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At least 73 records · Page 4Linked to original sources

PubMed1993

Divergent selection for postweaning feed conversion in Angus beef cattle: III. Linear body measurements of progeny.

Postweaning performance data were obtained on 401 group-fed, purebred Angus calves from 24 selected sires (12 high- and 12 low-feed-conversion sires) from 1983 through 1986 at the Northwestern Branch of the Ohio Agricultural Research and Development Center. Body measurements of progeny were taken from 1983 through 1986 for hip height and backfat, whereas others, except chest measurements (depth and width) that were available only in 1985, were taken from 183 progeny born in 1985 and 1986. The objective of this portion of the study was to determine whether differences in linear body measurements exist between progeny of high- and low-feed-conversion sires. Differences between progeny of high- and low-feed-conversion sires tended to exist (P < .10) for heart girth (176.3 +/- 1.2 vs 173.2 +/- 1.2 cm) and were significant for backfat thickness (.94 +/- .01 vs .87 +/- .02 cm). No significant differences were observed for hip height (115.3 +/- .5 vs 115.5 +/- .5 cm), chest depth (58.8 +/- .6 vs 57.4 +/- .6 cm), chest width (44.4 +/- .5 vs 44.0 +/- .5 cm), head width (21.2 +/- .2 vs 21.1 +/- .2 cm), head length (42.4 +/- .3 vs 41.6 +/- .3 cm), muzzle circumference (41.0 +/- .4 vs 41.6 +/- .3 cm), length between hooks and pins (46.7 +/- .5 vs 46.2 +/- .5 cm), length between shoulder and hooks (94.9 +/- 1.0 vs 93.1 +/- 1.0 cm), or volume (361,199 +/- 4,885 vs 352,718 +/- 5,026 cm3).

Animals↗

PubMed1986

Influence of zeranol implants and electrical stimulation on the palatability traits of five muscles in Angus and Limousin bulls and steers.

A split-plot design was used to study effects of male status (bull vs steer), zeranol implants, breed types (Angus vs Limousin) and electrical stimulation on palatability traits of five major muscles when all animals were fed to a similar fat-thickness endpoint. Warner-Bratzler shear (WBS) determinations and taste-panel evaluations were performed on the longissimus, adductor, semimembranosus, semitendinosus and biceps femoris muscles removed 24 h postmortem. Breed was the most consistent main effect difference, with Angus cattle having lower WBS values than Limousin for the longissimus and semitendinosus muscles. Angus cattle also were favored in many sensory traits. Few significant differences were noted between bulls and steers in taste-panel traits. Differences due to electrical stimulation were most evident in the longissimus muscle, with higher panel-evaluation scores, an enhancement of marbling and lean color and a lower incidence of heat ring. The implant tended to have negative effects on palatability in this trial. An overall ranking of the five muscles based on WBS from most tender to least tender was: adductor, semimembranosus, longissimus, semitendinosus and biceps femoris. Correlations of palatability traits of one muscle to other muscles within an experimental unit were found to be low.

Animals↗

PubMed1984

An evaluation of bias in estimated breeding values for weaning weight in Angus beef cattle field records. III. Estimates of bias due to nonrandom mating.

Field records from 15 herds involved in the Angus Herd Improvement Records program of the American Angus Association indicated that positive assortative mating for weaning weight estimated breeding value (EBV) was being practiced. For each dam, a separate EBV was calculated from information on each progeny with all other progeny data deleted. Individual, paternal and maternal half-sib data available in all years were included in each calculation and thus, were held constant. Bias in cow EBV caused by nonrandom mating was measured as the pooled within dam regression of dam EBV on progeny's sire EBV deviated from the contemporary site average EBV. Across herds, the average estimated bias associated with positive assortative mating ranged from .05 to .08 ratio units.

Animals↗

PubMed1984

An evaluation of bias in estimated breeding values for weaning weight in Angus beef cattle field records. I. Estimates of within herd genetic trend.

