SEARCH · PubMed Health

Results for “Angus cattle”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed2001

Interleukin-8 haplotype structure from nucleotide sequence variation in commercial populations of U.S. beef cattle.

The aim of the present study was twofold: first, to design a panel of 96 sires that reflects the breadth of genetic diversity in U.S. beef cattle, and second, to use this panel to discover nucleotide sequence diversity and haplotype structures of interleukin (IL)-8 in commercial populations. The latter is a requisite for epidemiological studies designed to test whether IL8 alleles are risk factors for acquiring or maintaining bacterial infections in production environments. IL-8 encodes a proinflammatory cytokine that plays a central role in cell-mediated immunity by attracting and activating neutrophils in the early stages of host defense against bacterial invasion. Seven single-nucleotide polymorphism (SNP) markers were identified by sequencing two IL8 DNA segments amplified from the panel of 17 popular cattle breeds (MARC beef cattle diversity panel, version 2.1). Assays for automated genotype scoring by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) were developed to independently verify the seven SNP alleles in the 96 bulls and 313 cattle from the MARC reference population. Five haplotype structures, spanning the two IL8 DNA segments, were unambiguously defined for the set of seven IL8 SNPs. Based on the breadth of germplasm in bovine diversity panel, the five haplotype structures for IL8 are estimated to represent >98% of those present in these DNA segments in commercial populations of U.S. beef cattle. The frequencies of the five respective haplotypes in the eight Angus sires of the diversity panel (0.75, 0.25, 0.00, 0.00. 0.00) were similar to those scored in 150 purebred Angus cattle from six herds in four Midwestern states (0.82, 0.18, 0.01, 0.00 0.00), suggesting that the diversity panel may also be useful for estimating allele frequencies in commercial populations.

Animals↗

PubMed1978

Hip dysplasia in beef cattle.

A bilateral hip lameness has been found in young beef bulls of the Hereford, Aberdeen Angus, Galloway and Charolais breeds in the United Kingdom, North America and Australia. The incidence is usually small and sporadic, but up to half of the male animals on one farm may be affected clinically by the time they are one year old. Clinical lameness begins at three months to two years old, and very occasionally up to three years of age; some calves are obviously affected at birth. Aberdeen Angus cattle tend to be affected earlier than other breeds. Clinical evidence of the condition is almost entirely confined to the male.

Animals↗

PubMed2003

A triad of bovine inherited diseases (abstract).

Three inherited diseases of cattle seen in the past 2 years were described. Familial acantholysis of Angus cattle was seen in 9/54 calves born to cows inadvertently mated to a full sibling bull. Sloughing skin from the joints, nose and palate were seen at 1 day of age, confirmed as suprabasilar clefts on histopathology. A 2-year-old Charolais steer was noted at ante-mortem slaughter inspection with a whole body tremor and nystagmus. Histopathologically, eosinophilic plaques expanded white matter throughout the brain, consistent with a syndrome of 'progressive ataxia' of Charolais cattle. Two calves born from Red Devon cattle had marked hyperkeratosis, microtia and periocular reddening with deep fissuring of the keratin, characteristic of congenital ichthyosis.

Journal Article↗

PubMed1990

Effect of selection for growth traits on age and weight at puberty in bovine females.

