Incisor Disorders of Merino Sheep (Ovis aries).

Abstract

This study documents dental anomalies in 2414 Merino ewe sheep (Ovis aries) from 7 Australian Merino Sire Evaluation Association sites observed during routine husbandry. Teeth were photographed and evaluated using visual scoring protocols to assess plaque accumulation, enamel wear, and other anomalies across all incisors. Plaque scoring revealed a median plaque score of 3 (IQR ± 1) on buccal surfaces and 2 (IQR ± 2) on lingual surfaces, indicating substantial plaque accumulation across incisors. Two cases of geminated incisors and one case of fused central incisors were identified, representing the first documented cases in sheep and expanding existing knowledge of dental anomalies in sheep. Dental wear assessments showed that 13% of 10-month-old ewes and 33% of 20-month-old ewes had significant enamel loss or pulp exposure, with an average of 2 teeth per affected ewe displaying pulp necrosis. Amelogenesis imperfecta was recorded in 5% of the younger and 37% of the older groups. Missing incisors, suggesting early dentition changeover, were observed in 9% of 20-month-old sheep. Localized enamel hypoplasia, potentially resulting from trauma or disruptions during enamel development, was noted in 1% of both age groups. Dental caries was identified in five 20-month-old ewes with permanent incisors. These findings provide a comprehensive overview of the range and prevalence of dental conditions in Merino sheep, including common wear patterns and rare anomalies. Documenting such conditions in sheep contributes valuable information to veterinary dentistry, highlighting the need for further research into incisor health in sheep.