The three most common conditions affecting the eyes of cattle are:
1. Pink eye or Infectious Bovine Keratoconjunctivitis is a contagious eye disease that can affect cattle of all ages. It is caused by Moraxella bovis, but the severity of the disease is influenced by the presence of other micro-organisms. Flies are the main cause of infection spread; carrier animals are also important reservoirs of infection within a herd.
Damage to the cornea, from UV light, dust or pollen, is the main predisposing factor. Pink eye can resolve spontaneously but may cause blindness if left untreated. Signs include eye ulcers, cloudiness of the eye and weeping, and swelling of the eyelids. Affected animals seek shade. The outcome is production loss and decreased growth rate due to reduction in feeding.
Treatment is antibiotic eye ointment. Prevention is aimed at reducing exposure to dust and contact with flies (use of insecticides), minimising grazing on long stalky pasture and overcrowding as well as prompt removal of affected cattle from the mob. In the face of an outbreak, vaccines may be useful to reduce the spread and severity of disease.
2. Cancer eye or Squamous Cell Carcinoma is highly malignant and can affect the eyeball, eyelids or third eyelid. Tumors start as small gray/white elevated lesions and evolve to larger irregular cauliflower-like lesions. They may become infected and metastasize to local lymph nodes, lungs and liver. In the early stages, surgical removal may be warranted however there is no guarantee that all cancer cells will be removed and the cancer may recur. Consequently culling is often advised and a certificate of suitability for transport is mandatory. Be aware that a works' certificate does not guarantee that the carcass will pass meat inspection if there is evidence of spread. Regular inspection of all cows and culling of early cases is the best approach to dealing with cancer eye.
3. Trauma to the eye can occur if a foreign body contacts or lodges in the eye. The extent of the injury determines the outcome. Superficial injuries generally respond to conservative treatment while deep penetrating wounds may necessitate removal of the eye.
