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PubMed1999

Case life of seven retail products from beef cattle supplemented with alpha-tocopheryl acetate.

Packages (n = 660) of clod, strip loin, tenderloin, bottom round, eye-of-round, and top round steaks, as well as ground beef, from beef cattle fed diets supplemented with vitamin E (500 IU/d for 100 d preharvest) were compared with packages of products derived from carcasses of beef cattle fed control diets to determine the duration of acceptable muscle color during simulated retail display. In addition, the effect of storage before steak fabrication, simulating distribution time, on the acceptability of each treatment and each cut during retail display was investigated. Dietary supplementation of animals with vitamin E increased muscle alpha-tocopherol concentrations (P < .05) in all cuts. The acceptable retail display time of ground beef from vitamin E-supplemented cattle was longer (P < .05) compared to ground beef from unsupplemented cattle by 10.2, 15.6, and 17.6 h following 7, 14, and 21 d of storage in chub packages prior to final grinding and retail display, respectively. However, length of storage in a vacuum package before retail display did not have a consistent effect on retail case life of steaks. Product drip loss during retail display was not affected by storage time or vitamin E treatment. The trained panel color score during retail display of high vitamin E strip loin, bottom round, inside round, and eye-of-round steaks remained acceptable longer (P < .05) by 11.5, 25.2, 8.4, and 29.4 h, respectively, than that of control steaks. The results demonstrated that vitamin E supplementation of cattle feed can be used as a management tool to reduce the economic losses associated with beef muscle color deterioration during retail display of products.

Animal Feed↗
PubMed2002

Mitochondrial DNA polymorphisms and fertility in beef cattle.

Four hundred and twenty-two beef cattle of two different breeds (purebred Hereford and composite multibreed) were characterized by polymerase chain reaction-restriction fragment length polymorphism, using the restriction enzymes ApaI, AvaII, HindIII, PstI, SpeI, SspI and TaqI in two regions (the D-loop and the ND-5 gene) of mitochondrial DNA. The association between molecular haplotypes and records on calving rate, defined as the mean number of live calves born per year over 4 years, were examined by analysis of variance. A significant association was found between calving rate and mitochondrial polymorphisms in both breeds. This may have implications for genetically improving cow fertility.

Animals↗
PubMed1999

Congenital joint laxity and disproportionate dwarfism in a herd of beef cattle.

Three calves from a herd of beef cattle were examined because of disproportionate dwarfism and excessive extension of metacarpophalangeal and metatarsophalangeal joints. Abnormalities had been noticed at birth, 1 to 6 days earlier. A thorough herd investigation revealed that 16 calves born to 70 multiparous cows were affected during the calving season. The condition did not adversely affect calf survival. Affected calves had limbs that were disproportionally short, compared with their trunk size, and wide epiphyses of the femurs and humeri. Radiographic evaluation revealed incomplete maturation of carpal and tarsal bones and incomplete maturation and abnormal flaring of epiphyses of the short humeri and femurs. Histologic findings were consistent with chondrodystrophy. This disorder had not been seen in the herd in previous years and was traced to feeding of dry, spoiled silage to the dams during midgestation. Covering the silage prevented problems in the subsequent year.

Animal Husbandry↗
PubMed1989

Neutralizing antibody responses to bluetongue and epizootic hemorrhagic disease virus serotypes in beef cattle.

Blood samples were obtained from sentinel beef cattle at monthly intervals, and the sera were tested for antibodies, using a bluetongue virus (BTV) immunodiffusion test (IDT) and virus-neutralization test (VNT), for 5 BTV serotypes (2, 10, 11, 13, and 17) and 2 epizootic hemorrhagic disease virus (EHDV) serotypes (1 and 2). The cattle tested were transported from Tennessee to Texas in 1984 and 1985. All cattle were seronegative by the BTV IDT at the initial bleeding in Texas in 1984 and 1985. In 1984, 16 of 40 (40%) cattle seroconverted as assessed by results of the BTV IDT. In the 16 seropositive cattle in 1984, neutralizing antibodies were detected to BTV serotypes 10 (n = 7), 11 (n = 3), and 17 (n = 11), and EHDV serotypes 1 (n = 1) and 2 (n = 7). In 1984, no cattle seroconverted to BTV-2 or BTV-13. In 1985, 10 of 36 (27.8%) cattle seroconverted as assessed by results of the IDT. Of the 10 seropositive cattle in 1985, neutralizing antibodies were detected to BTV serotypes 10 (n = 10), 11 (n = 10), 13 (n = 7), and 17 (n = 5), and EHDV serotypes 1 (n = 1) and 2 (n = 7). In 1985, no cattle seroconverted to BTV-2. Clinical diseases attributable to BTV or EHDV was not detected in these cattle in 1984 or 1985.

