic fat weight was reduced 26% by BAA (P < .05). Knife separable lean weight and whole carcass proximate composition were not affected (P > .05) by BAA or male sex condition. Administration of BAA increased calpastatin activity at 20 d (1.1 vs 1.5 units/g), but not at 0 h (3.9 vs 4.8 units/g) postmortem, decreased myofibril fragmentation index (60.7 vs 44.9), and increased shear force (8.2 vs 10.9 kg) at 20 d postmortem (P < .05). These data suggest that muscle growth rates are near maximum in lambs expressing the callipyge gene, regardless of male sex condition or BAA treatment. Therefore, it seems that the callipyge gene exerts most, but not all, of its effect through intracellular events similar to those initiated by administering BAA.

Adrenergic beta-Agonists↗

PubMed1996

Characterization of biological types of cattle (Cycle IV): carcass traits and longissimus palatability.

Carcass and longissimus thoracis palatability traits from 888 steers obtained from mating Hereford and Angus cows to Hereford or Angus (HA), Charolais (Ch), Gelbvieh (Gb), Pinzgauer (Pz), Shorthorn (Sh), Galloway (Gw), Longhorn (Lh), Nellore (Ne), Piedmontese (Pm), and Salers (Sa) sires were compared. Data were adjusted to constant age (426 d), carcass weight (324 kg), fat thickness (1.2 cm), fat trim percentage (23%), and marbling (small00) end points. At a constant age of 426 d, carcasses from Ch steers were heaviest (P < .05) and Gw and Lh carcasses were lightest (P < .05). Adjusted fat thickness was greatest (P < .05) on carcasses from HA and least (P < .05) on carcasses from Ch, Gb, Lh, and Pm steers. USDA numerical yield grades were lowest (P < .05) for carcasses from Pm and highest (P < .05) for carcasses from HA, Ne, and Sh steers. Marbling scores were highest (P < .05) for carcasses from HA, Pz, and Sh and lowest (P < .05) for carcasses from Ch, Ne, and Pm steers. Longissimus thoracis from Pz had a lower (P < .05) shear force than that from all other breeds except HA, Gb, and Pm. Longissimus thoracis of carcasses from Ne steers was least (P < .05) tender. Adjustment of traits to various end points resulted in some changes in sire breed differences depending on the end point and the trait being considered but had little effect on palatability traits. Carcasses from Pm-sired steers provided the most desirable combination of carcass and longissimus palatability traits.

Analysis of Variance↗

PubMed1996

Sampling, cooking, and coring effects on Warner-Bratzler shear force values in beef.

A series of experiments was conducted to determine the effects of various factors on Warner-Bratzler shear force measurement of cooked beef. As the extent of thawing of frozen steaks before cooking for shear force evaluation increases (-2 vs 12 degrees C), shear force decreases (P < .05; 7.34 vs 5.99 kg). Location within the longissimus thoracis et lumborum from which steaks were obtained (caudal, medial, or cranial) did not affect (P > .05) shear force (5.21, 5.15, or 5.26 kg, respectively) or any sensory trait. Mean shear force of longissimus steaks cooked to either a constant temperature of 70 degrees C (6.97 kg) or for a constant time of 30 min (6.38 kg) was not different (P = .06), but shear force repeatability was higher for steaks cooked to constant temperature (.79 vs .53). Mean shear force (6.20 vs 6.33 kg) and shear force repeatability (.74 vs .68) of longissimus steaks cooked by either electric broiler or convection oven broiler, respectively, were not different (P > .05). Meat cores obtained perpendicular to the steak surface, from one location within the muscle, had lower (P < .05) mean shear force (3.41 vs 4.17 kg) and much less repeatable shear force (.12 vs .66) than cores obtained parallel to muscle fiber orientation. Use of more than five cores per animal did not significantly increase repeatability of mean shear force. Numerous factors must be carefully controlled to ensure measurement of shear force is as accurate and repeatable as possible.

Animals↗

PubMed1996

Effect of vitamin C concentration and co-injection with calcium chloride on beef retail display color.

The objectives of these experiments were to determine 1) the most effective vitamin C concentration to stabilize color of beef cuts during retail display and 2) the effect on color of incorporating vitamin C into a calcium chloride (CaCl2) injection solution. Top round cuts (semimembranosus and adductor) were injected with 5% by weight of a 0, .25, .5, 1, 2, or 4% sodium ascorbate solution (Exp. 1) or a 0, .5, 1, or 1.5% sodium ascorbate solution (Exp. 2). In Exp. 1, vitamin C resulted in more (P < .05) stable lean color during 9 degrees C display, and .5, 1, and 2% vitamin C were most (P < .05) effective. In Exp. 2, all concentrations of vitamin C maintained redder (P < .05) steaks after 3, 5, and 7 d of display than control steaks and had a lower (P < .05) percentage of surface discoloration after 5 and 7 d of display at 1 degree C. Experiment 3 used beef bottom round cuts (biceps femoris) to compare control, vitamin C- (1%), CaCl2-(200 mM) and vitamin C + CaCl2-treated steaks displayed at 1 degree C. Calcium chloride-treated steaks were more (P < .05) brown and had a higher (P < .05) percentage of surface discoloration on d 5 and 7 than control steaks, whereas steaks treated with vitamin C or vitamin C + CaCl2 were more (P < .05) red and had lower (P < .05) discoloration on d 5 and 7 than control steaks. Vitamin C can be injected into beef subprimals to enhance lean color stability and extend retail display life. Vitamin C also can be used in combination with CaCl2 to offset potential color deterioration, after 5 d of display, due to salt-induced oxidation.

Animals↗

PubMed1995

The effects of in utero exposure of lambs to a beta-adrenergic agonist on prenatal and postnatal muscle growth, carcass cutability, and meat tenderness.

The objectives of the present experiment were to examine the effects of in utero exposure to a beta-adrenergic agonist (L644,969) on prenatal and postnatal muscle growth and meat tenderness of lambs. Thirty twin-pregnant Composite IV (1/2 Finnsheep, 1/8 Dorset, 1/8 Rambouillet, 1/8 Targhee, 1/8 Suffolk) ewe lambs were used for this experiment. All ewes were fed an alfalfa hay-corn-based diet throughout gestation and lactation. From d 25 to 95 of gestation, the diet of one-half of the ewes contained 2 ppm of L644,969 on an as-fed basis. Treatment did not ( P > .05) affect lamb weights at any point in the growth cycle (birth to 43 kg). Heart weights of neonatal and market lambs were increased ( P < .05) by in utero exposure to L644,969. However, weights of lamb carcass components and weights of individual muscles were not affected by treatment (P > .05). Additionally, treatment did not alter the activities of any of the components of the calpain proteolytic system in neonatal or market lambs. Concomitantly, there was no effect of treatment on myofibril fragmentation index or Warner-Bratzler shear force. Moreover, there was no effect of treatment on muscle fiber type distributions, fiber sizes, or apparent fiber number. It seems that the lack of an effect of treatment on apparent fiber number would explain the lack of an effect on muscle weight. Thus, in utero exposure to L644,969 does not seem to have promise as a method for improving lamb carcass cutability. Other methods of improving the rate and composition of lamb carcass growth while maintaining acceptable meat tenderness must be developed.

Adrenergic beta-Agonists↗