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J D Crouse

Publications and source records attributed to J D Crouse.

At least 37 records · Page 2Linked to original sources
PubMed1990

Predicting beef-longissimus tenderness from various biochemical and histological muscle traits.

Our objective was to determine the predictive value of various biochemical and histological traits for tenderness of the longissimus muscle. Data collected from 27 crossbred cattle included longissimus pH, temperature, sarcomere length, total and percentage of soluble collagen, muscle-fiber type and area, cathepsin B and B + L activities, calcium-dependent protease (CDP)-I, -II and inhibitor activities, myofibril fragmentation indices (MFI), Warner-Bratzler shear (WBS) force, sensory-panel tenderness (SPT) ratings and carcass traits. Stepwise regression analyses were performed among breeds or pooled within breeds with WBS and SPT as dependent variables. When MFI were included in the analysis, MFI at d 7 explained 50% of the variation in WBS and SPT at d 14. An additional 19% of SPT was accounted for by the addition of CDP inhibitor d 1 activity and percentage-area of alpha R fibers to the model. However, because variation in MFI was not significant within breed subclasses and MFI could be classified more as a dependent variable, it was removed from the model. This resulted in CDP inhibitor d 1 activity explaining 44% of the variation in WBS and SPT at d 14. Also, percentage-area of beta R fibers, 6 h pH and cathepsin B + L d 14 activity appeared in the model. In addition, CDP inhibitor activity was the only variable to be significant within breed groups. These data suggest that d 7 MFI could be used as a single predictor of d 14 longissimus muscle tenderness; however, CDP inhibitor d 1 activity (a biological event) also may be useful in predicting tenderness.

Animals↗
PubMed1990

Effect of plane of nutrition and age on carcass maturity of sheep.

One hundred twenty ewe and wether lambs were fed high (76% TDN, 12.3% crude protein) or low (70.6% TDN, 16.1% crude protein) energy diets and slaughtered at average ages of 261, 356 or 469 d. High planes of nutrition for lambs at 356 or 469 d of age resulted in heavier carcasses, thicker fat depth and higher flank streaking scores compared to lambs fed low planes of nutrition. Rib bone, break joint and overall maturity scores were not influenced (P greater than .05) by diet. Metacarpal and metatarsal bones from lambs fed high planes of nutrition were slightly longer and heavier and required more force to break (P less than .05) compared with bones from lambs fed low planes of nutrition. The majority of the ewes fed high or low planes of nutrition had fused growth plates and possessed spool joints by 469 d; none of the wethers had spool joints. An additional 27 wethers were slaughtered at an average of 480, 578 or 662 d. Rib bone, break joint and overall maturity scores were not different (P greater than .05) for animals fed the high or low energy diets, but bone weight and shaft break force values were higher for those fed high energy diets. At 662 d of age, only 20% of the wethers on each dietary regimen possessed fused growth plates. Overall, plane of nutrition in market-weight lambs and yearlings had very little influence on the presence or absence of a break joint or on other bone maturity scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Myofibrillar protein turnover in feed-restricted and realimented beef cattle.

The objective of this study was to determine the effect of feed restriction and repletion on myofibrillar protein turnover in cattle. Crossbred steer calves (n = 12) about 310 d of age were assigned randomly to a diet of corn and silage that was 1) provided ad libitum for 146 d (ALC) or 2) restricted so steers gained .2 kg/d for 80 d but received ad libitum access to feed thereafter for 66 d (RFC). At 27, 55, 97, 118 and 146 d a 24-h urine sample and a blood sample were obtained. Urine was analyzed for N tau-methylhistidine (N tau-MH), creatinine (C), urea nitrogen (UN) and total nitrogen (TN). Serum samples were analyzed for hydroxyproline (HYP), C and albumin (A). Body weights were lower (P less than .05) in RFC at 55, 97, 118 and 146 d. Excretion of N tau-MH was lower (P less than .05) in the RFC at 27 and 55 d but higher at 118 d. Urinary C excretion was higher in ALC at the last four sample times. Urinary UN and TN excretion were lower (P less than .05) in RFC at 55, 97 and 118 d; urinary UN also was lower (P less than .05) at d 146. Serum A was higher (P less than .05) in ALC at 55 and 118 d, respectively. Serum HYP was higher (P less than .05) in RFC at 27 and 55 d. Calculated myofibrillar protein breakdown rates (FBR) and fractional synthesis rates (FSR) were higher (P less than .05) in RFC at the last two sampling periods; FSR was lower for the RFC at the first sampling period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1990

Evaluation of attributes that affect longissimus muscle tenderness in Bos taurus and Bos indicus cattle.