Animals↗
PubMedDate not supplied

[The intrabreed genotypic variability of Ukrainian beef cattle].

The intrabreed genotype heterogeneity in Ukrainian beef cattle was studied for 13 genetic-biochemical systems in relation to the differentiation of animals by sex, age color, birth weight and the weight increase during the first 6 months of life. The greatest value of genetic distance was revealed between animal groups, distinguished by the weight increase. The locus of purine nucleoside phosphorylase greatly contribute to this genetic differentiation.

Animals↗
PubMed1989

Multiple ovulation and embryo manipulation in the improvement of beef cattle: relative theoretical rates of genetic change.

Theoretical rates of annual genetic responses to selection in beef cattle were compared for conventional and multiple ovulation and embryo transfer (MOET) breeding schemes. Several combinations of replacement policy, mating ratio and type of selection were considered for both schemes with low, medium and high heritabilities. For MOET, four rates of embryo transfers per donor were used to represent low to moderate MOET levels. The results indicated that annual genetic responses to selection could be up to 1.3, 1.6 and 1.8 times as great for MOET compared with conventional breeding for traits of low, medium and high heritability, respectively; however, the annual inbreeding rates also were high for the MOET schemes considered. Embryo splitting, or cloning, was shown to increase accuracy of selection by 8 to 35% through the production of identical genotypes. The use of MOET in conjunction with embryo splitting in elite nucleus units could substantially increase genetic improvement for traits with low, medium and high heritabilities in beef cattle populations.

Animals↗
PubMed1992

A computer model to predict the effects of level of nutrition on composition of empty body gain in beef cattle: II. Evaluation of the model.

A computer model developed to predict composition of empty body gain of beef cattle fed at different levels of nutrition was evaluated with data from one unpublished and seven published experiments. These experiments used several breeds of beef cattle growing at rates that varied from negative to fast and various combinations of these growth rates. There was close agreement between observed and simulated absolute treatment means for fatness, except when animals were fed diets low in protein. In this case, experimental animals fed inadequate protein grew at slower rates and became fatter than contemporaries fed adequate protein, whereas the model predicted the opposite. Ability of the model to predict effects of nutrition not associated with changes in BW was evaluated using the proportion of residual variation in experimental fat percentage accounted for by the model, after fitting linear and quadratic terms for empty BW. The model accounted for 13.8 to 56.2% of the residual variation in observed fatness in four experiments in which significant differences in fatness were observed among nutritional treatments after accounting for differences in empty BW. Regression of observed fatness on model-simulated fatness resulted in regression coefficients that were positive and close to 1 in these four experiments. This suggests that the model can accurately predict some of the effects of nutrition on fatness that are not associated with changes in empty BW.

Adipose Tissue↗
PubMed1998

The seasonal variation of thermophilic campylobacters in beef cattle, dairy cattle and calves.

The epidemiology of clinical cases of campylobacter in temperate climates shows a striking seasonality. In the search for a seasonal environmental reservoir changes in the carriage rate and population size of campylobacters in bovine hosts with time have been measured. Most probable number (MPN) methodology was used to enumerate thermophilic campylobacters in samples taken from the small intestines of beef cattle at slaughter and the fresh faeces of four dairy herds and new-born calves. Statistical analyses revealed significant evidence for seasonal periodicity in the data from dairy herds (P = 0.044). Not only was there a departure from constancy within a 12-month interval but these data revealed a true seasonality, that is, the same periodicity in numbers from one year to the next. Each herd had two peaks per year, in approximately spring and autumn. Peaks coincided in herds on neighbouring farms but those on farms in the north preceded those on farms in the south by 2 and 1 months, respectively (P = 0.0057). Intestinal carriage by beef cattle at slaughter was 89.4% (n = 360) with an average MPN campylobacters per gram fresh weight (MPN gfw-1) of 6.1 x 10(2). Average MPN gfw-1 in faeces from the dairy herds and calves were 69.9 (S.D. 3) and 3.3 x 10(4) (S.D. 1.7 x 10(2)). There was no evidence of seasonal periodicity in the size of the campylobacter population in beef cattle at slaughter. Calves were campylobacter free at birth but became colonized with a few days.

