As the weather warms up and we start to plan for summer, we need to start to plan for facial eczema season too. Facial eczema is a condition caused by a fungus growing in the dead litter at the base of pasture in warm, humid weather. The spores of this fungus produce the toxin sporidesmin. When the spores are eaten by stock, the toxin they release damages the animals liver. There is no treatment for this liver damage but if mild, the liver will regenerate over time. However, severe cases will die because of this liver damage. When the liver is damaged, it can no longer break down chlorophyll from the grass. This continues to circulate in the blood stream and reacts to the sunlight causing the external signs of facial eczema. However, these signs are only the tip of the iceberg. When one is showing clinical signs, another ten can have liver damage going undetected.
What does it look like?
Signs to look out for include animals seeking shade, drooping ears, red and swollen skin, restless or itchy stock. Signs are most obvious in the unpigmented areas and where hair is thin such as the face, ears and udders. These areas can peel, leaving large wounds that often get infected or flyblown.
Spores are produced when the grass temperature at night remains above 12C and humidity is high. The high risk period usually runs from January and can last until May in bad years.
What can I do?
As there is no treatment for this condition, it is important that we focus on prevention. Zinc binds to sporidesmin, protecting the animal from its toxic effects. Many people use zinc in the water but this is very unreliable. There is no way to know how much each animal is drinking, and therefore how much zinc they are getting so many do not get enough by this method. I have also seen cases where stock have been poisoned by getting too much zinc in the troughs. The safest and most effective method to prevent facial eczema is using zinc boluses in sheep and cattle and zinc pellets in alpacas. There are different types of boluses, but all release zinc at a steady rate over a period of weeks to ensure long lasting protection. If you would like a hand with this job, our friendly technicians will be organising bolus days and would love to add you to the list. For any questions about your zinc requirements or to express your interest in the bolusing days, contact your local Anexa team.