Predisposing Factors
Ultraviolet (UV) radiation is implicated in cattle with no pigmentation around the eyelids and cattle with prominently placed eyes. Exudate from the sun-burnt skin around the eyes becomes a culture medium for bacteria and attracts flies. UV also directly damages the corneal epithelium leading to a break-down in host innate immunity.
Dust, dried-up plants, tall vegetation and over-sized or incorrectly-placed ear tags may cause mechanical damage to the eye and facilitate bacterial colonization.
The disease may be complicated by concurrent infection with viruses such as infectious bovine rhinotracheitis virus (bovine herpesvirus 1) or adenovirus, bacteria such as Mycoplasma boviculi or Listeria monocytogenes, or infestation by Thelazia, a nematode.
Vitamin A deficiency is also implicated.
IBK is most prevalent in summer and early autumn.
A recent Meat & Livestock Australia (MLA) report "estimates that the disease costs Australian beef producers $23.5 million annually in lost production and treatment costs".
Read more about this topic: Infectious Bovine Keratoconjunctivitis
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