More than one in five roadkill badgers which were tested by DAERA last year for bovine TB returned a positive result.

New figures released by the Department show that 459 carcases were collected across NI during 2023, as part of a long-running survey of badgers killed by road traffic.

Of the badgers collected, 428 were deemed to be in a suitable condition for laboratory testing, and 91 of these carcases were confirmed positive for bovine TB. The figures for 2023 equate to a positive rate of 21.3%. It is down slightly from 22.9% the year before, but remains well ahead of positive rates of 16.4% and 13.7% seen in 2021 and 2020 respectively.


Despite the high positive rates, there are concerns that the survey could be under-estimating the extent of bovine TB infections in local wildlife.

In a typical post-mortem test, if a badger has no visible lesions, tissue samples are taken for a culture test in a laboratory to see if TB bacteria are present.

However, infections that are latent or at an early stage may not be detected under this technique, and so a false negative test result is returned.

Previous research published in the scientific journal Veterinary Record found the sensitivity of the standard TB test used on dead badgers in Britain was around 55%.

This means that 45% of badgers that are truly infected with TB are not detected.

Another potential issue with DAERA’s long-running survey surrounds the sampling technique, as badgers that are killed along roadsides may not be representative of the wider badger population.