Caner Eye
General description
- Eye cancers can occur in older cattle following prolonged exposure to sunlight.
- Cattle with unpigmented eyelids and eyeballs are at most risk.
- Elevated risk for developing eye cancers can be inherited.
- Selection of resistant cattle (cattle with more eyelid pigment) is effective.
- You should not breed from affected cattle.
- Cancer eye is a painful condition.
- Cattle with a poor prognosis should be sent for immediate slaughter if fit to travel.
- Severely affected cattle that are unfit for travel should be immediately euthanised.
- Affected carcases with evidence of spread of the cancer at meat inspection (enlarged lymph nodes that drain the head) are condemned.
Cause
- Ultraviolet light exposure increases the risk of cancerous cell formation in the skin of the eyelid, third eyelid and sclera (junction between the whites of the eye and cornea).
- Factors such as viruses, nutrition and pregnancy may also be risk factors for eye cancer.
Clinical signs
- Cancer can develop after the emergence of protruding lesions around the eyelid, third-eyelid or sclera, but not all lesions will go on to become cancer.
- If the lesion becomes cancerous, a spreading ulcer (erosion of tissue) will form. This can become infected, producing pain and result in weeping.
- Eye cancers grow at different rates, but large cancers grow rapidly and often spread to internal organs. They can outgrow their blood supply resulting in a foul smell from the rotting core of the cancer.
- They can take years to reach these final stages.
- Affected cattle can become thin and weak, reflecting pain, difficulty seeing (if both eyes affected and/or internal spread of the cancer.
Diagnosis
- The presence of characteristic plaques or ulcers on the eyelid, third eyelid or sclera.
Treatment
- Small lesions can be surgically removed by a veterinarian. Suitable sedation and local anaesthesia may be necessary.
- Lesions often recur, so treated cattle should be followed up and sent for salvage slaughter if evidence of recurrence is present.
- Extensive and severe cancers can be removed by surgical removal of the eye by a veterinarian, but this is only warranted if there is no evidence of spread from the eye.
- Severely affected cases should be immediately destroyed if they are in pain or are deemed not fit to travel for slaughter.
Prevention
- Breeding to select resistant cattle is the most suitable option for producers.
- Susceptible stock should be examined regularly for early eye cancers, especially in the warmer months.
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