Genetic trends for weaning weight were evaluated in 15 purebred herds in the United States participating in the Angus Herd Improvement. Records production testing program. Regression techniques were used for separate estimates of sire and dam contributions that were summed to estimate total herd trend. Sire contributions, calculated as the pooled within sire regression of weaning weight ratio on year of calf birth, ranged from .01 +/- .23 to 1.30 +/- .24 across the herds and average .51 ratio units/yr. Dam contributions, estimated as the pooled within dam regression of offspring weaning weight ratio, deviated from the contemporary paternal half-sib average ratio, on year of calf birth, ranged from .06 +/- .06 to .68 +/- .11 and averaged .34 ratio units/yr. A positive trend in direct effects was associated with a possible negative trend in maternal effects. The annual trend within herds ranged from .21 to 1.50 ratio units and averaged .85 units over all herds, representing 1.8 kg annual genetic gain in weaning weight.

Animals↗

PubMed2006

Genetic parameter estimates for serum insulin-like growth factor I concentrations, and body weight and weight gains in Angus beef cattle divergently selected for serum insulin-like growth factor I concentration.

Data for the current study were obtained from a divergent selection experiment in which the selection criterion was the average serum IGF-I concentrations of 3 postweaning blood samples collected from purebred Angus calves. Multiple-trait derivative-free REML procedures were used to obtain genetic parameter estimates for IGF-I concentrations and for BW and BW gains measured from birth to the conclusion of a 140-d postweaning performance test. Included in the analysis were 2,674 animals in the A(-1) matrix, 1,761 of which had valid records for IGF-I concentrations. Direct heritability estimates +/- SE for IGF-I concentration at d 28, 42, and 56 of the postweaning period and for mean IGF-I concentrations were 0.44 +/- 0.07, 0.51 +/- 0.08, 0.42 +/- 0.07, and 0.52 +/- 0.08, respectively. Heritability estimates for maternal genetic effects ranged from 0.10 +/- 0.05 to 0.20 +/- 0.06. The proportion of total phenotypic variance due to the maternal permanent environmental effect was essentially zero for all measures of IGF-I concentrations. Genetic correlations of IGF-I concentrations with weaning and post-weaning BW ranged from 0.07 +/- 0.12 to 0.32 +/- 0.11 and generally demonstrated an increasing trend during the postweaning period. Averaged across the various measures of IGF-I, the genetic correlation of IGF-I with preweaning gain was 0.14, whereas the genetic correlation with postweaning gain was 0.29. Genetic correlations between IGF-I and BW gain were positive during all time intervals, except between weaning and the beginning of the postweaning test and from d 84 to 112 of the postweaning period. Environmental and phenotypic correlations of IGF-I with BW and BW gains were generally positive, but small. These results indicate that postweaning serum IGF-I concentration is moderately to highly heritable and has small positive genetic, environmental, and phenotypic correlations with BW other than birth weight and with pre- and postweaning gain. Therefore, if IGF-I proves to be a biological indicator of an economically important trait (e.g., efficiency of feed use for growth) in beef cattle, it should be possible to rapidly change IGF-I concentrations via selection without significantly altering live weight or rate of gain.

Aging↗

PubMed2003

Genetic parameter estimates for serum insulin-like growth factor-I concentration and ultrasound measurements of backfat thickness and longissimus muscle area in Angus beef cattle.

A divergent selection experiment for serum IGF-I concentration began at the Eastern Ohio Resource Development Center in 1989 using 100 spring-calving (50 high line and 50 low line) and 100 fall-calving (50 high line and 50 low line) purebred Angus cows. Following weaning, bull and heifer calves were fed in drylot for a 140-d period. Real-time ultrasound measurements of backfat thickness and longissimus muscle area were taken on d 56 and 140 of the postweaning test. Only ultrasound data from calves born from fall 1995 through spring 1999 were included in the analysis. At the time of this study, IGF-I measurements were available for 1,521 bull and heifer calves, and ultrasound data were available for 636 bull and heifer calves. Data were analyzed by multiple-trait, derivative-free, restricted maximum likelihood methods. Estimates of direct heritability for IGF-I concentration at d 28, 42, and 56 of the postweaning period, and for mean IGF-I concentration were 0.26 +/- 0.07, 0.32 +/- 0.08, 0.26 +/- 0.07, and 0.32 +/- 0.08, respectively. Direct heritabilities for ultrasound estimates of backfat thickness ranged from 0.17 +/- 0.11 to 0.28 +/- 0.12, whereas direct heritabilities for longissimus muscle area ranged from 0.20 +/- 0.10 to 0.36 +/- 0.12, depending on the time of measurement and the covariate used for adjustment (age vs. weight). Direct genetic correlations of IGF-I concentrations with backfat thickness at d 56 and 140 and with longissiumus muscle area at d 56 and 140 averaged 0.02, 0.20, -0.08, and 0.23, respectively, when age was used as the covariate for both IGF-I and ultrasound measurements. Corresponding genetic correlations when age was used as the covariate for IGF-I and weight was used as the covariate for ultrasound measurements were 0.05, -0.07, -0.22, and -0.04, respectively. Therefore, the positive associations of serum IGF-I concentration with backfat thickness and longissimus muscle area at d 140 seem to have been partially mediated by weight. Results of this study do not indicate strong associations of serum IGF-I concentration with fat thickness or muscling of bulls and heifers during the postweaning feedlot period.

