Our advice is by purchasing from herds with risk level 1 for Johne’s disease you have the lowest risk of buying a Johne’s disease infected animal. The risk increases step wise for herds at levels 2, 3 and 4. The other important pieces of information that should be taken into consideration are the number of years that the herd has been accredited at risk level 1 and the size of the herd. Therefore if a herd of 200 cows has been at risk level 1 for several years the cattle in this herd are extremely low risk.
Assessing The Risk
This way of assessing the risk can also be used in herds at the other risk levels. If you are trying to decide whether to take a risk in purchasing cattle from herds that are not risk level 1 then you should consider the herd size, the number of positives that were detected at the last three herd tests and how many years the herd has been actively involved in the Johne’s programme.
Remember that should you purchase an animal from a herd that is not risk level 1 then you will need to have it tested by both blood and faeces with negative results before you add it to the herd.
George Caldow, email@example.com
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