Johne's disease: how to spot and report the disease

How to control Johne's disease

Herd health and welfare plans

It is good practice to implement a health and welfare herd plan in conjunction with your veterinary surgeon designed to reduce the chances of introduction and spread of infection within the herd, regardless of whether you believe you have infection or not.

Whether or not Johne's disease has been detected in your herd, you should implement a number of basic biosecurity measures, incorporated into your herd health and welfare plan. They will help stop the disease, and other diseases, being introduced into your herd, and, should it already be present, they will help to prevent its spread to other unaffected cattle.

Stocking

The major source of infection is the purchase of infected cattle or other livestock that are not yet showing the signs of the disease. To keep the disease out of your herd or to prevent re-infection it is preferable to maintain a closed herd. If you have to bring in replacements (including stock bulls), try to obtain them from herds that are undergoing regular testing and where no evidence of infection has been found. The longer a herd has regularly tested negative, the lower the risk of purchasing an infected animal. It is recommended to look for herd health accredited farms to source new stock that will be low risk. If you cannot find a fully tested herd as a source of replacement stock or hired bulls, you should at least assure yourself that Johne's disease has not been diagnosed in the herd, and ask what tests have been carried out.

Bear in mind that embryo transfer is potentially the safest way to introduce new blood lines into your herd, provided the recipient animals are known to be free of disease.

Clean water

Johne's disease can spread by contaminated watercourses. You should:

• provide mains water for drinking wherever possible
• ensure any private water sources are checked regularly for presence of Map
• ensure that drinking troughs are kept as clean as possible
• provide water through a mains supply or a clean private source, fence off your herd's access to ponds, streams and rivers, particularly slow moving watercourses or stagnant water that the cattle may wade in, where possible
• you should try to delay grazing as long as practicable after flooding has occurred and subsided if grazing is in flood meadows or in cases where a slurry pit has been flooded

Pasture management

Map may be present in dung or slurry. Because it is a tough and persistent organism, it may be found on pasture for at least a year after slurry or manure has been applied or has been contaminated by grazing cattle. Even if manure has been well composted, Map may still be present. You should avoid grazing young animals on land for at least three months and ideally a year after application in order to minimise the likelihood of infection, where practical.

Deer, sheep, goats and South American camelids (including llamas and alpaca) are also susceptible to the disease. On farms where the disease is present in cattle it may spread into these animals that will then act as an infection reservoir. Infection could therefore be reintroduced to a herd through these species. You should therefore avoid co-grazing. Sequential grazing with such animals in the same grazing season should be avoided.

Protecting calves and young cattle from Johne's disease

An important source of infection of calves is faecal contamination of the milk, teats soiled with dung, or faecal soiling on a calf's coat, which the calf then swallows when grooming itself. It is therefore important to use good hygienic practices to minimise as much as possible the exposure of young animals to dung or slurry from adult animals. This begins from the moment the calf is born. To achieve this it is highly desirable to:

• ensure cows calve in clean well-bedded areas. Ideally calving boxes should be thoroughly cleaned and disinfected between cows. The dam's teats must be as clean as possible to prevent ingestion of faecal matter
• ensure that calves are subsequently reared in a clean environment, free of adult faecal contamination
• do not graze young stock on pasture where adults have grazed or where slurry has been applied in the past three months (ideally in the past year)

If you have Johne's disease in your dairy herd

New-born calves

If Johne's disease has been found in your herd, you must be aware that Map may be present in the milk of infected cows and is commonly found in their colostrum. When calves are born in such a herd they are particularly vulnerable to infection, and specific measures are necessary to minimise the likelihood of infection occurring.

When calves are born it is important to follow the advice in the Welfare of cattle: code of practice (the code is intended to encourage all those who care for cattle to adopt the highest standards of husbandry). By law, all stockmen must have access to the code and be familiar with its provisions. Employers must ensure their staff receives guidance on the code. In order to minimise the likelihood of infection you may need to consider removing the calf from its dam earlier than the recommended 12-24 hours after birth. You should seek the advice of your veterinary surgeon in advance of calving to decide when a calf should be removed, and this should be recorded in your herd health and welfare plan.

It is also essential that new-born calves receive sufficient colostrum, so you must ensure that:

• calves only receive colostrum from their own mother, or in the absence of their own dam's colostrum, preferably only from a single animal that has repeatedly tested negative for Map
• after receiving colostrum they are reared on milk replacer or milk that has been heated to boiling point
• where calves are allowed to remain with their dam, teats must be as clean as possible, to prevent ingestion of faecal matter, and the pen must be kept clean

Do not feed discarded milk to calves. If discarded milk is to be fed to calves it should be heated to boiling point.

Do not pool colostrum and feed to calves. Pooling colostrum from a herd where Johne's disease is present should, if possible, be avoided, even from cows that have tested negative. It cannot be guaranteed that an animal that has tested negative will not be shedding Map, and pooling colostrum will increase the risk of infecting calves. However, if you are considering pooling colostrum as a strategy, you should seek the advice of your veterinary surgeon, taking into account the particular needs of your herd.

You should note that this specific action to protect calves from infection is wasted if you do not make sure that they are reared in areas free from adult faecal contamination and by carrying out the other important actions stated.

Herd management

If Johne's disease is confirmed as being present in your herd you should, in consultation with your veterinary surgeon, you may wish to join a scheme to manage disease in your herd.

The Cattle Health Certification Standards body (CHeCS)  has defined the industry standard screening and control programme for Johne's disease that provides an agreed mechanism for herds to follow a test and cull programme.

You could also consider managing disease through a scheme such as The National Johne’s Management Plan through Action Johne’s, which also supports farmers to reduce disease.