This 20-yr study, using 584 beef heifers born in the spring of 1984 or 1985, was conducted to determine whether selection for growth traits affected age and weight at puberty. Heifers were from three Hereford lines selected for weaning weight, final weight, and final weight plus muscling score, a control line and a line of Angus cattle. In addition, heifers from reciprocal crosses among the selection lines, control and Angus groups were evaluated. Intact bulls and androgenized heifers fitted with marking harnesses were used to aid in detection of estrus for heifers born in 1984 and 1985, respectively. The time of puberty was identified by the first behavioral estrus. During both years, heifers were weighed at 56-d intervals; these weights were used to calculate weight at puberty. Mean age at puberty was determined using survival analysis; percentages of heifers that were pubertal by the end of the study were transformed to logits for analysis. Heifers born in 1985 were heavier (P less than .05) at puberty than those born in 1984. Heifers in lines selected for growth traits were younger at puberty (P less than .05; 20 d) than were heifers in the control line because of combined direct and maternal genetic effects. Heifers from the final weight, control (P less than .05) and weaning weight lines (P less than .10) weighed less at puberty than Angus heifers; selection line x Angus crossbred heifers were heavier at puberty (P less than .05) than their respective pureline or purebred contemporaries due to heterotic effects. Selection for weaning weight, final weight or final weight plus muscling score did not have a detrimental effect on age at puberty in heifers.

Age Factors↗

PubMed1995

Divergent selection for blood serum insulin-like growth factor I concentration in beef cattle: I. Nongenetic effects.

Data were obtained from an ongoing experiment involving divergent selection for blood serum IGF-I concentration in purebred Angus cattle. The experiment includes approximately 100 spring-calving (50 high and 50 low line) and 100 fall-calving (50 high and 50 low line) cows. The selection criterion is the mean of IGF-I concentrations measured on each animal at d 28, 42, and 56 of the postweaning performance test. Mean IGF-I values were available for a total of 526 bull and heifer calves. Pooled across years and breeding seasons, high line progeny averaged 21 +/- 6, 17 +/- 6, and 23 +/- 5 ng/mL more IGF-I (P < .01) than low line progeny at d 28, 42, and 56 of the postweaning test. Season effects on IGF-I approached statistical significance only at d 42 and 56 of the postweaning period. Pooled across years and selection lines, spring minus fall differences were 9 +/- 10 (P = .52), -17 +/- 10 (P = .10), -22 +/- 9 (P = .07), and -9 +/- 6 (P = .45) ng/mL for IGF-I concentrations at d 28, 42, and 56 of the postweaning test and for mean IGF-I, respectively. Sex effects on serum IGF-I concentration were highly significant, with greater IGF-I expression in bulls, but were confounded with diet and location. Age of dam effects were not significant. Regressions of IGF-I concentration on on-test age of calf ranged from .46 +/- .13 to 1.08 +/- .20 ng.mL-1.d-1 and were highly significant for all measures of IGF-I.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed2001

DNA damage induced by copper deficiency in cattle assessed by the Comet assay.

Cattle hypocuprosis is a well-known endemic disease in several parts of the world. In a previous paper, the clastogenic effect of copper deficiency in cattle has been described although the occurrence of DNA damage was not directly tested. For this reason, the relation between DNA damage assessed by the Comet assay and Cu plasma concentration was studied in Aberdeen Angus cattle. Blood samples were obtained in heparinized Vacutainer tubes from 28 female Aberdeen Angus cows during pregnancy or immediately after to give birth. Each sample was divided into two aliquots for Comet assay and Cu plasma determination, respectively. From the 28 cattle sampled, 17 were normocupremic and 11 were hypocupremic. Results obtained showed that whereas the average plasma Cu level in normocupremic cattle was 67.6 microg/dl, in hypocupremic cattle it was 32.1 microg/dl. The increase of DNA damage was mostly evidenced by the decrease of comet degree 1 cells and an increase of comet degree 2 cells. Correlation analysis comparing plasma Cu levels and degree 1 cells showed a correlation coefficient 0.72 (P<0.01). The comparison between plasma Cu levels and comet degree 2 cells was -0.65 (P<0.01). The comparison between plasma Cu levels and the comet length-head diameter medians determined in 23 out of 28 animals showed a correlation coefficient of -0.54 (P<0.01). The induction of DNA damage was clearly supported by the fact that the decrease of plasma Cu levels was correlated with the increase of comet length-head diameter. These findings could be considered as a contribution to the hypothesis that DNA and chromosome damage are a consequence of the higher oxidative stress suffered by hypocupremic animals.

