Eye cancer, a tumour on the eyelid or eyeball, is the most common form of cancer in cattle, and in the early stages can be mis-identified as pink-eye.
These cancers are most commonly seen in Hereford or Poll Hereford cattle or white-faced Friesians and occur because of lifelong exposure to sunlight.
Eye cancers may cause losses for producers due to condemnation at the abattoir and loss of potential production of affected stock.
The tumour begins as a tiny growth and steadily increases in size and will cause suffering if left unchecked. It may invade surrounding tissues and spread to other parts of the body.
The severity of eye cancers can be reduced by the early identification of growths and prompt action by either seeking veterinary treatment or culling.
The incidence can be reduced by genetic selection, by selecting animals with pigmentation in the sclera ‘white’ of the eye and the eyelid.
The course of action that should be followed depends largely upon the size and severity of the cancer.
Small eye cancers may be readily cured by prompt veterinary treatment.
However, if the owner elects to cull the affected animal, the following guidelines should be used:
■If the cancer is smaller than a five-cent piece, clean and not fly-blown, the animal can be sold through a saleyard for slaughter only.
■If the cancer is sized between a five and 20-cent piece, clean and not fly-blown, the animal can be sold directly to an abattoir only.
■If the cancer is bleeding, infected, fly-blown or larger than a 20-cent piece, the animal should be immediately disposed of on-farm or via a knackery.
Owners who fail to take reasonable action to prevent suffering in their animals may be considered for prosecution under the Prevention of Cruelty to Animals Act 1986.
■A photographic guide regarding the course of action that should be followed for different sized eye cancers is available at: https://bit.ly/2COgHIR
■For further information, contact your local veterinarian or an Agriculture Victoria veterinary or animal health officer, or in NSW your Local Land Services.