Monday, 20 May 2013

Warning over deadly sheep virus

VETS are warning Tynedale farmers not to become complacent about the deadly sheep virus Schmallenberg.

The midgie-spread bug has faded from the public eye in recent months but vets fear it could return with a vengeance.

Vet Jenny Hull, of the Alnorthumbria practice – which has a surgery in Ponteland – has posted a warning for Tynedale farmers looking to buy in new stock from the South, or even thinking of taking their prize sheep to a show down South this summer.

She said: “Though the disease and its consequences have faded from view – it may not be beaten, and there are sensible precautions that should be taken as farmers and shepherds go about their summer business.”

As a primarily South of England outbreak, the disease never really hit the North-East hard.

However, 90% of sheep in the South have been infected, and are now immune, but Northern flocks are still at risk.

Jenny went on: “When the disease will arrive here in the North-East is uncertain, but there is a high probability that it will come.

“Factors about infection and timings of early pregnancy, and when the virus gets into the local midgie populations all predominate, and are difficult to determine.”

Jenny is advising farmers to take sensible precautions, but not to necessarily alter farming practices or stay at home.

She told farmers: “There is a small risk, and we don’t know what’s going to happen next lambing season – but it shouldn’t be seen as requiring a total change in what you do in terms of sheep husbandry.

“However, farmers should take extra care when buying stock in.”

She said there was a negligible risk of sheep-to-sheep infection; the biggest risk was sheep bitten by infected midgies in early pregnancy.

After four to five days, the sheep acquires lifelong immunity from the disease.

Jenny’s recommendations to minimise risk are:

lGive serious consideration as to whether purchasing from the infected areas really is necessary.

lAny sheep that are bought in should be treated with Spot On, nine days prior to movement to avoid risk of bringing actively infected animals north.

lStock brought in should be quarantined for four weeks.

lVigilance for signs of the infection should be maintained, a high temperature and general appearance of being off colour are both signs.

lSpring calving cows will now be in early pregnancy, therefore treatment with Spot On or Butox Swish this summer is advisable. In addition, to preventing midgies biting, this also controls flies and minimises mastitis risk.

lBreeding bulls/tups, should also be protected from midgie bites as the virus causes high temperatures, and may affect fertility. Again Spot on or Swish is recommended.

lBe very wary of buying pregnant animals from the South/disease margin regions that may have been infected and be carrying a deformed foetus.

Jenny concluded that other precautions or tests are unlikely to be more effective.

Suggestions that animals at risk should be blood tested are likely to be unhelpful, as the tests cannot distinguish between an animal infected and likely to pass of the effects of the disease to unborn young, and one that has developed immunity, is no longer infectious and is therefore safe.

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