Animals↗

PubMed2004

Association between copper deficiency and DNA damage in cattle.

Cattle hypocuprosis is the second most widespread mineral deficiency affecting grazing cattle. The consequences of hypocuprosis include a failure of copper metalloenzymes, many of which form part of the antioxidant defence system. This work focuses on the association between copper (Cu) plasma concentration and DNA damage in Aberdeen Angus cattle. Two-hundred and ninety-nine heparinized blood samples from 2-year-old Aberdeen Angus cows were obtained from different farms located in the Salado River basin, Argentina. Plasma copper level analysis was carried out in whole samples, while cytogenetic analysis and single cell gel electrophoresis assay (comet assay) were carried out in 82 and 217 samples, respectively. Cytogenetic analysis showed a significant increase in the frequency of abnormal metaphases in moderate/severe hypocupremic groups (groups B and C) in relation to the normocupremic group (group A) (4.5 and 1.5 abnormal metaphases/100 cells, respectively, P < 0.01). The Spearman correlation test showed a negative association between cupremic values and the yield of chromosomal aberrations (r = -0.708, P < 0.0001). In the comet assay greater migration was observed in cells from the hypocupremic group, from a median of 54 in the severe hypocupremic group to 31 in the normocupremic group (P < 0.01). Accordingly, the Spearman correlation test showed a significant positive relationship between copper levels and cells without DNA migration and a significant negative relationship between copper levels and cells with a tiny tail (P < 0.0001 in both cases). The results obtained show that hypocupremia in cattle is associated with an increase in the frequency of chromosomal aberrations as well as in DNA migration as assessed by the comet assay. Whereas the comet assay could differentiate copper plasma level groups, chromosomal aberrations only detected differences between normal and hypocupremic animals. The increase of DNA damage found in hypocupremic animals could be explained by higher oxidative stress suffered by these animals.

Animals↗

PubMed2001

Establishment and maintenance of a longitudinal study of bovine spongiform encephalopathy (the ULiSES scheme).

This paper addresses the issues of tracing and compliance encountered in setting up and maintaining a UK-wide 5-year observational study of beef cattle. The 5-year prospective study was initiated in 1997 to investigate the occurrence of bovine spongiform encephalopathy (BSE) in a single herd of pedigree Aberdeen Angus cattle, in which BSE had been detected at low prevalence. The study was given the acronym ULiSES (University of Liverpool Spongiform Encephalopathy Scheme). All cattle present on the farm at the start of the scheme were registered as members of the study population (n=320), as were all calves subsequently born on the farm (n=350). Animals that were sold (n=291) were traced and monitored at destination farms. Farmers were requested to give advance notification of slaughter of any ULiSES animal and an attempt was made to collect post-mortem samples of nervous tissue, peripheral lymphoid tissue and striated muscle from all animals in the scheme at the time of slaughter, death or euthanasia. Sections of medulla were examined (by standard histopathological techniques) for the presence of spongiform change. Remaining samples were stored at -70 degrees C for future investigation by alternative tests. At the halfway point of the scheme in October 1999, 75.2% (506/673) of the study population was still alive; 42% (284) of the population was still alive on the study farm and 33% (222) was distributed on other farms throughout the UK. Complete sets of specimens had been recovered from 77% (129/167) of dead animals. All brainstem sections were negative by histopathological examination. No suspect cases of BSE were reported in ULiSES animals. Failure to recover specimens occurred principally in animals which had left the study farm. The main cause of specimen loss was a failure of compliance in a small number of individuals who had purchased large numbers of ULiSES animals, and subsequently slaughtered them without contacting the University. Despite this, farmer compliance was generally high. The ULiSES scheme shows the feasibility of a country-wide longitudinal observational study spanning a period of several years and indicates the large impact of small numbers of non-compliant individuals.

Animals↗

PubMed2005

Phenotypic relationships between hair whorl characteristics and spermatozoal attributes in Holstein bulls.

