AgResearch scientists have made progress in a search for a genetic aid to help control the livestock disease, facial eczema.
They've found genes on two chromosomes which they say will help identify dairy cattle that are more resistant to the disease.
Outbreaks of facial eczema occur in summer, mainly in the North Island.
Grazing livestock can catch it from spores in dead pasture. It causes skin and liver damage and in extreme cases can kill infected animals.
Researchers have been working for the past five years to identify the genes, or set of genes, that are resistant to facial eczema.
Scientist Chris Morris, who specialises in animal breeding, says samples needed for the DNA testing will be easy to collect - from an ear punch, hair follicles or a blood sample.
He says facial eczema is a very seriously, and costly, problem.