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1.
The association between ocular squamous cell tumors and various measures of solar radiation was evaluated for 2,775 contemporaneous Hereford cattle. The animals were from 34 herds located in 21 states in the United States and in one Canadian province. Examinations and photographs were made of the eyes of all cows and heifers in a herd; 33 herds were examined between June and August 1957 and 1 herd was examined in 1958. Solar radiation was measured by altitude and mean annual hours of sunshine applying to an individual herd, and global radiation, a cloudiness index, and elevation of nearby National Weather Service stations. All measures of solar radiation provided evidence of a significant association between increasing risks of developing cancer eye and increasing levels of radiation; adjustments were made for possible confounding effects of age and corneoscleral pigmentation. Associations were evident whether affliction was defined as the occurrence of any type of tumor (ie, plaque, papilloma, or carcinoma), or as the occurrence of only papilloma or carcinoma. Average ages of affected cattle also tended to be lower at high radiation levels than at low levels, further supporting the hypothesis that solar radiation has an important role in the development of this disease. In view of the heritability of eye pigmentation and its inhibitory effect on lesions, cancer eye may be controlled by selective breeding for increased pigmentation in and around the eye to afford protection against the harmful effects of incident UV radiation.  相似文献   

2.
Antioxidative status consists of two mechanisms: nonenzymatic and enzymatic mechanisms. Nonenzymatic mechanisms are composed of antioxidants, scavengers of free radicals, transition metal ions, sequester transition metal ions, albumins, ceruloplasmin, and metallothioneins. On the other hand, enzymatic mechanisms are composed of superoxide dismutase (SOD), peroxidase, catalase and reductase. In cattle, characteristics of these mechanisms depend on the nutritional status of anti-oxidant minerals, especially copper, zinc, iron, selenium, silicon, and manganese. The nutritional status of the cattle in different regions of the world and in Poland is often characterised by the lack of these minerals; therefore, there is a great potential for changes in the activity of defence mechanisms against free radicals.  相似文献   

3.
The levels of oxidative stress markers are an important indicator of the physiological state of the parasite and its host. In the present study levels of lipid peroxidation, glutathione S transferase, glutathione, superoxide dismutase and catalase were determined in the Clinostomum complanatum progenetic metacercaria, obtained from the fish peritoneum (a hypoxic habitat). The in vivo transformed ovigerous adult worms were obtained from the aerobic environment of the buccopharyngeal region of experimentally infected chickens. Levels of antioxidant molecules were also determined in the blood of experimentally infected chickens. An increase in the levels of lipid peroxidation, and a significant decrease in the levels of glutathione S transferase, glutathione, superoxide dismutase and catalase was observed in the infected host as compared to the controls. In the ovigerous worms, the levels of lipid peroxidation, glutathione S transferase, glutathione, superoxide dismutase were found to be significantly less than the levels observed in the progenetic metacercaria. Since the establishment of worm in the buccal cavity of the avian host would lead to its exposure to oxygen and the haematophagous nature of the parasite also exposes it to the free radicals in the host blood, the progenetic metacercaria has evolved to produce excess free radical scavenging molecules reserved to combat the oxidative stress encountered within the microhabitat of the definitive host.  相似文献   

4.
Uruguayan Creole cattle inhabit areas that cannot sustain conventional farming. They have adapted to fragile environments and are influenced only by natural selection. In this study, random amplified polymorphic DNA (RAPD) and microsatellite (MS) markers were used to analyse Creole cattle genome polymorphism. A comparative analysis using the RAPD technique was performed in pooled DNA of three cattle breeds (Holstein Friesian, Creole and Hereford) in order to evaluate their amplification patterns. A primary screening of RAPD primers allowed us to select and use those with higher percentage of GC base composition. A total of 215 loci ranging between 300 and 2500 bp were amplified. Bandsharing frequency (BSF) among breeds showed that less related fingerprints were observed between Creole and Hereford cattle (0.77), while the highest similarity frequency corresponded to Holstein Friesian compared to Hereford (0.81). Specific RAPD bands were identified in the three DNA pools and they were tested in every individual of each breed. It may be possible to isolate and sequence these bands to create breed-specific molecular markers. The identification of multiple alleles of the MSCYP 21 in Creole cattle with an heterozygosity of He = 0.846 supported the variability of this genetic resource. The use of molecular markers such as RAPD s and microsatellites is proposed to establish genetic distance among American Creole cattle and possibly related ancestral Iberian breeds.  相似文献   

