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Biomedical subjects

J B Morgan

Publications and source records attributed to J B Morgan.

At least 55 records · Page 3Linked to original sources
PubMed1995

Injection-site lesions in carcasses of cattle receiving injections at branding and at weaning.

Crossbred steer and heifer calves (n = 84) were given injections at branding and at weaning (using a completely randomized block design); 225 to 376 d later, pairs of two subprimal cuts from each animal were evaluated for incidence and severity of injection-site lesions. The four products compared were 1) a 2-mL clostridial, 2) a 5-mL clostridial, 3) vitamin AD3, and 4) a long-acting oxytetracycline antibiotic (OTC). Branding-age calves (mean 48.3 d of age) received intramuscular injections of two of the four products, in the semimembranosus (inside round) muscles (one in the left muscle and one in the right); at weaning age (mean 199.3 d of age), calves received injections of the remaining two products in the gluteus medius (top sirloin butt) muscles (one in the left and the other in the right). Injections at branding of 2 mL of clostridial, 5 mL of clostridial, vitamin AD3, and OTC caused injection-site lesions in 72.5, 92.7, 5.3, and 51.2%, respectively, of inside rounds from slaughter cattle. Incidence of injection-site lesions was lowest (P < .05) among inside rounds and top sirloin butts from animals given vitamin AD3 (as calves, and at both branding and weaning times) and was highest (P < .05) in inside rounds from cattle given, as calves, injections of 5 mL of clostridial at branding or of OTC at weaning. Less trimming was required to remove the lesions resulting from injections of all four products when they were given at weaning time. Before completion of the present study, it was thought that injection-site lesions were from damage that subsisted only briefly following an inoculation; these results make it abundantly clear that intramuscular administration of clostridials and certain antibiotics will cause damage so severe that it will be evident in beef muscle 7.5 to 12 mo later.

Aging↗
PubMed1995

Effects of a dexamethasone implant on deposition of intramuscular fat in genetically identical cattle.

Administration of exogenous glucocorticoids has been shown to enhance deposition of intramuscular fat in cattle. In this study, six pairs of genetically identical (cloned) steers were used to determine the effects of an implant containing 100 mg of dexamethasone on intramuscular fat deposition and on other carcass and meat quality traits. One steer in each pair served as a negative control (CON), whereas the other steer received a dexamethasone implant 30 to 60 d from slaughter (DEX). Treatment with dexamethasone did not (P > .05) enhance intramuscular fat deposition. However, DEX steers had greater (.33 cm; P < .05) thickness of external fat, larger (5.94 cm2; P < .05) longissimus muscle areas, and higher (1.9 percentage points; P < .05) dressing percentages than did CON steers. In addition, treatment with dexamethasone increased (P < .01) serum insulin concentrations. Dexamethasone had no effect (P > .05) on cooked beef palatability traits or on 24-h calpastatin activity. Although the DEX implant tested in this study was not effective for improving carcass quality grade, use of the implant increased external fat thickness and was effective for increasing carcass muscularity and dressing percentage.

Adipose Tissue↗
PubMed1995

Use of genetically identical (clone) steers to determine the effects of estrogenic and androgenic implants on beef quality and palatability characteristics.

Six sets of four genetically identical Brangus steers (n = 24; mean weight = 413 kg, SD = 19.8) were used to study the effects of estradiol and trenbolone acetate on beef quality and palatability characteristics. Steers in each clone set were randomly assigned to the following treatment groups: 1) a nonimplanted control; 2) a single estrogenic implant, containing 20 mg of estradiol benzoate and 200 mg of progesterone; 3) a single androgenic implant, containing 140 mg of trenbolone acetate; or 4) a single combination implant, containing 24 mg of 17-beta estradiol and 120 mg of trenbolone acetate. Following implantation, the steers were fed a high-concentrate finishing diet for a period of 112 d. Compared with control steers, implanted steers had higher (P < .05) average daily gains and heavier (P < .05) finished live weights and carcass weights. However, there were no differences (P > .05) among treatment groups with respect to their effects on growth rate, live weight, carcass weight, dressing percentage, fat thickness, longissimus muscle area, percentage of kidney, pelvic, and heart fat, or USDA yield grade. Moreover, marbling scores for implanted steers were not statistically different from marbling scores for control steers. However, a comparison among implant types showed that steers implanted with the estrogenic implant had significantly lower marbling scores than did steers implanted with the androgenic or combination implants. Use of androgenic and combination implants had no effect (P > .05) on beef tenderness of strip loin, top sirloin, or top round steaks; however, use of estrogenic implants decreased (P < .05) tenderness of top sirloin steaks.