Adipose Tissue↗

PubMed2000

Genetic parameter estimates for serum insulin-like growth factor-I concentration and carcass traits in Angus beef cattle.

Divergent selection for serum insulin-like growth factor-I (IGF-I) concentration began at the Eastern Ohio Resource Development Center (EORDC) in 1989 using 100 spring-calving (50 high line and 50 low line) and 100 fall-calving (50 high line and 50 low line) purebred Angus cows. Following weaning, bull and heifer calves were fed in drylot for a 140-d postweaning period. At the conclusion of the postweaning test, bulls not selected for breeding were slaughtered and carcass data were collected at a commercial abbatoir. At the time of this analysis, IGF-I measurements were available for 1,283 bull and heifer calves, and carcass data were available for 452 bulls. A set of multiple-trait, derivative-free, restricted maximum likelihood (MTDFREML) computer programs were used for data analysis. Estimates of direct heritability for IGF-I concentration at d 28, 42, and 56 of the postweaning period, and for mean IGF-I concentration were .32, .59, .31, and .42, respectively. Direct heritabilities for carcass traits ranged from .27 to 1.0, .26 to 1.0, and .23 to 1.0 when the age-, fat-, and weight-constant end points, respectively, were used, with marbling score having the smallest heritability and longissimus muscle area having the highest heritability in each case. Maternal heritability and the proportion of phenotypic variance due to permanent environmental effect of dam generally were < or = .21 for IGF-I concentrations and for carcass traits other than longissimus muscle area. Additive genetic correlations of IGF-I concentrations with backfat thickness, longissimus muscle area, hot carcass weight, marbling score, quality grade, and yield grade averaged -.26, .19, -.04, -.53, -.45, and -.27, respectively, when carcass data were adjusted to an age-constant end point. Bulls with lower IGF-I concentrations had higher marbling scores and quality grades, but also had higher backfat thickness and yield grades regardless of the slaughter end point. Serum IGF-I concentration may be a useful selection criterion when efforts are directed toward improvement of marbling scores and quality grades of beef cattle.

Animals↗

PubMed1992

Characterization of bovine MHC class II polymorphism using three typing methods: serology, RFLP and IEF.

Various methods, with different strengths and weaknesses, are currently used to define polymorphism of the bovine major histocompatibility complex (MHC) class II genes. A more complete characterization of bovine lymphocyte antigen (BoLA) haplotypes can be achieved by combining several of these methods. In this study BoLA class II polymorphism was characterized using three typing methods: serology, restriction fragment length polymorphism (RFLP), and isoelectric focusing (IEF). Twenty six Holstein-Friesian and 15 Angus cattle that carried an array of serologically defined BoLA haplotypes were selected for the study. The panel included 12 BoLA complex homozygotes. The three class II typing methods recognized polymorphism associated with the same or very tightly linked genes in the DQ-DR class II subregion. In total 25 BoLA-A locus (class I)--DQ-DR subregion (class II) haplotypes were defined. Three of the serological class II specificities, Dx1, Dx3, and Dx4, were associated with more than one RFLP defined DQ-DR haplotype. The other 4 class II specificities behaved as private specificities. One BoLA haplotype was found in both Holstein and Angus cattle. Two other BoLA haplotypes defined here have previously been described in other breeds. This suggests that these haplotypes exist in strong linkage disequilibrium.

