Facial Eczema is a disease which causes lowered milk production, skin irritation, peeling and sometimes death.
It occurs when cattle ingest the spores of the fungi Pithomyces chartarum which is found on growing pasture, especially from January to May (in New Zealand). This fungi contains a compound called sporidesmin, which is toxic to the liver and causes extensive liver damage.
Then when the cows eat, the normal by-products from the grass that are usually excreted by the liver are not excreted properly because of the damage to the liver and bile ducts. These by-products then build up in the skin where they are exposed to sunlight, and cause a severe sunburn.
Just like with us, severe sunburn for cows causes major discomfort. They will seek shade and decrease their grazing time, which impacts their growth and overall health. Milking cows will have a significant drop in milk production, and may even dry off.
Facial Eczema Damages the Liver Before You Can Even See It
Liver damage occurs even before facial eczema is visible (which is known as clinical facial eczema). Scientists estimate that for every one clinical case (an animal with visible facial eczema) there will be 10 other cows suffering some degree of liver damage from facial eczema (known as subclinical facial eczema).
Subclinical facial eczema can cause reduced milk production of up to 50%.
The Worst Cases
In the worst cases, massive damage to the liver will cause liver failure resulting in death. Most affected animals do survive, but will suffer production losses that season, and in further seasons, because liver tissue that is badly damaged will not regenerate. Severe loss of health or death can occur at the time facial eczema, or even months later when the cow is under stress (e.g. in calving).
Preventing is critical, because there is no cure
There is no cure for facial eczema.
Cows that suffer from facial eczema can recover, but there is no “cure” as such. Recovery comes from cows being dried off immediately, kept in shade (e.g. indoors) and fed supplementary feed instead of pasture. With the right treatment they can slowly recover, but they are unlikely to regain their previous level of milk production because of the liver damage.
Prevention is the only way of protecting your animals, and zinc is what protects them.
Preventing Facial Ezcema with Zinc
Treating cows with zinc prevents facial eczema and liver damage. Zinc forms a complex with sporedesmin and stops it from forming by-products that are toxic to the liver. This keeps means your livestock stay health. Zinc treatments significantly reduce the risk of facial eczema, however, no treatment method is guaranteed to be 100% effective, so you should still monitor you stock for signs of any animals that might be extra susceptible.
There are three basic methods of applying zinc:
- Slow release boluses
- Water trough treatment
Drenching with Zinc Oxide
Long term drenching with zinc oxide is effective for preventing facial eczema, however it is very labour intensive and expensive.
Slow Release Boluses
Slow release boluses are also effective for preventing facial eczema, but is a fairly expensive treatment option.
Trough Water Treatment
The most cost effective reliable method is to treat your stock with Zinc Sulphate through their drinking water, using a trough dispenser.
There are two forms of Zinc Sulphate available for use in trough treatment; Zinc Sulphate heptahydrate (normally a coarse greenish crystal), and Zinc Sulphate monohydrate (normally a white powder or fine crystal). Monohydrate is the more concentrated form and is used at 2/3 the dose rate of heptahydrate.
The labour required when using PETA Zinc Dispensers is minimal and you have clear peace of mind knowing your livestock are getting the treatment is calculated on a per-animal-per-day basis.
“We use the PETA Dispensers to dispense Mono Zinc into the troughs for our 900 cows. We find the dispensers are reliable, efficient and never need replacing.”
Laurette Strude, Tuit Farm, Dairy Farmer
Start Dosing Early
Zinc treatment should be started 2-3 weeks before the spore growth danger period for maximum protection.
When water trough treatment is first started, cows are sensitive to the taste of zinc. It is advisable to use a smaller dose for a few days to get them used to it.
Once Zinc treatment is established, on cold, wet days, water intake can be much reduced. This could result in a high concentration of Zinc Sulphate. Under these conditions the dose rate may be reduced, or even omitted, since the troughs are already treated at an adequate level from previous days which accommodates the occasional drinker.
The most cost effective method
It is very important to control facial eczema, for the health of your cows and your levels of milk production. The most cost effective method for prevention of facial eczema is by using Zinc Sulphate treatment in the water troughs, with the PETA Zinc Dispenser.
Read more about the PETA Zinc Dispenser.