Animals↗
PubMed1994

Voluntary intake and digestibility by mature beef cattle and Holstein steer calves consuming alfalfa or orchardgrass hay supplemented with soybean oil and(or) corn.

Effects and interactions of corn and soybean oil supplementation and forage source on feed intake and digestibility by mature and growing cattle were determined. Eight mature beef cattle (571 +/- 17 kg initial body weight) were used in two simultaneous 4 x 4 Latin squares. Cattle in each square consumed long-stemmed alfalfa (AL; 16% crude protein, 54% neutral detergent fibre and 6.1% acid detergent lignin) or orchardgrass (OR; 11% crude protein, 71% neutral detergent fibre and 9.4% acid detergent lignin) hay ad libitum for 15 d followed by 6 d of restricted consumption (85% of ad libitum). Supplement treatments were Control, ground corn (C; 0.5% body weight), soybean oil (O; 0.125% body weight), or C + O. Total ad libitum dry matter (DM) intake was greater for AL than for OR (P < 0.05) and with than without C (P < 0.05), and a corn x soybean oil interaction occurred (P = 0.07; 11.8, 14.0, 13.6, 14.2, 8.4, 10.7, 9.3 and 10.3 kg/d); total tract neutral detergent fibre (NDF) digestibility was 66.0, 67.7, 65.8, 68.8, 52.5, 50.6, 55.1 and 59.4% for AL, AL - C, AL - O, AL - C + O, OR, OR - C, OR - O, and OR - C + O, respectively (SE 2.46). Eight Holstein steer calves (83 +/- 5 and 131 +/- 11 kg initial and final body weight, respectively) were subjected to the same dietary treatments, except for higher levels of C (1.0% body weight) and O (0.25% body weight) and periods with 21 d of ad libitum forage intake. Total DM intake was greater (P = 0.06) for AL than for OR, increased (P < 0.05) by C, and decreased (P < 0.05) by O (3.92, 4.17, 3.51, 4.00, 2.53, 2.90, 2.09 and 2.51 kg/d), and total tract NDF digestibility was affected by forage source (P < 0.05) and a corn x soybean oil interaction (P = 0.08; 58.8, 56.9, 60.1, 56.0, 41.9, 44.5, 45.8 and 40.1% for AL, AL - C, AL - O, AL - C + O, OR, OR - C, OR - O and OR - C + O, respectively). In conclusion, effects of supplementation with corn and (or) soybean oil on feed intake and digestibility were similar for AL and OR, which differed in voluntary intake and digestibility, and animal characteristics such as stage of maturity may have influenced effects of soybean oil on feed intake.

Aging↗
PubMed1993

Effects of grazing management practices on parasite load and weight gain of beef cattle.

Stocking rate, method of grazing (rotational vs. continuous) and supplementation are three grazing management variables which strongly affect weight gain of beef cattle. However, reports on the interaction between these variables and parasitism in beef cattle are often conflicting or not conclusive. Although several studies have shown increased parasite loads with increased stocking rates, few studies have included animals treated and untreated with anthelmintics at several stocking rates. Those that did have this treatment combination did not show greater response in weight gain to treatment with anthelmintics at high stocking rates than at low stocking rates. Experiments designed to investigate the effect of rotational and continuous grazing on parasitism have provided variable results. However, as the high stock densities associated with rotational grazing will probably cause animals to graze closer to the ground and to dung pats, and to spread dung more with their hooves, it is not likely that rotational grazing will reduce the need for chemotherapy. Some studies have shown reduced parasite loads with supplementation of untreated animals, but none has apparently investigated whether weight gain response to treatment with anthelmintics is greater for non-supplemented animals than for supplemented animals. Published studies on the interaction between management factors and parasitism in grazing animals reveal many weaknesses. Elimination of these weaknesses and cognisance of recent trends in design and conduct of grazing experiments will substantially improve the quality and value of research in this field.