Animals↗

PubMed1981

Estimation of genetic and maternal effects in crossbred cattle of Angus, Charolais and Hereford parentage. III. Optimal breed composition of crossbreds.

Methods for estimating genetic and maternal effects in crossbred populations were extended and generalized to allow estimation of optimal breed combinations. Coefficients of the effects were expressed in terms of the probabilities of obtaining genes from a given parental breed through the sire (PiS), dam (PiD) and maternal grandsire (píS). The formulas are applicable to crosses involving any number of breeds. For purposes of graphic presentation, available genetic and maternal parameters for 205-day weight derived from data involving the Angus (A), Charolais (C) and Hereford (H) breeds were used to develop response surfaces for all two-breed combinations of the A, C and H breeds. PiS, PiD and PíS ranged from 0 to 1. In crosses involving varying proportions of the A and C or the H and C breeds, an increased proportion of C genes resulted in increased 205-day weight, and the shape of the performance surface was largely determined by the breed additive effects of the C breed. Individual and maternal heterosis effects influenced the shape of the performance surface of crosses involving varying proportions of A and H. Application of results to the formation of synthetic breeds is discussed.

Animals↗

PubMed1997

Genetic parameter estimates for serum insulin-like growth factor I concentration and performance traits in Angus beef cattle.

Data for this study were obtained from an experiment involving divergent selection for blood serum IGF-I concentration in beef cattle. Multiple trait derivative-free REML procedures were used to obtain genetic parameter estimates for IGF-I concentration at d 28, 42, and 56 of the postweaning period and for mean IGF-I concentration, as well as for weights and gains. Included in the analysis were 1,563 animals in the A-1 matrix, 731 of which had valid records for mean IGF-I concentration. Direct heritabilities (hd2) were .42 +/- .13, .53 +/- .15, .71 +/- .16, and .48 +/- .13 for IGF-I at d 28, 42, and 56 of the postweaning period and for mean IGF-I, respectively. Heritability of maternal genetic effects (hm2) ranged from .02 to .12, whereas the proportion of the total variance due to the maternal permanent environmental effect (c2) was essentially zero for all measures of IGF-I. Genetic correlations of IGF-I with weaning and postweaning weights and with postweaning weight gain ranged from -.21 to -.54 and averaged -.38. The environmental correlation between IGF-I and performance traits varied from .10 to .35 and averaged .22. Phenotypic correlations of IGF-I concentrations with weaning weight and postweaning weights and gains ranged from -.01 to .12 and averaged .04. Estimates of hd2 indicate that it should be possible to change IGF-I concentration in beef cattle via selection. Negative genetic correlations imply that, if the goal is to make genetic improvement in weaning weights, postweaning weights and (or) postweaning gain in beef cattle, selection should be for decreased postweaning serum IGF-I concentration.

Animals↗

PubMed1989

The relationship of insulin-like growth factor-I with postweaning performance in Angus beef cattle.

This study was designed to evaluate the ontogeny of serum IGF-I (SI) concentrations and its relationship to animal performance in a 140-d postweaning feeding trial. Ninety-eight progeny representing six sires (three high and three low feed conversion) and two sexes (43 bulls and 55 heifers) with ad libitum access to feed were allocated by sire and sex to monitor individual weights and pen feed consumption. Blood serum samples were obtained at the beginning of test (average age of 230 d) and every 28 d thereafter until each animal reached a fat thickness (estimated by sonoray) of 8.9 mm. Individual serum samples were acid-ethanol extracted and measured for IGF-I peptide by heterologous RIA. Serum IGF-I concentrations differed (P less than .10) between high (H) and low (L) feed conversion progeny groups at the end of the first 28-d period (125.12 vs 89.52 ng/ml) and tended to differ at the conclusion of the second 28-d period (P less than .15). Weight gains of H and L groups tended to differ in the second and third 28-d periods (P = .11 and .10, respectively). Serum IGF-I concentrations differed (P less than .05) between bulls and heifers for the first through fourth 28-d periods (P less than .01, P less than .05, P less than .10 and P less than .01, respectively). Phenotypic correlations indicated that pens with higher mean SI concentrations at the beginning of the test consumed less feed and had lower cumulative feed:gain ratios.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2005

Supplementing a ruminally undegradable protein supplement to maintain essential amino acid supply to the small intestine when forage intake is restricted in beef cattle.

