Bovine Infectious Keratoconjunctivitis — Pink Eye in Cattle

Infectious bovine keratoconjunctivitis, or pink eye, is one of the most common and painful diseases in beef cattle, causing corneal ulceration, temporary or permanent blindness, and significant welfare harm in affected herds.

Key Facts

Infectious bovine keratoconjunctivitis (IBK) is caused primarily by Moraxella bovis, with M. bovoculi also implicated in many outbreaks
Face flies (Musca autumnalis) are the primary mechanical vector, spreading bacteria between cattle eyes during summer months
Young cattle under 2 years old are most susceptible; Hereford cattle with unpigmented eyelids are particularly vulnerable
Clinical progression moves from excessive tearing and photophobia through corneal cloudiness to ulceration, perforation, and blindness
Blindness severely impairs cattle welfare: blind cattle cannot navigate to water and feed, are vulnerable to predators, and show signs of fear and disorientation
Treatment with penicillin G — injected subconjunctivally or given parenterally — is highly effective when started early
Eye patches reduce UV exposure and fly access to affected eyes, accelerating healing

Welfare Considerations

Pink eye causes genuine suffering: the photophobia of early infection means affected cattle seek shade, avoid feed, and show clear signs of ocular pain. As corneal ulceration progresses, the pain intensifies, and temporary or permanent blindness adds fear, disorientation, and difficulty accessing resources to the welfare burden. Treatment is both effective and cheap when applied early, making delays in detection and treatment a preventable welfare failure. Herd-level prevention through face fly control, vaccination where available, and removal of eye-irritating vegetation reduces incidence significantly. Eye patching affected cattle reduces suffering duration and supports healing. The key welfare intervention is attentive monitoring that catches cases early, when treatment is most effective.

What You Can Do

Train farm staff to identify early signs of IBK including excessive tearing and eye-rubbing
Implement face fly control programmes during summer using insecticide ear tags or pour-on products
Ensure adequate veterinary supplies for prompt treatment of identified cases on farm
Consider vaccination with Moraxella bovis bacterin in herds with recurrent IBK problems
Promote shade access and removal of tall grass that contacts cattle faces in high-risk periods