5.
Important differences are noted between the New Zealand and European cattle industries, in terms of both breeds and farming systems. Under pasture feeding, experimental data strongly suggest that selection and genetic evaluation for growth performance should be based on weight-for-age rather than on post-weaning weight gains. Carcass merit is more appropriately measured by the yield of trimmed boneless retail cuts than by accepted commercial grades.Relative to the nationally predominant Angus beef breed, research results demonstrate an advantage in final and carcass weight per animal of 5–10% for the Hereford and 20–30% for the Friesian, with the superiority being approximately halved in crossed with the Angus. In terms of weaning performance, the Friesian dam is greatly superior, the Hereford slightly inferior, to the Angus. Heterosis for growth traits is of the order of 5%.In crosses over Jersey cows the Charolais sire is superior to the Hereford but not to the Friesian for total meat output. Carcasses from the dairy breeds and dairy x beef crosses slaughtered at the same age contain a higher bone percentage and are less acceptable on traditional export grading standards than those of the British beef breeds, but nevertheless achieve high output and quality of lean meat.Preliminary results from current large-scale trials suggest that the larger European breeds have potential for improving growth rate and meat yield in crosses with local Angus and Hereford cattle but are more prone to difficult calvings and show later sexual maturity.  相似文献   

6.
The aim of this study was to estimate direct and maternal genetic parameters for calving difficulty score, stillbirth, and birth weight at first and later parities for Charolais and Hereford cattle in Sweden. Calving traits have long been recorded for pure-bred beef cattle in Sweden, but only birth weight has been used in the selection in order to avoid calving difficulties. Linear animal model analyses included records on birth weight for 60,309 Charolais and 30,789 Hereford calves born from 1980 to 1999, and calving traits for 74,538 Charolais and 37,077 Hereford calves born from 1980 to 2001. The frequencies of difficult calvings and stillbirths were approximately 6% at first and 1 to 2% at later parities for both breeds. Fewer than half the stillborn calves were born from difficult calvings. Heritabilities estimated for birth weight in different univariate and bivariate analyses for Charolais and Hereford calves born at first and later parities ranged from 0.44 to 0.51 for direct effects and 0.06 to 0.15 for maternal effects. Heritabilities on the observable scale for calving difficulty score of Charolais and Hereford, scored in three classes, ranged from 0.11 to 0.16 for direct and 0.07 to 0.12 for maternal effects at first parity, and lower at later parities. All estimated heritabilities for stillbirth were very low (0.002 to 0.016 on the observable scale). Direct-maternal genetic correlations were negative, with few exceptions. Genetic correlations between the traits and between parities within traits were generally moderate to high and positive. Calving difficulty score should be included in the genetic evaluation of beef breeds in Sweden, whereas progeny groups in Swedish beef populations are too small for stillbirth to be considered directly.  相似文献   

7.
Epithelial sheets from the limbus, cornea, and third eyelid of Hereford and non-Hereford cattle were examined for the presence of Langerhans cells (LC) using the membrane enzyme ATPase as a marker for LC. The aim of the study was to test the hypothesis that differences in LC density exist between the various ocular epithelia of these animals producing depressed immune surveillance in the case of Hereford cattle. The presence of LC in ocular tissues was confirmed by parallel studies which detected epithelial cells bearing T6, an antigen expressed by human LC. Studies using serial sections demonstrated that T6+ cells also reacted with an anti-human HLA-DR monoclonal antibody. The detection of T6+, DR+ and ATPase+ cells in ocular epithelium in the absence of infiltrating macrophages suggested that LC are present in these tissues. While there were no significant differences in the density of T6+ cells between non-Hereford and Hereford cattle, in the latter ATPase+ cells were significantly fewer in the lateral, medial, and upper limbus.  相似文献   

8.
Bilateral convergent strabismus with exophthalmus (BCSE) is a heritable eye defect prevalent in many cattle breeds and known worldwide. BCSE shows a progressive course often terminating in complete blindness. The onset of the defect can sometimes be slowly progressing (late in life) and, as the first signs of the defect are frequently not noticed prior to first breeding, prevention cannot be achieved only by exclusion of affected animals from the breeding program. This paper provides an overview of the clinical signs, histopathology and genetics of BCSE, its distribution in different cattle breeds and analyses the association between milk production traits and US Brown Swiss. There were different modes of inheritance proposed for BCSE, but although an autosomal dominant major gene is considered most likely in German Brown cattle, an association with milk production traits could not be found. Comparative molecular genetic approaches could help to characterize the responsible genes for this ocular disease in cattle.  相似文献   

