Biomedical subjects

C R Calkins

Publications and source records attributed to C R Calkins.

At least 19 recordsLinked to original sources

PubMed2007

Carcass traits and M. longissimus lumborum palatability attributes of calf- and yearling-finished steers.

A 2-yr experiment was conducted to compare carcass characteristics and meat palatability attributes of steers ((3/4) British, (1/4) Continental) finished postweaning as calves or yearlings. Calves and yearlings of the same contemporary group were designated to a finishing system at weaning. Calves (n = 73) were finished in the feedlot (191 d) on a high-concentrate diet. Yearlings (n = 84) grazed crop residues after weaning, followed by spring and summer pasture grazing, and concluded with a short finishing period (91 d) in the feedlot. All steers were fed to a constant, fat thickness endpoint of 1 cm. The M. longissimus lumborum steaks from each production system were aged for 7, 14, or 21 d for Warner-Bratzler shear force determination and for 7 or 14 d for in-house sensory panel evaluation. Insoluble, percent soluble, and total collagen were determined. Yearlings produced heavier (P < 0.001) carcasses with larger (P < 0.001) LM areas and lower (P < 0.001) marbling scores and quality grades. Calves possessed greater amounts of total collagen (P < 0.001), with a significantly greater percentage of soluble collagen compared with yearlings (39.72 vs. 24.38%). Calves produced steaks with lower (P < 0.001) shear force values and greater (P < 0.001) sensory ratings for flavor. The USDA Choice steaks from the calves were more (P < 0.001) tender and more (P < 0.050) palatable than Choice steaks from yearlings, and USDA Select steaks from calves were rated more tender (P < 0.001), juicy (P = 0.012), and desirable (P < 0.001) than Select steaks from yearlings. As expected, increasing aging time from 7- to 14- to 21-d produced steaks with lower (P < 0.001) shear force values, regardless of the production system. Risk probabilities showed 1.24% of the steaks from calf-finished steers and 21.22% of steaks from yearling-finished steers to be tough. Sensory rating probabilities showed the steaks from the calves were most likely to be desirable for tenderness, whereas steaks from the yearlings were most likely to be undesirable for tenderness, juiciness, flavor, and overall acceptability. Thus, calf-finished steers produce carcasses superior in quality and palatability compared with those from yearling-finished steers. However, yearling-finished steers can produce tender beef with extended aging.

Aging↗

PubMed2006

Consumer sensory acceptance and value of wet-aged and dry-aged beef steaks.

To determine sensory preference and value of fresh beef steak differing in aging technique, strip steaks were evaluated by consumers in Denver (n = 132 consumers) and Chicago (n = 141 consumers). Wet-aged Choice strip loins were matched with dry-aged Choice strip loins, whereas wet-aged Prime strip loins were matched with dry-aged Prime strip loins. Dry-aged strip loins were commercially aged in air in a controlled environment for 30 d and vacuum-aged for 7 d during shipping and storage. Wet-aged strip loins were vacuum-packaged and aged for 37 d in a 1 degrees C cooler. Pairs of strip loins were matched to similar Warner-Bratzler shear force values and marbling scores. Twelve sensory evaluation panels (of 12 scheduled panelists each) were conducted over a 3-d period in each city. Individual samples from a pair of steaks were evaluated by the panelists for sensory traits. Bids were placed on the samples after sensory traits were obtained utilizing a variation of the Vickery auction with silent, sealed bids. No significant differences for sensory traits of flavor, juiciness, tenderness, or overall acceptability were detected between wet-aged Choice samples and dry-aged Choice samples. Although wet-aged Choice samples were numerically superior for all sensory traits, consumers placed similar bid values (P = 0.12) on wet- and dry-aged Choice samples ($3.82 per 0.45 kg and $3.57 per 0.45 kg, respectively). Wet-aged Prime samples were rated more desirable (P < 0.001) for flavor, tenderness, and overall acceptability than dry-aged Prime samples. Wet-aged Prime samples were valued at $4.02 per 0.45 kg, whereas dry-aged Prime samples brought $3.58 per 0.45 kg (P = 0.008). Consumers (29.3%) who preferred the dry-aged Choice samples over the wet-aged Choice samples were willing to pay $1.99/0.45 kg more (P < 0.001) for dry-aged samples. The consumers who preferred the wet-aged Choice over the dry-aged Choice samples (39.2%) were willing to pay $1.77/0.45 kg more (P < 0.0001). Consumers who preferred wet-aged Prime over dry-aged Prime samples (45.8%) paid $1.92/0.45 kg more (P < 0.0001). Consumers who preferred dry-aged Prime samples (27.5%) were willing to pay $1.92/0.45 kg more than for the wet-aged Prime samples. Although more consumers preferred wet-aged samples, markets do exist for dry-aged beef, and consumers are willing to pay a premium for this product.

