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- Hot, humid summer conditions in South Africa create an ideal environment for the spread of eye diseases in cattle and sheep, significantly impacting their health and productivity.
- Common eye diseases include infectious bovine keratoconjunctivitis (pink eye), infectious keratoconjunctivitis in sheep, and photosensitivity, which can cause symptoms ranging from redness and swelling to blindness in severe cases.
- Effective prevention measures include implementing fly control, maintaining pastures for proper airflow, reducing overcrowding, and providing ample shade to minimize UV exposure.
- Treatment options for bacterial infections like pink eye include topical antibiotics, injectable antibiotics for severe cases, and protective eye patches to shield affected eyes from sunlight and dust.
- The key to managing eye health in livestock involves a combination of proactive prevention, early diagnosis, prompt treatment, and consulting a veterinarian for accurate care.
The hot summer months in South Africa pose a number of challenges that producers must navigate, especially when it comes to eye health in cattle and sheep. Hot, humid conditions create the ideal environment for the spread of eye diseases, with an often-severe impact on animal health and productivity.
Dr Johan van Rensburg, managing director of Axiota Animal Health, says flies contribute to the incidence of eye diseases. The warmer the conditions, the more active flies become. They also act as vectors for eye disease-causing bacteria and viruses. Dry and dusty conditions also contribute to eye irritation, increasing livestock’s susceptibility to infections.
Bright sunlight is another contributing factor – photosensitivity, which may worsen existing eye problems, is a big concern due to increased ultraviolet (UV) exposure in summer. Subpar grazing management coupled with dense vegetation and animal overcrowding promote the spread of disease, especially if air movement is poor. Poisonous plants are more common in the growing season and their toxins can exacerbate photosensitivity and cause eye issues.
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Common eye diseases
Infectious bovine keratoconjunctivitis (pink eye) is caused by bacteria such as Moraxella bovis and Mycoplasma spp. It is mainly spread by flies, through direct contact, and by way of environmental factors such as dust. Cattle are mostly affected although it can infect sheep as well. Symptoms include inflammation, redness, tearing and clouding of the eye and, in severe cases, ulcers and blindness.
Infectious keratoconjunctivitis affects especially flocks in which sheep are grouped close together. The disease is caused by Mycoplasma conjunctivae and Chlamydia spp. and transmission occurs when animals are in close contact with each other, as well as through flies and dirty equipment. Symptoms include conjunctivitis (inflammation of the eye mucous membrane), swollen eyelids, tears, eye discharge and in severe cases, temporary or permanent blindness.
Photosensitivity affects cattle and sheep. It is caused by a heightened sensitivity to UV light; it can also be aggravated when livestock ingest poisonous plants or if the liver is damaged. This leads to the accumulation of photosensitive chemical compounds which heightens the animal’s sensitivity to UV light. Although not contagious, the disease can affect several animals on the same farm. Symptoms include swelling around the eyes, redness, tears, and in severe cases, ulcers.
Prevent infection
Dr Van Rensburg emphasises the importance of being proactive in terms of prevention and suggests the following measures:
- Implement effective fly control measures, such as utilising fly traps and nets, and effective insecticides for dipping cattle and sheep. Clean up feeding and drinking areas regularly to reduce the number of fly breeding sites.
- Maintain pastures to ensure adequate airflow, which helps reduce dust formation.
- Avoid overcrowding of animals on pastures and ensure animals have access to shade to shelter them from the heat.
- Ensure that there is ample shade available to reduce UV exposure and protect animals from harsh sunlight. Consider adding more shelter to protect animals from the sun and wind.
- Check animals daily in summer for signs of eye infections, such as excessive tearing or red eyes.
- Isolate affected animals to prevent infectious diseases from spreading to other animals in the herd/flock.
Treatment options
Topical antibiotics, such as ointments containing oxytetracycline, are often applied to treat bacterial infections such as pink eye. Prevent complications such as corneal ulcers by treating animals timeously. In severe cases or when topical treatment is not sufficient, a veterinarian may prescribe injectable antibiotics.
Cover the eyes of cattle suffering from severe pink eye with a protective eye patch that will protect their eyes from sunlight and dust – it also speeds up recovery. Non-steroidal anti-inflammatory agents can help relieve pain and inflammation. Prevent the spread of infection by isolating animals with infectious eye conditions.
According to Dr Van Rensburg, some producers utilise saline solutions or herbal eyewashes containing chamomile to treat eye infections; however, this does not replace proper veterinary care. The key to effective control is a combination of sound management practices, early diagnosis, and prompt treatment.
Be sure to consult a veterinarian for an accurate diagnosis, as this forms the basis for prompt and effective treatment. – Christal-Lize Muller, Stockfarm
Send an email to Dr Johan van Rensburg at johan@axiota-sa.co.za for more information.