The objective of this study was to characterize facial whorl characteristics in Holstein stud bulls (n = 485) and to investigate their association with measures of semen quantity and quality. Bulls had 1 (n = 454), 2 (n = 21) or no facial hair whorls (n = 5). Some 39% of bulls had whorls in the middle of their forehead, whereas 43% had whorls very low down on their forehead. Spiral whorls were present on 77% of bulls while 22% had elongated whorls. Abnormally shaped whorls were found more often on bulls with low whorls (27% versus 17%, P = 0.01) than on bulls with high or middle whorls. Semen production data were obtained from the AI center database to provide a representative sample of each sires most recent semen production characteristics. The number of semen collections per bull averaged 38 with a range of 1 (n = 9) to 272 (n = 1). The average number of days between collections was 5 but varied from 1 to 425 days. Average age of bulls at first recorded collection was 679 days and ranged from 307 to 4555 days. There were no significant differences between black and white bulls in semen quality or quantity. Semen quality over the summer months was reduced in comparison to the winter months. Age of the bull at time of collection had no effect on any of the semen quality traits. Older bulls had larger scrotal circumference and produced more semen (P > 0.01). Bulls with whorls located in the center of the forehead were not significantly different in semen quality or quantity for the 10 traits considered when compared to bulls with whorls located outside the center. In contrast to previous research findings with Angus cattle, semen attributes were not significantly different between bulls characterized with round (or spiral) epicenters and those with abnormally shaped whorls. The difference between the two studies may be due to the fact that Angus bulls have a higher percentage of abnormal elongated whorls compared to Holsteins.

Animals↗

PubMed1995

Cutaneous melanocytomas in 10 young cattle.

Ten melanocytomas from 10 cattle were diagnosed by histopathologic examination of biopsy specimens submitted to the Veterinary Medical Diagnostic Laboratory, University of Missouri, between 1 January 1986 and 31 December 1993. One tumor was congenital; the others were first noticed between 2 months and 2 years of age (means = 9.9 months). Six tumors occurred in purebred (3) or crossbred (3) Angus cattle; one tumor each occurred in a Holstein, a Shorthorn, a Simmental, and a beef calf of unrecorded breed or coat color. Five calves were female, and five were male. Five tumors occurred in truncal dermis or subcutis (three in abdominal skin), four occurred on a limb, and one occurred on the jaw. Tumors varied in histologic appearance, but all were pigmented and all had few mitotic figures. Outcome was known for 8/10 cattle. In four cattle followed for at least 1 year, the tumor did not recur after surgical excision. Another heifer had residual gray tissue at the tumor site after surgery but remained in the herd without regrowth of the tumor 30 months after excision. Three other calves were slaughtered within 6 months of excision without apparent recurrence of the tumor.

Animals↗

PubMed1995

Adrenal responses of Angus x Hereford cattle to the stress of weaning.

To test adrenal responsiveness of beef cattle to stress, plasma norepinephrine, epinephrine, and cortisol responses of Angus x Hereford cattle to weaning were measured in blood samples taken from 1) eight cows and their 4- to 6-mo-old calves before and after separation and, the following day, before and after being reunited and 2) an equal number of control animals. After separation and before they were reunited, dams were returned to their original pen and calves to an adjacent pen. Experimental trials were conducted every 2 wk and included two cow/calf pairs per trial. Norepinephrine concentrations tended to increase in calves after separation, were increased (+82 pg/mL, P < .01) on the 2nd d before animals were reunited, and decreased (-88 pg/mL, P < .01) after animals were reunited. Epinephrine concentrations tended to increase in calves after separation, were increased in calves (+128 pg/mL, P < .001) and dams (+104 pg/mL, P < .001) on the 2nd d before animals were reunited, and decreased after calves (-162 pg/mL, P < .001) and dams (-101 pg/ml, P < .001) were reunited. There were no significant effects of time on catecholamine concentrations for control animals. Cortisol concentrations for treated and control animals tended to increase in sequential samples each day; however, the increases were small (approximately 1 ng/mL) and concentrations remained low (> 5 ng/mL). In conclusion, peripheral catecholamine concentrations in beef calves and epinephrine concentrations in dams increased in response to stress associated with weaning and separation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗

PubMed2001

Relation of growth hormone response to growth hormone-releasing hormone before weaning and postweaning growth performance in beef calves.

