An investigation is under way into a rare bovine TB outbreak on the Lancashire/Cumbria border.
DEFRA said five herds had tested positive for the disease over the last few months, including four in one area surrounded by the M6/A65. It is understood dozens of cows have already been slaughtered although no official figures are available.
The Animal Health and Veterinary Laboratories Agency (AHVLA) said contiguous testing was being carried out on surrounding farms in a bid to identify the source of infection, which is unknown.
A 3km enhanced surveillance testing area has been set up around Flookburgh on the Cartmel peninsula, Cumbria
Cases of bovine TB and herd breakdown are relatively rare in the North West. The last major outbreak occurred in Penrith in July 2011 when more than 100 cows had to be killed.
In 2012, out of the 3,500 cattle herd registered in Cumbria, there were five confirmed officially tuberculosis free status withdrawn (OTFW). And out of 2,100 cattle herd registered in Lancashire, there were five OTFW TB breakdowns. Therefore, the percentage of cattle herds infected with bovine TB was 0.001% and 0.002% respectively.
"Their greatest fear is that Cumbria's reputation as a world class sheep and cattle producing county is tarnished by the slur of TB."
Trevor Wilson, NFU's Cumbrian livestock representative
Gonzalo Sanchez, AHVLA veterinary lead for the north of England, said: "Cumbria and Lancashire remain low risk areas of bovine TB, however there are a small number of TB breakdowns each year, typically as a result of bought-in infection from TB high risk counties.
"So far there is no evidence of bovine TB infection in wildlife in either Cumbria or in Lancashire."
But he added the majority of bovine TB breakdowns found in both counties is usually attributed to bought-in infection from TB high-risk areas of south-west England and Wales.
NFU's Cumbrian livestock representative Trevor Wilson said Cumbria was one of the best livestock breeding areas in the country and farmers prided themselves on the fact their stock was hugely sought after.
"Their greatest fear is that Cumbria's reputation as a world class sheep and cattle producing county is tarnished by the slur of TB," he added.
"We can all be lulled into the false sense of security that TB has nothing to do with us here in Cumbria and that it's largely a problem for farmers in the south west of the country. That is a fallacy and it's down to each and every one of us as livestock keepers to be as vigilant as possible when bringing livestock into the county."
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