Bovine cancer eye
“CANCER eye” (bovine ocular squamous cell carcinoma) is the most common form of cancer in cattle.
It is essentially a skin cancer occurring on the eyelids, third eyelid and eyeball and estimates of its prevalence vary form 1-20 per cent in some herds.
Overall, cancer eye represents 47 per cent of all cancers in cattle that cause carcass condemnations.
The disease occurs almost exclusively in cattle with areas of unpigmented skin around the eyes, with breeds including Herefords, Poll Herefords and Friesians being the most susceptible.
Cancer eye has been shown to be moderately heritable in that skin pigmentation and facial conformation is heritable.
Other recognized risk factors include protruding eyeballs being more susceptible than the “hooded” breeds and prolonged exposure to ultraviolet radiation. Cancer eye in Herefords is almost unheard of in the UK where the breed originates.
Cancer eye begins as a small, pink, proliferative growth although there may be some crusty, scabby precursors if it is on one of the eyelids (usually the lower one).
Specifically eye cancers occur in three sites: the eyelids proper (upper and lower), the third eyelid (a small flap lymphatic tissue in the medial corner of the eye), and on the eyeball itself. Ocular cancers may remain the same size for many months but then begin to grow rapidly in all directions forming grotesque, putrid masses that can become infected and fly struck.
The cancers can also grow inward and although cancer eyes do not metastasize (spread in the blood) quickly, they do tend to be locally invasive spreading into the surrounding tissue and lymphatic vessels.
It is regarded as an offence under the Prevention of Cruelty to Animals Act to allow a cancer eye to develop to the advanced stages and owners failing to cull or treat such animals may face prosecution if the animal is not immediately treated or destroyed.
Many cases of bovine cancer eye can be treated quite successfully by a veterinarian especially if treated early using either surgical or cryosurgical (liquid nitrogen sprays) methods.
More advanced cases may be treatable where the eye and the surrounding soft tissue is removed and this will avoid the necessity of culling and may completely resolve the cancer altogether providing it has not infiltrated beyond the surgical field.
If you have any questions about cancer eye in cattle please contact your veterinarian.