Pinkeye (Infectious keratoconjunctivitis) is a highly contagious, painful and debilitating disease that can severely affect animal productivity.
With low stocking rates and abundant spring growth some properties have plenty of long grass, and recent rain events have increased fly populations, both these factors increasing the spread of pinkeye.
The summer season brings increased sunlight and dust, which can make the eye more vulnerable to the disease.
Pinkeye usually occurs in young cattle in their first summer. After this initial infection, cattle develop immunity to the disease but may remain carriers of the bacteria, Moraxella bovis, which potentially can lead to future outbreaks in following years.
The clinical signs of pinkeye include clear and watery tears, signs of irritation, an aversion to sunlight, reddening and swelling of the eyelids and cloudiness of the eye.
In a small percentage of cases, an affected eye may form an abscess and rupture, leading to permanent blindness.
While most affected eyes completely recover after 3 to 5 weeks, a number may be left with scarring on the surface.
Pinkeye can be treated with antibiotic ointments, sprays, injections and patches or a combination of these treatments.
Extra care should be taken when mustering cattle for the purposes of treatment for pinkeye, as factors such as dust and flies may enhance the spread of the disease.
There is also a vaccine available that helps give immunity against three of the strains of Moraxella bovis.
Other control measures include controlling fly numbers to limit the spread of bacteria from animal to animal, prompt segregation and treatment in affected stock, and avoiding unnecessary yarding of cattle during periods where the risk of outbreak is higher.
Attention should also be taken not to confuse pinkeye with other eye conditions, such as a grass seed in the eye, eye cancer and other eye infections.
For further advice contact your local veterinarian or Agriculture Victoria veterinary or animal health officer, or in NSW your Local Land Services.
Dr Jeff Cave is an Agriculture Victoria senior veterinary officer.
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