Keratoconjunctivitis in a hill sheep flock.

Keratoconjunctivitis affected many ewes on a large, experimental husbandry, hill farm in early and midwinter in two consecutive years. Small sporadic outbreaks occurred among ewes during the following winters and among ewes and lambs in the summer and autumn. Mycoplasma conjunctivae was isolated from conjunctival swabs taken from affected sheep. Keratoconjunctivitis had not been recognised on the farm before and the infection was probably introduced with purchased rams. Prompt treatment prevented blindness; a single application of aureomycin topical powder with an intramuscular injection of a long acting oxytetracycline was an effective clinical treatment. Prophylactic treatments with aureomycin powder did not prevent the spread of the disease. The outbreak appeared to have no effect on the weaning percentage and blackface and Cheviot ewes were equally susceptible.