Farm Ireland
Independent.ie

Sunday 22 October 2017

Keeping Johnes in mind when feeding colostrum

Dr Sam Strain

Feeding calves at least three litres of clean colostrum from the first milking of their own dams within the first two hours of life is an essential component of successful calf rearing.

This method allows the calf to gain essential passive immunity against a range of common disease-causing bacteria and viruses.

Colostrum and milk feeding practices are also important in reducing the risk of calves becoming infected with Johnes Disease (JD).

In JD infected cows, the Johnes-causing bacterium Map can be present in colostrum and milk.

This is through both the direct excretion of the bacteria into the milk and through contamination of the milk with Map contaminated dung.

Colostrum or milk containing the bacteria is a major risk factor for calves becoming infected with JD. Therefore it is essential that calves are fed colostrum or milk which has a low risk of carrying Map.

During calf rearing the following measures should be considered:

1.Test cows individually to identify high-risk cows.

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The AHI Voluntary Johne's Disease Control Programme for dairy herds recommends that cows are tested annually by blood, or twice yearly by individual milk samples.

2.Avoid the use of colostrum or milk from any test positive or test inconclusive cow for any calf.

3.Do not pool colostrum or milk. If one of the donors to the pool is infected, her milk could contaminate the entire pool, placing all of the calves drinking that milk at risk of acquiring the infection.

4.Harvest colostrum cleanly - there should be no faecal contamination.

5.Ensure all calf feeding utensils are thoroughly and frequently washed with hot water and detergent.

6.Build up a bank of frozen colostrum from low-risk cows (i.e. cows that have tested negative over multiple cycles of individual testing) in your own herd for emergency situations where colostrum is not available for calves from their own dam.

7.If calves are fed colostrum or milk from cows other than their own dam, record these details.

8.Avoid the use of waste milk for feeding calves, particularly any calves that will be kept for breeding purposes.

JD predisposes cows to a range of other diseases; therefore a cow that has been treated for one disease could also be harbouring JD.

9.Where calves are pastured they should be kept on land not recently spread with the slurry of adult cattle or land recently grazed by adults.

10.Avoid any contact between adult cattle and calves less than six months of age, for example through cow traffic or communal drinking troughs.

Irish Independent