Infectious bovine keratoconjunctivitis (IBK), commonly called pinkeye, is a painful and highly contagious eye disease of cattle that, if untreated, can cause permanent blindness. It is one of the most common cattle diseases globally.
Pinkeye causes significant, measurable pain. Affected calves avoid bright light, hold the affected eye closed, have reduced feeding and activity, and show weight loss during active disease. The corneal ulceration is painful and progresses rapidly without treatment — delay worsens both pain severity and long-term vision outcome. Bilaterally affected calves are functionally blind and unable to navigate, feed normally, or avoid hazards, compounding their welfare burden. Permanent unilateral or bilateral blindness — a common outcome of untreated or late-treated IBK — causes lasting disadvantage and welfare compromise. Because the disease spreads rapidly in groups, herd-level treatment and prevention are important to limit the number of animals experiencing acute eye pain.