Farming

‘False positives’ must be eliminated

Published

10 years ago

March 12, 2015

New bovine TB tests needed?: Cambridge University has recommended

A NEW study performed by researchers from Cambridge University has recommended that new tests are needed to make vaccination against bovine tuberculosis (bovine TB). The report points out that in order for vaccination to be viable, the number of false positives from these tests must be significantly reduced. The scientists have said the reduction in false positives in cattle is feasible, but that a vaccination programme would be challenging. Despite an intensive, and costly, control program in the United Kingdom, bovine TB persists. Although vaccinating cattle with the human BCG vaccine offers some protection in cattle, doing so is currently illegal within the EU, due to the vaccine’s interference with the skin test used for surveillance.

The Cambridge team worked alongside researchers at the government’s Animal & Plant Health Agency (APHA), to show the importance of specificity – the proportion of uninfected animals that test negative – to making disease control strategies work. The skin test currently in use has a very high estimated specificity of over 99.97%, which means that less than three animals in 10,000 will test falsely positive. However, the test as carried out in Great Britain is thought to have at best an 80% sensitivity – a measure of how many infected animals will correctly test positive – missing around 1 in 5 bovine TB-infected cattle. It is used to determine if animals, herds and countries are officially free of bovine TB.

Vaccinated animals that test positive have to be treated as infected animals. Under European law, if an animal tests positive, it must be slaughtered. The remaining herd is put under movement restrictions and tested repeatedly using both the skin test and post-mortem examinations until it can be shown to be officially clear of infection. Researchers said the duration of movement restrictions is important due to the considerable economic burden they place on farms. Also, the cost to the UK government alone is estimated to amount to half a billion pounds over the last decade; this cost includes visits to farms by veterinarians, tests carried out and compensation for the slaughter of infected animals.

For vaccination to be economically viable and acceptable within the EU, the benefits of vaccination must be great enough to outweigh any increase in testing. A new generation of diagnostic tests, known as ‘Differentiate Vaccinated from Infected Animals’ (DIVA) tests, has opened up the opportunity for the use of BCG within current control programmes. The EU has recently outlined the requirements for changes in legislation to allow cattle vaccination and a recent report from its European Food Safety Authority (EFSA) emphasized the importance of demonstrating that BCG vaccine works, and that DIVA tests can be shown to perform in large-scale field trials.

However, a key factor overlooked in the EU report was that the currently viable DIVA tests have a lower specificity than tuberculin testing; this could lead to vaccinated herds being unable to escape restrictions once a single test-positive animal has been detected, as the more times the herd is tested, the more likely the test is to record a false positive. In their study, the researchers from Cambridge and APHA used herd level models to show that the level of infection can be reduced in vaccinated herds even when DIVA sensitivity is lower than tuberculin skin testing.

However, in order to see this benefit of vaccination over 99.85% of uninfected animals will need to test negative in the DIVA test. This improved accuracy will be necessary to avoid increasing the duration of breakdowns and the number of animals condemned. Using data from previous tests on cattle, the researchers said this level of ‘specificity’ is achievable, though they said there will be challenges associated with improving accuracy. The researchers said, “Currently, there is no gold standard test to diagnose TB in cattle. Cattle that test positive are slaughtered immediately and therefore have rarely developed any physical signs – in fact, only around a half of animals examined post-mortem show physical signs of infection even if they are, indeed, infected.”

Dr Andrew Conlan from the Department of Veterinary Medicine at the University of Cambridge explained “In order for vaccination to be viable, we will need a DIVA test that has extremely high specificity. If the specificity is not good enough, the test will find false positives, leading to restrictions being put in place and a significant financial burden for the farmer. “But validating a test that has a very high specificity will in itself be an enormous challenge. We would potentially need to vaccinate, test and kill a large number of animals in order to be confident the test is accurate. This would be very expensive.”

Crime

Farmer cleared of restraining order breach at Haverfordwest court

Published

4 days ago

January 23, 2025

Tom Sinclair

A PEMBROKESHIRE man has been found not guilty of breaching a restraining order after being accused of referencing a protected individual in a Facebook post.

Philip Stoddart, 58, of Monkhill Farm, St Ishmaels, appeared at Haverfordwest Magistrates’ Court on Monday (Jan 20) to face the charge. The prosecution, led by Ann Griffiths on behalf of the crown, alleged that between December 4 and December 13, 2023, Stoddart made a Facebook post that, by inference, referred to a person he was prohibited from contacting under a restraining order imposed by Swansea Crown Court on April 16, 2021.

