Monday, 24 November 2014 10:53

Tick alert

Written by 
Theileria fully fed adult tick. Theileria fully fed adult tick.

DairyNZ IS alerting all farmers, including graziers, to keep an eye out for signs of a tick-carried disease that causes anaemia in cattle.

 The warning comes after MPI confirmed that a case of Theileriosis had hit a South Island West Coast farm this spring. MPI has concluded that a local population of infected ticks in Canterbury or the West Coast was responsible for transmitting infection to the 188-cow dairy herd.

Theileriosis is a disease caused by a species of Theileria, a blood-borne parasite primarily transmitted by ticks that only affects cattle. First identified in Northland in late 2012, this new strain of the disease, called ikeda, has been associated with anaemia and death in cattle.

"We are concerned that there may be infected tick populations in the South Island now. This latest case was linked to cows being grazed in the Canterbury area and then being brought back to the West Coast," says DairyNZ technical veterinary advisor, Dr Nita Harding.

Harding says that cases of Theileriosis are usually higher in autumn and spring and it is important that farmer remain vigilant at this time of year.

"We are advising farmers to consider the risk of moving young stock to grazier or run-off properties where the level of tick activity and Theileria may be greater than on the home property.

"This is a disease that can result in serious illness and death of cattle, and has affected some herds quite badly," says Harding

According to DairyNZ with the disease now present in the South Island, more cases are likely, especially in Nelson/Marlborough, where ticks are known to be present.

"At this stage, we just don't know exactly the degree of infestation or location of local tick populations and therefore the level of risk to different regions in the South Island," says Harding.

MPI have reported around 116 new cases of Theileriosis since September, with the disease now widespread over the northern half of the North Island and some cases reported in the lower half of the North Island.

1. Farmers should regularly check stock for ticks and treat animals as necessary.
2. Treat any new animals – particularly before moving cattle from one property to another.
3. Manage the tick population – inspect cattle for ticks. Tick treatments can reduce the tick load and severity of the disease.
4. Ease underlying disease or stress – for example, transition management, trace element deficiency, BVD (bovine viral diarrhoea) and facial eczema.

Signs of anaemia in dairy cows
• Cows straggling on the walk to the shed
• Increased respiratory and heart rate.
• Pale, rather than healthy pink, vulva.
• Pale udder, yellow eyes
• Cows with no strength or energy to do anything

For more information visit:

Ministry of Primary Industries

DairyNZ website 



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