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Should I be worried about Johne’s?

Krzysztof Reich MRCVS, Molecare Veterinary Services

It has been almost four years since The National Johne’s Management Plan commenced. As part of assessing the industry’s progress on the issue, Action Johne’s has arranged a Conference which will be held in Worcester on 30th January 2019. Key points will include raising further awareness among farmers and how the position of the UK compares internationally.

What is Johne’s?

Johne’s disease is a bacterial infection caused by Mycobacterium Avium Paratuberculosis (MAP). It targets the intestine, causing significant economic impact in affected dairy herds.   A big challenge is the disease’s subclinical component where affected animals are infectious to others, but are difficult to diagnose. Some animals will shed bacteria long before they show up on diagnostic tests as infected animals.

Clinical signs

The signs all come from the effect that Johne’s infection has on the intestines. The animals suffer from scour which results in dehydration and weight loss. This progresses to serious signs of emaciation and eventually death, though most animals are culled before this stage.  The symptoms appear gradually and usually in older animals. Unfortunately, there is no effective treatment, therefore culling plays a major part of disease control.

Biosecurity is key.

Calves are particularly susceptible and infection is often acquired through milk and colostrum. The bacteria are also shed in faeces and so infection is also transferred directly through faeces, but also anything ingested that is contaminated with it. Using milk replacers helps to reduce spread. Avoid grazing young stock on fields where slurry has been applied. Purchase of replacement breeding stock is also a major way of buying in Johne’s infection and infecting clear herds.

Control

This is focussed on searching out infected animals in the herd and changing their management to limit new infections. There are six control strategies to choose from, and these should be carefully chosen and implemented with the guidance of your vet to suit your system. Control strategies include improved biosecurity, management, culling, use of terminal sire and vaccination. Whatever control strategy is selected, the first step is determining your herd status and risk.

So why is it important?

The economic impact of Johne’s is more than just the clinical cases. In the affected animals, milk yield losses can be as high as 25%. Infected animals are also susceptible to other conditions, e.g. high cell counts, lameness and infertility, which have economic impact. The national control programme in Denmark has proved to be successful with the prevalence of the disease on farms dropping from 10% to just 2% over the course of six years.

Action Johne’s Conference looks like a great chance to discuss the progress of the National Management Plan in the UK so far.

For more information on Molecare Veterinary Services, please phone 01392 872934 or visit www.molecarevetservices.com

 

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