Cancer of the eye and eyelids unfortunately is a common occurrence in cattle. It has major implications including welfare concerns, condemnation of carcasses, shortened lifespan due to need for culling as well as treatment costs.
Most eye cancers occur on non-pigmented areas around and on the eye and are more common in cattle with protruding rather than ‘hooded’ eyes. Metastasis (spread) to other areas can occur, either into local areas or even throughout the carcass (although this is more rare than just local growth). Unfortunately it is impossible to tell whether a cancer has invaded elsewhere from just looking at the animal or the cancer.
Treatment can be attempted in certain circumstances. Usually the best results are obtained with small cancers (less than 1cm) and where the cancer can be removed completely (third eyelid or entire eye removal) or can have cryotherapy applied (freezing). Any animals treated should be monitored very carefully for recurrence of the cancer.
There are welfare implications which determine whether an animal can be sold through saleyards, must go directly for slaughter or must be put down on farm. It is always worth checking with the abattoir or saleyards. Cattle with cancers that are larger than 3cm, ones that involve the whole eye and surrounding area, are discharging pus, are flyblown or are bleeding profusely cannot be transported for slaughter.
The best results occur when we identify and treat the animal early in the development of the cancer and are able to surgically remove all the cancer tissue.