Approximately 98% of the national herd was tested for bovine tuberculosis (TB) in 2020, according to the Department of Agriculture, Food and the Marine’s (DAFM) Annual Report 2021.

There was an increase in the number of reactors detected – 22,604 in 2020 compared to 17,058 in 2019. Herd incidence of TB increased from 3.72% to 4.38% in the same period.

Tuberculosis is now at its highest level since 2009, according to the department.

Just last month, the department published figures showing that the incidence rates of bovine TB have continued to rise in 2021, with almost 22,000 TB reactors identified in the second quarter (Q2) of this year.

Source: DAFM

The underlying risk of the disease is increasing due to more cattle in the national herd and larger individual herd sizes, according to the report.

Previous information from DAFM showed that on a 12-month rolling basis, 4,513 herds were restricted at the end of Q2 2021, compared to 4,225 herds at the end of the same quarter in 2020.

TB reactors

Overall reactor numbers include not just skin-test positives, but also gamma interferon (GIF) blood test positives, which make up approximately 21% of reactors.

A GIF test is used in high risk bovine TB (bTB) breakdowns and can identify infected animals which may be missed by the standard skin-test.

DAFM has said that trends in reactor numbers and herd incidence support the need for a renewed focus on the TB eradication programme.

As the below map confirms, there has been a relatively high level of tuberculosis concentrated in the northeast of Ireland throughout 2020 i.e. Monaghan, Cavan, north Meath.

Image: DAFM

Badger vaccination programme

Badgers are vaccinated by veterinary staff with BCG to reduce the transmission of TB between badgers, according to the department.

This has been demonstrated in field trials to reduce the reproduction number (R0) in badgers from 1.2 to 0.5.

A further field trial was published in 2020 which indicated that vaccination has a similar effect as badger removal in reducing the spread of TB from badgers to cattle.

The removal of badgers in areas around a farm where epidemiological investigation indicates a badger source, will remove the risk associated with confirmed breakdowns, according to DAFM.

In 2020, 3,004 badgers were vaccinated in the vaccination zone and 4,723 badgers were removed in the removal capture blocks.

Bovine TB strategy 2030

Earlier this year, Minister for Agriculture, Food and the Marine, Charlie McConalogue launched a new Bovine TB Eradication Strategy.

According to the Annual Report 2021, department officials in consultation with the TB Forum will, during 2021 and beyond, develop and implement the policy options outlined in the Bovine TB Eradication Strategy.

The implementation of the strategy is overseen by the established TB Forum group with support from three new working groups on science, implementation and finance.

Each working group is composed of officials from the department, farming organisation representatives and other relevant stakeholders.