Farming

‘False positives’ must be eliminated

Published

11 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.”

Farming

Plaid urged to move faster on farming reforms amid subsidy concerns

Published

15 hours ago

May 25, 2026

Tom Sinclair

Welsh Conservatives accuse Plaid Cymru of failing farmers as ministers call for patience over changes to agricultural support

CONCERNS over the pace of farming reforms in Wales have intensified after the Welsh Conservatives accused the Welsh Government of failing to act quickly enough on promised changes to agricultural subsidy schemes.

The criticism comes after Welsh Government Rural Resilience and Sustainability Minister, Llyr Gruffydd, urged farmers to be patient as major changes to support payments continue to be developed.

Speaking to ITV Wales, Mr Gruffydd acknowledged that “change is difficult” as the government seeks to reshape agricultural support across rural Wales. The comments come at a time of growing unease among parts of the farming community over the future of post-Brexit subsidy arrangements and concerns about financial pressures facing farms.

The reforms centre on replacing previous support systems with a new approach intended to balance food production, environmental sustainability and rural resilience. However, some farmers and unions have warned that uncertainty over payments and policy changes risks damaging confidence in the sector.

Reacting to the minister’s remarks, Welsh Conservative Shadow Farming Minister, Andrew RT Davies, said Plaid Cymru was not moving quickly enough to deliver on commitments made to Welsh farmers.

Mr Davies said: “Change is not difficult – contrary to Plaid Cymru separatists’ claims.

“If the will is there, there’s no reason reforms can’t be implemented immediately.

“Plaid Cymru separatists must fulfil their promises to Welsh farmers now.”

The comments reflect wider political tensions over the direction of farming policy in Wales, with opposition parties arguing that delays and uncertainty are creating anxiety for agricultural businesses already facing rising costs and economic pressures.

Farming remains a major part of the Welsh economy, particularly in rural counties such as Pembrokeshire, Carmarthenshire and Ceredigion, where many communities rely heavily on agriculture and associated industries.

The Welsh Government has previously said changes to support schemes are aimed at creating a more sustainable long-term future for farming, though ministers have acknowledged the transition period will take time and may prove challenging for some in the industry.

The debate over subsidy reform is likely to remain a key political battleground as the government finalises details of its future support model and seeks to reassure farmers concerned about their livelihoods.

Farming

Pembrokeshire new potato harvest begins as first crop hits shops

Published

2 weeks ago

May 15, 2026

Tom Sinclair

Locally grown early potatoes arrive in stores as farmers begin lifting the first Pembrokeshire crop of 2026

PEMBROKESHIRE’S famous new potato season has officially begun, with the first crop of locally grown potatoes being harvested and delivered to shops across the county.

Farmers at Norton Farm began lifting the first Pembrokeshire new potatoes of the year this week, with the freshly harvested crop expected to reach local stores by Friday morning.

The arrival of Pembrokeshire new potatoes marks the unofficial start of the county’s summer growing season and is eagerly anticipated by shoppers keen to enjoy one of Wales’ best-loved seasonal foods.

Photographs shared by the farm show workers hand-picking potatoes from freshly turned soil as machinery lifted the crop from fields overlooking the Pembrokeshire countryside.

The potatoes, prized for their distinctive flavour and soft skins, benefit from the county’s mild climate and coastal growing conditions.

Brian Llewelyn a’i Ferched shared the news on social media, telling customers: “Arriving with us this afternoon!!!!” as excitement builds around the first deliveries.

Locally grown Pembrokeshire new potatoes are expected to be available in selected shops from around 10:00am on Friday.

For many in Pembrokeshire, the arrival of the first new potatoes is a sign that summer is just around the corner — and that it is finally time to get the butter on.

Photo caption:

First crop: Workers begin lifting Pembrokeshire new potatoes at Norton Farm as the 2026 harvest season gets underway (Pics: Norton Farm).

Farming

New Narberth farmers’ market to champion Pembrokeshire produce

Published

2 weeks ago

May 15, 2026

Tom Sinclair

LOCAL FOOD PRODUCERS GIVEN NEW MONTHLY PLATFORM

A NEW monthly farmers’ market is set to launch in Narberth next month, giving Pembrokeshire producers a regular space to sell and showcase food grown, reared and made in the county.

Pembrokeshire Local Food Partnership is launching the market at the Queen’s Hall, Narberth, on Saturday, June 13. It will then run monthly from 10:00am to 2:00pm.

The market has been developed in collaboration with local growers Rufus and Ffion, of Hael Natural Produce, based in Clunderwen.

Organisers say it will bring together a wide range of local food and drink producers, with stalls expected to include fresh seasonal produce, artisan foods, baked goods and speciality items.

Among those taking part are Spirit Wood Wales, Big Green Elephant, Foxhill Preserves and Pencw Cheese.

Pembrokeshire Local Food Partnership will lead on marketing and subsidise stall costs for the first three markets, in a bid to encourage strong early participation and reduce barriers for small and emerging producers.

The launch will also see Rufus and Ffion introduce a new local veg box scheme through Hael Natural Produce.

Rufus said: “I’m really excited to be launching my new veg box scheme at the farmers’ market.

“It’s a great opportunity to get fresh, locally grown produce directly to people in the community and to build something that connects people more closely with where their food comes from.”

Sue Latham, Coordinator of Pembrokeshire Local Food Partnership, said: “We are looking forward to creating a regular space in Narberth that supports local producers and gives the community consistent access to high-quality, local food.

“This market is about strengthening those connections and building something that can grow over time.”

Organisers are encouraging residents, visitors and food lovers to attend the launch and support the new initiative, which forms part of Pembrokeshire Local Food Partnership’s wider work to strengthen local food networks across the county.