Facial eczema is a liver disease caused by cows ingesting spores from the fungus Pseudopithomyces toxicarius. It is most common in the North Island, where warm, humid conditions create the perfect environment for spore growth. The majority of animals affected by facial eczema show no visible skin damage, most of the harm goes unnoticed. Once liver damage occurs there is no cure, early prevention and consistent zinc protection is the only defence.
Get ahead
Start monitoring now. Don’t just rely on regional reports - check spore counts on your farm, as levels can differ widely between farms and even paddocks. Work with your vet to take pasture samples correctly and interpret results. Begin zinc treatment before spore counts reach 30,000 and continue through the season until levels stay below 10,000 for at least three weeks.
Right zinc, right dose
Zinc only protects the liver when given at the correct dose. In New Zealand, research shows that up to 70% of cows treated aren’t fully protected. Zinc in drinking water alone can be unreliable, as daily water intake varies. Talk to your vet about other options such as oral drenching or zinc capsules, which help ensure every cow is covered.
Test your zinc coverage
Fonterra’s ZincCheck programme makes it easy to see whether your herd is getting enough zinc. It uses a bulk milk sample to measure zinc levels over multiple days. A green result means at least 70% of cows are protected, while orange or red shows levels are too low. Your first test is free, with additional tests available for $99. Book your ZincCheck between January and May at nzfarmsource.co.nz/zinccheck
Impact on your herd
Even if there are no signs of skin damage, facial eczema can still hit your bottom line. Hidden liver damage can reduce milk production by up to 2 kgMS per cow per week and shorten lactation by around 60 days. That adds up fast.
Data collected from farms using regular ZincCheck monitoring showed herds with zinc levels in the optimal range (“ZincCheck in the green”) experienced:
- A 3% increase in production compared to cows with marginal or deficient zinc levels.
- An average lift of 23 kgMS per herd per day.
Next steps
- Monitor local spore counts and begin testing pasture from your own paddocks as risk levels rise.
- Start zinc protection early, check herd zinc levels one week after reaching full dosing rates, and continue treatment through the season.
- If your ZincCheck status is not in the green take action to investigate why.
- Talk to your vet about spore counting and adequate zinc protection.
- Book your free ZincCheck test here or contact your local TSR to find out more.
Stay ahead of facial eczema this season - protect your cows, your milk, and your peace of mind.