Animal Feed↗
PubMed2004

Chronic shedding of Campylobacter species in beef cattle.

AIMS: To determine the prevalence of chronic shedding of Campylobacter species by beef cattle, a longitudinal study of shedding patterns was conducted in a cohort of 60 beef steers over a 4-month period. METHODS AND RESULTS: Steers were maintained in a simulated feedlot setting but individually in pens to minimize transmission among animals. At each collection time, campylobacters in faeces were detected using conventional PCR. In addition, quantities of Campylobacter jejuni and C. lanienae in faeces were measured using real-time quantitative (RTQ) PCR. All of the steers tested shed Campylobacter species during the course of the study, and overall, 90% of the 299 samples tested were positive for Campylobacter DNA. The majority of the animals (86%) shed campylobacters at >/=4 sample times. The most prevalent taxon detected in bovine faeces was C. lanienae (56% of samples) followed by C. jejuni (13%), C. hyointestinalis (8%), and C. fetus (2%). No C. coli was detected, and 13% of the faecal samples contained two or more of the above species. Seven (12%) and 34 (57%) animals shed C. jejuni and C. lanienae at >/=3 sample times, respectively. For both C. lanienae and C. jejuni, a substantial number of cells were detected in faeces using RTQ-PCR; 27% of the samples positive for C. jejuni contained populations >10(4) cells g(-1) (maximum of 5 x 10(5) cells g(-1)), and 44% of samples positive for C. lanienae possessed populations >10(6) cells g(-1) (maximum of 4 x 10(8) cells g(-1)). A significant correlation was observed between shedding of C. lanienae and the severity of liver abscesses. In 27% of the samples, an amplicon was obtained for genus-specific but not for the species-specific primers. Sequencing of the partial 16S rRNA gene suggested the presence of at least two undescribed Campylobacter species but this has yet to be confirmed. CONCLUSIONS: A high percentage of feedlot cattle shed large quantities of Campylobacter species in their faeces over a protracted period of time (ca 112 days). SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study of longitudinal shedding patterns of campylobacters in beef cattle using PCR-detection methods. In addition, this is the first use of RTQ-PCR to directly quantify C. jejuni or C. lanienae in faeces. The results of the study show that a large number of cattle (>85%) chronically shed campylobacters in feedlots.

Animals↗
PubMed2006

Serologic study of anti-Neospora caninum antibodies in household dogs and dogs living in dairy and beef cattle farms in Tehran, Iran.

A few studies have been done on the seroepidemiology of anti-Neospora caninum antibodies in dairy and beef cattle farms in Iran, which suggested the presence of N. caninum in these areas, but there is no published information directed on the presence or epidemiology of this organism in the dogs in Iran. To investigate anti-N. caninum antibodies in household dogs and dogs living in cattle farms, 100 blood samples were collected: 50 from dogs living in dairy and beef cattle farms and 50 from household dogs. Serum samples were screened for detection of anti-N. caninum IgG antibodies using indirect fluorescent antibody test (IFAT; > or = 50). Antibodies were seen in 10 (20%) of 50 household dogs and in 23 (46%) of 50 farm dogs. There were significant statistical differences in seropositivity between these two groups (P = 0.005). The IFAT antibody titers were as follows: 1:50 in seven dogs, 1:100 in eight dogs, 1:200 in six dogs, 1:400 in seven dogs, 1:800 in three dogs, 1:1,600 in one dog, and 1:12,800 in one dog. There were no significant differences in seropositivity between males and females. The positive results were increasing with age, and positive results were significantly different in the age group of older than 2 years compared to the dogs of age group under 1 year (P = 0.000) and 1-2 years (P = 0.007). The results confirm the exposure of household and farm dogs to N. caninum in Tehran and the higher rate of exposure for the dogs of dairy and cattle farms around Tehran.

