Pink eye in cattle (Infectious Bovine Keratoconjunctivits) is certainly making its presence felt at the moment. It is a highly contagious and painful disease of the eye, having negative effects on welfare and production.
Risk Factors: Most cases are seen in the summer months, but it can occur year-round. It commonly occurs in dry, dusty conditions, coupled with high fly activity, grazing of stalky pastures, yarding, feeding of hay and silage, and when feeding rations in bunks. Flies act as a carrier, helping the spread between animals.
Cause: It is caused by bacteria, most commonly, Moraxella bovis. Time from exposure to clinical signs takes approximately two to three days. Outbreaks often occur in younger animals with more susceptible immune systems. Peak infection of a mob occurs roughly three to four weeks after the first cases and up to 80 per cent of the mob can be affected in a bad season.
Clinical Signs: Typically, the first signs can be subtle and therefore go unseen. Tearing occurs initially, followed by the development of a small white-blue discolouration in the centre of the eye, eventually turning into a large yellow ulcer surrounded by a pink ring. Abscessation, bulging or rupture of the eye can occur in severe cases. If left to advance to this stage, it can cause permanent scarring, vision loss, and even loss of the eye. Hidden costs include decreased feed intake resulting in decreased production, whether it be decreased weight gains, condition loss or dropped milk production, as well as welfare concerns associated with pain and blindness.
Treatment: Specific treatment regimens should be discussed with your vet and may involve use of topical antibiotics, patching and occasionally injectable preparations. Cases may resolve spontaneously, and producers need to keep in mind that the act of yarding itself to treat small numbers of affected animals can cause increased spread to other animals.
Prevention and control: Prior infection can lead to development of immunity, but this is only temporary and should not be relied upon. Animals can also become carriers of the bacteria and a source of infection in following seasons. A vaccine is available, however it is only specific to certain bacterial strains and it must be given three to six weeks prior to the start of the pink eye season. Fly control is extremely important and includes the use of pour-ons, insecticidal ear tags, fly traps and fly baits. Decreasing dust in hay and feed fed in bunks will reduce irritation to eyes. If possible, separate affected animals if requiring treatment. Ideally, use clean gloves when treating.