Animals↗

PubMed2006

Flavor relationships among muscles from the beef chuck and round.

This research compared off-flavor notes and the relationship of pH and heme-iron content to off-flavor for different beef muscles. After grading, knuckles and shoulder clods were removed from 16 USDA Choice and 14 USDA Select beef carcasses, vacuum-packaged, and aged for 7 d. The rectus femoris (REC), vastus medalis (VAM), vastus lateralis (VAL), teres major (TER), infraspinatus (INF), and triceps brachii-long head (TRI) were separated, cut into steaks, and frozen (-16 degrees C). Sensory analysis was conducted using a trained taste panel, with steaks grilled to an internal temperature of 65 degrees C. Heme-iron concentration and pH were determined. The INF had lower (P < 0.05) off-flavor intensity ratings and less frequent sour flavor than the other muscles, and the VAL had the most intense (P < 0.05) off-flavor ratings and among the greatest frequency of sour, charred, and oxidized flavors. The frequencies of liver-like, bloody, and rancid flavors were not affected by muscle type. Heme-iron concentration did not differ among muscles. Three USDA Select carcasses had intense off-flavor in the muscles. Liver-like flavor was highly negatively correlated with off-flavor intensity for each of the muscles tested. Muscles rated a 5 or below (on an 8-point rating scale, where 1 = extremely intense off-flavor and 8 = no off-flavor) in off-flavor intensity and identified as liver-like by 30% or more of the panelists were grouped together and compared to normal muscles. Those in the liver-flavored group were less frequently identified as charred, probably because the liver-like flavor was so intense. There were no differences between the 2 groups for sour, metallic, bloody, oxidized, or fatty off-flavor notes. Regression equations containing the linear and quadratic functions of heme-iron concentration, muscle pH, and their interaction were established for the frequency of off-flavor notes within each muscle. The REC, TER, VAL, and VAM showed a relationship between pH, heme iron, and off-flavor intensity (P < 0.05). Liver-like flavor was explained partially by pH and heme iron in the REC, VAM, and VAL (R2 = 0.45 to 0.55; P < 0.05). Few other significant relationships were found. Heme iron and pH were unrelated to metallic, oxidized, or rancid flavors for any of the muscles tested. These data suggest that liver-like off-flavors are specific to individual animals, and that pH and heme iron are not strongly related to off-flavor notes.

Analysis of Variance↗

PubMed2005

Consumer sensory acceptance and value of domestic, Canadian, and Australian grass-fed beef steaks.

