Testing regime helping to tackle Mycoplasma bovis

THE debilitating cattle disease, Mycoplasma bovis, appears to be more widespread than previously thought, according to a new survey.

“For a few years, I suspected that M bovis was more prevalent than expected,” explained Graeme Fowlie, director of Meadows Vets, in Aberdeenshire. “From working with vets across the country taking part in a surveillance programme, it’s clear that that is the case.”

The results, from vet practices across England, Scotland, Wales and Northern Ireland, show that it is present in every region, in both beef and dairy herds. “It is probably present in your area, so you should be aware of it.”

The disease causes pneumonia, mastitis, swelling, sore joints and otitis, and is also responsible for a range of chronic underlying issues, which have an impact on welfare and productivity.

As part of the surveillance programme, vets were offered free tests, regardless of whether herds were exhibiting signs of disease or not. Of the 41 farms from across the UK taking part, 18 tested positive, six were inconclusive or void, and 17 were negative. But the results also revealed that some types of analysis were more sensitive than others.

Of the 25 blood tests, 52% were positive while 20% were inconclusive and 28% were negative – despite the fact that eight of those negative/inconclusive results were from farms with symptomatic animals. An interesting result was that the five bulk milk serology tests all came back positive. The 11 PCR tests – mainly of bulk milk samples – failed to show a single positive result.

Ben Pedley, farm clinical director at Willows Farm Vets, in Cheshire, added: “In the past two years we have found M bovis on a number of farms after PCR testing lung samples taken post-mortem from pneumonia cases. Since diagnosing the infection, calf pneumonia on these units has been greatly reduced via management changes including specific vaccination programmes for mycoplasma.”

Meadows Vets have found similar results to this study, said Mr Fowlie. “We have been using blood tests on calves over five months old to screen herds. Dairies could also be screened via bulk milk serology and sick animals can be identified with PCR testing of either nasal swabs, post mortem material, joint fluid or milk samples.”

Since he started using these tests two years ago, he’s returned more positive samples than in the previous 20 years. “We are suspicious some of these would have been false negative results when using traditional bacterial culture testing, which we know is less sensitive.

“One of the biggest problems is that it’s very hard to treat – it doesn’t respond to many common antibiotics, so prevention is better than cure,” added Mr Fowlie. “That means screening herds via blood/bulk milk serology testing and PCR testing of sick animals/ post-mortem samples to confirm the presence of the disease initially and have confidence in those results.”