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Farming

‘False positives’ must be eliminated

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New bovine TB tests needed?: Cambridge University has recommended

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.”

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Farming

Appeal for dog walkers to keep pets under control during lambing season

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THE LAMBING season is upon us and with many public paths crossing fields of sheep, the Pembrokeshire Coast National Park Authority is appealing to dog walkers to follow best practice when out in the countryside.

While walking the Pembrokeshire Coast Path National Trail and other public footpaths and bridleways:

Always keep dogs on a short lead and under close control when sheep or any other livestock are present.
Clean up after your dog; bag it and bin it wherever you can or take it away –please do not leave poo bags in the countryside.

National Park Authority Public Rights of Way Officer, Meurig Nicholas said: “If your dog is out of your sight or left out of control, it may chase after, attack or worry sheep. Worried and stressed pregnant sheep can miscarry or abort their lambs.

“Young lambs are also very vulnerable at this time, and can get distressed and even die if they are separated from their mothers or abandoned after being chased by dogs.”

There have also been incidents where dogs have had to be rescued from cliffs because they were not kept under close control.

Mr Nicholas added: “These situations have resulted in emergency services such as the Coastguard and RNLI having to retrieve and rescue dogs. These incidents are avoidable and add unnecessary pressure to our busy emergency services.”

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Farming

Plan for ‘collaborative approach’ to tackling rural crime issues

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THIS week (Mar 9) Police and Crime Commissioner Dafydd Llywelyn chaired a strategic meeting with key stakeholders to identify collaborative opportunities to tackle rural and wildlife crime in the Dyfed-Powys area.

Following a meeting with the Farming Unions in Wales earlier this year, Police and Crime Commissioner Dafydd Llywelyn is keen to establish a Strategic Partnership Working Group with key stakeholders that will aim to identify ways of working collaboratively to tackle some of the rural and wildlife crime issues in Dyfed-Powys.

Dyfed-Powys Police have recently appointed a Sergeant for the Rural Crime Team, and the Police and Crime Commissioner has been keen to consult with key stakeholders to gain an input from partners to support the development of a new Rural Crime Strategy for the Force.

Key Stakeholders that were invited to be part of the strategic group include both NFU Cymru and FUW unions, as well as local authorities, National Parks, RSPCA and many others.
Police and Crime Commissioner, Dafydd Llywelyn said: “I had positive discussions with representatives from both unions earlier this year to highlight some of the rural crime issues in the Dyfed-Powys area.

“One of the priorities identified was the need to take a collaborative approach to tackling rural and wildlife Crime, and the meeting with several key partners today was an opportunity to develop discussions and ideas further”.

Earlier in March, PCC Dafydd Llywelyn published a Rural Crime bulletin, which highlights some of the work that has taken place recently in the Dyfed-Powys area, and cross border collaborative initiatives.

PCC Dafydd Llywelyn noted that this multi agency partnership will aim to build on some of the great work that is already happening, and said;  “This meeting today comes a year on from the successful St. David’s Day Conference focusing on Rural Crime that I held at Police Headquarters last year. The last 12 months have been like no other but sadly crime and incidents affecting the rural community have continued.

“Today’s multiagency Strategic meeting was an opportunity to present the new Sergeant for the specialist team, and to discuss a new website that we are developing in partnership with North Wales Police to provide key crime prevention messages to the agricultural industry – the Future Farms Cymru initiative.

“I’m grateful to all partners who attended the meeting today, and I now look forward to take all comments on board as we look to re-energise and refocus the work of the Dyfed Powys Rural Crime Team.”

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Farming

NFU Cymru ‘responds robustly’ to WG

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NFU CYMRU has said that many proposals within the Welsh Government and Defra’s Welfare in Transport consultation will cause significant disruption to livestock transportation in the UK.

In a robust response to the joint Welsh Government / Defra consultation, the union has stressed the significant impact the proposals would have on the livestock and poultry sectors, and raised concerns that if the proposals are implemented, they will fail to deliver any meaningful benefit to animals’ welfare.

Wyn Evans, NFU Cymru Livestock Board Chairman said: “In order to ensure the best possible welfare outcomes, the main priorities should be the animal’s fitness to travel, loading and unloading, driver training and experience, rather than the length of the journey or the external temperature at the time of transport.

“We firmly believe that the current regulations for domestic transport already deliver high welfare, as a result of the standards, cleanliness and adaptability to different weather conditions of transport boxes in the UK. But as an industry, we want to strive for even better. We believe that in order to do that there should be more focus on certified training and providing clearer, sector-specific guidance, particularly during loading and unloading rather than what is proposed in the consultation. Good welfare and healthy livestock go hand in hand; safe arrival at a destination, be that at market or abattoir, must be and is a priority.

“The transporting of livestock is an integral part of UK food production. The suggested changes to journeys based on duration and weather conditions would cause serious delays and disruption, potentially damaging welfare outcomes, while changes to vehicle requirements would add significant costs. It will also lead to many more journeys being made, increasing greenhouse gas emissions, which work against both farming’s and the government’s net-zero targets.

“Turning to the part of the consultation on live exports, we have inputted our views into a proposed NFU assurance scheme, which is detailed in an appendix in the response. This would be extremely effective in delivering welfare outcomes at the same time as maintaining this trade, as assessing the animals’ health and reporting back to producers is a fundamental part of the scheme.”

Richard Williams, Chairman of NFU Cymru’s Poultry Group said: “Looking at the month of January for example, over the last three years on average there were 10 days where temperatures were five degrees or less. If the proposals were implemented to stop transport at this temperature, no broilers could be collected off-farm in those days. If we had a prolonged cold snap; this would have a massive effect on the food chain.

“With any policy developments government makes, it is essential they are based on the latest evidence.  We have an industry to be proud of, with world-leading standards, and that includes our current transportation requirements for all farmed livestock.”

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