Biological tenderness differences between longissimus muscles (LM) from Bos indicus and Bos taurus breeds were evaluated. Steers and heifers of Hereford x Angus (H x A, n = 10), 3/8 Sahiwal x H, A or H x A (3/8 SAH, n = 6) and 5/8 Sahiwal x H, A or H x A (5/8 SAH, n = 11) crosses were utilized. Muscle temperature and pH were monitored every 3 h for the first 12 h and at 24 h. Samples were obtained within 1 h and at 24 h postmortem from the LM for determination of calcium-dependent protease (CDP) -I and -II and CDP inhibitor (INH) activities. At 1 and 14 d postmortem, LM samples were removed for determining cathepsin B and B + L activity, soluble and total collagen, sarcomere length, muscle-fiber histochemistry, shear force and sensory-panel traits. Data were analyzed using least squares procedures with fixed effects of breed cross, sex and their interaction. No significant breed cross effects were observed for carcass traits or rates of pH and temperature decline. Steaks from H x A had lower (P less than .05) shear-force values and higher (P less than .05) sensory scores for tenderness at 1 and 14 d postmortem than steaks from 3/8 and 5/8 SAH. Correspondingly, 5/8 SAH had lower (P less than .05) myofibril fragmentation indices than H x A at 1, 3, 7 and 14 d postmortem. Breed cross effects were not significant for sarcomere length, fiber types, soluble and total collagen, cathepsin B and B + L specific activity, CDP-I and -II activity and INH activity within 1 h postmortem. However, INH total activity/100 g of muscle was greater (P less than .01) at 24 h postmortem for 5/8 SAH (208.8 +/- 14.8) and 3/8 SAH (195.6 +/- 19.3) than for H x A (136.3 +/- 14.9). For H x A, SDS-PAGE revealed that by d 1 desmin had been subjected to proteolysis, and by d 14 desmin could not be detected, but a 30,000-dalton component was clearly evident. However, in 5/8 SAH, desmin remained visible at d 14 without a 30,000-dalton component appearing. This reduced protein hydrolysis may account for less tender meat in SAH; INH apparently influences this process.

Animals↗
PubMed1989

Effects of nisin on growth of bacteria attached to meat.

Nisin had an inhibitory effect on gram-positive bacteria (Listeria monocytogenes, Staphylococcus aureus, and Streptococcus lactis) but did not have an inhibitory effect on gram-negative bacteria (Serratia marcescens, Salmonella typhimurium, and Pseudomonas aeruginosa) attached to meat. Nisin delayed bacterial growth on meats which were artificially inoculated with L. monocytogenes or Staphylococcus aureus for at least 1 day at room temperature. If the incubation temperature was 5 degrees C, growth of L. monocytogenes was delayed for more than 2 weeks, and growth of Staphylococcus aureus did not occur. We also found that the extractable activity of nisin decreased rapidly when the meats were incubated at ambient temperatures and that this decrease was inversely related to the observed inhibitory effect. These findings disclosed that nisin delays the growth of some gram-positive bacteria attached to meat. However, nisin alone may not be sufficient to prevent meat spoilage because of the presence of gram-negative and other nisin-resistant gram-positive bacteria.

Animals↗
PubMed1989

Carcass, muscle and meat characteristics of lean and obese pigs.

Six pigs obtained from a lean selected strain and six pigs obtained from an obese selected strain were slaughtered at about 110 kg live-animal weight. Carcasses were evaluated; hams were dissected into bone, skin, fat and lean, and loin samples were obtained for fiber type characteristics, percentage of fat and moisture, collagen analysis, sensory characteristics, textural properties and objective color analysis. Carcasses from lean pigs were longer, had less backfat and larger longissimus muscle cross-sectional areas than carcasses obtained from obese pigs. Hams from lean pigs had less fat, more bone and more lean than hams from carcasses of obese pigs. The percentages and cross-sectional areas of red and white muscle fibers of the longissimus muscle from lean and obese pigs were not different. However, lean pigs had intermediate fibers that were only 79% as large (P less than .10) as intermediate muscle fibers from obese pigs. Intermediate fibers represented only 7 and 10% of total fiber area, whereas white fibers represented 84 and 79% of total fiber area in longissimus muscle of lean and obese pigs, respectively. Overall, lean pigs tended to possess fewer fibers (-16%) per unit of area than obese pigs, indicating that total muscle fiber hypertrophy was partially responsible for the increased longissimus muscle area of the lean strain. Sensory properties of longissimus meat samples from lean and obese strains were not different. However, the shear force requirement of the longissimus samples from the lean strain were slightly, but significantly (P less than .10), higher than those from the obese strain. No differences were observed in meat color.