To determine US consumer acceptance and value of beef from various countries, 24 taste panels of consumers (n = 273 consumers) were conducted in Denver and Chicago. Two pairs of strip steaks were evaluated for flavor, juiciness, tenderness, and overall acceptability on eight-point hedonic scales. One pair consisted of an Australian grass-fed strip steak and a domestic strip steak, whereas the other pair included Canadian and domestic strip steaks. The pairs were matched to similar Warner-Bratzler shear values and marbling scores to decrease variation associated with tenderness and juiciness. A variation of the Vickery auction was used to obtain silent, sealed bids on steaks (0.45 kg) from the same strip loins sampled in the taste panel. Consumers gave higher (P < 0.001) scores for flavor, juiciness, tenderness, and overall acceptability for domestic steaks compared with Australian grass-fed steaks. Domestic steaks averaged 3.68/0.45 dollars kg, whereas consumers placed an average value of 2.48/0.45 dollars kg on Australian grass-fed steaks (P < 0.001). Consumers rated Canadian steaks numerically lower for juiciness (P = 0.09) and lower (P < 0.005) for flavor, tenderness, and overall acceptability than domestic samples. Consumers placed an average value of 3.95/0.45 dollars kg for domestic steaks and 3.57/0.45 dollars kg for Canadian steaks (P < 0.01). Consumers (19.0%) who preferred Australian grass-fed steaks over domestic steaks paid 1.38/0.45 dollars kg more (P < 0.001), whereas consumers (29.3%) who favored the Canadian steaks over the domestic steaks paid 1.37/0.45 dollars kg more (P < 0.001) for the Canadian steaks. A majority of US consumers seem to be accustomed to the taste of domestic beef and prefer domestic steaks to beef from Australia grass-fed and Canadian beef.

Animal Feed↗

PubMed2004

Consumer visual preference and value for beef steaks differing in marbling level and color.

To determine visual preference and value for fresh beef steaks differing in marbling level and color, consumers in Chicago and San Francisco (n = 124 per city) evaluated two pairs of steaks in a retail case. Steaks differing in marbling level (Modest/Moderate vs. Slight) and color (bright, cherry-red vs. dark red) were purchased at retail stores in each city. Consumers selected their preferred steak in each pair, described their selection criteria, and provided the price they were willing to pay for each of the four steaks. There was a difference in visual preference in each city, with most consumers preferring (P < 0.01) low (Slight) over high (Moderate/Modest) marbling; however, more (P < 0.01) consumers in Chicago (86.7%) preferred low marbling than in San Francisco (67.0%). Selection criteria were categorized into five groups: marbling, fat, color, appearance, and palatability. Marbling was mentioned by 65.4% of consumers who preferred high marbling, whereas 64.9% of consumers who preferred low marbling mentioned fat as a selection criterion. Bright, cherry-red color was preferred by a higher (P < 0.01) percentage of consumers in both Chicago and San Francisco (67.6 and 76.5%, respectively). Color was mentioned both by consumers who preferred bright, cherry-red color (64.8%) and those who preferred dark red color (63.9%). All preference groups were willing to pay more for their preferred steak (P < 0.01), but consumers who preferred low marbling were willing to pay more (P < 0.01) for their preferred steak than consumers who preferred high marbling. Consumers who preferred bright, cherry-red color were willing to pay more (P < 0.01) for their preferred steak than consumers who preferred dark red color. Consumers who preferred low marbling seemed to desire lean products, and consumers who preferred high marbling seemed to desire products with high eating quality. In this study, consumers were willing to pay more to purchase their preferred product; however, most consumers preferred low marbling and bright, cherry-red color.

Adipose Tissue↗

PubMed2004

Consumer sensory acceptance and value for beef steaks of similar tenderness, but differing in marbling level.

