Monitoring equine head-related pain with the Equine Utrecht University scale for facial assessment of pain (EQUUS-FAP)

This study validates a recently described pain scale, the Equine Utrecht University scale for facial assessment of pain (EQUUS-FAP), in horses with acute or postoperative pain originating from the head, including dental pain, ocular pain, or trauma to the skull. This cohort study of 23 horses with head-related pain and 23 normal, healthy controls revealed significant differences in EQUUS-FAP scores between control horses and horses with acute or postoperative pain (P <0.001). Moreover, pain scores after surgery decreased significantly over time (P <0.001). The scale showed good inter-observer reliability (intra-class correlation coefficient = 0.92), sensitivity (80%), specificity (78%), and positive (80%) and negative predictive values (78%).