Animals↗
PubMed1989

Acceleration of postmortem tenderization in ovine carcasses through infusion of calcium chloride: effect of concentration and ionic strength.

Ovine carcasses were arterially infused with a volume equal to 10% of the live weight after electrical stimulation. The infusion solutions contained .075 M, .15 M or .3 M calcium chloride. Results indicated that .3 M calcium chloride treatment was the most effective concentration of CaCl2 to reduce the shear force value measured at 24 h postmortem. To examine the contribution of ionic strength to tenderization that occurs by infusion of carcasses with .3 M CaCl2, ovine carcasses were infused with CaCl2 and NaCl solutions of identical ionic strength. Results indicated that the tenderization that occurred by infusion of carcasses with CaCl2 was not due to ionic strength of the CaCl2 solution. Results also indicated that, compared to control animals, NaCl-infused carcasses were more tender after 6 d of postmortem storage (but not after 1 d, as observed with CaCl2-infused carcasses). Evidence is presented that indicates that activation of calcium-dependent proteases could be responsible for the observed tenderization (reduction in shear force) due to infusion of ovine carcasses with CaCl2.

Animals↗
PubMed1987

Lipogenesis in adipose tissue from ovariectomized and intact heifers immunized against estradiol and (or) implanted with trenbolone acetate.

Forty-two heifers were allotted randomly to six treatment groups: intact controls, intact heifers implanted with trenbolone acetate, ovariectomized heifers, ovariectomized heifers implanted with trenbolone acetate, intact heifers immunized against estradiol and intact heifers immunized against estradiol and implanted with trenbolone acetate. Blood titers of estradiol-17 beta were increased over 100-fold in heifers immunized against estradiol in Freund's complete adjuvant or saline:squalene/arlacel containing Mycobacterium. Lipogenic enzyme activities and acetate incorporation into fatty acids were increased in subcutaneous adipose tissue obtained at slaughter from heifers receiving immunization or the combination of immunization and trenbolone acetate. The increased lipogenic capacity was not reflected in either cell diameter or cells per gram adipose tissue. Ovariectomy in combination with trenbolone acetate caused the lowest activities for all enzymes measured. This treatments also caused the greatest decrease in cell diameter, which resulted in the largest number of cells per gram of adipose tissue. Trenbolone acetate alone had no detectable effect on lipogenesis in the intact heifer, but the combination of ovariectomy and trenbolone acetate caused substantial decreases in enzyme activities, in most cases a significant decrease as compared with ovariectomized heifers. The data suggest that trenbolone acetate is able to depress lipogenesis only when not competing with the effects of circulating estradiol.

Adipose Tissue↗
PubMed1987

Growth and carcass traits of heifers as affected by hormonal treatment.

Seventy-seven heifers weighing about 200 kg were assigned randomly to intact control (C), ovariectomized (OVX) immunized against estradiol (BSA-E), BSA-E + trenbolone acetate (BSA-E + TBA), TBA or ovx + TBA groups. The objective of the study was to determine the effects of ovariectomy, immunoneutralization of estradiol and trenbolone acetate treatment on growth rate and carcass merit. Heifers were fed a corn-corn silage diet and were slaughtered when treatment groups attained live-animal weights of 433 kg. Observations of rate of growth, efficiency of feed conversion, characteristics of carcasses and characteristics of organoleptic properties of the cooked meat were made. Average daily gains (ADG) were similar in the control and OVX groups and tended to be less than in other treatment groups (P less than .36). Although not statistically significant, the observed mean for the BSA-E + TBA treatment suggests improved ADG and TDN per unit of gain, indicating a possible immunization X TBA interaction. Data also suggested that heifers implanted with TBA had increased ADG and efficiencies of gain. Possibly, immunoneutralization of endogenous estradiol can improve ADG as compared with control and OVX groups. Treatments had no effect on color or texture of lean muscle at the 12th rib interface. The OVX + TBA group had less (P less than .01) 12th rib fat cover than other groups and lower percent fat in the rib than C. The BSA-E + TBA and TBA groups also possessed larger (P less than .02) longissimus muscle areas than the control group. Observations of juiciness, tenderness and flavor were similar among all treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Yield grades and cutability of carcass beef with and without kidney and pelvic fat.