To determine consumer sensory acceptance and value of beef steaks differing in marbling level (high = upper USDA Choice and low = USDA Select), but similar in Warner-Bratzler shear value, consumers in Chicago and San Francisco (n = 124 per city) evaluated two matched pairs of high- and low-marbled strip steaks, and had the opportunity to participate in a silent, sealed-bid auction to purchase steaks from the same strip loins as the samples. Consumers who purchased steaks also evaluated the steaks when prepared in their homes. Based on overall acceptability ratings, consumers were categorized into three groups: 1) those who consistently found high marbling more acceptable, 2) those who consistently found low marbling more acceptable, and 3) those who were indifferent. Consumers who evaluated at least one high-marbled and one low-marbled sample in their home were included in an evaluation environment analysis (n = 50). High-marbled steaks were rated higher (P < 0.01) in juiciness, flavor, and overall acceptability than low-marbled steaks. In Chicago, consumers tended to bid more (P < 0.10) for high-marbled steaks, whereas consumers in San Francisco did not. Consumers who found high-marbled steaks more acceptable and those who found low-marbled steaks more acceptable were willing to pay more (P < 0.01) for the more acceptable product. Consumers who evaluated high- and low-marbled samples in both the laboratory and home environments rated high- and low-marbled samples similar (P > 0.10) in flavor, juiciness, tenderness and overall acceptability when evaluating the steaks in their homes. In addition, these consumers were willing to pay similar (P > 0.10) amounts for high- and low-marbled samples in both environments. Overall, consumers found high-marbled steaks to be more acceptable than low-marbled steaks in flavor and overall acceptability when tenderness differences were minimized in the laboratory environment. Consumers were willing to pay more for their preference, whether that preference was for high-marbled or low-marbled steaks.

Adipose Tissue↗

PubMed2004

A comparison of consumer sensory acceptance and value of domestic beef steaks and steaks from a branded, Argentine beef program.

To determine consumer sensory acceptance and value of branded, Argentine (grass-finished, aged 30+ d) and domestic (U.S. grain-finished beef, aged 9 d) strip loins were paired based on similar Warner-Bratzler shear force values (P = 0.34) and similar marbling levels (P = 0.82). Consumers in Chicago, IL, and San Francisco, CA (n = 124 per city), evaluated one pair of Argentine and domestic steaks, and had the opportunity to participate in a silent, sealed-bid auction to purchase steaks matching the taste panel samples. Consumers were categorized into three groups based on overall acceptability ratings: 1) those who found Argentine steaks more acceptable, 2) those who found domestic steaks more acceptable, and 3) those who were indifferent. Consumers rated domestic steaks higher (P < 0.05) in juiciness, tenderness, flavor, and overall acceptability. Consumers in both Chicago and San Francisco were willing to pay more (P < 0.05) for domestic steaks (0.86 dollars and 0.52 dollars per 0.45 kg, respectively). In both cities, consumers who found Argentine samples more acceptable were willing to pay more (P < 0.05) for Argentine steaks (0.74 dollars per 0.45 kg in Chicago and 1.82 dollars per 0.45 kg in San Francisco), and consumers who found domestic samples more acceptable were willing to pay more (P < 0.05) for domestic steaks (1.66 dollars per 0.45 kg in Chicago and 1.34 dollars per 0.45 kg in San Francisco). Consumers who were indifferent were willing to pay similar (P = 0.99) amounts for Argentine and domestic steaks. Although some consumers found Argentine beef more acceptable than domestic beef (19.7 and 16.5% in Chicago and San Francisco, respectively) and were willing to pay more for it, most consumers found domestic beef to be more acceptable (59.0% in Chicago and 61.5% in San Francisco) and were willing to pay more to obtain a more acceptable product.

Animals↗

PubMed2003

Prerigor injection using glycolytic inhibitors in low-quality beef muscles.

The objective of this experiment was to determine the effect of prerigor injection of several glycolytic inhibitors on pH, color, tenderness, and related traits of low-value beef cuts. The semimembranosus, triceps brachii, and supraspinatus muscles from each of 10 steer carcasses were removed 1 h postmortem. Control samples remained in the carcass at 2 degrees C for 24 h. Prerigor muscles were injected and tumbled with 10% (by weight) of one of four solutions: sodium citrate (NaC; 200 mM), sodium fluoride (NaF; 200 mM), sodium acetate (NaA; 200 mM), and calcium chloride (CaCl2; 300 mM). All muscles treated with NaC and NaF showed the highest pH and glycogen content (P < 0.05), indicating that glycolysis was inhibited. Injection of NaC in semimembranosus and supraspinatus produced the tenderest meat (P < 0.05), showing a greater increase in tenderization at 3 d than at 7 d postmortem. Treatment did not affect color or oxidation-reduction potential, but all treated muscles tended to be more oxidative (higher oxidation-reduction potential). Sodium citrate was identified as a potential compound to enhance tenderness of prerigor muscle without altering color. Further studies are required to investigate its effect on palatability traits and to provide a basis for commercial application of the process.

