Infectious bovine keratoconjunctivitis (pinkeye) is one of the most painful common diseases in cattle, causing ocular inflammation and potential permanent blindness without prompt treatment.
Pinkeye causes severe acute pain — the combination of corneal ulceration, photophobia, and blepharospasm is intensely painful and distressing. Affected cattle withdraw from the herd, avoid sunlight, and have difficulty navigating to food and water. Weight loss and production losses in milking cows are substantial. The light sensitivity causes cattle to stand with their head lowered and eyes pressed against fencing — a clear indicator of significant suffering. Prompt treatment dramatically reduces the duration and severity of pain. Analgesic treatment alongside antibiotics provides faster pain relief than antibiotics alone. Prevention through fly control is highly welfare-positive — reducing face fly populations reduces both transmission and the chronic irritation that precedes infection.