Age Factors↗
PubMed2004

Associations of polymorphisms in the Pit-1 gene with growth and carcass traits in Angus beef cattle.

The Pit-1 gene was studied as a candidate for genetic markers of growth and carcass traits. Angus beef cattle that were divergently selected for high- or low-blood serum IGF-I concentration were used in this study. The single-strand conformation polymorphism method was used to identify polymorphism in the Pit-1 gene including regions from intron 2 to exon 6. Two polymorphisms, Pit1I3H (HinfI) and Pit1I3NL (NlaIII), were detected in intron 3 of the Pit-1 gene. One polymorphism, Pit1I4N (BstNI), was found in intron 4, and a single nucleotide polymorphism, Pit1I5, was found in intron 5. The previously reported polymorphism in exon 6, Pit1E6H (HinfI), was also studied in 416 Angus beef cattle. Associations of the polymorphisms with growth traits, carcass traits, and IGF-I concentration were analyzed using a general linear model procedure. No significant associations were observed between these polymorphisms and growth and carcass traits.

Animals↗
PubMed2002

Escherichia coli O157:H7 infection in cows and calves in a beef cattle herd in Alberta, Canada.

Escherichia coli O157:H7 infection of cows and calves in a naturally-infected beef cattle herd in Alberta, Canada, was investigated over 2 years, encompassing two calf production cycles. In both years of the study, E. coli O157:H7 was isolated from the faeces of cows shortly after but not before parturition in late winter: 6/38 (16%) in 1996 and 13/50 (26%) in 1997. At < 1 week post-partum, 13/52 (25%) calves born in 1997 were shedding the organism. Faecal shedding of E. coli O157:H7 by cows and calves continued over the 7 weeks that they were in the calving pens, with the organism being isolated from the faeces of 2-18% of cows and 23-26% of calves during this period. Five weeks after they were moved onto a native grass pasture, all the calves and all but one cow in 1997 had ceased shedding the organism. When the calves were weaned in the fall, E. coli O157:H7 was isolated from the faeces of 0-1.5% of the calves 1 week prior to weaning and from 6-14% of the calves within 2 weeks after weaning. Parturition, calving pens and weaning appear to be important factors in maintaining E. coli O157:H7 infections in this beef cattle herd. Isolates from cows and calves during the immediate post-partum period were mostly of the same pulsed-field gel electrophoresis (PFGE) type of E. coli O157:H7. Similarly, at weaning a common PFGE type of E. coli O157:H7, which differed slightly from the post-partum PFGE type, was isolated from the calves. These typing data suggest a common source of infection for the animals as well as demonstrate clonal turnover of resident populations of this pathogen.

Animals↗
PubMed1998

Brucellosis in adult beef cattle of Mexican origin shipped direct-to-slaughter into Texas.

OBJECTIVE: To compare prevalence estimates of brucellosis (BR) in adult beef cattle that originated from different states and regions of Mexico and that were shipped direct-to-slaughter into Texas during 1995. DESIGN: Epidemiologic survey. ANIMALS: About 65,000 adult beef cattle. PROCEDURE: Blood samples were collected during postmortem examinations and were tested for serum antibodies to Brucella abortus, using the particle concentration fluorescence immunoassay and automated complement-fixation test. Prevalence estimates and 95% confidence intervals of BR were calculated by state of origin in Mexico. The difference among prevalence estimates of BR in cattle from different states and regions was tested for significance (P < 0.05), using the proportion test. RESULTS: On the basis of serologic test results, the overall prevalence estimate of BR was 0.32%. The prevalence estimate of BR in cattle from the state of Chihuahua (0.10%) was significantly different than that in cattle from the states of Nuevo Leon (0.23%), Zacatecas (0.34%), Durango (0.47%), Chiapas (1.81%), Tamaulipas (2.71%), Aguascalientes (7.89%), and Campeche (12.24%). In addition, prevalence estimates of BR in cattle were significantly different among the northern (0.22%), south-central (3.18%), and south coastal (9.42%) regions of Mexico. CLINICAL IMPLICATIONS: Results of this study indicate that the number of cattle exposed to B abortus may be significantly different among states and regions of Mexico. Current import sanitary requirements should continue to mitigate potential risk of transmission of BR from sexually intact cattle of Mexican origin to Texas cattle.

