A new report by the Ministry for Primary Industries says the cattle industry is facing a severe challenge from the new theileria parasite that's spreading through the North Island and it needs to urgently develop tools to monitor herds for it.
It says theileria ikeda, which is spread by ticks and can make cattle anaemic, is putting a severe dent in the performance of some dairy herds.
The report says the parasite is having a devastating impact on some farms and the mortality and morbidity rates are far greater than has ever seen before with other strains of theileria.
A survey of 122 of the farms hit by theileria ikeda showed the average mortality rate for affected stock was just under 1%, but on some farms 15% of affected cattle have died.
One of the worst hit herds battled with anaemia for eight months. The herd developed serious fertility troubles and milk solid production fell by 80kg of milk solids per cow per year.
The report says after spreading through dairy herds in Waikato and Auckland over winter, the disease is now moving through farms in Waipa, Bay of Plenty, Manawatu and South Taranaki.
Officials are particularly concerned about areas such as lower Waikato, where tick numbers are patchy. They believe the disease could keep re-emerging in such areas as herds will not necessarily build up immunity.
The report says New Zealand has the same strain that was first identified in New South Wales in 2006 and has spread throughout other Australian states through cattle movements.
The Ministry for Primary Industries has previously said it is possible the disease got to the country in cattle imported from Australia.
