Cancer Eye is Treatable if Caught Early
Eye cancer is the most common type of cancer in cattle, but if detected early, it can be treated because the first stages are not malignant. It is generally a problem in mature cattle, not young ones. Whiteface or light-skinned cattle seem most susceptible, because sunlight damages non-pigmented skin. Thus a light-skinned animal is more likely to develop a tumor on the eyelids. Sunlight is reflected into the animal’s eyes, which can irritate them. Dark skin absorbs more light, and is tougher and less susceptible to irritation, but dark skinned cattle do occasionally have problems.
There are two types of cancer eye growths on the eyeball and growths on the eyelids. The latter is more serious, especially if neglected, since the tumor grows inward and can spread to other tissues sooner. Tumors on the eyeball tend to grow out from the surface, rather than inward. One of the most common sites is where the white and dark portions meet, at the edge of the eyeball. The growth begins as a small white (slightly raised) flat area. It grows slowly and may take months before becoming a malignant tumor; 30 percent of all cases will actually get smaller and disappear without treatment. If the white spot starts to grow, however, it should be removed before it becomes malignant. With the animal restrained, a vet can carefully cut the growth away with a sharp scalpel, then cauterize the area to kill any stray cancer cells.
Other common sites for cancer are the lower eyelid, third eyelid, and corners of the eye. Growths on these tissues (instead of on the eyeball itself) are not malignant in early stages but can quickly progress to an irregularly shaped wart-like pink or red tumor. Usually on the lower lid, these small tumors are often crusted with scab-like material that resembles dried eye matter.
If it seems directly attached to the lid, and removal of this scab reveals a small growth and bleeds, it is probably precancerous.
Having your vet treat the lesion with heat or cold (liquid nitrogen) can be successful if done before the tumor has invaded underlying tissue, and these methods can usually save the eye. But if the tumor is already malignant, the eye and its surrounding tissues must be removed. Cancer of the eyelid is more serious than on the eyeball, because it can get into the eye socket and lymph nodes sooner, to spread quickly, killing the cow. A visible lump below the base of the ear is indication that the lymph system is already invaded; it is too late to sell the cow because her carcass will be condemned at slaughter. Trying to delay slaughter a few months to allow the cow to finish raising a calf, or to finish pregnancy, is a mistake because the cancer may spread explosively and you won’t be able to salvage her. When a malignant tumor is discovered, the cow should immediately be sold. Check eyes closely at routine workings (when cows are in a chute for vaccinations--when you can look at each eye carefully).
If you discover small growths, have your vet remove them, or watch them closely over the next few weeks to see if they grow or regress on their own. It is usually wise to remove small white eyeball plaques if they start to enlarge, and closely watch any suspicious growths on eyelids, selling the cow if they start to grow.
easy-to-read articles designed to increase overall awareness among the feedlot community.