Anabolic Agents↗
PubMed1995

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

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

Animals↗
PubMed1995

Feedlot performance, carcass traits, and palatability traits of Hereford and Hereford x Brahman steers.

Short-yearling steer of known genotypes-straightbred Hereford (100H, n = 80) 75% Hereford x 25% Brahman (75H:25B, n = 80), and 50% Hereford x 50% Brahman (50H:50B, n = 80) were sampled serially at four time-on-feed endpoints (84, 98, 112, 126 d) to compare feedlot performance and carcass and palatability traits of Hereford and Hereford x Brahman steers. After slaughter, USDA yield grade and quality grade factors were recorded, and a portion of the longissimus muscle was removed from the left side of each carcass and fabricated into four 2.54-cm steaks for palatability analyses. Paired steaks from each carcass were aged (6 and 18 d after death), and sensory panel and shear force evaluations were performed. At a constant live weight, 100H steers had higher ADG and produced less mature carcasses with smaller longissimus muscle areas and higher marbling scores than did 75H:25B and 50H:50B steers. The 50H:50B steers had the highest (P < .05) values for dressing percentage. Loin steak tenderness and juiciness decreased (P < .05) and shear force values increased (P < .05) as the percentage of Brahman breeding increased. EXtending the postmortem aging period from 6 to 18 d improved shear force values by 20% and panel tenderness ratings by approximately 14%. Beef from steers of the three breeds responded similarly to aging. When Certified Hereford Beef (CHB) specifications were applied, steaks from 100H steers and 75H:25B steers had similar shear force values, suggesting that beef from quarter-blood Brahman crossbred steers could be included in the CHB Program without detrimental effects on product tenderness.

Aging↗
PubMed1995

Effects of dietary supplementation of vitamin E on storage and caselife properties of lamb retail cuts.

Thirty wether lambs were randomly assigned to three treatments consisting of a control (C) and two vitamin E-supplemented treatments (VE), one fed 500 IU of vitamin E.lamb-1.d-1 (E500) and the other fed 1,000 IU of vitamin E.lamb-1.d-1 (E1000). After a 56-d feeding period, lambs were slaughtered and carcass traits were evaluated. Wholesale legs and loins were vacuum-packaged, stored at 4 degrees C for 7, 14, 21, or 28 d, fabricated into retail cuts, and packaged and displayed to simulate retail industry conditions. The E1000 lambs gained less (P < .05) (kg/d; total gain) and had lower (P < .05) carcass weights than the E500 lambs. Alpha-tocopherol levels in the longissimus lumborum were higher (P < .05) (5.79 vs 3.50 micrograms/g of tissue) for VE than for C; however, there was no difference in alpha-tocopherol level in longissimus lumborum between E500 and E1000. Leg retail cuts experienced greater (P < .05) lipid oxidation and received lower (P < .05) lean color scores than did loin retail cuts. Less (P < .05) lipid oxidation occurred from 1 to 7 d of display in VE retail cuts than in C retail cuts. Longer storage periods before retail display resulted in greater (P < .05) lipid oxidation at both 1 and 7 d of display and a higher (P < .05) rate of lipid oxidation during the display period. Supplementing vitamin E had the greatest effect in reducing lipid oxidation when cuts were stored for longer periods before retail display.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The immunological and long-term atopic outcome of infants born to women following a milk-free diet during late pregnancy and lactation: a pilot study.