Twelve Angus crossbred cattle (eight heifers and four steers; average initial BW = 594 +/- 44.4 kg) fitted with ruminal and duodenal cannulas and fed restricted amounts of forage plus a ruminally undegradable protein (RUP) supplement were used in a triplicated 4 x 4 Latin square design experiment to determine intestinal supply of essential AA. Cattle were fed four different levels of chopped (2.54 cm) bromegrass hay (11.4% CP, 57% NDF; OM basis): 30, 55, 80, or 105% of the forage intake required for maintenance. Cattle fed below maintenance were given specified quantities of a RUP supplement (6.8% porcine blood meal, 24.5% hydrolyzed feather meal, and 68.7% menhaden fish meal; DM basis) designed to provide duodenal essential AA flow equal to that of cattle fed forage at 105% of maintenance. Experimental periods lasted 21 d (17 d of adaptation and 4 d of sampling). Total OM intake and duodenal OM flow increased linearly (P < 0.001) as cattle consumed more forage; however, OM truly digested in the rumen (% of intake) did not change (P = 0.43) as intake increased. True ruminal N degradation (% of intake) tended (P = 0.07) to increase linearly, and true ruminal N degradation (g/d) decreased quadratically (P = 0.02) as intake increased from 30 to 105%. Duodenal N flow was equal (P = 0.33) across intake levels, even though microbial N flow increased linearly (P < 0.001) as forage OM intake increased. Total and individual essential AA intake decreased (cubic; P < 0.001) as forage intake increased because the supply of nonammonia, nonmicrobial N flow from RUP was decreased (linear; P < 0.001) by design. Total duodenal flow of essential AA did not differ (P = 0.39) across these levels of forage intake. Although the profile of essential AA reaching the duodenum differed (P < or = 0.02) for all 10 essential AA, the range of each essential AA as a proportion of total essential AA was low (11.1 to 11.2% of total essential AA for phenylalanine to 12.3 to 14.3% of total essential AA for lysine). Duodenal essential AA flow did not differ (P = 0.10 to 0.65) with forage intake level for eight of the 10 essential AA. Duodenal flow of arginine decreased linearly (P = 0.01), whereas duodenal flow of tryptophan increased linearly (P = 0.002) as forage intake increased from 30 to 105% of maintenance. Balancing intestinal essential AA supply in beef cattle can be accomplished by varying intake of a RUP supplement.

Amino Acids↗

PubMed2006

Examination of potential methods to predict pulmonary arterial pressure score in yearling beef cattle.

Susceptibility of beef cattle to high altitude disease (HAD) is of major importance to economic and genetic selection on high elevation ranches. However, currently the best indicator of HAD susceptibility is the pulmonary arterial pressure (PAP) test, a test with high cost and invasive nature. Therefore, 2 experiments were undertaken to determine whether emerging technologies that predict blood components could be used to predict the PAP score in yearling Angus cattle. In Exp. 1, 39 yearling Angus bulls were used to determine if a relationship existed between PAP score and 10 blood components provided by a hemogram using whole blood or oxygen saturation as predicted by pulse oximetry in nonanesthetized cattle measured rectally or orally. Three of the hemogram values (packed cell volume, hemoglobin concentration, and red cell distribution width) were correlated (P < 0.10) with the PAP score. Prediction equations for PAP score were generated using the hemogram values and resulted in R2 values of 0.375 and 0.305 for the regression model using all of values and the best 2-variable model, respectively. Pulse oximetry was able to provide oxygen saturation predictions rectally or orally; however, the predicted values were not correlated with the PAP score (P > 0.10) or with each other (P > 0.10). In Exp. 2, 84 yearling Angus cattle (62 bulls, 22 heifers) were used to evaluate the ability of a portable clinical analyzer to predict the PAP score using 11 blood components from a sample of whole blood evaluated at the processing chute. The portable clinical analyzer was able to provide values for all of the 11 blood components; however, none of the predicted values were correlated with the PAP score (P > 0.10). In these preliminary experiments, 3 blood component values provided via the hemogram were the only variables both correlated with the PAP score and able to contribute to the development of a useful PAP prediction equation that could reduce the cost of traditional measures of HAD susceptibility. Future research is needed to determine whether additional blood components or emerging blood analysis technologies are able to accurately predict the PAP score in beef cattle.

