Frequency and Characterisation of Anomalies and Fractures of the Caudal Spine in Sheep with Undocked Tails

SIMPLE SUMMARY: Due to the widespread practice of tail docking in sheep, no data exist regarding the incidence of caudal spine deformities and injuries in this species. The aim of this study was to describe the type and frequency of tail abnormalities in an undocked Merinoland sheep population using radiographic studies. The findings demonstrated that anomalies of the tail bones (such as fractures and block or wedged vertebrae) were predominantly found in the middle and caudal third of the spine. Additionally, a correlation between the occurrence of vertebral fractures and the tail length and number of vertebrae was observed. No significant differences were found in terms of different litter sizes and sex. These results suggest that the proportion of animals with tail malformations and injuries is relatively high, which should be considered when breeding for short tails in the context of a docking ban. ABSTRACT: As tails are often docked within the first days of life, studies investigating tail malformations and injuries in sheep do not exist thus far. To address this gap in the literature, this research aimed to analyse the occurrence of vertebral anomalies and fractures in the tail within an undocked Merinoland sheep population. At 14 weeks of age, the caudal spines of 216 undocked Merinoland lambs was radiographically examined, and tail length and circumference were measured. Anomalies were documented and statistical correlation and model calculations were performed. The occurrence of block vertebrae was observed in 12.96% and wedged vertebrae in 8.33% of the sample. Of the animals, 59 (27.31%) exhibited at least one vertebral fracture, which were observed in the middle and caudal third of the tail. A significant correlation was found between the occurrence of fractures and tail length (r = 0.168) and number of vertebrae (r = 0.155). Conversely, the presence of block and wedged vertebrae was not significantly correlated with tail length, circumference, or number of vertebrae. Only the sex showed significant differences in the probability of axis deviation. These results emphasize the importance of breeding for short tails to avoid fractures.