Browsing by Author "Makin J"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Seasonal corneal oedema in small ruminants and camelids in New Zealand: case investigations in sheep and goats
    (Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-04-13) Hunt H; Green D; Doohan S; Vaatstra B; Makin J; Price P
    Case history: A seasonal syndrome, presenting as corneal oedema and distinct from infectious keratoconjunctivitis, has been reported in sheep, goats, and camelids in New Zealand. This study details the diagnostic investigation on two properties, of multiple cases of corneal oedema in small ruminants. Outbreak 1 occurred in a mob of sheep in April/May 2023 in the Manawatū region, with 27/52 sheep affected. Outbreak 2 occurred in a group of farmed goats in February/March 2024 in the Auckland region, with 4/5 goats affected. Clinical findings: A spectrum of corneal abnormalities, including focal and diffuse corneal oedema and bullous keratopathy/corneal hydrops, were observed in both the sheep and goats. All animals had normal menace responses and pupillary light reflexes, and there was no associated blepharospasm, epiphora or ocular discharge, except in five sheep that developed secondary ulcerative keratitis. These five sheep had severe ulceration or corneal perforation necessitating euthanasia, while the other affected sheep all recovered within 5 months. The corneal oedema in all goats improved over the following 6 months, but one required a thermokeratoplasty procedure to aid resolution of the oedema and the other three goats had residual focal oedema that did not appreciably affect vision. Diagnosis: It is proposed that a primary corneal endothelial dysfunction was the cause of the oedema, but the aetiopathogenesis is not well understood. Clinical relevance: This is the first peer-reviewed description of this presentation in New Zealand. In contrast to other causes of corneal oedema in ruminants, seasonal corneal oedema is, in some cases, self-limiting with minimal impacts on production and welfare. However, secondary ulceration and corneal perforation may occur, which is painful and may lead to deep infections and permanent visual deficits. Topical antibiotic therapy does not appear to aid in the resolution of the oedema.