Facial eczema is caused by a toxin produced by the spores of a fungus growing on pasture.  When ingested by cattle and sheep, the toxin damages the liver and bile ducts.

The damaged liver cannot rid the body of wastes and a breakdown product of chlorophyll builds up in the blood causing sensitivity to sunlight, which in turn causes inflammation of the skin.

The resulting liver damage can severely affect their welfare, affect production and fertility or cause death.

Timing:

The fungus produces spores when grass minimum temperatures are above 12°C for two or three nights and humidity is high (usually January to May).The fungus grows on soft litter at the base of the pasture so hard grazing during danger periods increases the risk of spore intake as does topping which increases the build-up of soft litter.

Do spore counts on paddocks before grazing to assess their risk.  Avoid grazing to very low levels as most spores are concentrated towards the base.  Safe feeds eg hay, silage and crops can also be used during risk periods to prevent spore intake.

Prevention of Facial Eczema:

There is no cure for FE so prevention is the only way of protecting animals. To be effective, preventative measures need to be in place before eczema spores are found.

Preventative measures include monitoring pasture spore count and either dosing animals with zinc or spraying pastures with a fungicide.  Zinc protects the liver against the oxidative damage caused by the FE fungal toxin.

Dosing of Zinc for cows and sheep:

Zinc boluses given orally sit in the rumen and slowly release zinc.  Start early – at least two to three weeks before the spore growth danger period.  Fully dose cows with zinc: drenching with zinc oxide, water dosing with zinc sulphate, administering in feed or as an intraruminal bolus (i.e. Face-Guard).

Sheep are very susceptible to facial eczema (FE).  The resulting liver damage can severely affect their welfare, affect production and fertility or cause death.  Prevention is imperative.

The most practical way of supplementing sheep with zinc is to give zinc capsules (Face-Guard).

Do spore counts on paddocks before grazing to assess their risk.  Avoid grazing to very low levels as most spores are concentrated towards the base.  Safe feeds eg hay, silage and crops can also be used during risk periods to prevent spore intake.

Len Paki BVSc