NADIS Health Bulletin for South West England

Johnes’s disease (Paratuberculosis)

Cause

• Chronic enteritis of adult cattle, sheep and goats.

• Caused by a bacterium Mycobacterium avium subspecies paratuberculosis (MAP).

Infection can be acquired in three ways; within the womb, through infected colostrums or through faecal infection (oral route) and contamination from infected cattle.

The estimated to cost the UK cattle industry is up to £13m annually.

• £2600 in a 100 cow dairy herd with clinical cases - likely to be a gross underestimate.

Clinical signs

• Diarrhoea

• Poor milk yield

• Poor coat

• Three to five year-old cattle

• Onset following calving or other stressful event (sale, transportation etc.)

• No fever

• Animal maintains a good appetite until the terminal stages.

• Clinical signs may continue for several months – emaciation.

Diagnosis

When observing livestock with these clinical signs your veterinary surgeon will also consider the following possible causes:

• Chronic fasciolosis

• Persistently infected with MD/BVD virus

• Chronic salmonellosis

• Type I or Type II ostertigiasis

• Chronic bacterial infection leading to debility

There is no single reliable test for confirming Johne’s disease during the early stages so diagnosis is best made using a combination of serology and faecal examination. Once Johne’s disease has been diagnosed, veterinary involvement is essential

Control of Johne’s disease is difficult as it has a long incubation period, often several years. It is complicated by the fact that their is shedding of infection before showing clinical signs and there are poor detection rates in the early stages of disease.

To eradicate Johne’s disease requires substantial commitment by the farmer. Vlood testing and/or faecal examination may be done every six to 12 months with slaughter of positive cases. Two consecutive herd negatives may indicate eradication.

Practical control measures to limit losses in a diseased herd include:

• Rapid culling of diseased animals.

• Minimise faecal contamination of food, water and pasture

• Raising feed and water troughs,

• Strip grazing

• Mains/piped water rather than surface/pond water

• Avoid spreading yard manure on pasture

• Do not feed waste milk to calves

• Do not raise calves from known infected dams as breeding replacements.

• Re-stock only from accredited herds especially bulls.

• Keep clinical cases and Johne’s disease test-positive cows out of the calving accommodation/pens.

• Clean the calving accommodation/pens often.

• Remove the calf from the calving accommodation/pens within one hour after birth.

• Feed each calf four litres of colostrum before the calf is six to 12 hours old.

• Cow’s teats should be prepped before colostrum collection to limit faecal contamination.

• Colostrum should be fed from one test-negative cow to one calf. The cow that donated the colostrum should be recorded on the calf’s health record card.

• Pooled colostrum should not be fed in Johne’s disease positive herds

• After colostrum, feed only milk replacer or on-farm pasteurized milk.

• Rear calves well away from adult cattle ensuring no contact with slurry or contamination of water or feed with faeces/slurry.

• In terms of welfare there is no effective treatment and animals must be culled as soon as the diagnosis is confirmed. Progeny of infected cows should not be kept as breeding replacements.

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