Cut-out data from 2,550 steer carcasses representing British, Continental and Zebu breeding were analyzed to evaluate yield grade classes based on three equations: 1) Ya = 2.5 + .984 AFT + .0084 HCW - .05 REA + .2 KPF; 2) Yb = same as Ya with intercept changed to 3.2 and KPF deleted; 3) Yc = 3.0 + .984 AFT + .0041 HCW - .03 REA, as proposed by USDA in 1984; where AFT = adjusted fat thickness (cm), HCW = hot carcass weight (kg), REA = rib-eye area (cm2), and KPF = kidney and pelvic fat (%). Essentially boneless, closely trimmed (8 mm) roasts and steaks of the four major retail cuts (MRC) were made from one side of each carcass. Cutability was calculated as: Ca, % = 100 (MRC/side) and Cb,c % = 100 (MRC/side, KPF removed). Cutability increased (P less than .01) an average of two percentage points when KPF was removed. In general, removing KPF from the estimation of cutability and changing the coefficients for REA and HCW resulted in a decrease in the number of carcasses yield graded 1 or 4 and an increase in the number of carcasses in yield grade 2. Redistribution of carcasses was greater for Yc than for Yb. Carcasses classified with equation Yc tended (P greater than .05) to have greater cutability in yield grades 1 and 2, and lower (P less than .01) cutability in yield grades 3, 4 and 5.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1986

The effects of rate change in body weight on tissue development and meat quality of youthful bulls.

Forty-eight Angus bulls about 13 mo of age were used to study the effects of rate of change in live weight on muscle fiber, collagen and sensory characteristics of meat. Bulls were fed a finishing diet before treatment, and assigned to three treatments: negative, zero or positive weight gain for 30 or 60 d prior to slaughter. Treatments were imposed by adjusting feed intake. Seventy-two hours after slaughter, carcasses were observed for quality and yield grade characteristics and longissimus muscle samples were obtained for fiber type, collagen and sensory characterization. Carcass lean at the 12th rib interface became darker in color (P less than .01), softer (P less than .05), coarser textured (P less than .01) and more physiologically mature (P less than .01) when bulls were fed an additional 30 d. Increases in average daily gain improved lean texture (P less than .05), but had insignificant effects on lean color. Marbling scores and percentages of kidney and pelvic fat increased (P less than .01) with length of time fed. Quantities of carcass fat were reduced by reducing daily weight gains through restricting dietary intake. Neither length of time fed nor rate of change in live weight affected (P greater than .05) muscle fiber characteristics. Increased age of bulls tended (P greater than .05) to be associated with an increase in red muscle-fiber quantity. Length of time fed or rate of change in live weight did not affect collagen characteristics or tenderness of meat.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Bovine longissimus muscle glycogen concentration in response to isometric contraction and exogenous epinephrine.

Isometric contraction was elicited in cattle by electrical stimulation (electrical immobilization) and was used as a means of investigating the interaction between muscle contraction and epinephrine-induced muscle glycogen degradation. At 0.5 and 24 hours after a 15-minute period of continuous muscle contraction, glycogen content of longissimus muscle specimens collected via needle biopsy was not different from precontraction concentrations. Epinephrine (13.2 mg/kg of body weight) given subcutaneously resulted in a 30% to 35% reduction of muscle glycogen. Reduction of muscle glycogen was slightly greater when epinephrine was used in conjunction with isometric contraction, compared with epinephrine treatment alone. Muscle glycogen increased, and free glucose, lactate, and glucose-6-phosphate decreased, with increases in body weight. In younger, lighter cattle (370 kg), epinephrine decreased muscle glycogen and lactate concentrations and generally decreased muscle glucose concentrations. Muscle-free glucose and lactate concentrations were increased in older, heavier cattle (446 kg) by contraction and epinephrine injection when the animals were immobilized for 30 minutes, with intermittent periods of muscle relaxation. In these cattle, muscle glycogen concentration slightly decreased with isometric contraction. Data indicate that reports of increased glycogenolysis observed in cattle subjected to stress by mixing strange animals or exercise is due to dynamic muscle contraction and not due to isometric muscle contraction.

Animals↗
PubMed1985

Genetic variation in North Amerindian populations: the geography of gene frequencies.

