Evaluation of an automated assessment system for ear and tail lesions as animal welfare indicators in pigs at slaughter

The aim of this pilot study was to develop and evaluate an automated system for the assessment of ear and tail lesions as welfare indicators in pigs at the abattoir. A camera-based system was constructed to enable automatic assessment. This was evaluated in comparison to a standard observer, defined as skilled human veterinary observer, based on 5952 carcasses. We detected significant values for ear lesions (sensitivity, 77.0; specificity, 96.5; accuracy, 95.4%) and good values for tail lesions (sensitivity, 77.8%; specificity, 99.7%; accuracy, 99.5%). The reliabilities of assessments by four individual human observers directly at the abattoir and the camera system were calculated using Krippendorff's alpha. These varied between 0.42 and 0.67 for ear lesions and 0.42 and 0.55 for tail lesions, while better values were reached for the agreement between the system and picture-based evaluation (0.64 for ear lesions and 0.75 for tail lesions). More scientific evaluations at different abattoirs are now needed to further test and improve the camera-based system and its various scopes of application.