Moraxella bovis

From Cow
Pink eye in a cow, showing severe corneal ulceration

Infectious keratoconjunctivitis (IBK) ('pink eye') is a bacterial eye disease of cattle caused by Moraxella bovis and characterised by conjunctivitis, epiphora and corneal ulcers.

Concurrent infections with infectious bovine rhinotracheitis and/or Mycoplasma spp have been reported and tend to exacerbate clinical disease.

Clinical signs

Ocular disease in one or a number of cattle, which is acute in onset and spreads rapidly is characteristic of the disease.

Younger cattle tend to be more predisposed. In severely affected cattle, anorexia, epiphora, photophobia, central corneal ulcers and blindness in the affected eye are common.


A presumptive diagnosis is based on presenting clinical signs of eye disease.

Exclusion of other diseases such as Thelazia spp (eye worm), bovine malignant catarrh, Chlamydophila spp, Mycoplasma spp and infectious bovine rhinotracheitis need to be addressed.


M. bovis bacterins are available and can be administered before the beginning of fly season. Modified live IBR vaccines has been associated with outbreaks of IBK in cattle[1].

Broad-spectrum antimicrobials administered topically and systemically are usually effective.

Tetracyclines and fluoroquinolones are effective when given as systemic injections.

A third-eyelid flap may reduce morbidity in severely affected animals[2].

Topical atropine ointment may alleviate uveitis in valuable cattle.


  1. di Girolamo FA et al (2012) Evaluation of cytokines as adjuvants of infectious bovine keratoconjunctivitis vaccines. Vet Immunol Immunopathol 145(1-2):563-566
  2. Merck Vet Manual