It has also been seen in Northland, the Bay of Plenty and wider Waikato region, with some cases in Taranaki, Manawatu/Whanganui, Hawke's Bay and Gisborne.
DairyNZ technical policy advisor (veterinary) Nita Harding says in 2013 cows that calved in the second half of the calving period had the highest incidence of theileriosis.
"This may be due to exposure to the disease four to six weeks earlier, resulting in the peak of the clinical effects coinciding with calving," says Nita.
"The signs of the disease are those of anaemia due to the damage theileriosis causes to the red blood cells. Cows will have yellow (jaundiced) or pale mucous membranes - this can be checked by looking inside the vulva."
Other signs include lethargy, dull/depressed appearance, hollow sides from not eating, loss of condition and dry faeces. If a blood sample is taken, this will be very watery.
Down cows an issue
Farmers also report cases of down cows that do not respond as expected to normal treatment and management.
"As the most severe impact appears to occur around calving, checking the springer and colostrum mobs daily for anaemia is advised. Cows that are anaemic should be managed to minimise energy use and stress, and veterinary advice should be sought," says Nita.
Milking cows once-a-day, minimising distances walked, providing easy-toeat high quality feed, dealing with any concurrent health issues and providing shelter in adverse weather are suggested management strategies.
Extra mob management
Farmers with theileriosis in their herds have had success with an ‘intensive care mob' for theileriosis cases.
This does mean an extra mob however it enables specific care for these animals and reminds staff to be vigilant.
Early signs of the disease can be a cow out of normal order or displaying unusual or dull behaviour. Good observation will pick these cows up and enable special care.
Unless very severely affected, cows will recover from theileriosis and, the earlier specific care is provided, the sooner cows will recover.
Signs of theileriosis
- Anaemia (yellow [jaundiced] or pale mucous membranes)
- Lethargy, dull/depressed appearance
- Hollow sides from not eating
- Loss of condition
- Dry faeces
- A cow out of normal order or displaying unusual or dull behaviour.
This article was originally published in Inside Dairy September 2014.