B+LNZ’s Senior Biosecurity Advisor Will Halliday, says zinc binds to the fungal toxin Sporidesmin in the animal’s rumen, rendering the toxin inactive. So, while zinc doesn’t stop animals ingesting the toxin, it does stop the symptoms of Facial Eczema (FE) developing.
Will says sheep farmers have two options to get the zinc into the animal. The first is zinc oxide powder which can be mixed with water and used to drench sheep either weekly or fortnightly.
This is time consuming and can put sheep at risk of developing pneumonia by frequently running them in and out of hot, dusty yards.
The second option is a slow-release capsule, which is essentially a bolus of zinc. The capsule provides protection from FE for up to six weeks.
Will says ideally, the capsule should be administered one or two weeks before a risk period, which can be difficult to predict.
“It relies on people keeping a very close eye on spore counts within their district and talking to vets or other relevant professionals.”
He says as a rule of thumb, if it’s warm enough at night to be kicking blankets off the bed yet there is dew on your windscreen in the morning, then conditions are perfect for FE.
Sheep don’t drink enough water to make trough treatment with zinc an option, but this is option for cattle.
Will says FE is typically more of a problem in dairy cattle, but it can be seen in young beef animals.
Zinc boluses are also an option for cattle, but Will says it is important farmers discuss their treatment options with their vet, particularly as there can be an interaction between zinc and copper.
There is wealth of information about the prevention and treatment of Facial Ezcema in the B+LNZ-produced book Facing up to Facial Eczema
Facing up to Facial Ezcema can be downloaded at https://beeflambnz.com/knowledge-hub/PDF/facing-facial-eczema