A leading expert on bovine TB has said the disease can be defeated in NI, but it will take time and require fundamental changes in our approach.

Addressing a Farmers For Action meeting in Cookstown on Tuesday, Dr Sam Strain, the CEO of Animal Health and Welfare NI (AHWNI), said other countries such as Australia and New Zealand have got on top of the disease by using the same tools available in NI.

“Various parts of the world have eradicated TB, or are on the verge of eradicating the disease, with the same current tools we have. It can be done,” he said.

However, until all those tools are fully deployed, he suggested the “disease is going to continue to beat us,” adding that the standard playbook in international control always involves an element of disease control in wildlife and movement controls in cattle.

TB spread

On the issue of wildlife, research has confirmed most TB is spread from cattle to cattle. However, the key issue in any outbreak is the source of the original infection.

“If we stop it [at source], none of the consequential disease happens. Estimates suggest only 8% of TB spread is from badgers to cattle, which leads some to conclude it is only a cattle problem.

“That is wrong. It is the top of the pyramid that is really important. Badgers are absolutely a risk to TB –the spark that starts the fire,” said Strain.

While he believes targeted badger culling is necessary, he said farmers should take action to minimise the incentive for badgers to visit yards, while on grazing land they should fence off badger latrines, raise feed troughs and not feed any meal to cattle on the ground.

Movements

In general, dairy herds tend to carry the same strain of TB as badgers, which potentially suggests infection is spreading between both species. However, in beef herds, the infection source tends to be from animals moved into the herd.

“There is an extraordinary amount of animal moves across farms in NI. If you wanted to invent a system to spread infectious disease in livestock, you would invent something like this,” said Strain.

He believes that risk-based trading (eg where restrictions are put on movements from herds with a history of TB) is a “nettle that will have to be grasped” in NI, but warned that given current disease levels here, it cannot be done right now.

“It would kill the patient in NI – it would be too tough,” he said.

Test

He also defended the use of the current skin test. It has high levels of specificity, which means a reactor animal almost certainly has the disease. However, the sensitivity of the test is around 60% which means the test misses some TB infected cattle – as a result, the TB programme is built around repeat testing.

Ownership

Looking ahead, Strain said breeding for TB resistance will be another tool in the toolbox. He is also a strong advocate of farmers taking ownership of the disease and getting involved in shaping future control programmes. “Unless farmers are involved in governance, we will continue to go around in circles,” he said.

Latest bovine TB figures in NI

The latest data on TB rates in NI show annual herd incidence (defined as the number of new reactor herds out of the total number of herds tested) in the 12 months to the end of November 2024 at 10.63%, up from 10.41% in the previous month.

Individual animal incidence continues to be a particular concern, although the annual rate fell slightly in November to 1.155% compared to 1.158% in the previous month.

Across the first 11 months of 2024, the total number of reactors at a TB test was 18,850, which is up 15% on the 16,372 over the same period in 2023.