TB levels down on 2014 levels – here’s where has the worst herd incidence

Incidences of TB levels in cattle herds last year fell on 2014 levels, the latest figures from the Department of Agriculture show.

In 2015, there were 15,317 reactor cattle, down 828 head on 2014.

The highest number of reactor cattle was in Co. Clare with 1,383, followed by Co. Wicklow with a total of 1,184 reactors and Cork South with 1,127.

The lowest number of reactor cattle in 2015 was in Co. Dublin with 63 reactors, followed by Co. Louth with 120 reactors and Co. Kildare which had 138.

TB incidence in herds also fell from 3.64% to 3.37% on 2014 and the number of reactors per 1,000 tests fell from 1.91 to 1.82.

The south east of the country recorded the highest levels of TB incidence in herds.

Wicklow, which was split into east and west, recorded herd incidences of 6.78% and 12.89%.

Wexford had the next highest level of incidence with 6.29%. The lowest herd incidence was in Mayo with 1.45%.

Meanwhile, with many farms expanding in numbers in the past year and many planning to do so, recent research has found that herds of 150 cattle or more are 50% more likely to suffer a bovine TB outbreak than those with herds of 50 or fewer.

Intensive farming practices have been linked to higher risks of TB, the research by the University of Exeter found.

Patterns of crop production and feeding were also important, with the risks increasing with practices linked with higher productivity systems, it found.

For every 10ha of maize – a favourite food of the badgers that play a role in transmitting the disease – TB risk increased by 20%.

The feeding of silage was linked with a doubling of the risk in both dairy and beef systems.

Landscape features such as deciduous woodland, marshes and hedgerows were also important e.g. on farms with 50km of field boundaries, each extra 1km of hedgerow was linked with a 37% reduction in risk.