Angry French farmers are calling for more protests over the government-backed slaughter of cattle herds affected by so-called Lumpy Skin Disease (LSD).

On Thursday there were clashes between riot police and demonstrators in the southern Ariège department, after vets were called in to destroy potentially contaminated cattle at a farm.

Elsewhere in the south, farmers have dumped manure outside government buildings and blocked roads. The offices of several environmentalist groups were ransacked in the Charente-Maritime department.

LSD is a highly contagious bovine disease which is transmitted mainly by fly-bites. The symptoms are fever, mucal discharge and nodules on the skin.

Though mainly non-fatal, it can badly affect milk-production and the cows are unsaleable.

The disease arrived in Europe from Africa about ten years ago. France's first outbreak was in the Alps in June, when an infected herd forced the Tour de France cycle race to cut short one of its stages.

The government's policy of slaughtering entire herds where a single animal has been infected has run up against bitter opposition from two of the three main farmers' unions.

Conféderation Rurale and Conféderation Paysanne say the policy is being brutally applied, and is in any case unnecessary because a combination of selective culling and vaccination would suffice.

But most vets disagree.

"Right now we are unable to tell the difference between a healthy animal and a symptomless animal carrying the virus. That is the only reason we have to carry out these whole-herd slaughters," said Stephanie Philizot who heads the SNGTV vets' union.

Since June there have been around 110 outbreaks of LSD in France, originally in the east but now increasingly in the south-west. Ministry officials blame the illegal movement of cattle from affected zones. Around 3,000 animals have been slaughtered.

The French government is worried the protests could snowball into a wider movement among a farming population that feels itself under growing threat from the imposition of EU norms and competition from abroad.

A big protest is planned in Brussels next week during the summit of EU leaders. Several French farming sectors are in deep crisis, from wine-growers hit by falling consumption to poultry farmers hit by avian flu.

There is also widespread opposition to the impending signature of an EU free-trade agreement with South American countries, which farmers fear will open France to more cheap food imports, much of it produced under looser environmental and sanitary constraints.

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