9.
Data from feeder cattle teleauction sales in Georgia from 1977 to 1988 were analyzed using least squares analysis of variance to detect significant (P less than .05) influential factors on price. The sample was divided into two periods, 1977 to 1982 and 1983 to 1988, to test whether the influence of factors had changed over the time periods. The test of equality was rejected (P less than .01) using a Chow test, thus suggesting a change had occurred. Hereford breeds were discounted in the latter period whereas Angus breeds generated a premium in the earlier period. Treatment for specific diseases resulted in premium prices, as did preconditioning, during the 1983 to 1988 period. The effect of seasonality on prices decreased over the two time periods. The optimal lot size increased from 228 to 280 cattle during the time periods.  相似文献   

10.
Oxytropis sericea and Astragulus mollissimus (commonly referred to as locoweeds) are responsible for significant monetary losses annually to producers in the western United States. Therefore, a study was conducted over 2 yr to evaluate the influence of beef breeds (Brangus, Charolais, and Hereford) on locoweed consumption. Twenty-one steers (seven per breed group) were used initially in each year of the study on pastures located near Sofia, NM in yr 1 and on pastures located near Des Moines, NM in yr 2. Steers were placed in separate pastures for each breed (3 pastures/yr) and were rotated through pastures on a weekly basis. Number of bites taken of cool and warm season grasses, forbs, and locoweed were recorded daily for each steer. Blood samples were collected on d 0, 7, 21, and 28 for determination of serum alkaline phosphatase. A breed x year interaction (P < 0.10) was observed for locoweed consumption. During yr 1, Brangus cattle consumed more locoweed during wk 1 of the study than Charolais or Herefords (12, 2, and 3% of bites recorded for Brangus, Charolais, and Hereford, respectively). During yr 2, Brangus cattle consumed more (P < 0.10) locoweed during wk 1 (15, 2, and 0%), wk 2 (6, 1, and 1%), and wk 3 (9, 4, and 0% for Brangus, Charolais, and Hereford, respectively) of the experiment compared with Charolais and Hereford cattle. No differences were noted among breeds for serum alkaline phosphatase (AP) concentrations during yr 1. Serum AP was increased (P < 0.01) for Brangus versus Charolais and Hereford on d 7 and 14 during yr 2. Results suggest that differences among breeds exist for locoweed consumption.  相似文献   

11.
British breeds of cattle are not so effective as Zebu in extracting nutrients from low-quality roughages, and these breeds differ in their nutrient metabolism and animal physiology. Breeds of cattle may differ in their requirements for Mg. Brahman cows are less susceptible to death from disease and metabolic disorders than are British breeds of cattle, whereas cows with 50% or greater dairy breeding (Holstein and Jersey) are more susceptible than British or Brahman breeds when maintained in beef production herds. Brahman or Brahman crossbred cows are less susceptible than other breeds to metabolic disorders such as grass tetany. Magnesium absorption has been shown to be greater in Brahman than in Jersey, Holstein and Hereford cows. These differences in the efficiency of Mg absorption between different breeds of cows may be due to genetic variation in the absorptive mechanisms of Mg, in feeding behavior, in gastrointestinal tract motility, in gastrointestinal tract fill or to some combination.  相似文献   

12.
The objective of this study was to determine the inbreeding levels and to analyze the pedigree of Irish purebred populations of Charolais, Limousin, Hereford, Angus, and Simmental beef cattle, as well as the Holstein-Friesian dairy breed. Pedigree analyses included quantifying the depth of known pedigree, average generation intervals, effective population size, the effective number of founders, ancestors, and founder genomes, as well as identifying the most influential animals within the current population of each breed. The annual rate of increase in inbreeding over the past decade was 0.13% (P < 0.001) in the Hereford, 0.06% (P < 0.001) in the Simmental, and 0.10% (P < 0.001) in the Holstein-Friesian breeds. Inbreeding in the other breeds remained relatively constant over the past decade. Herefords had the greatest mean inbreeding in 2004, at 2.19%, whereas Charolais had the lowest, at 0.54%. Over half of each purebred population in 2004 was inbred to some degree; the population with the greatest proportion of animals inbred was the Hereford breed (85%). All 6 breeds displayed a generation interval of approximately 6 yr in recent years. In the pure-bred females born in 2004, the 3 most influential animals contributed between 11% (Limousin) and 24% (Hereford) of the genes. Effective population size was estimated for the Hereford, Simmental, and Holstein-Friesian only, and was 64, 127, and 75, respectively. The effective number of founders varied from 55 (Simmental) to 357 (Charolais), whereas the effective number of ancestors varied from 35 (Simmental and Hereford) to 82 (Limousin). Thus, despite the majority of animals being inbred, the inbreeding level across breeds is low but rising at a slow rate in the Hereford, Simmental, and Holstein-Friesian.  相似文献   