Altitude Sickness↗

PubMed1988

Phosphorus supplementation of cattle.

Severe lameness in a large proportion of an Angus cattle herd was attributed to phosphorus deficiency. The diagnosis was supported by a rapid response to phosphorus supplementation of the diet. A brief review of the development and diagnosis of phosphorus deficiency is presented. Practical considerations severely limit the choice of a phosphorus supplement. Directions for the use of the supernatant of high-phosphorus fertiliser and water mixtures, as feed or stock water additive and the production of a phosphorus lick are described. Other phosphorus supplements are discussed with particular reference to the fluorine hazard.

Animal Feed↗

PubMed1986

Seroepizootiology of types 3 and 7 adenoviruses and bovine viral diarrhea virus infections of beef cattle from birth to first parturition.

Twenty-nine female Angus cattle were monitored from birth until 24 months of age for infection with types 3 and 7 adenoviruses (AV3, AV7) and bovine viral diarrhea (BVD) virus by virus isolation and neutralization tests. Twenty-seven animals remained in the study for 450 days, whereas 16 animals remained at the conclusion of the tests. Viruses were not isolated from test animals. Seroepizootiologic examination indicated that there were 28 infections with AV3, 33 infections with AV7, and 13 infections with BVD virus. Of these infections, 5 with AV3, 6 with AV7, and 2 with BVD virus were reinfections. All but 1 primary AV3 infection had occurred between 180 and 360 days after parturition. Infection with AV7 occurred earlier than that with AV3, as shown by 6 seropositive animals by 180 days. Most adenovirus infections were documented after animals had left confinement and were turned out to pasture. Most BVD virus infections occurred within the first 90 days after parturition. At completion of the study, only 1 animal had not shown evidence of AV3 infection, 2 animals had not been infected with AV7, and 7 cows had remained free of BVD virus infection.

Adenoviridae↗

PubMed1994

Oviposition and development of face flies in dung from cattle on herbage and supplemented herbage diets.

Dung was collected from Angus cattle (Bos taurus L.) fed (ad libitum) hays of endophyte-free (EF) and endophyte (Acremonium coenophialum Morgan-Jones and Gams) infected (EI) tall fescue (Festuca arundinacea Schreb.), smooth bromegrass (Bromus inermis Leyss.), red clover (Trifolium pratense L.), alfalfa (Medicago sativa L.), and alfalfa-smooth bromegrass (1:1 w/w) and green-chopped Kentucky bluegrass (Poa pratensis L.). Samples of dung were subsequently collected from the same animals offered the same herbage diets supplemented each day with ground maize (Zea mays L.) kernels at 0.35 kg per body weight. Dung from both sources were used in bioassays to establish oviposition preferences of face flies (Musca autumnalis De Geer). When offered dung from herbage diets, face flies deposited 38.3% of their eggs on dung derived from EF tall fescue diets, 9.9% on dung from EI tall fescue diets, 21.0% on dung from alfalfa diets, 7.4% on dung from red clover diets and 22.8% on dung from alfalfa-bromegrass diets. Face flies avoided ovipositing in dung from cattle ingesting bromegrass hay and Kentucky bluegrass green-chop. Supplements increased oviposition preference of face flies for dung from cattle ingesting Kentucky bluegrass greenchop to 19.1% at the expense of oviposition on dung from cattle ingesting alfalfa hay diets (4.5%), otherwise, they had little effect on oviposition preference ranking. Growth and development of first instar larvae of face flies was also measured in bioassays of dung from cattle on herbage and supplemented herbage diets. The presence of endophyte reduced pupation in dung from cattle on tall fescue hay diets from 86.3 to 79.8% and from 90.1 to 73.2% in dung from cattle on supplemented tall fescue hay diets. Pupal liveweights averaged 27.5 mg on dung from cattle on EF tall fescue diets, 22.1 mg from dung of cattle on EI tall fescue diets, 22.2 mg from dung of cattle on supplemented EF tall fescue diets and 24.0 mg from dung of cattle on supplemented EI tall fescue diets. Eclosion and the sex ratio of adults were not affected by dung from cattle on different source diets.

