Disease control strategy key

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Farmers need to adopt more stringent management strategies to control a wasting disease in cattle which is costing them millions of pounds a year.

This was the message yesterday from a three-year study led by Scotland’s Rural College (SRUC) into Johne’s disease, which affects 42 per cent of Scottish dairy herds and 35 per cent of beef herds.

There is no known cure for the disease, which causes severe diarrhoea in cattle leading to loss of milk, weight gain, fertility and ultimately death. Calves pick up infection from the faeces of infected cows but the disease generally remains sub-clinical until cows are five or six years of age.

Farmers complain that blood tests to identify infected cattle before the disease manifests itself clinically are notoriously unreliable but the college’s Paraban project has demonstrated that regular blood testing and the culling of infected animals, followed by the adoption of management practices to prevent the spread of infection, will dramatically reduce the incidence of the disease over time.

“More than 13,000 blood samples were taken from cattle in the nine participating farms throughout Scotland with known Johne’s disease problems,” said SRUC researcher, Dr Selene Huntley.

“Over the three years of the project, the number of blood tests showing positive for the disease dropped by 65 per cent.

“That is real progress. But no-one should believe that there is a single, simple solution to tackling this disease. Control requires long-term thinking, strategic planning and the determination to carry it through.”

Nearly all the farms in the project showed significant reductions, although two units have recorded unexplained spikes in the number of positive tests which Huntley admits is not uncommon.

She was speaking at an open day to announce the results of the project at Glenbervie Home Farm, Stonehaven, where efforts to eradicate Johne’s disease have been going on for 12 years.

Farm manager John Lohoar said food ingredient manufacturers Macphie’s of Glenbervie, who own the farm, had made a considerable investment in tackling Johne’s, including £8,000 on blood testing and £24,000 on double fencing to prevent infection spreading from neighbouring farms.

Heifers in the 200 cow pedigree Aberdeen-Angus herd are kept in separate calving groups until calved a second time to combat cross-infection, all animals tested positive are culled and the herd is closed with only stock bulls being bought in.

Soils are also being tested for acidity, which is believed to be a factor in the spread of the disease.

The programme has identified animal testing positive or inclusive at an earlier age and no clinical cases in older have been found in recent years.

“It is worth the effort to identify animal testing positive at an early age and get them away when they are worth £1,500 to £1,600 compared to having to pay £150 to get rid of an old diseased cow,” said Lohoar.