Lip and gum lesions in sheep in two abattoirs in New Zealand

AIM: To build a profile of the oral lesions that occur in sheep in New Zealand that need to be considered within the differential diagnosis of foot-and-mouth disease. METHODS: Lesions of the anterior lips and gums of sheep were surveyed in two abattoirs, photographed, and described grossly and histopathologically. RESULTS: A sequence of lesions in order of age and stage of healing are described and illustrated, and their pathogenesis discussed. Lesions of the midline of the lips and gums of traumatic or irritant aetiology were common, and the prevalence was higher in adult sheep than in lambs. CONCLUSIONS: The majority of lesions observed appeared to be primarily of traumatic aetiology. They probably arose from the fright/flight response behaviour of sheep, resulting in the mouth impacting against wire fences or yard railings while being handled. A smaller percentage of lesions may have been due to abrasive or irritant feed or soil. The presence of plant material and bacteria in lesions delayed healing and contributed to the formation of ulcers.