Previously, GH response to GHRH challenge at weaning has been shown to be indicative of ADG during a standard postweaning growth performance test in Angus cattle. In this study, we tested the hypothesis that GH response to GHRH before weaning would predict postweaning ADG. Bulls with the highest and lowest GH responses to GHRH over a 3-yr period, relative to their contemporaries, were used as sires, to allow for examination of the persistence of GH response to GHRH through selection. The selected calves in this study were sired by one of four Angus bulls chosen based on their GH response to GHRH (high response, n = 2; low response, n = 2). Forty-nine Angus calves (bulls, n = 24; heifers, n = 25) were challenged with GHRH at approximately 60, 105, and 150 d of age and at weaning (219 d; SD = 25). Blood samples were taken immediately prior to and 10 min following an i.v. clearance dose of 4.5 microg of GHRH/100 kg BW and, 2 h later, immediately prior to and 10 min following a challenge dose of either 1.5 or 4.5 microg of GHRH/100 kg BW. Two hours later, the procedure was repeated, with each calf receiving the other challenge dose. Body weight was measured every 28 d and ADG was calculated over a 140-d growth performance test (heifers and bulls maintained separately). Data were log-transformed for statistical analyses. In the selected bulls and heifers, response of GH to 1.5 microg of GHRH/100 kg BW at 60 and 105 d of age was positively related (P < 0.05) to postweaning ADG. Response to 4.5 microg of GHRH/100 kg BW at 105 d of age and at weaning was positively related (P < 0.01) to postweaning ADG. Inclusion of sire in the analysis improved the relationship between GH response and ADG for calves of sires with high GH responses from R2 = 0.18 (P = 0.01) to R2 = 0.33 (P = 0.02). When the GH response to GHRH of the unselected calves at weaning was added to the data from the selected animals and analyzed, the GH response of the bulls was related to postweaning ADG (R2 = 0.09; P = 0.04). In conclusion, GH response to GHRH as early as 60 d of age is indicative of postweaning ADG in beef cattle. In addition, the relationship between GH response to GHRH and postweaning ADG is improved with selection for greater GH response to GHRH.

Animals↗

PubMed1989

Restriction fragment length polymorphisms for growth hormone, prolactin, osteonectin, alpha crystallin, gamma crystallin, fibronectin and 21-steroid hydroxylase in cattle.

Genomic DNAs from animals representing six breeds of cattle (Angus, Brahman, Hereford, Holstein, Jersey and Texas Longhorn) were screened with cloned gene probes in a search for restriction fragment length polymorphisms (RFLPs). Eleven RFLPs were identified using seven different probes: growth hormone, prolactin, osteonectin, alpha A-crystallin, gamma crystallin, fibronectin and 21-steroid hydroxylase. The frequencies of the alleles identified by each probe were calculated and compared in a limited sampling of the six bovine breeds. These polymorphisms greatly enhance the pool of immunogenetic, biochemical and molecular markers available in cattle for linkage analysis, testing of parentage, and distinction of breeds.

Alleles↗

PubMed1993

Factors contributing to dystocia due to fetal malpresentation in beef cattle.

