The hidden threat of Johne’s Disease

NMR (National Milk Records) veterinarian Karen Bond highlighted the growing challenge of Johne’s Disease on dairy farms throughout the UK and Ireland, courtesy of her presentation at this week’s Open Day hosted by Co. Down milk producer Charlie Weir. The Waringstown farm is home to 600 cows, currently averaging 11,000 litres per lactation.

Karen prefaced her comments with the assertion that the absence of cows showing the physical symptoms of the condition should not be taken as confirmation that the disease does not exist within a herd. The fact that Johne’s will contribute markedly to increased fertility, mastitis and lameness problems means that, on many farms, cows will be culled before they start to demonstrate the tell-tale signs of the disease. The NMR veterinarian encouraged farmers to have 30 cows within their herds initially tested for the disease and to use these results as a benchmark to determine whether an on-farm Johne’s problem does or does not exist. The current milk test for the disease is extremely accurate.

“On foot of these results, herdowners have two options: make plans to keep the disease out, if it is not present, or devise an eradication strategy in the event of affected animals being identified,” she said.

“If there is a problem then the only assumption to make is that the current herd represents a pool of infection and it is only the future calves born on the farm that will be those animals that are guaranteed to be free of the disease, provided the proper eradication procedures are followed.

“These start with feeding calves colostrum that is guaranteed not to constitute a source of Johne’s infection. Pasteurising colostrum can make a positive difference in this context. Obviously, it is important to test animals within the herd for Johne’s on an ongoing basis and remove affected stock accordingly.”

She also said that farmers should not be under any illusion that there is a quick fix to eradicating Johne’s Disease. “Any plan put in place will take a number of years to come to full fruition.”

 

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