Ovine Infectious Keratoconjunctivitis: Welfare in Sheep Flocks

Key Facts

• IKC in sheep is caused by Mycoplasma conjunctivae, often with secondary bacterial involvement
• Clinical signs progress from watery eye to corneal opacity and ulceration — blinded sheep cannot graze effectively
• Face flies (Musca autumnalis) are a major transmission vector during summer
• Oxytetracycline eye ointment or spray combined with an eye patch provides effective treatment
• Untreated cases lead to permanent corneal scarring and blindness in 10-15% of severe cases

Welfare Considerations

IKC causes significant welfare suffering through ocular pain and visual impairment. Affected sheep squint, have ocular discharge, and become reluctant to move in bright light. Corneal ulceration is painful and the progression to blindness means affected animals cannot graze normally, losing body condition and social status. Blind sheep cannot navigate to water or avoid dominant individuals, creating a welfare cascade. Prompt treatment is both welfare- and productivity-effective — most cases respond rapidly to antibiotic therapy. Face fly control through pour-on insecticides or fly traps reduces transmission significantly during summer.

What You Can Do

• Apply antibiotic eye treatment promptly for all sheep with eye discharge or corneal opacity
• Use eye patches alongside treatment to protect the affected eye and reduce photophobia
• Implement face fly control in summer using appropriate insecticide products
• Isolate severely affected sheep to prevent transmission and allow undisturbed access to food and water
• Check treated animals daily — failure to improve within 48 hours requires veterinary reassessment