Analysis of Variance↗

PubMed1997

Influence of sample orientation on prediction of fresh ham lean content by electromagnetic scanning.

To evaluate the effect of orientation of hams during electromagnetic scanning on the estimation of dissected lean content, hams were scanned horizontally, posterior first (POS) or dorsal first (DOR), and vertically, medial side (aitchbone) first (MED; standing on the butt face). Weight and percentage of dissected lean were estimated using scan peak for each orientation, ham weight, and fat thickness. The mean scan peak for the MED orientation was approximately twice as great as peaks for the POS and DOR orientations, which suggests that this orientation may offer greater predictive accuracy by reducing the signal to noise ratio. Results, however, indicated that all orientations were equally effective at predicting lean weight and percentage, with R2 values of .95 and .75 and root mean square errors of .21 kg and 2.6%, respectively.

Animals↗

PubMed1997

Comparison of USDA quality grade with tendertec for the assessment of beef palatability.

Carcasses (n = 265) selected to differ in USDA yield grade were evaluated by expert graders and assessed for tenderness with the Tendertec Mark III Beef Grading Instrument. Tendertec measurements were collected on longissimus lumborum muscles in both sides of each carcass. During fabrication of each left carcass side, a rib section (later converted into three steaks) was removed for aging and subsequent sensory panel evaluation at 14 d and for Warner-Bratzler shear force measurements at 14 and 28 d. Correlation coefficients for repeatability of Tendertec output variables, between left and right carcass sides, were .57, .44, .70, and .65 for Area-2, Area-2B, Power-2, and Power-2B, respectively. Correlations between Tendertec output variables and Warner-Bratzler shear force evaluations performed on steaks aged 14 or 28 d were not different from zero. Sensory panel ratings for amount of connective tissue were correlated (P < .01) with Tendertec output variables Area-2 and Area-2B (r = -.168 and -.154, respectively), and ratings for overall tenderness were correlated (P < .05) with the Area-2 output variable (r = -.131) but the coefficients were very low. Segregation analysis, using Tendertec output variables Area-2 and Power-2, significantly (P < .05) stratified sensory panel ratings for connective tissue amount and overall tenderness. Even though the Tendertec probe detected some differences in connective tissue contributions to rib steak tenderness, it was not better than USDA quality grade at segmenting A-maturity carcasses into anticipated tenderness outcomes, and thus its applicability as a grading instrument may be limited to use on more mature beef carcasses.

Analysis of Variance↗

PubMed1996

Use of expected progeny differences for marbling in beef: I. Production traits.

Six Angus bulls with HIGH ( > .4) and six bulls with LOW ( < -.16) expected progeny differences (EPD) for marbling were used to evaluate the impact of marbling on progeny production and carcass traits. Bulls were randomly bred to MARC II (1/4 Hereford, 1/4 Simmental, 1/4 Angus, 1/4 Gelbvieh) composite cows in each of 2 yr to calve in the spring. At weaning, steers and heifers were separated and managed in different production systems. Steers (n = 131) were fed a growing diet (1.1 Mcal of NEg/kg) for 48 d followed by adaptation to a 93% concentrate finishing diet. Heifers (n = 125) were fed a growing diet (.79 Mcal of NEg/kg) for 191 d followed by adaptation to the same 93% concentrate diet. Steers and heifers from each treatment were slaughtered at two times spaced about 60 d apart within both years. Marbling EPD class had no effect on fat thickness, USDA yield grade, carcass weight, finishing daily gain, finishing DMI, or finishing efficiency (P > .18). More (P < .05) carcasses of calves from sires with HIGH EPD for marbling graded USDA Choice than from LOW EPD sires, 74% vs 47%, respectively. Angus sires can be selected to produce progeny that have increased ability to grade Choice without increasing yield grade or decreasing animal growth or feed efficiency.

