A very common condition affecting sheep, characterized by severe inflammation of one or both eyes
Symptoms of the Disease/Condition
A very common condition affecting sheep, characterized by severe inflammation of one or both eyes.
The condition is caused by infection of the eye by infective agents Chlamydia and/or Mycoplasma species with secondary bacterial infection.
Most outbreaks are mild, affecting adult sheep during the summer and autumn. However outbreaks can be severe and affect sheep of any age.
Risk factors include dust, pollen in grass and flies. It is common in flocks which are being fed hay and in dry warm weather when large numbers of flies and dusty farm conditions predominate. The watery secretions seen in the early infection stages are very contagious. Spread through a flock is rapid.
The appearance of Pinkeye in sheep can be confused with grass seed or barley grass contamination of the eye and entropion (inverted eye lids) in young lambs.
Cost/Impact on Herd/Farm Revenue
Outbreaks may be severe in some flocks with as many as 50% of the flock affected. More commonly 10-15% of the flock is affected. The condition can be significant when it affects pregnant ewes making feeding difficult and often leading to metabolic disease prior to lambing. Where ewe deaths occur prior to lambing, the cost of a 1% increase in ewe wastage may be as high as $4.50 per ewe in a flock scanning 170%.
Management and Control
In most cases recovery commences within 3-4 days and is complete in 10-14 days although in some animals the cloudiness of the cornea may persist for several weeks or even permanently. Carrier animals are common where the Chlamydia organism persists well after an outbreak. It is thought more than 50% of recovered animals remain resistant for periods of up to a year.
Because recovery of the condition is quick and spontaneous in Chlamydia caused pinkeye, it is often questionable whether treatment and isolation of infected sheep is warranted.
Early treatment can aid recovery and reduce the number of Pinkeye affected sheep in the flock but treated sheep are more likely to relapse and become reinfected than untreated sheep.
Contact your nearest VetEnt clinic to learn more about how to manage Pinkeye in your flock.