WHAT IS PINKEYE?
Pinkeye, or infectious bovine keratoconjunctivitis (IBK), is an infection of the eye caused by the bacterium Moraxella bovis. The bacterium produces a toxin that causes aggressive inflammation of the eye, often resulting in short term or permanent blindness in cattle.
Pinkeye is a contagious disease which can affect up to 80% of a mob. In Victoria, the infection usually affects young cattle during the summer and autumn months. Young cattle can lose up to 10% of their body weight as a result of infection.
The disease has the potential to cause economic loss through increased costs associated with treatments, reduced weight gains, reduced milk production in cows and reduced marketing opportunities.
IS MY HERD SUSCEPTIBLE?
There are a number of factors that increase the susceptibility of cattle to pinkeye. These factors include:
- British breeds are generally more at risk, particularly animals with low pigment around their eyes, protruding or unhooded eyes
- Flies feeding on the infected secretions from the eye and transferring the disease to clean cattle
- Dusty conditions that aggravate the eyes predispose the animal to pinkeye
- High ultraviolet radiation
- Physical irritation of the eye by grass seeds, thistles or long grass
- Following infection cattle can develop short-term immunity of up to a year. Continual exposure to the causative agents prolongs immunity
WHAT ARE THE SIGNS OF PINKEYE?
Clinical signs of pinkeye include:
- Irritated eyes, excess tear production, eye partially closed or excessive blinking
- Intolerance to sunlight
- Inflammation and swelling of the third eyelid
- Cloudiness/opacity forming in the middle of the eye
- Eye ulceration
- Blindness
TREATMENT OF PINKEYE
Many pinkeye cases recover in 3-5 weeks after infection without treatment. However, scarring and partial blindness may remain and in severe, bilateral cases, complete blindness. Mustering cattle solely for the purpose of treating pinkeye may be impractical in some situations. Dust stirred by mustering may worsen the problem rather than assist in the treatment of infection.
The possibility of further spread should be considered by determining the percentage of infected stock in the mob. Producers should aim to treat any eye infections when animals are yarded for other reasons such as; vaccination, drenching or other treatments.
There are a number of antibiotic treatments available from your local veterinarian. Producers should handle and store treatments according to label recommendations.
Different treatments available include:
- Eye Ointments; Cloxacillin (a long acting antibiotic) administered under the upper and lower eyelids, into the conjunctival sac. In mild cases only a single application is required which will last up to 48 hours. In persistent cases a second dose will need to be given at least 48 hours following initial treatment.
- Powder and sprays; are of limited use offering only short-term treatment and often requiring continual application to be effective while potentially causing some irritation.
- An injectable antibiotic and anti-inflammatory drug for use in severe cases. This form of treatment is more expensive. The solution is injected under the conjunctiva of the affected eye usually by a veterinarian and requires good head restraint.
- A third eyelid flap can be performed by a veterinarian in conjunction with an injection to aid healing of the eye and reduce scarring (white opacity on the cornea).
- Use of eye patches is recommended to improve the effectiveness of antibiotic treatments. They are not effective on their own. Eye patches ease the pain to the animal as result of direct exposure to sunlight and reduces irritation to the eye from dust, long grass and flies.
TAKE HOME MESSAGES:
- Pinkeye usually affects young cattle during the summer and autumn months in Victoria.
- Treatment with long acting eye ointment is usually very effective.
- A vaccine is available that prevents cases against 80% of Australian strains of pinkeye.
PREVENTION
Vaccinate susceptible young stock with Cooper's Piliguard®. The vaccine blocks the attachment of the Moraxella bacteria "pili" to the cornea of the eye preventing the establishment of pinkeye. Piliguard® contains three different strains of M bovis which covers, or protects, around 80% of outbreaks of pinkeye in Australia.
The vaccine requires a single 2ml dose administered 3-6 weeks prior to the commencement of the pinkeye season. Annual revaccination at the beginning of the pinkeye season is required to maintain protection.
Producers can help reduce the incidence of pinkeye by reducing fly numbers and making cattle less susceptible;
- Early detection, segregation and treatment of infected stock
- Reduce the incidence of flies and subsequent spreading of bacteria with the application of pour-on treatments
- Encourage dung beetles to reduce fly breeding sites
- When selecting whiteface cattle for breeding purposes, choose cattle with full pigment around their eyes
- Avoid excessive yarding in dusty yards during the pinkeye season
For further information, please contact Stock Sense on 1300 020 163 or email [email protected].
FURTHER LINKS
Agriculture Victoria Pink- eye in beef cattle
Coopers - Piliguard
Author; VFF, original version published December 2018. Disclaimer: The Victorian Farmers Federation (VFF), its partners, agents and contractors do not guarantee that this publication is without flaw and do not accept any liability whatsoever for any errors, defects or omissions in the information provided. This publication is intended for general information purposes only and does not constitute financial, legal, investment, production or marketing advice. The VFF excludes all liability for any loss or damage of any kind arising in relation to this publication including any reliance on the information contained herein.