Records on 3873 calvings over a 21-year period (1971 to 1991) from the Colorado State University Resident Instruction beef cattle herd were used to examine factors associated with malpresentations at birth. Approximately 82% of the calvings were unassisted and 18% were assisted in some manner. Of the assisted deliveries, severe traction, mild traction, malpresentation and caesarean section accounted for 44.5, 31.8, 22.4 and 1.3%, respectively, of the total. Ninety-six percent of all births were normal presentations and 4% were malpresentations. The incidence of malpresentations was affected by year, sex of calf, and sire of calf within breed. Most of the malpresentations were in the posterior dorsal position (72.8%) followed by unilateral carpal or shoulder flexion (11.4%), breech (8.2%), lateral deviation of the head (2.5%), incomplete extension of the elbow (1.9%), posterior ventral (1.3%), transverse (1.3%) and oblique ventro-vertical (0.6%). Factors influencing the incidence of posterior dorsal presentations were year, sex of calf, sire of calf within breed, and age of dam. Malpresentation heritability estimates as traits of the calf were 0.088 and 0.003 for Hereford and Angus breeds, respectively. Posterior presentation heritability estimates for Hereford and Angus cattle were 0.173 and 0.0, respectively. Heritabilities as traits of the dam and repeatabilities for malpresentation, and posterior presentation were minimal.

Journal Article↗

PubMed1994

Productivity through weaning of nine breeds of cattle under varying feed availabilities: I. Initial evaluation.

The effect of varying dry matter availability on the conversion of dry matter resources to weight of calf at weaning was evaluated for nine breeds of cattle; Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Red Poll, Pinzgauer, and Simmental were recorded for 5 yr. Within each breed, four cows were assigned to each of four feeding levels of dry matter intake: 58, 76, 93, or 111 g of DM/wt75. Cows remained on their assigned diet regimen throughout the study. Individual cow consumption, daily feed allowance adjusted for refusal, was recorded weekly. Production information included birth and weaning weight of the progeny, calving rate, and cow weights and condition scores. Cows were exposed to bulls of the same breed for 90 d. Reasons for cow replacement included failure to conceive in two successive years, injury, Caesarean section, chronic illness, and death. Response to dry matter intake (DMI) was curvilinear and differed among breeds (P < .10) for calving rate, calf survival, and weight of calf weaned per cow exposed. Significant differences occurred among the breeds for the linear response to DMI for cow weight and condition score. The response to DMI was curvilinear for birth weight (P < .10), but the response did not differ among breeds (P > .20). Red Poll exhibited more effective conversion at DMI less than 4,000 kg/yr, but breeds with greater genetic potential for growth and(or) milk production (Gelbvieh, Charolais, Braunvieh, Simmental, Pinzgauer, and Limousin) were more efficient at DMI greater than 6,000 kg/yr. Ranking for biological production efficiency (weight of calf weaned-cow exposed-1.kg DMI of cow-1) through weaning among breeds of cattle varied with dry matter intake.

Analysis of Variance↗

PubMed1999

Effect of timing of artificial insemination on gender ratio in beef cattle.

It was recently reported that cows inseminated at approximately 10 or 20 h before an expected ovulation deliver predominately a bull or heifer calf, respectively. The objective of this study was to further investigate the effect of timing of insemination on the gender of offspring in cattle. Angus heifers (n = 41) and cows (n = 98) were used in the study. Heifers were synchronized with a 16-d treatment of melengestrol acetate followed 17 d later with an injection of PGF2alpha. Cows were synchronized with GnRH followed 7 d later with PGF2alpha. A HeatWatch electronic estrus detection system was used to determine the onset of estrus. Based on previous studies, it was assumed that ovulation occurs approximately 32 h after the onset of estrus. Therefore, animals were artificially inseminated at either 8 to 10 h (early; > or = 20 h before expected ovulation) or 20 to 25 h (late; < or = 10 h before expected ovulation) after the onset of estrus. Sixty to 80 d after insemination, ultrasonography was used to confirm pregnancy status and to determine the gender of fetuses. Gender of calves was subsequently confirmed at calving. Data were analyzed for effects of time of insemination and sire or semen batch on gender ratio, as well as any effect of length and/or intensity of estrus on conception rate and gender ratio. Twenty-nine of 41 heifers and 69 of 98 cows were detected in estrus after synchronization and were inseminated; 20 of 29 heifers and 48 of 69 cows were subsequently confirmed pregnant. Neither the length of estrus nor its intensity (number of mounts) had an effect on pregnancy rate or gender ratio (P > or = 0.418). Timing of insemination (early versus late) had no effect on gender ratio (P = 0.887). Semen from 13 sires representing 17 lots was used to inseminate the cows and heifers. No differences (P = 0.494) were detected in the gender ratios resulting from different sires or semen batches. In contrast to previous findings, our results indicate that inseminating beef cattle at approximately 20 or 10 h before an expected ovulation does not alter the gender ratio of the resultant calves.