The restraining order, issued under Section 360 of the Sentencing Act 2020, barred Stoddart from making any form of contact with her.

Prosecutors argued that the Facebook post constituted a breach of the order, contrary to Section 363 of the same act.

Stoddart denied the allegations and entered a not guilty plea during a prior hearing on October 1, 2024.

Magistrates Professor N. Negus, Mr. J. Steadman, and Mrs. J. Morris presided over the trial, which concluded on Monday.

After reviewing the evidence, the bench found Stoddart not guilty, dismissing the case.

The dismissal brings to a close legal proceedings that had been ongoing for over a year.

Farming

Get up to £5,000 for on-farm trials in Wales

Published

4 days ago

January 23, 2025

Tom Sinclair

FARMERS in Wales are being called to apply for the next round of funding for on-farm trials.

The Farming Connect initiative, which has funded projects such as growing lucerne in Brecon, is inviting applications for the Try Out Fund.

The new application window opens on January 27, 2025, and will run until February 17.

Successful applicants will be awarded up to £5,000 to help fund trials that experiment with new ideas on their farms.

The last round of funding supported several projects, including integrated pest management at a pick-your-own strawberry enterprise.

Menna Williams, the Farming Connect project lead, said: “Farming Connect has developed the Try Out Fund to address specific local problems or opportunities with the aim of improving efficiencies and profitability within agricultural businesses whilst protecting the environment.”

She added: “There are many changes on the horizon for agriculture, and now is a great time for farm businesses to explore an idea that could benefit them, allowing farms to tackle ‘real’ problems or check if a research idea works in practice.”

The fund is open to individuals or groups of up to four farmers and/or growers in Wales who have identified a local or specific problem or opportunity.

Ms Williams said: “Because these ideas are initiated by farmers themselves, they are really passionate about them, giving them 100 per cent effort right from the start.”

Projects should focus on enhancing production efficiencies and profitability while ensuring environmental protection through adherence to sustainable land management principles.

A guidance handbook is accessible on the Farming Connect website, providing support for farmers in outlining their projects and completing the application process.

To apply, individuals must be registered with Farming Connect and capable of finishing their projects by January 2026.

Ms Williams explained: “Funding can be used for technical assistance, sampling, testing and other reasonable expenses such as those relating to short-term hire of specialist equipment or facilities directly relating to the project.”

The findings will be shared with other producers in Wales by collaborating with a Farming Connect team member.

Interested parties can apply on the Farming Connect website.

To receive the link or get further information, contact [email protected].

Farming

Funding window to re-open for on-farm trials in Wales

Published

4 days ago

January 23, 2025

Tom Sinclair

WITH Farming Connect-funded trials ranging from growing lucerne in Brecon to establishing sunflowers as a companion crop with maize, farmers are being invited to apply for the next round of funding from the initiative that brought these projects to life.

The new application window for the Try Out Fund opens on 27January2025 and will run until 17 February. Successful applicants will be awarded up to £5,000 to help fund on-farm trials that experiment with new ideas. The last round of funding saw farmers supported for several projects including integrated pest management at pick your own strawberry enterprise.

Project lead Menna Williams of Farming Connect said the aim is for farmers to compare different treatments or management systems – the project is not intended to fund new equipment she stressed.

“Farming Connect has developed the Try-Out Fund to address specific local problems or opportunities with the aim of improving efficiencies and profitability within agricultural businesses whilst protecting the environment,’’ she said. “There are many changes on the horizon for agriculture, and now is a great time for farm businesses to explore an idea that could benefit them, allowing farms to tackle ‘real’ problems or check if a research idea works in practice.’’

The fund is open to individuals or groups of up to four farmers and/or growers in Wales who have identified a local or specific problem or opportunity.

“Because these ideas are initiated by farmers themselves, they are really passionate about them, giving them 100% effort right from the start,’’ said Ms Williams.

Suitable projects must aim to improve production efficiencies and profitability whilst protecting the environment by aligning with sustainable land management outcomes. A guidance handbook is available on the Farming Connect website to help farmers scope their project and complete the application form.

Applicants must be registered with Farming Connect and be able to complete their projects by January 2026.