Animals↗

PubMed1996

Use of expected progeny differences for marbling in beef: II. Carcass and palatability traits.

A 2-yr study was conducted to determine the effect of EPD for marbling on marbling score, palatability traits, and carcass fatness in beef. Steer (n = 122) and heifer (n = 123) carcasses were obtained by mating Angus bulls having a high ( > .4) or low ( < -.16) EPD for marbling to MARC II cows (1/4 Angus, 1/4 Hereford, 1/4 Simmental, and 1/4 Gelbvieh). Carcass traits, composition of primals, quarters, and sides, palatability, and shear force data were obtained and adjusted to the mean number of days on feed, equal marbling score (Small50), fat thickness (1.0 cm), and carcass weight (318 kg) end points. Steer carcasses from the high marbling EPD group, adjusted to the mean number of days on feed, had significantly more marbling (P < .01) and less subcutaneous fat in the side and the hindquarter (P < .10) than their low marbling EPD counterparts. Adjusting steers to Small50 marbling produced smaller longissimus muscle area (by 5 cm2), less fat thickness (1.15 vs 1.28 cm), and lighter side weights (306 vs 333 kg) for high marbling vs low marbling EPD groups, indicating a faster rate of marbling deposition. Similar relationships of a greater magnitude were found for heifers, perhaps because the heifers were older than the steers at slaughter. No differences in taste panel ratings or shear force values were noted among steer carcasses. Heifer carcasses from the high marbling EPD group had better (P < .05) ratings for juiciness, muscle fiber tenderness, and overall tenderness than the low marbling EPD group heifers. These results indicate that it is possible, using existing genetic resources, to maintain marbling score and decrease fat in other depots of the carcass without compromising palatability.

Animal Feed↗

PubMed1995

Relationship of restriction fragment length polymorphisms (RFLP) at the bovine calpastatin locus to calpastatin activity and meat tenderness.

Restriction fragment length polymorphisms (RFLP) have been identified at the bovine calpastatin locus. The objective of the present study was to determine whether these polymorphisms are related to variations in calpastatin activity or beef tenderness in unrelated animals of mixed breeding. A sample of 83 crossbred steers from sires representing eight different breeds was examined to determine this relationship. A 2.2-kb cDNA coding for domains 2 through 4 plus a 3' untranslated region of bovine skeletal muscle calpastatin was used as a probe for calpastatin RFLP. Polymorphisms were found using the restriction enzymes BamHI and EcoRI. Polymorphic restriction fragments for BamHI were 9.0 and 5.0 kb and for EcoRI were 6.0 and 4.0 kb. Allelic frequencies for BamHI restriction fragments were .53 for the 9.0-kb allele and .47 for the 5.0-kb allele. Allelic frequencies for EcoRI restriction fragments were .43 for the 6.0-kb allele and >57 for the 4.0-kb allele. No polymorphisms were identified using the restriction enzymes BglII, DraI, or PstI. No associations between EcoRI and BamHI RFLP and 24-h calpastatin activity of Warner-Bratzler shear force at 14 d postmortem were detected. Therefore, the polymorphic EcoRI and BamHI restriction sites within the bovine calpastatin locus do not detect DNA sequence differences responsible for variation in calpastatin activity or tenderness of aged beef. Therefore, these polymorphisms cannot be used to predict tenderness of aged beef from unrelated animals of mixed breeding. These results do not exclude the possibility that other DNA sequences in or near the bovine calpastatin gene are responsible for variation in calpastatin activity or meat tenderness. The lack of a relationship between these calpastatin RFLP and meat tenderness must be distinguished from the well-documented relationship between calpastatin activity and meat tenderness. Therefore, further development of calpastatin-based methods for predicting beef tenderness in unrelated animals of mixed breeding should focus on basic factors influencing calpastatin activity at the molecular and cellular level.

