Recent rain that eased drought conditions in some areas has triggered a fresh threat for North Island farmers: facial eczema in livestock.
The fungal disease, which is sometimes fatal, usually appears in late summer as spores multiply in the base of dried out pasture and are ingested by livestock.
This year, the widespread drought conditions have kept infection rates at bay until the past week or so, when rain has sent facial eczema spore counts soaring in many areas.
AsureQuality field technician Leo Cooney, who monitors facial eczema levels, said spore counts have risen to dangerous levels in some places and livestock are now showing signs of the disease.
Areas showing an increase in the last week or so have been Northland, Bay of Plenty, Waikato, Taranaki and the lower North Island including Manawatu and particularly Horowhenua which has had some very high counts.
Mr Cooney said scientists say that for every 5% of animals showing clinical signs of facial eczema there will be another 70% with some degree of liver damage.
Cooler temperatures that arrived with the rain have modified the facial eczema risk in some areas.
But Mr Cooney said soil temperatures are still generally high enough to allow toxic spores to multiple and he said farmers should be keeping a close watch on spore counts, especially in areas with a history of the disease.