Infants born to atopic parents have been found to be at high risk of allergy development. The present study investigated the effect of a maternal milk-free diet during late pregnancy and lactation on the immune response and allergy incidence in at-risk and control infants. Atopic mothers were randomly allocated into an intervention group (n 12) or an unrestricted-diet group (n14) and compared with non-atopic mothers following an unrestricted diet (n 12). The intervention involved a maternal milk-free diet during late pregnancy and lactation. Infants were followed up for 18 months postnatally. A significant fall in maternal serum beta-lactoglobulin (beta-Lg)-immunoglobulin G (IgG) antibody levels (P < 0.05) was observed after a 7-week milk-exclusion diet. In maternal and cord serum samples the levels of beta-Lg-IgG and alpha-casein-IgG antibodies were significantly correlated (r 0.89, P < 0.0001 and r 0.71, P < 0.001 respectively). Higher levels of beta-Lg-IgG (P < 0.05) were observed in the cord serum samples compared with paired maternal serum samples. Single-blind allergy assessment by a paediatrician at 12 and 18 months showed that the infants born in the non-atopic group had a significantly lower allergy incidence compared with the infants born in the atopic group following an unrestricted diet (P < 0.008 and P < 0.02 respectively). The allergy incidence in the infants born in the atopic diet group was significantly lower compared with that of the atopic group following an unrestricted diet (P < 0.04). It was observed that the atopic nature of the parents significantly affected the allergy incidence in their children. A trend towards a beneficial effect of a maternal milk-free diet during late pregnancy and lactation was also observed in infants born to atopic parents.

Adult↗
PubMed1994

Incidence of injection-site blemishes in beef top sirloin butts.

The occurrence of damaged muscle tissue resulting from intramuscular injections of animal-health products represents a "quality control" problem and an economic loss to the beef industry. Five individual and sequential national audits of injection-site blemishes in beef top sirloin butts have been conducted at the steak-cutter level. During the most recent audit (March 1993), the incidence of injection-site blemishes in top sirloin butts was determined to be 10.87 +/- 2.99%, with an average weight per blemish of 123.39 +/- 5.48 g. A 5-point classification system used to partition the blemishes into chronological stages of the healing process suggested that the majority of the blemishes originated at the cow-calf or stocker levels, or early in the finishing period. Evaluation of blemish data by geographic location of plant-of-origin suggests that the problem occurs throughout the beef production sector.

Animals↗
PubMed1993

Type of milk feeding in infants and young children up to 19 months of age in three socio-economic groups in Madrid.

The feeding practices of 344 children in Madrid between 3 and 19 months were investigated by controlled interview or their mothers of care-takers. Four different types of milk were given to the children: human milk, infant formula, follow-on formula and cow's milk. Three periods could be defined when infants were most likely to change from one milk type to another. The majority of babies changed from human milk to infant formula some time in the first three months of life. At between four and six months, about half the sample changed to a follow-on formula and, finally, around the baby's first year formula was substituted for cow's milk. Differences in feeding behaviour could be observed among socio-economic groups, but were not statistically significant. Feeding patterns closely followed international recommendations for infant feeding.

Animals↗
PubMed1993

Transfer of cow's milk beta-lactoglobulin to human serum after a milk load: a pilot study.

A sensitive and specific enzyme linked immunosorbent assay (ELISA) was developed for the quantification of cow's milk beta-lactoglobulin in human serum. The assay had a sensitivity of 80 pg/ml (2 standard deviations from zero) and did not cross react significantly with any other tested milk proteins. The absorption of cow's milk beta-lactoglobulin and beta-lactoglobulin immunoglobulin G antibody levels after a milk load was investigated in eight healthy non-allergic individuals. There was a significant variation in the circulating beta-lactoglobulin antigen levels during the six hour period after feeding (p < 0.01) for the combined data. A biphasic absorption pattern was seen in all subjects except one subject who had undetectable levels. No significant variation with time was observed for the beta-lactoglobulin IgG antibody levels and no correlation was found between the beta-lactoglobulin antigen levels and the beta-lactoglobulin IgG antibody levels. This pilot study offered information on the quantity of immunogenic cows' milk protein transferred to the blood after a milk load in non-allergic healthy adults and confirmed a biphasic profile of antigen transfer. The sensitivity of the assay used has shown that transfer of food antigen does occur in the majority of healthy nonallergic subjects.

