Spatial analysis of seroconversion of sentinel cattle to bluetongue viruses in Queensland     

MP WARD  TE CARPENTER  SJ JOHNSON 《Australian veterinary journal》1996,74(2):128-131

Objective To assess quantitatively the spatial distribution of seroconversion of Queensland cattle to bluetongue viruses.
Design A sentinel herd study. Sample population Sixty-nine sentinel herds at 30 locations.
Procedure Spatial clustering of seroconversion to blue-tongue viruses was investigated during the period from 1990 to 1994.
Results Seroconversion to only two bluetongue virus serotypes, 1 and 21, was observed. The 14 herds, in which seroconversion to bluetongue virus serotype 1 was detected, were located only along the eastern coastal and subcoastal region of Queensland, and were significantly (P < 0.05) clustered. Locations at which seroconversion to serotype 21 was detected, were not significantly clustered. The results generally agree with field observations, except for the failure to detect seroconversion to bluetongue viruses in north-western Queensland.
Conclusion Bluetongue infection of cattle in north-western Queensland may be temporally sporadic. The dominance of serotype 1 in the Queensland cattle population may be the result of differential transmission by potential vector species. Long-term surveillance programs are important for defining disease status of animal populations.  相似文献   

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SJ JOHNSON 《Australian veterinary journal》1992,69(3):70-70

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Large-scale molecular dynamics simulations of dislocation intersection in copper     

SJ Zhou  DL Preston  PS Lomdahl  DM Beazley 《Science (New York, N.Y.)》1998,279(5356):1525-1527

The results of massively parallel three-dimensional molecular dynamics simulations of the perpendicular intersection of extended dislocations in copper are reported. The intersection process, which involves three of the four possible 111 glide planes in the face-centered cubic lattice, begins with junction formation, followed by unzipping, partial dislocation bowing, cutting, and, finally, unit jog formation. The investigation provides insights into this complex atomistic process, which is currently not accessible to experimental investigation.  相似文献   

Past temperatures directly from the greenland ice sheet   总被引：3，自引：0，他引：3  

D Dahl-Jensen  K Mosegaard  N Gundestrup  GD Clow  SJ Johnsen  AW Hansen  N Balling 《Science (New York, N.Y.)》1998,282(5387):268-271

A Monte Carlo inverse method has been used on the temperature profiles measured down through the Greenland Ice Core Project (GRIP) borehole, at the summit of the Greenland Ice Sheet, and the Dye 3 borehole 865 kilometers farther south. The result is a 50, 000-year-long temperature history at GRIP and a 7000-year history at Dye 3. The Last Glacial Maximum, the Climatic Optimum, the Medieval Warmth, the Little Ice Age, and a warm period at 1930 A.D. are resolved from the GRIP reconstruction with the amplitudes -23 kelvin, +2.5 kelvin, +1 kelvin, -1 kelvin, and +0.5 kelvin, respectively. The Dye 3 temperature is similar to the GRIP history but has an amplitude 1.5 times larger, indicating higher climatic variability there. The calculated terrestrial heat flow density from the GRIP inversion is 51.3 milliwatts per square meter.  相似文献   

Alteration of oceanic volcanic glass: textural evidence of microbial activity     

MR Fisk  SJ Giovannoni  IH Thorseth 《Science (New York, N.Y.)》1998,281(5379):978-980

The subsurface biosphere may constitute as much as 50 percent of Earth's biomass. Direct and indirect evidence suggests that an extensive biosphere exists in the rocks below the sea floor. This survey of basalts of the Atlantic, Pacific, and Indian Oceans supports the hypothesis that bacteria have colonized much of the upper oceanic crust, which has a volume estimated at 10(18) cubic meters. Although this is the largest habitat on Earth, its low abundance of bacteria constitutes much less than 1 percent of Earth's biomass.  相似文献   

Global trends in milk quality: implications for the Irish dairy industry     

SJ More 《Irish veterinary journal》2009,62(Z4):S5

The quality of Irish agricultural product will become increasingly important with the ongoing liberalisation of international trade. This paper presents a review of the global and Irish dairy industries; considers the impact of milk quality on farm profitability, food processing and human health, examines global trends in quality; and explores several models that are successfully being used to tackle milk quality concerns. There is a growing global demand for dairy products, fuelled in part by growing consumer wealth in developing countries. Global dairy trade represents only 6.2% of global production and demand currently outstrips supply. Although the Irish dairy industry is small by global standards, approximately 85% of annual production is exported annually. It is also the world's largest producer of powdered infant formula. Milk quality has an impact on human health, milk processing and on-farm profitability. Somatic cell count (SCC) is a key measure of milk quality, with a SCC not exceeding 400,000 cells/ml (the EU milk quality standard) generally accepted as the international export standard. There have been ongoing improvements in milk quality among both established and emerging international suppliers. A number of countries have developed successful industry-led models to tackle milk quality concerns. Based on international experiences, it is likely that problems with effective translation of knowledge to practice, rather than incomplete knowledge per se, are the more important constraints to national progress towards improved milk quality.  相似文献   

An outbreak of tuberculosis affecting cattle and people on an Irish dairy farm,following the consumption of raw milk     

Doran P  Carson J  Costello E  More S 《Irish veterinary journal》2009,62(6):390-397