Animal Feed↗

PubMed1991

Relationship between fatty acid-binding protein activity and marbling scores in bovine longissimus muscle.

Studies were conducted in an attempt to establish a relationship between fatty acid-binding protein (FABP) activity and marbling score in bovine longissimus muscle. Longissimus muscle was obtained from four 20-mo-old Charolais-Hereford crossbred heifers, three 16-mo-old Angus steers, and four 18-mo-old Angus steers. Immediately after slaughter, longissimus muscles were removed for the extraction of FABP. Supernatant (S104) fractions containing 41.3 to 144 mg of protein (depending on animal group) were eluted over Sephadex columns, and elution fractions were analyzed for the binding of radiolabeled palmitoyl-coenzyme A (CoA). Specific activities of FABP were 23, 32, and 101 nmol palmitoyl-CoA bound/mg protein for the Charolais-Hereford, 16-mo-old Angus, and 18-mo-old Angus cattle, respectively. These preliminary results suggested that longissimus muscle FABP activity was positively correlated with marbling score. To test specifically for this possibility, longissimus muscle was obtained at slaughter from each of four Wagyu steers, Angus heifers and Braford heifers. Marbling scores taken at the 12th-13th rib junction were Sm45, Sm43, and SI50 for the Wagyu, Angus, and Braford cattle, respectively. Interfascicular adipose tissue was exhaustively removed from sections of the 5th to 8th thoracic region of the longissimus muscle to eliminate any contribution of adipose tissue to FABP activity. For each animal, 300 mg of the S104 were eluted over Sephadex columns. Specific activities for the Wagyu, Angus, and Braford longissimus muscle FABP were 3.1, 3.8, and 3.9 pmol palmitoyl-CoA bound/mg protein, respectively, and were not different (P greater than .05) among the three animal groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed2004

Partitioning variances of growth in ultrasound longissimus muscle area measures in Angus bulls and heifers.

The objective of the study was to estimate variance components, heritability, and repeatability of ultrasound longissimus muscle area (ULMA) measures. Data included 4,653 serial ULMA measures from 882 purebred Angus bulls and heifers. Animals were born over a 4-yr period from 1998 to 2001. Each year, bulls and heifers were ultrasonically scanned four to eight times, with a 4- to 6-wk interval between scans. Initially, data were subdivided by scan session across years and were analyzed in a multitrait model (MTM). Data pooled across years and scan session were then analyzed using random regression models (RRM) to estimate trends in genetic parameter estimates. Additive direct genetic variance increased with advancing scan session ranging from 8.67 cm4 at the first scan (mean age = 35 wk) to a maximum of 19.48 cm4 at the sixth scan (mean age = 56 wk). Heritability of ULMA increased from 0.35 at first scan to a maximum of 0.48 at the fourth scan (mean age = 50 wk). Additive direct genetic variance and heritability values at about 1 yr of age (fifth scan) were 18.24 cm4 and 0.45, respectively. Estimates from RRM also showed an increase in sigma(a)2 and h2 with age. Trends in sigma(pe)2 estimates, although tending to fluctuate, also increased with age. Additive direct genetic variance at 1 yr of age ranged from 15.8 cm4 to 17.0 cm4 for the different models. Heritability of yearling ULMA measures ranged from 0.40 to 0.42 and repeatabilities ranged from 0.80 to 0.84. For the range of ages used in the current study, both MTM and RRM showed close to maximum heritability values at around 1 yr of age. Therefore, phenotypic differences in yearling ULMA between Angus cattle are better indicators of genetic differences than earlier measurements. Angus breeders could, therefore, use ULMA measures made at around 1 yr of age to select next generation parents.

Animals↗