Pink Eye in cattle (Infectious Bovine Keratoconjunctivitis) is a highly infectious disease caused mainly by the bacterium Moraxella bovis. After initial infection, the bacteria attach to the surface of the eye and produce toxins that erode the cornea causing ulceration, severe inflammation (uveitis) and pain. For beef cattle, Pink Eye occurs mainly in young animals in Summer and Autumn, according to Agriculture Victoria.
The economic cost of Pink Eye in Australia has been estimated at $23.5 million annually through loss of production, weight gain, fertility, increased culling, treatment costs etc. Pink Eye causes significant pain in affected stock and therefore has important animal welfare implications. Factors that may drive Pink Eye include flies, UV light, long grass or hay, dust, viral infections (IBR), reduced immune status and lastly stress.
Stages of the Disease
The clinical signs of Pink Eye vary with the severity and progression of the disease.
Firstly in Stage 1 – excessive tearing occurs. The animal will blink and squint due to increased sensitivity to light and pain. As the disease progresses, a small ulcer appears in the centre of the cornea which appears cloudy
Secondly in Stage 2 – The ulcer becomes large and deeper and the eye becomes increasingly cloudy. Blood vessels grow across the cornea making the eye look pink.
Thirdly in Stage 3 – The ulcer covers the entire surface of the eye and extends into the inner structures of the eye. This severe inflammation makes the eye appear yellow.
Finally in Stage 4 – The ulcer extends completely through the cornea resulting in the eye rupturing. The iris will plug the rupture and may protrude through the ulcer. At this stage the animal will not regain sight in this eye and the eyeball may collapse or end up being permanently swollen (glaucoma).
Prevention of Pink Eye
To prevent pink eye in cattle, control flies and reduce competition around hay and grain feeders. Also minimise yarding and optimise health and nutrition. Furthermore, vaccinating and isolating affected animals from the rest of the mob will reduce spread.
Treatment of Pink Eye
Vaccination with Pilligard (TM) is an important part of the control of pink eye in cattle. Pilligard covers 3 of the 5 strains of Moraxella bovis present in Australia. It is not 100 percent effective in preventing Pink Eye. However, studies have shown that in about 70 % of outbreaks of Pink Eye, at least one of the three strains present in Pilligard is responsible. Administer Pilligard 3 – 6 weeks before the start of the Pink Eye season as a single vaccination. Vaccinate calves as young as 2 weeks old. Pilligard is an oil emulsion vaccine therefore an accidental “self-inoculation” is serious. Seek immediate medical advice if this occurs!
Treatment of Pink Eye in cattle is often frustrating and time consuming. Treat cattle with eye ointments containing cloxacillin for a small number of affected animals. Apply the registered products every second day, to reduce stock handling. Treat the entire mob at once with a long acting antibiotic injection containing oxytetracycline if a high percentage of cattle are affected. This will be more cost and time effective. Administer a long acting anti-inflammatory injection containing meloxicam to any affected animals. This will control the pain and reduce the inflammation in the affected eye(s). Apply a patch to protect the eye from sunlight and to reduce spread to other stock.
Treat and improve healing in severely affected animals (stage 3 and 4) or valuable individual animals, with an injection of antibiotics and cortisone under the sclera (white part of the eye) and a third eye lid flap to protect the eye and promote healing.
For more information on controlling or treating Pink Eye in cattle, contact our Livestock and Equine Centre. Call us on 5662 2251 extension 2 and talk to one of our cattle vets. In addition, Pilligard is on special until the end of January 2020 for $230 (inc GST) for 100 ml (50 doses).