Using simulation to estimate the power of a badger vaccine trial

The aim of this study was to estimate the power of a badger vaccine field trial using simulation techniques. The effects of sample size, sensitivity and specificity of the diagnostic test, transmission rate between unvaccinated badgers, Vaccine Efficacy for Susceptibility (VES) and Vaccine Efficacy for Infectiousness (VEI) on study power were determined. The most striking result was the large effect of the specificity of the diagnostic test on study power. Sample size had a small effect on power. Study power increased with increasing transmission rate between non-vaccinated badgers. Changes in VES had a higher impact on power than changes in VEI. In summary, study power in group randomized trials depends not only on sample size but on many other parameters. In the current vaccine trial, power was highly dependent on the specificity of the diagnostic test. Therefore, it is critical that the diagnostic test used in the badger vaccine trial is optimized to maximise test specificity

Temporal trends in the retention of BVD+ calves and associated animal and herd-level risk factors during the compulsory eradication programme in Ireland

AbstractThe national BVD eradication programme in Ireland started on a voluntary basis in 2012, becoming compulsory in 2013. The programme relies on accurate identification and prompt removal of BVD+ calves. However, a minority of herd owners have chosen to retain BVD+ animals (defined as still being alive more than seven weeks after the date of the initial test), typically with a view to fattening them to obtain some salvage value. During each year of the programme, additional measures have been introduced and implemented to encourage prompt removal of BVD+ animals. The objective of this study was to describe temporal trends in the retention of BVD+ calves and associated animal and herd-level risk factors during the first three years of the compulsory eradication programme in Ireland.The study population included all BVD+ calves born in Ireland in 2013–2015. A parametric survival model was developed to model the time from the initial BVD test until the animal was slaughtered/died on farm or until 31 December 2015 (whichever was earlier). A total of 29,504 BVD+ animals, from 13,917 herds, were included in the study. The proportion of BVD+ animals that were removed from the herd within 7 weeks of the initial test date increased from 43.7% in 2013 to 70.3% in 2015. BVD+ animals born in 2015 had a much lower survival time (median=33days) compared to the 2013 birth cohort (median=62days), with a year on year reduction in survival of BVD+ calves. In the initial parametric survival models, all interactions with herd type were significant. Therefore, separate models were developed for beef and dairy herds. Overall the results of the survival models were similar, with birth year, BVD+ status, herd size, county of birth and birth month consistently identified as risk factors independent of herd type (beef or dairy) or the numbers of BVD+ animals (single or multiple) in the herd. In addition, the presence of a registered mobile telephone number was identified as a risk factor in all models except for dairy herds with a single BVD+, while the sex of the BVD+ calf was only identified as a risk factor in this model.Significant progress has been made in addressing the issue of retention of BVD+ calves, however, there is a need for further improvement. A number of risk factors associated with retention have been identified suggesting areas where future efforts can be addressed

PHYSICAL APPEARANCE OF Cd-SUBSTITUTED COBALT FERRITE NANOPARTICLES

Objective: Ferrites are an important class of magnetic materials and the most important property of ferrite is its high electrical resistivity, low eddy current, and dielectric losses. The nanostructured ultrafine samples of the ferrite series are prepared by using the Sol-Gel auto combustion method. The prepared samples were characterized by X-ray diffraction (XRD) and Scanning Electron Micrograph (SEM) techniques. X-ray analysis confirms the formation of a single-phase cubic spinel structure. Materials and Methods: A series of polycrystalline nano ferrite having the chemical formula Co1-xCdxFe2O4 (where, x= 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by using Sol-Gel auto combustion method. The starting materials cobalt nitrate (Co(NO3)2·6H2O), ferric nitrate (Fe(NO3)2·9H2O), Cadmium nitrate (Cd(NO3)2·9H2O), citric acid (C6H8O7·H2O) and ammonia (NH3) solution were taken in 99.9% AR grade. Results: In the Co1-xCdxFe2O4 ferrite system, the lattice constant, hopping length (LA and LB) and A-site (A-O) and B-site (B-O) bond length of the samples has been increased due to the increase in cadmium content. The crystalline size of the samples lies in the range between 18nm to 33nm calculated by using Sherrer’s formula Conclusion: Nanaosized Co1-xCdxFe2O4 system was synthesized by using the sol-gel technique

An evaluation of four private animal health and welfare standards and associated quality assurance programmes for dairy cow production

peer-reviewedPrivate standards in animal health and welfare (AHW) and associated quality assurance (QA) programmes are an important instrument for food policy with the potential to substantially improve AHW. However, there are concerns that they do not necessarily do so. In this study, we evaluated four private AHW standards and associated QA programmes for dairy cow production, from Denmark, Ireland, the Netherlands and the United Kingdom, using an existing (but adapted) conceptual framework. The framework considers criteria relating to programme goals including relevance to AHW, programme beneficiaries, effectiveness, efficiency and transparency. The current study focused on information that was publicly available online. We found limited objective information to support programme claims, although there were considerable differences between programmes. Across all programmes, problems were identified with respect to transparency, and attempts to scrutinise claims would not be a straightforward process for most consumers. Among the programmes, there were notable examples of best-practice in AHW, relating to science-based evidence, separation of risk assessment and risk management, animal-based measures, farm benchmarking, ongoing programme-level metrics and measurement, and ongoing programme review. There is a need for careful scrutiny of private standards and QA programmes, to provide consumers with assurance with respect to programme effectiveness and transparency. Further, it is important that programme efficiencies are maximised. There is a strong case for regulatory oversight of private standards in AHW and associated QA programmes. This could be within existing or defined policy instruments, both to facilitate the positive impact of these programmes and to build confidence among consumers of the validity of programme claims