Adult↗
PubMed1993

IgG subclasses to food proteins in atopic and normal individuals.

IgG subclass antibodies to ovalbumin (OVA), gliadin (GLI) and beta-lactoglobulin (beta-lac) were determined in 18 atopic subjects and 18 age- and sex-matched controls. IgG antibodies to OVA and GLI were found predominantly as IgG4 subclass, with the IgG antibodies to beta-lac distributed evenly between IgG2, IgG3 and IgG4 in both groups. The proportion of anti-OVA IgG antibodies in the IgG3 subclass was significantly higher in the atopic group (22%) than in the nonatopic group (8%: p < 0.001). The proportion of anti-GLI IgG3 antibodies was also higher in the atopic group (43%) than the nonatopic group (24%: p < 0.001). OVA subclass antibodies in the atopic and nonatopic subjects were mainly IgG4, and GLI subclass antibodies were mainly IgG3 and IgG4. This study provides information on the distribution of IgG subclasses to food proteins, and in particular those related to protein GLI. The importance of IgG3 subclasses in atopic disease is highlighted; this phenomenon, to our knowledge, has not previously been reported.

Adult↗
PubMed1993

Effect of castration on myofibrillar protein turnover, endogenous proteinase activities, and muscle growth in bovine skeletal muscle.

The effect of castration on endogenous proteinase activity and myofibrillar protein turnover was investigated in cattle. Six each of MARC III composite bulls and steers weighing approximately 210 kg were given ad libitum access to a typical growing diet. At 0, 42, 84, 126, and 168 d, two consecutive 24-h urine samples were obtained. Urine was analyzed for N tau-methylhistidine (N tau MH) and creatinine. Following slaughter after 170 d on feed, a longissimus muscle sample was removed immediately from each carcass for quantification of mu-calpain, m-calpain, calpastatin, cystatin(s), cathepsin B, and cathepsin B + L activities. Bulls were heavier (P < .05) at 126 and 168 d and more efficient (P < .05) in conversion of feed to gain at 84 and 168 d than were steers. Compared with steers, bulls excreted less (P < .05) N tau MH at 84, 126, and 168 d and displayed lower (P < .05) fractional degradation rates (FDR) at all sample times. No differences (P > .05) in calpain or cathepsin activities were observed between bulls and steers. However, muscle from bulls had greater (P < .05) activities of calpastatin and cystatin(s) than that from steers. A negative relationship existed between d-168 FDR and calpastatin (r = -.72; P < .05) and cystatin (r = -.62; P < .05) activities. These results indicate that decreased FDR of skeletal muscle from growing bulls contributes to their greater efficiency of growth and could be related partially to cystatin-mediated cathepsin activity and(or) calpastatin-mediated calpain activity.

Animals↗
PubMed1993

Meat tenderness and the calpain proteolytic system in longissimus muscle of young bulls and steers.

The objectives of this study were to examine the effects of castration on the calpain proteinase system (mu-calpain, m-calpain, and calpastatin) activities and meat tenderness. Six each, MARC III bulls and steers were slaughtered at approximately 12 mo of age. Longissimus muscle samples were obtained for determining myofibril fragmentation index, Warner-Bratzler shear force, and sensory panel evaluation at 1, 7, and 14 d postmortem, and mu- and m-calpain and calpastatin activities at 24 h postmortem. Bulls produced leaner carcasses with lower (P < .05) quality grades than did steers. Meat from bulls had higher (P < .05) shear force values than meat from steers; however, sensory panelists were unable (P > .05) to detect differences in tenderness or other sensory traits between bulls and steers. Activities of mu- and m-calpain were not affected (P > .05) by castration; however, calpastatin was higher (P < .05) in muscles from the bull carcasses. Lower (P < .05) myofibril fragmentation index values indicate that less proteolysis occurred in muscle from bulls than in muscle from steers during the first 7 d postmortem. Greater calpastatin 24-h activity may be associated with the increased shear force of meat from bulls.

Animals↗
PubMed1993

Enzyme-linked immunosorbent assays for gliadin and ovalbumin and their application in normal subjects.