Bovine tuberculosis is an ongoing problem in Ireland, and herd incidence has remained at approximately 5% for some years. Spillover of infection from cattle to people remains an ever-present possibility, given the ongoing pool of infection in the Irish cattle population. This paper describes an outbreak of tuberculosis affecting cattle and people on a dairy farm in southeastern Ireland following the consumption of milk from a seven-year-old cow with tuberculous mastitis. Twenty-five of 28 calves born during autumn 2004 and spring 2005 were subsequently identified as TB reactors, and five of six family members were positive on the Mantoux test. During 2005, milk from this cow had mainly been used to feed calves, and was added only occasionally to the bulk tank. Therefore, the calves each received infected milk on an almost continuous basis between birth and weaning. The family collected milk from the bulk milk tank, and consumed it without pasteurisation. This case highlights the risks associated with the consumption of raw milk. In this family, TB has had a very significant impact on the health of two young children. These risks are well recognised, and relevant information for farmers is available. It is of concern, therefore, that raw milk consumption remains prevalent on Irish farms. New strategies are needed, in partnership with industry, to address this important issue. Keywords: bovine tuberculosis, Ireland, mastitis, milk, Mycobacterium bovis, pasteurisation, TB, zoonosis.  相似文献   

An evaluation of Irish cattle herds with inconclusive serological evidence of bovine brucellosis     

Hayes M  Ashe S  Collins D  Power S  Kenny K  Sheahan M  O'Hagan G  More S 《Irish veterinary journal》2009,62(3):182-190

Since 1998, there has been a steady decline in herd restrictions and de-populations in Ireland due to bovine brucellosis. There is concern that the interpretation of laboratory results may become increasingly problematic, as brucellosis prevalence falls in Ireland. Therefore, the purpose of the current study was to evaluate the infection status of Irish herds and animals with inconclusive serological evidence of bovine brucellosis. During 12 months from September 1, 2004, laboratory and observational epidemiological data were collected from all Irish herds where animal testing identified at least one animal with a complement fixation test (CFT) reading greater than zero and/or a positive result to the indirect enzyme-linked immunosorbent assay (iELISA). Due to the observational nature of the study, we have robust estimates of the relative, but not the absolute, performance of the CFT, iELISA and brucellin skin test (BST). Herds were divided into three categories (Group A, B or C) on the basis of test results at initial assessment. A total of 639 herds were enrolled into the study, and observed for at least two years following enrolment. A rising CFT titre, with a CFT reading of 111 International CFT Units (IU) or greater at the subsequent blood test, was generally associated with herds where other evidence of infection was also available. Knowledge of the CFT reading at the initial and a subsequent blood test proved useful in distinguishing false-positive and true-positive brucellosis results. There was poor correlation between the CFT and iELISA results, and between the CFT and BST results. As a result of this study, national policy has been modified to include re-sampling of all animals with CFT readings of 20 IU or greater. This project has also led to a reduction in the number of herds restricted, as well as restriction duration. It has also contributed to a reduction in the number of herds listed for contiguous tests, and therefore the potential for contiguity testing of false positive results.  相似文献   

Effects of Superovulation with oFSH and Norgestomet/GnRH‐Controlled Release of the LH Surge on Hormone Concentrations,and Yield of Oocytes and Embryos at Specific Developmental Stages     

HM Knijn  W Fokker  GC van der Weijden  SJ Dieleman  PLAM Vos 《Reproduction in domestic animals》2012,47(2):177-183

The objective of this study was to evaluate a new superovulation procedure with oFSH after temporary suppression of the endogenous LH surge by norgestomet followed by administration of GnRH, to collect bovine oocytes and embryos at specific developmental stages. Since 1999, our research group applies this superovulation procedure with controlled release of the endogenous LH surge. The objective of this study is to verify if this procedure is reliable for collection of oocytes and embryos at specific time points of development and if it produces a sufficient number of both oocytes and embryos of good quality. This procedure was validated regarding to hormonal characteristics, superovulatory response and both oocyte and embryo yield at different times of in vivo development. The results demonstrate that the procedure used to control the occurrence of the pre‐ovulatory LH surge was effective in 92% of the animals (n = 238) and even in 99% of the animals the oocytes and embryos were collected at the intended stage of development. The superovulatory response and both oocyte, embryo yield and quality were similar to the average yield in Europe reported by Association Européenne de transfert embryonnaire (AETE). In conclusion, this superovulation procedure provides a valid tool to collect oocytes and embryos at specific time points of development.  相似文献   

Farm management factors associated with bulk tank somatic cell count in Irish dairy herds     

PT Kelly  K O'Sullivan  DP Berry  SJ More  WJ Meaney  EJ O'Callaghan  B O'Brien 《Irish veterinary journal》2009,62(Z4):S45

The relationship between bulk tank somatic cell count (SCC) and farm management and infrastructure was examined using data from 398 randomly selected, yet representative, Irish dairy farms where the basal diet is grazed grass. Median bulk tank SCC for the farms was 282,887 cells/ml ranging from 82,209 to 773,028 cells/ml. Two questionnaires were administered through face-to-face contact with each farmer. Herd-level factors associated with bulk tank SCC were determined using linear models with annual somatic cell score (i.e., arithmetic mean of the natural logarithm of bulk tank SCC) included as the dependent variable. All herd level factors were analysed individually in separate regression models, which included an adjustment for geographical location of the farm; a multiple regression model was subsequently developed. Management practices associated with low SCC included the use of dry cow therapy, participation in a milk recording scheme and the use of teat disinfection post-milking. There was an association between low SCC and an increased level of hygiene and frequency of cleaning of the holding yard, passageways and cubicles. Herd management factors associated with bulk tank SCC in Irish grazing herds are generally in agreement with most previous studies from confinement systems of milk production.  相似文献