Facial eczema is not a problem in the Bay of Plenty at the moment but farmers are advised to check stock for any outbreaks over summer.
Bay of Plenty Federated Farmers' provisional president, Rick Powdrell, says it is a production killer and one of the nastiest diseases stock can get.
From an animal welfare perspective, it's one of the cruellest stock can suffer from, he says.
Dairy and beef cattle, sheep, deer and goats are susceptible to facial eczema.
It attacks the liver and is picked up by animals ingesting fungal spores from the pasture.
Mr Powdrell says sheep would first lose all the skin on their ears while skin could peel off dairy cows' udders.
"When an animal breaks out, usually it looks horrible and it's very hard on the animal."
He had experienced serious outbreaks over the years on his sheep farm but says the industry has been proactive in breeding resistance into flocks.
"A lot of work has been done that has been very successful," he says. "The dairy industry hasn't gone down that track in any great degree and they tend to use zinc supplements."
Focus Genetics' chief executive, Gavin Foulsham, says they have upped the game and are testing more sheep in order to breed rams which are resistant to facial eczema.
"Facial eczema resistance is a highly heritable trait so farmers can significantly manage the disease in their ewe flocks by selecting for facial eczema-tolerant rams."
Ballance Agri-Nutrients animal nutrition product manager Jackie Aveling says even before physical signs appear, exposure to facial eczema can have a significant impact on animals, particularly cows, in which it results in an immediate drop in milk production.
Prevention is the best form of defence, she says.
"If as little as three per cent of the herd show clinical signs of facial eczema, then subclinical cases can affect up to 70 per cent of the herd."
Monitoring spore counts through summer and autumn through websites like the AsureQuality spore count site, and having an early plan of attack for facial eczema in place, would ensure the hard work being put into maintaining a healthy herd pays off in sustained production, says Mrs Aveling.
Zinc treatment from late December to May is recommended. Usually, zinc sulphate is added to water but it can taste bitter and may reduce the cow's water intake.
However, Zincmax+ offers another solution that tastes like peppermint and which also includes organic copper.