Risk factors associated with increased mortality of farmed Pacific oysters in Ireland during 2011

Peer-reviewed. Released with a Creative Commons Attribution Non-Commercial No Derivatives LicenseThe Pacific oyster, Crassostrea gigas, plays a significant role in the aquaculture industry in Ireland. Episodes of increased mortality in C. gigas have been described in many countries, and in Ireland since 2008. The cause of mortality events in C. gigas spat and larvae is suspected to be multifactorial, with ostreid herpesvirus 1 (OsHV-1, in particular OsHV-1 μvar) considered a necessary, but not sufficient, cause. The objectives of the current study were to describe mortality events that occurred in C. gigas in Ireland during the summer of 2011 and to identify any associated environmental, husbandry and oyster endogenous factors. A prospective cohort study was conducted during 2010–2012, involving 80 study batches, located at 24 sites within 17 bays. All 17 bays had previously tested positive for OsHV-1 μvar. All study farmers were initially surveyed to gather relevant data on each study batch, which was then tracked from placement in the bay to first grading. The outcome of interest was cumulative batch-level mortality (%). Environmental data at high and low mortality sites were compared, and a risk factor analysis, using a multiple linear regression mixed effects model, was conducted. Cumulative batch mortality ranged from 2% to 100% (median = 16%, interquartile range: 10–34%). The final multivariable risk factor model indicated that batches imported from French hatcheries had significantly lower mortalities than non-French hatcheries; sites which tested negative for OsHV-1 μvar during the study had significantly lower mortalities than sites which tested positive and mortalities increased with temperature until a peak was reached. There were several differences between the seed stocks from French and non-French hatcheries, including prior OsHV-1 μvar exposure and ploidy. A range of risk factors relating to farm management were also considered, but were not found significant. The relative importance of prior OsHV-1 μvar infection and ploidy will become clearer with ongoing selection towards OsHV-1 μvar resistant oysters. Work is currently underway in Ireland to investigate these factors further, by tracking seed from various hatchery sources which were put to sea in 2012 under similar husbandry and environmental conditions

A serological survey of bovine babesiosis in northern and eastern Zimbabwe

The geographical distribution of Babesia bovis and Babesia bigemina antibodies in communal herds in northern and eastern Zimbabwe was determined using the ELISA technique. The animals in different herds in the study region had different levels of natural exposure to B. bovis (mean 32 %, range 0-79%) and B. bigemina (mean 52%, range 5-92%) infections. The majority of herds (90%) were endemically unstable for B. bigemina and 62 % were unstable for B. bovis. Natural region 5 and Manicaland province had the highest seroprevalence of B. bovis infection, while natural region 5 and Masvingo province had the highest seroprevalence of B. bigemina infection.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Australian Agency for International Development. Australian Centre for International Agricultural Research. Central Veterinary Laboratory, Harare.mn201

Dynamics of individual animal Bovine Herpes Virus-1 antibody status on 9 commercial dairy herds

Bovine Herpes Virus 1 (BoHV-1) is an important viral disease of cattle worldwide. In endemically infected herds, there is an incomplete understanding of the epidemiology of BoHV-1 infection. We describe the dynamics of animal-level BoHV-1 antibody status on 9 endemically infected commercial dairy herds, based on the results of serial milk antibody testing. Results were used to identify primary exposure, secondary exposure (from re-activation or re-exposure) and development of test-negative latent carrier (TNLC) status. 4153 test results from 828 cow-lactations were analysed. Primary exposure occurred on two herds, secondary exposure occurred on all herds and development of TNLC status occurred in eight herds. Incidence of secondary exposure reduced over time and may have been related to increasing time since parturition. Regular secondary exposure is required to maintain measurable antibody status

Cosmological distance indicators

We review three distance measurement techniques beyond the local universe: (1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and (3) HI intensity mapping. We describe the principles and theory behind each method, the ingredients needed for measuring such distances, the current observational results, and future prospects. Time delays from strongly lensed quasars currently provide constraints on $H_0$ with < 4% uncertainty, and with 1% within reach from ongoing surveys and efforts. Recent exciting discoveries of strongly lensed supernovae hold great promise for time-delay cosmography. BAO features have been detected in redshift surveys up to z <~ 0.8 with galaxies and z ~ 2 with Ly-$\alpha$ forest, providing precise distance measurements and $H_0$ with < 2% uncertainty in flat $\Lambda$CDM. Future BAO surveys will probe the distance scale with percent-level precision. HI intensity mapping has great potential to map BAO distances at z ~ 0.8 and beyond with precisions of a few percent. The next years ahead will be exciting as various cosmological probes reach 1% uncertainty in determining $H_0$, to assess the current tension in $H_0$ measurements that could indicate new physics.Comment: Review article accepted for publication in Space Science Reviews (Springer), 45 pages, 10 figures. Chapter of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Ag