# Incisor Disorders of Merino Sheep (Ovis aries)

## TL;DR

This study examines dental issues in Merino sheep, revealing common plaque and wear patterns, as well as rare anomalies like fused teeth.

## Contribution

The paper documents the first cases of geminated and fused incisors in sheep, expanding knowledge of dental anomalies in this species.

## Key findings

- Plaque scores indicated significant plaque accumulation on incisors, with higher scores on buccal surfaces.
- Dental wear assessments showed enamel loss and pulp exposure in 13% of 10-month-olds and 33% of 20-month-olds.
- Amelogenesis imperfecta was recorded in 5% of younger and 37% of older sheep, indicating age-related dental development issues.

## 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.