Ten-level synthetic gene frequency maps derived from a principal component analysis of seven polymorphic loci are displayed for a large sample of North Amerindian populations. These maps are useful for assessing population affinities over broad geographical regions and perhaps, as others have argued, for inferring recent migrations. The influence of European admixture is investigated by deleting highly admixed populations and regenerating the maps. In broad outline the resultant geographic patterning, while appearing more homogeneous, preserves many features of the maps that include the highly admixed samples--especially with respect to the Eskimo/non-Eskimo dichotomy. Further, in an effort to evaluate how varying the number of display levels affects patterning as well as interpretation, the maps were replotted at 5 and 20 levels. The 5-level maps are found to accentuate differences between the full data set and the less admixed data set, while the 20-level maps tend to obscure these differences.

Gene Frequency↗
PubMed1985

Genetic variation in North Amerindian populations: association with sociocultural complexity.

A survey of nine polymorphic loci for 82 North Amerindian populations was undertaken to test the hypothesis that increasing levels of sociocultural complexity are ineluctably accompanied by increased heterozygosity. The data reveal a significant relationship in the predicted direction. Moreover, the significant correlation between average heterozygosity and sociocultural complexity is substantially increased by the removal of 19 highly admixed samples. However, this relationship, at least among North Amerindian populations, may be more apparent than real since both mean heterozygosity and the level of sociocultural organization are significantly negatively correlated with latitude. When this latter variable is controlled for, all correlations between heterozygosity and sociocultural complexity are rendered nonsignificant.

Cultural Characteristics↗
PubMed1985

Genetic variation in North Amerindian populations: covariance with climate.

Allelic frequencies at seven polymorphic loci in 74 North Amerindian populations are examined relative to patterns of climatic variation. Canonical correlation analysis reveals strong and significant associations of heterozygosity at the ABO, Ss, Duffy, and P loci with climatic variability. Principal component analysis demonstrates that these loci tend to form correlated ensembles. Moreover, canonical correlation analysis of component scores provides support for an association between polymorphism at these loci and environmental variability. The results are concordant with two previous investigations which suggested a relationship between polymorphism for the ABO, Duffy, and Diego systems and climate. It is suggested that the examination of broad geographic patterns of genetic variation at multiple loci is a valuable, but underutilized, method of screening for the effects of long-term systematic pressures.

Climate↗
PubMed1984

Relative contributions of acetate, lactate and glucose to lipogenesis in bovine intramuscular and subcutaneous adipose tissue.

Intramuscular adipose tissue from the fifth-eighth thoracic vertebrae region of the longissimus dorsi muscle, and portions of the overlying subcutaneous adipose tissue, were obtained at 16 and 18 months of age from Angus steers fed ad libitum either a corn silage (low energy) or ground corn (high energy) diet. Carcass weight, backfat thickness, and kidney, pelvic and heart fat were significantly greater in the steers fed the high energy diet; however, there were no significant differences in marbling scores between diet groups. Additionally, feeding steers the high energy diet did not result in differences in adipocyte diameter or number of adipose cells per gram tissue in either adipose tissue depot. Intramuscular adipocytes had a peak diameter (the diameter represented by the greatest number of cells) of 104 +/- 2 microns; peak diameter in subcutaneous adipose tissue was 141 +/- 5 microns. The activities of ATP-citrate lyase and NADP-malate dehydrogenase increased with age in the subcutaneous adipose tissue; feeding steers the high energy diet increased enzyme activities further. Age and diet had no effect on enzyme activities in intramuscular adipose tissue. A similar pattern was observed for the incorporation of lipogenic precursors into fatty acids. Acetate provided 70-80% of the acetyl units to in vitro lipogenesis in subcutaneous adipose tissue, but only 10-25% in intramuscular adipose tissue. Conversely, glucose provided 1-10% of the acetyl units in subcutaneous adipose tissue, but 50-75% in the intramuscular depot.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1984

Bovine muscle glycogen as affected by fasting and refeeding.

Twelve bulls about 12 mo of age were used to study the effects of dietary stress and realimentation on muscle glycogen depletion and repletion over time. Needle biopsy techniques were used to obtain longissimus muscle samples 11 d before fasting, at the end of fasting, and 3, 7, 10 and 14 d postfasting. Fasting reduced (P less than .05) muscle glycogen from 77 to 50 mumol glycogen-glucose/g. Depressed muscle glycogen content persisted through d 3 while animals were reestablishing normal feed consumption. A glycogen repletion rate of 3 mumol glycogen-glucose X g-1 X d-1 was observed from d 3 to 7.

Animals↗