Alleles↗

PubMed1995

The effects of orientation and storage time on the prediction of beef rib composition using electromagnetic scanning.

To investigate the effects of orientation of beef ribs in an electromagnetic field and storage time on the prediction of rib composition, 64 ribs (IMPS 103) were scanned (2.5 MHz) in three different orientations: posterior end first (POS), dorsal end first (DOR), and fat side first, blade end down (BLD). Scans were obtained after 1 and 5 d of storage. Scan peak, rib weight, 3/4 fat depth, length, and temperature were used to predict percentage and weight of dissectable and fat-free lean. The mean peak for the BLD scans was four to six times higher than the POS or DOR scans. Ribs scanned in the BLD orientation on d 5 had the highest coefficient of determination (CD; 94.0) and the lowest residual standard deviation (RSD; .22 kg) for prediction of lean weight. The POS and DOR scans were similar at d 5 (CD = 91.4 and 90.3, respectively) with RSD of .30 and .31 kg, respectively. Prediction of lean percentage resulted in lower CD than predicting lean weight. For percentage of lean, BLD scans at d 5 once again resulted in the best CD (81.6) and lowest RSD (1.5%). Prediction of percentage lean using POS or DOR orientation resulted in CD of 71.2 and 67.1 and RSD of 2.0 and 2.1%, respectively. The CD were similar for POS and DOR scans at d 1 and d 5. Predicting fat-free lean weight resulted in equal or lower CD than dissected lean and higher CD for lean percentage. It seems that orientation during scanning, when consistent, is not a major concern.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Electromagnetic scanning of beef quarters to predict carcass and primal lean content.

To study the use of electromagnetic scanning in prediction of lean content in beef carcasses and cuts, 100 beef cattle (60 steers and 40 heifers), representing a broad range in external fat thickness (.1 to 2.9 cm) and live weight (414 to 742 kg), were selected. Chilled right sides were divided into streamlined (foreshank, brisket, and ventral plate removed) forequarters (FQ) and full hindquarters (HQ) and scanned. Primal rounds, loins, ribs, and chucks were fabricated from the right side, scanned, and physically separated into lean, fat, and bone. Prediction equations for dissected lean content and percentage of lean included the peak of the electromagnetic scan response curve (obtained from scanning the HQ or FQ), length, temperature and weight of the scanned cut, and fat thickness at the 12th rib. Using the coefficient of determination, root mean square error, and Mallows' Cp statistic, the best model for each dependent variable (weight and percentage of lean) that included up to five independent variables was selected. Prediction equations for the HQ or FQ of steers accounted for 84 to 93% of the variation in lean weight of beef sides and quarters and 71 to 93% of primals. Sixty-one to 75% of the variation in percentage of lean in sides and quarters and 48 to 65% of primals was also explained. Similar results were obtained for heifer carcasses. Predicting percentage of lean in any scanned cut, rather than weight of lean, accounted for less of the variation. Weight and fat thickness contributed significantly when predicting percentage of lean.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Temporal response of rabbits to beta-adrenergic agonist feeding: tissue weight, calpains and calpastatin activities, and nucleic acid and protein concentrations.

