Pinkeye in cattle is also known as Infectious Bovine Keratoconjuctivitis (IBK). The longer name accurately describes the fact that the conjunctivae and cornea of the eye are the tissues most often affected by this condition. Signs displayed by affected cattle include squinting, excess tear production, conjunctival vessel infection, swelling of the eyelids, a bluish discoloration of the cornea, and corneal ulceration. Cattle with pinkeye may also display blindness when both eyes are severely affected. Outbreaks can vary from a few affected animals with minimal signs that respond very well to treatment all the way to severe, unresponsive cases in a large number of animals.
Causes
Several infectious organisms are associated with this condition including Moraxella bovis, Mycoplasma spp. and infectious bovine rhinotracheitis virus (IBRV). Like many disease syndromes that affect cattle, multiple factors are involved. In addition to infectious organisms, physical factors that cause irritation to the eyes, such as hay, forage, dust, pollen, intense sunlight, feed troughs, and hay racks can be involved in this condition. Flies, in addition to causing irritation of the eyes, can also serve as vectors to transfer the infectious organisms to other animals. Younger animals are also more susceptible to pinkeye. Shipping, weaning, and other stressors can contribute to this condition.
Diagnosis
Diagnosis is usually made by clinical signs and history, but laboratory testing can be helpful in definitively identifying the infectious organisms involved. TVMDL offers several tests that may assist producers in detecting pinkeye including bacterial culture and antibiotic susceptibility test on organisms isolated as well as PCR testing for Myscoplasma spp. and IBRV.