Two quick, sensitive and direct sandwich enzyme-linked immunosorbent assays (ELISAs) for the measurement of gliadin and ovalbumin in serum have been developed. The ovalbumin assay has a sensitivity of 0.14 ng/ml (2 SD from zero). Cross-reactivities with ovomucoid and conalbumin were 58% and 0.2%, respectively. No cross-reactivity was observed with bovine serum albumin (BSA), human serum albumin (HSA), gliadin and beta-lactoglobulin. The gliadin assay did not cross-react with BSA, HSA, ovalbumin and beta-lactoglobulin and had a sensitivity of 7 pg/ml. In an acute feeding study, of 6 h duration, serum ovalbumin levels were measured in five non-food-allergic subjects who had been given raw eggs (5 g ovalbumin) after an overnight fast. Following a period of at least 1 week the same subjects were given 132 g wholemeal bread (5 g gliadin) after an overnight fast, and serum gliadin levels were measured. After the consumption of raw eggs ovalbumin levels peaked between 210 and 300 min with maximum serum concentration between 0.52 and 31.08 ng/ml. After the consumption of bread, gliadin levels reached a maximum between 180 and 300 min, reaching peak levels between 1.12 and 12.2 ng/ml. We conclude that levels of detected ovalbumin were higher than those for gliadin in this group of individuals.

Adult↗
PubMed1992

Estimates of subprimal yields from beef carcasses as affected by USDA grades, subcutaneous fat trim level, and carcass sex class and type.

One hundred beef carcasses were selected to represent the mix of cattle slaughtered across the United States. Selection criteria included breed type (60% British/continental European, 20% Bos indicus, and 20% dairy carcasses), sex class (beef and Bos indicus: 67% steers, 33% heifers; dairy: 100% steers), USDA quality grade (4% Prime, 53% Choice, and 43% Select), USDA yield grade (10% YG 1, 43% YG 2, 40% YG 3, and 7% YG 4), and carcass weight (steers: 272.2 to 385.6 kg, heifers: 226.8 to 340.2 kg). One side of each carcass was fabricated into boneless subprimals and minor cuts following Institutional Meat Purchase Specifications. After fabrication, subprimals were trimmed progressively of fat in .64-cm increments beginning with a maximum of 2.54 cm and ending with .64 cm. Linear regression models were developed for each individual cut, including fabrication byproduct items (bone, fat trim) to estimate the percentage yield of those cuts reported by USDA Market News. Strip loin, top sirloin butt, and gooseneck rounds from heifers tended to have a higher percentage yield at the same USDA yield grade than the same cuts from steers, possibly resulting from increased fat deposition on heifers. Percentage of fat trimmed from dairy steers was 2 to 3% lower than that from other sex-class/carcass types; however, due to increased percentage of bone and less muscle, dairy steers were lower-yielding. Fat trimmed from carcasses ranged from 7.9 to 15.6% as the maximum trim level decreased from 2.54 to .64 cm.

Adipose Tissue↗
PubMed1992

Beef carcass composition of slaughter cattle differing in frame size, muscle score, and external fatness.

Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as carcass adjusted 12th-rib fat thickness. After collection of USDA carcass grade data, one side of each carcass was fabricated into boneless primals, subprimals, and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the knuckle, tri-tip, and tenderloin, which were trimmed of all fat. Forced four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at the three fat trim levels as influenced by sex class, frame size, muscle score, and adjusted 12th-rib fat thickness. Independent variables that had the most influence on percentage yield of primals and boneless subprimals were adjusted 12th-rib fat thickness and sex class. Within the same phenotypic group, percentage of trimmable fat increased by 2.32% as 12th-rib fat thickness increased by .75 cm. Estimated percentage yield of the major subprimals from the loin and round tended to be higher or relatively equal for heifer carcasses at all trim levels compared with those subprimals from steer carcasses. Holding frame size, sex class, and fat thickness constant, there was a higher percentage yield of chuck roll, rib eye roll, and strip loin for carcasses from thick-muscled cattle than for those from average- and thin-muscled cattle. Frame size had little effect on percentage yield of boneless subprimals.

Abattoirs↗