Dairy farmers in parts of Gippsland are being warned to implement facial eczema preventative measures in their stock as a matter of urgency.
Dairy Australia lead - animal health and fertility Dr Stephanie Bullen, in DA's Facial Eczema Alert, said there had been a series of very high spore counts in the Macalister Irrigation District, West Gippsland and Orbost regions in the last week.
"Farmers in other regions are advised to continue to closely monitor sentinel farm spore counts or begin monitoring your own counts," the alert said.
Earlier this month, Dr Bullen advised that a permit had been granted for a new zinc protective treatment for the condition.
The permit to allow supply and emergency use of The Time Capsule slow-release zinc oxide boluses was granted by the Australian Pesticides and Veterinary Medicine Authority earlier this month.
"These boluses, when used correctly, are reported to provide four weeks of protection against facial eczema," Dr Bullen reported.
The product was not currently registered or available in Australia and would need to be imported by a farm's veterinarian from New Zealand, she said.
According to the Dairy Australia website, facial eczema occurs when cattle ingest spores of the fungus Pithomyces chartarum.
The spores contain a toxin, called sporidesmin, which damages the liver and bile ducts.
One of the first signs of facial eczema may be a sudden drop in milk production and a short period of diarrhoea.
However, often the most recognisable sign of facial eczema is inflammation of unpigmented skin and sensitivity to sunlight. This is called photosensitisation.
This occurs because the damaged liver is unable to process breakdown products from the chlorophyll in grass and they build up in the bloodstream.
Not all animals affected with facial eczema will show symptoms when liver damage has occurred.
Research conducted in New Zealand suggests that for every one clinical case of facial eczema, there may be a further 10 cows with liver damage and reduced milk production.
The treatment for facial eczema is non-specific and is aimed at reducing pain and irritation associated with photosensitisation. There is no cure for facial eczema.
Feeding zinc is protective for facial eczema.
To be effective, the cow's blood serum zinc levels need to be maintained in the range of 20-35mol/L. This is most reliably achieved by feeding zinc oxide in pre-formulated pellets at the correct dose rate.
For more information on facial eczema, pasture spore count monitoring, and facial eczema prevention, visit the Facial Eczema page of the Dairy Australia website.
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