Forty-eight crossbred rabbits were used in three replications of a 2 x 4 factorial arrangement to investigate the short-term responses of tissue accretion, calpains and calpastatin activity, and nucleic acid and protein concentrations to beta-adrenergic agonist (BAA) feeding. Rabbits were fed a 17% CP diet with or without 7 ppm of L644,969 and slaughtered after 1, 4, 8, or 16 d of treatment. Empty body dressing percentage and biceps femoris weight (as a percentage of empty body weight [EBW]) were significantly higher in the treated rabbits than in the controls after 16 d of treatment. Heart and liver weights (as a percentage of EBW) were higher (P < .05) after 1 d and liver weight (as a percentage of EBW) was lower (P < .05) after 16 d in treated vs controls. Except for an elevation of skeletal muscle m-calpain after 16 d, BAA-supplementation did not affect the calpain-calpastatin system. Muscle RNA concentrations and RNA:DNA ratios were higher (P < .05) in treated rabbits after 1 d and remained higher thereafter. Protein:RNA ratios were lower (P < .01) in treated than in control rabbits after 4 d and remained lower throughout the trial. Muscle DNA content was lower after 4 d and higher after 16 d; RNA content was higher after 4, 8, and 16 d; and protein content was higher after 16 d in treated vs control rabbits. Liver nucleic acid and protein concentrations were not affected by BAA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗

PubMed1993

Effects over time of feeding a beta-adrenergic agonist to wether lambs on animal performance, muscle growth, endogenous muscle proteinase activities, and meat tenderness.

Forty wether lambs were used in a 2 x 4 factorial arrangement to determine the response of animal performance, muscle growth, proteinase activity, and meat tenderness to beta-adrenergic agonist (BAA) supplementation. Lambs were fed a finishing diet with or without 4 ppm of L644,969 and slaughtered after 0, 2, 4, and 6 wk of treatment. The ADG was higher (P < .05) in the treated than in the control lambs after 2 wk and returned to control levels thereafter. Semitendinosus weight and calpastatin activity were higher and mu-calpain activity was lower in the treated than in the control lambs after 2, 4, and 6 wk. Cathepsin B activity was higher (P < .01) and cystatin-like activity was lower (P < .05) after 2 wk in treated than in control lambs but returned to control levels thereafter. Longissimus protein:DNA was higher after 4 (P < .05) and 6 (P < .01) wk in the treated lambs than in the controls. The concentration of RNA and RNA:DNA ratio were higher (P < .01) in the longissimus and semitendinosus muscles in the treated lambs after 2 wk and remained higher throughout the study. Semitendinosus protein and RNA content were higher after 2, 4, and 6 wk and DNA content was higher after 2 and 6 wk in the treated than in the control lambs. Longissimus shear-force values were higher (P < .001) in the treated than in the control lambs at all slaughter end points. These data indicate a rapid alteration of muscle growth, activity of the calpain-calpastatin system, and meat tenderness during BAA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗

PubMed1992

Response time of broiler chickens to cimaterol: meat tenderness, muscle composition fiber size, and carcass characteristics.

The response time to cimaterol (CIM), a beta-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were conducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet containing 1 ppm of CIM. Trial 1 consisted of 55, 31-d-old broiler chickens individually fed for up to 48 h. At 0, 6, 12, 18, 24, and 48 h, five CON and five CIM-fed chickens were killed. Trial 2 consisted of 160, 33-d-old broiler chickens group-fed for up to 14 d. At 2, 4, 6, 8, 10, 12, and 14 d, 10 CON and 10 CIM-fed chickens were killed. The breast muscle (BM) and leg muscle (LM) weight, cathepsin B and L activities, DNA, RNA, and protein concentration, and BM shear force value (SFV) were measured in both trials. Thigh muscle (TM) SFV were measured in Trial 2 only. Fiber size of BM was measured (five birds per treatment) at d 2, 6, 10, and 14. In Trial 1, BM weight and SFV were lower in CIM-fed birds at 6 h (P less than .05). In Trial 2 BM SFV were higher at d 8 (P = .06) and d 10 (P less than .05) in CIM-fed chickens. The SFV of CIM-fed chickens were higher at d 4, 8, 10, 12, and 14 (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