In 2018, of all herds tested for TB, 3.51% experienced a new breakdown, with at least one animal testing positive for TB.
While TB is at historically low levels, progress towards eradication appears to have slowed since 2015, according to the Department of Agriculture, Food and the Marine (DAFM).
And there has been a relatively high level of TB in Monaghan, Cavan, and north-Meath, throughout 2018.
During 2018, 3,874 of the 112,105 herds in Ireland experienced a TB restriction.
At the end of 2018, 2,176 herds were restricted.
Both figures were broadly unchanged from 2017.
The number of reactors identified in 2018 was 17,491m, the highest since 2012.
Increased use of Gamma Interferon (GIF) blood testing has been a significant factor in higher reactor numbers in the past few years, according to the DAFM.
In 2018, GIF testing accounted for over 20% of reactors.
The herd incidence for TB in Monaghan of 8.91% and Cork North of 5.66% (compared to 3.51% nationally) are seen as particularly relevant because of their higher cattle densities.
As a result, the Cork North veterinary region had the most reactors, at 2,086, with Monaghan second highest (1,677), followed by Tipperary North (1,296).
A targeted TB Control Plan was in place in Monaghan in 2018, to identify and eradicate the disease as quickly as possible. While Wicklow East had the highest herd incidence at 9.51% (596 reactors), it has less than 1% of the national herd.
Donegal and Limerick had the lowest herd incidences, at 1.7% and 1.79% respectively.
The TB 2030 Stakeholder Forum has been set up, with the objective to develop proposals to eradicate TB in Ireland by 2030.