Farm Ireland
Independent.ie

Friday 21 September 2018

Warning for farmers as Johne's disease continues to spread at an alarming rate

Animal Health Ireland's Lorna Citer
Animal Health Ireland's Lorna Citer

Martin Ryan

Johne's Disease has become a major concern for the industry with the challenge of eradication from the national herd a daunting undertaking for the years ahead with the rapid expansion.

With studies looking at the potential of a relationship between Johne's and the debilitating Crohns disease in humans, the spread of Johne's in cattle herds globally has continued at an alarming rate in recent years with estimates of infection levels at between 20pc and 50pc in intensive dairy regions.

Animals in the herd infected with Johne's disease see a reduction in production, lower milk yields, poorer feed conversion and it is more difficult to get cows back in calf, so the whole system is effected, Animal Health Ireland's, Lorna Citer (pictured) told the farmers.

"Infected animals are also more prone to lameness, because their immune system is effected and they are more likely to get mastitis so there are some good reasons why the disease should be controlled in the herd," she said.

The infection occurs because there are animals in the herd with the disease which are pushing out the bacteria from their udder and contaminating the environment

The most susceptible animals on the farm are calves and they can become infected from the day they were born and sometimes are already infected from birth.

"There are huge volumes of bacteria produced by infected animals. You can have up to 50 million bacteria per gram of milk, it is a huge amount of bacteria so there is potential for many calves to become infected and the infection dose for a calf is very low it is only a few thousand bacteria," she said.

"The first thing to do is remove the calf as soon as possible from the calving pen which reduces the time that the calf is exposed to infection in that environment. Make sure that the cow is clean coming into the calving pen and remove the bedding after each calving and get the calf out of that environment as soon as possible and you will be well on your way to controlling infection

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"On occasion calves are already infected at birth if the dam has infection at an advanced stage and sometimes one infected calf can spread infection to other calves in the pen early in life as a result of being fed colostrum with bacteria or through the environment in which they are becoming contaminated," she added.

She advised that if possible the calf should get colostrum from a non-infected cow, "because giving them colostrum from an infected cow you are giving them infection from the start and they will break down in the future.

"In an infected herd you should seriously consider putting the calves on milk replacer, because it is much better than feeding infected milk."

The advice is to make sure that the cows udder is clean before collecting colostrum and that your own hands have been washed and the containers used to hold the colostrum and any buckets or tubes have also been washed carefully between each use. Work clothing with dung on it can also be a source of spreading infection.

On the risk of a herd being infected with Johne's disease she warned "just because you don't think that your herd doesn't have it does not mean that the disease is not there" and precaution should be taken in all herds because the infection may be already spreading in the herd.

"It is not going to happen in one year or two years, but five years down the road you could have a major problem with infection that you did not think was there," she said.

She advised that individual cow testing is the most reliable, because the bulk milk test may not show up the infection if there is a high dilution and milk should not be tested within 90 days of a TB test in the herd because of cross reaction. The second phase of a control programme gets underway this year.


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