Feedlots and cattle trade cited for spread of TB

Cattle movements, poor quality skin testing and feedlots acting as a reservoir for infection were among the factors which contributed to a massive increase in TB levels in northwest Kilkenny and adjacent parts of counties Laois and Tipperary.

However, a seven-year Department of Agriculture investigation into disease levels in the area around Urlingford and Johnstown also noted a high level of TB in badgers that were culled locally.

This was despite the study zone being designated as a badger vaccination area since 2013.

The study, which ran from 2016 to 2023, identified “local spread” as the main driver of disease breakdown in the area when the findings were presented at a recent meeting of the TB Forum.

There was evidence of sub-standard testing by a small number of testers

High levels of cattle movements were cited in the presentation as a “potentially important” contributor to the spread of TB, with big numbers of animals purchased from what were described as “high-risk herds”.

However, it was accepted at the presentation that the presence of controlled finishing units or feedlots in the area inflated both these figures.

These feedlots also represented a “reservoir” for TB, the study maintained.

Skin testing

Interestingly, evidence of some poor-quality skin testing was also identified as contributing to the spread of the disease in the region.

“Generally, [the] quality of skin testing by PVPs (private veterinary practitioners) is in line with other parts of the country but there was evidence of sub-standard testing by a small number of testers,” it was stated in the presentation.

In terms of wildlife, the study found that high levels of TB were identified at post-mortem in badgers culled in the area.

However, the authors claimed that the sample on which this information is based was “heavily biased”.

The study noted that while just 77 of 1,518 herds in the area had at least one TB case in 2016, this figure increased to 179 out of 1,368 herds by 2023.

Infection levels

The herd incidence rate for TB rose from 5.1% in 2016 to 13.1% in 2023, with the total number of TB cases increasing six-fold from 272 to 1,595 over the same period.

Dairy cows accounted for a high percentage of these reactors.

In their key takeaway message, the authors noted that the level of Bovine TB in the study area is influenced by “multiple factors”, and that a “holistic, collaborative and integrated approach” will be required to tackle the disease.