There will continue to be sporadic cases of clinical disease in herds with high immunity.
Prevention is not possible in areas where ticks are present
Fig1. Current tick distribution in New Zealand
These will most commonly present when an animal become affected by another illness or stressor, but this should not be a frequent enough occurrence to warrant major herd health controls.
(see the tick distribution map inset). For people who are moving stock into areas with ticks, we would strongly advise that you carry out blood tests to determine if the animals being moved have been exposed to the parasite. If they have been exposed then there should be relatively little risk of them developing clinical disease, however if they haven’t come across the parasite before then they will be at a high risk of breaking down with clinical theileriosis.
If you are moving animals from one property to another it is paramount that you try to assess the risk you face of running into problems. There is a movement risk tool on our website which you can quickly use to see what risk you may face.
Avoid exposing naïve animals to infected ticks six to eight weeks prior to calving/peak milk production.
Most naïve dairy animals arrive into infected areas in May/June, two months prior to the major stress of calving and milk production. The parasite has a six to eight week incubation period this creates “the perfect storm”
where animals are undergoing a huge stress at the same time as fighting peak parasite numbers. This situation is unlikely to change; the only options we have available to us are to try and infect these animals earlier when they aren’t stressed or to protect these animals from infection till they are under less pressure.
Targeted tick control is most effective strategy we have to protect “naïve” animals when they move into a high risk area. A single quarantine dose of a tick pour-on (such as Flumethrin) is of little value unless incorporated into a whole herd strategy to manage the transition of animals from being naïve to developing resistance. Prior to using any tick treatment you should consult with one of our clinicians or commercial team which will allow you to get an effective personalised plan for your herd.
Published : September 2014