Animals↗

PubMed1980

Effect of feeding system on performance and carcass characteristics of yearling steers, steer calves and heifer calves.

Three types of cattle (Angus x Hereford yearling steers, Charolais x British breed steer calves and Hereford heifer calves) were evaluated for their response to different feeding systems utilizing high moisture corn, corn silage and soybean meal as major feed ingredients. Feeding ing systems for steers included: A = 85% concentrate; B = 40% concentrate; C = two phase, with switch from all corn silage to 85% concentrate in the middle of the feeding period; D = same as C except switch occurred late in the feeding period; E = all corn silage continuously. Heifer diets consisted of the following ratios of corn silage to concentrate: low energy = 89:11; medium energy = 67:33; and high energy = 100 fed at a moderate (10.9% for low energy and medium energy, and 11.7% for high energy) and high (13.8%) crude protein level. Treatments within each experiment were terminated at approximately the same final weight. Increasing percentage corn added to the total diet increased ADG in most comparisons. Adjusted to a constant carcass weight, increasing dietary energy increased fat thickness and reduced percentage retail product with no effect on quality grade in yearling steers and heifer calves. In Charolais cross-steer calves, increasing energy level increased quality grade with no effect on yield grade or percentage retail product. Energetic efficiency slightly favored system C in yearling steers while steer calves maximized efficiency on A. Hereford heifers were the most energetically efficient on medium energy diets.

Animal Feed↗

PubMed1992

Esterification of fatty acids by bovine intramuscular and subcutaneous adipose tissues.

Exogenous fatty acid esterification in intramuscular and subcutaneous adipose tissues from 72-hr fasted or ad libitum fed Angus cattle was investigated. Intramuscular (interfascicular) and subcutaneous adipose tissue snips were obtained from the longissimus dorsi muscle and were incubated with radioisotopically labeled fatty acids (palmitate, stearate, oleate, linoleate or linolenate) at three different concentrations (0.3 mM, 0.6 mM and 2.0 mM) to assess rates of fatty acid incorporation into glycerolipids. Rates of fatty acid esterification in vitro increased with fatty acid concentration in both intramuscular and subcutaneous adipose tissues. For all of the fatty acids investigated, triglycerides were the predominant products (60-85%). Subcutaneous adipose tissue had larger adipocytes and more actively (P less than 0.05) esterified fatty acids, with the exception of palmitate, than intramuscular adipose tissue. The rate of palmitate esterification was not different between tissues, although intramuscular adipose tissue esterified a greater proportion (P less than 0.10) of palmitate as triglyceride (85%) than did subcutaneous adipose tissue (75%). Relative rates of incorporation of fatty acids into lipids in intramuscular and subcutaneous adipose tissues were: palmitate greater than linolenate greater than linoleate greater than stearate. In general, 72-hr fasting did not significantly reduce the rates of fatty acid incorporation in bovine adipose tissues. Results of this study revealed that:i) rates of exogenous fatty acid incorporation into adipose tissue lipids were dependent on the medium fatty acid concentration and adipose tissue depot; and ii) the relative esterification rates of the various fatty acids in vitro did not necessarily reflect the proportion of these fatty acids in bovine adipose tissues.

Adipose Tissue↗