13.
To assess the antioxidant status and oxidative stress in bovine theileriosis due to Theileria annulata blood samples were collected from 35 clinically affected cattle referred to Veterinary Teaching Hospital, School of Veterinary Medicine, Urmia University, Urmia, Iran. Complete blood count, piroplasm parasitemia percentage, erythrocyte glutathione peroxidase, superoxide dismutase, catalase and glucose-6-phosphate dehydrogenase activities, malondialdehyde concentration, osmotic fragility test and median corpuscular fragility were determined and the results were compared with those of 50 healthy controls. Of 35 affected cattle, 12 (34.28%) had severe anemia and 23 had mild to moderate anemia and parasitemia varied from 5 to 40%. The activities of erythrocyte glutathione peroxidase, superoxide dismutase and glucose-6-phosphate dehydrogenase were significantly lower (P<0.0001) and the activity of catalase was significantly higher in the affected cattle than in healthy ones (P<0.001). Malondialdehyde concentration in erythrocytes of affected cattle was significantly more than those of healthy cattle (P<0.001). The affected cattle showed increased fragility of erythrocytes, so that median corpuscular fragility (MCF) in affected group was significantly lower than those of healthy group (P<0.0001). Median corpuscular fragility showed a positive correlation with the severity of parasitemia (r=0.81, P<0.0005) and a negative correlation with the activities of GSH-Px (r=-0.78, P<0.0001), SOD (r=-0.71, P<0.0005), catalase (r=-0.53, P<0.018) and G6PD (r=-0.58, P<0.0005). The results of this study suggest that oxidative damage to RBCs may contribute to the pathogenesis of anemia in bovine theileriosis.  相似文献   

14.
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.  相似文献   

15.
The chronic exposure to regular exercise training seems to increase resistance to oxidative stress and improves the antioxidant defense system. The purpose of the present study was to investigate the effect of an exercise test of moderate intensity on oxidative stress biomarkers, antioxidant enzymes activity, and osmotic resistance of erythrocytes in well-trained equine athletes. Eighteen middle-aged horses of Ukrainian warmblood (8.3 ± 1.6 years) and Holsteiner (7.4 ± 1.9 years) breeds were used in this study. All horses have been in regular training for several years. The exercise test induced a significant increase of erythrocyte values, hemoglobin concentration, and hematocrit in horses of both breeds. Regular training induces activation the antioxidant enzymes and thereby can reduce oxidative stress in athletic horses. Our results suggest that the exercise test in horses of both breeds attenuates oxidative stress and accompanied with a significant decrease of lipid peroxidation and oxidatively modified proteins in erythrocytes after exercise. The findings of the present study demonstrated the elevated level of erythrocytes' catalase and glutathione reductase in Ukrainian warmblood horses, as well as decreased level of superoxide dismutase and glutathione reductase in Holsteiner horses reporting changes in levels of exercise-induced oxidative stress biomarkers in horses of both breeds. Statistically significant differences in the percentage of hemolyzed erythrocytes between pre-exercise and postexercise tests were observed and thereby signifying an oxidative stress-dependent impairment of erythrocyte stability. Our data suggest that oxidative stress and enzymatic antioxidant defense biomarkers can be used for the monitoring of fitness level, health benefits, and performance of equine athletes.  相似文献   

16.
AIM: To investigate cases of coat-colour dilution and hypotrichosis in a group of Hereford x Friesian crossbred calves, and to define the underlying molecular genetics of the disorder. METHODS: The investigation was predicated on the hypothesis that this disorder was similar to a known dominantly inherited disorder of calves of black breeds crossed with Simmental cattle, for which there were candidate gene mutations. Sequence analyses of PCR amplicons from exon 1 and exon 11 of the premelanosome protein 17 gene (PMel17) were carried out. Restriction enzyme digestions of amplicons were followed using electrophoresis of digested fragments. RESULTS: It was shown that an affected calf and its Hereford sire were heterozygous for a three-base deletion in exon 1 of the PMel17 gene. These two animals were also heterozygous for a second mutation in exon 11 of the PMel17 gene. Four other related animals were likewise heterozygous for both mutations in the sire's herd of origin. CONCLUSIONS: Coat-colour dilution and hypotrichosis in Hereford crossbred calves in New Zealand is the same genetic disorder as that previously described in Simmental crossbred calves, and is linked to mutations in the PMel17 gene.  相似文献   