Abattoirs↗
PubMed1990

Markov chains as a shortcut method to estimate age distributions in herds of beef cattle under different culling strategies.

Markov chains were used to estimate the age distribution at equilibrium and average age in herds of beef cattle and the age distribution and average age of culled cows. These estimates are essential in systems simulation and economic analyses of beef production alternatives because the biological input and output from a beef production system depend on the age structure of the cows in the system. Ten sets of data on age-specific probabilities of culling for different reasons were found in the literature and used in simulation of different culling strategies. Three different culling strategies were simulated using these data. In addition to culling on maximum age, culling was either based on health alone, health and reproductive failure in one year (not pregnant) or health and reproductive failure in two consecutive years (not pregnant twice). The average herd age in the data sets reviewed under the actual culling strategies ranged from 4.58 to 6.73 yr and the average age of culled cows ranged from 5.41 to 9.94 yr. Description of the culling process as a Markov chain enables calculations of the age distribution at equilibrium by simple matrix operations, an advantage over the methods presently used. The scarcity of estimated age-specific probabilities of health and reproductive failure points to the need for more population analyses of beef cattle.

Age Factors↗
PubMed2003

Exposure of beef cattle to sub-clinical doses of Microcystis aeruginosa: toxin bioaccumulation, physiological effects and human health risk assessment.

Yearling beef cattle were fed 1 x 10(5) cells ml(-1) of toxic Microcystis aeruginosa in their drinking water for a period of 28 d. Feed and water intakes of four control and four treated animals remained unchanged following introduction of M. aeruginosa into the drinking water of the treatment animals, and there were no significant differences in feed and water intakes between control and treated animals. We tested the blood plasma of both control and treated animals twice each week for elevated concentrations of the liver enzymes gamma-glutamyl transferase (GGT), glyceraldehyde dehydrogenase (GADH), amino aspartate transferase (AST) and bilirubin. All tests were negative indicating no measurable liver dysfunction resulting from microcystin intoxication. We also tested for the presence of free microcystin in the liver and blood plasma by HPLC and ELISA and for total microcystin (free+bound) in the liver by GC-MS. If all the ingested microcystin was bioaccumulated within the liver, the concentration would have exceeded 3 microg MCYST-LR g(-1) fresh weight. HPLC and GC-MS analysis of the liver tissue and blood plasma from treated animals failed to detect any microcystins. ELISA analysis of liver tissue extracts from the treated animals indicated microcystin concentrations as high as 0.92 microg MCYST-LR equivalents g(-1) fresh weight although none was indicated in the blood plasma. The microcystin concentrations measured by ELISA in livers of treated animals were more than 1000 times higher than the limit of quantification by HPLC and GC-MS indicating the ELISA results were almost certainly due to cross reactivity with something other than intact MCYST-LR. Based on the detection limits of the HPLC and the per capita daily consumption of beef in Australia, it appears that consumption by beef cattle of water containing M. aeruginosa cell concentrations up to 1 x 10(5)cells ml(-1) for 4 weeks would not produce concentrations of microcystin within the liver or blood plasma that would present an unacceptable risk to human health based on World Health Organization protocols for determining such risks.

Animals↗
PubMed2004

Age-of-dam adjustment factors for birth and weaning weight records of beef cattle: a review.

Age-of-dam adjustment factors are used to preadjust birth and weaning weight data for national beef cattle genetic evaluations. Adjustments are used in order to make the means of the different age-of-dam subclasses similar so that a fair comparison of animals can be performed. A review was made of various research studies that have estimated age-of-dam adjustment factors for birth weight and weaning weight of beef cattle. In general, birth weight age-of-dam adjustment factors are the same across the sexes, but weaning weight age-of-dam adjustment factors differ across the sexes, with heifer calves receiving smaller adjustments than their male counterparts. Additionally, adjustment factors vary greatly across breeds. Preadjustment of records is difficult to do because a perfect estimate of adjustments is not possible. A more appropriate method for adjusting for age-of-dam is to simultaneously adjust during national genetic evaluations.

Age Factors↗