17.
SUMMARY Brahman x Hereford cattle carried only one-quarter as many engorging adult bush ticks ( Haemaphysalis (Kaiseriana) longicornis ) as Hereford, Simmental x Hereford or Friesian x Hereford cattle when grazed together on the north coast of New South Wales. Fourteen percent of a Brahman x Hereford herd carried half of the engorging ticks suggesting that infestation levels would be further reduced by culling procedures. The results indicate an additional advantage to those already established for Brahman x Hereford cattle on the north coast of New South Wales and have important implications for tick control.  相似文献   

18.
In 3 herds 737 Hereford cattle were examined for neoplastic ocular lesions at intervals ranging from 20 to 242 days. Initially all lesions greater than 3 mm diameter were treated by cryosurgery; smaller lesions were left untreated. At subsequent inspections, lesions which had increased to 5 mm diameter were treated. The prevalence of ocular lesions in the herds ranged from 8.1 to 45.7% at the commencement of the study, and from 1.5 to 8.8% after 3.5 years. In treated cattle 71% of lesions regressed after one or two treatments. Seventy-five percent of the small untreated lesions regressed. The progression of lesions and occurrence of new lesions was highest during summer and lowest during winter. It was concluded that inspection of eyes for lesions should be at intervals of 3 to 4 months, and include one during the summer. It is feasible for owners to detect and identify cattle with ocular lesions and to present for treatment those that have grown since the preceding inspection to a size nearing or exceeding 5 mm diameter.  相似文献   

19.
Two unselected herds of purebred Hereford and Angus cattle were created and their progeny evaluated during a 4-yr period (1964 to 1967) for 168-d postweaning gain when they were fed either a high- or medium-energy diet. Birth weight and 200-d adjusted weaning weight also were measured and the importance of sire x diet interactions for postweaning gain examined. Year effects were significant (P less than .001) for all traits in Herefords and for postweaning gain in Angus. Postweaning gain of both breeds increased in successive years, but no trend was observed for birth and 200-d weights. Bulls were heavier than heifers (P less than .05) for all three traits in both breeds. Hereford and Angus calves receiving the high-energy diet gained more (P less than .001) than their contemporaries fed the medium-energy diet. Sire differences were significant for birth weight in Herefords and for all three traits in Angus. Sire x diet interactions were not significant for postweaning gain in either breed. Genetic correlations were calculated by two methods: the two-way ANOVA approach using sire and sire x diet interaction variance components and the one-way ANOVA approach in which gains by progeny of each sire on each diet were considered to be two distinct traits. The genetic correlations for gain in Herefords could not be estimated by either method because of negative sire variance component estimates. The genetic correlations for gain in Angus were 1.08 for the two-way ANOVA method and 1.43 +/- .64 for the one-way ANOVA method. These results indicate that sires ranked the same based on progeny performance when fed either diet.  相似文献   

20.
[目的]为了提高云南黄牛的生产性能,优选主要的杂交改良父本,开展云南黄牛杂交改良。[方法]用西门塔尔牛、短角牛、安格斯牛、海福特牛等分别与云南黄牛母本杂交,测定不同杂交组合后代初生、6月龄、12月龄、24月龄的体重体尺。[结果]云南黄牛经过杂交改良后,改良效果良好,杂交后代对云南高原的气候条件适应性良好。在农村饲养条件下,西×云杂一代牛初生重平均为24.57kg,6月龄体重平均为135.83kg,12月龄体重平均为196.21kg,24月龄体重平均为344.24kg,分别比本地黄牛提高74.13%,59.20%,56.53%和78.10%。短×云杂交一代牛初生重平均为22.28kg,6月龄体重平均为117.20kg,12月龄体重平均为193.56kg,24月龄体重平均为314.86kg,分别比本地黄牛提高57.90%,38.10%,54.21%和62.90%;安×云杂交一代牛犊牛初生重平均为21.21kg,6月龄体重平均为134.34kg,12月龄体重平均为196.18kg,24月龄体重平均为268.45kg,分别比本地黄牛提高50.32%,57.45%,56.51%和38.89%;海×云杂交一代牛初生重平均为22.78kg,6月龄体重平均为124.97kg,12月龄体重平均为190.52kg,24月龄体重平均为289.50kg,分别比本地黄牛提高61.45%,46.47%,51.99%和49.78%。[结论]西×云杂一代牛、短×云杂交一代牛、安×云杂交一代牛和海×云杂交一代牛生产性能显著提高,效益明显。  相似文献   

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