Development of a Composite Pain Scale in Foals: A Pilot Study

SIMPLE SUMMARY: Recognition of pain is pivotal to its management and essential to enhance horses’ well-being and quality of life. Pain scales are important tools for this purpose. In the last years, various types of pain scales have been developed for adult horses, also considering different sources of pain. So far, only one scale based on facial expressions has been designed for foals. In this study, the first Foal Composite Pain Scale was developed and its application assessed. The scale was piloted on 35 control pain-free foals and 15 foals suffering from different pain-related conditions by multiple observers, and a preliminary analytical process of validation was performed. It was found that, despite some criticalities, the Foal Composite Pain Scale proved to be a valid tool to assess pain and quality of life in foals. Moreover, the criticalities highlighted by this pilot study are essential to refine the scale for future studies. ABSTRACT: Prompt pain management is crucial in horses; however, tools to assess pain are limited. This study aimed to develop and pilot a composite scale for pain estimation in foals. The “Foal Composite Pain Scale” (FCPS) was developed based on literature and authors’ expertise. The FCPS consisted of 11 facial expressions, 4 behavioural items, and 5 physical items. Thirty-five pain-free foals (Control Group) and 15 foals experiencing pain (Pain Group) were used. Foals were video-recorded at different time points: the Control Group only at inclusion (C), while the Pain Group at inclusion (T1), after an analgesic treatment (T2), and at recovery (T3). Physical items were also recorded at the same time points. Videos were scored twice by five trained observers, blinded to group and time points, to calculate inter- and intra-observer reliability of each scale item. Fleiss’ kappa values ranged from moderate to almost perfect for the majority of the items, while the intraclass correlation coefficient was excellent (ICC = 0.923). The consistency of FCPS was also excellent (Cronbach’s alpha = 0.842). A cut-off ≥ 7 indicated the presence of pain. The Pain Group scores were significantly higher (p < 0.001) than the Control Group and decreased over time (T1, T2 > T3; p = 0.001). Overall, FCPS seems clinically applicable to quantify pain and improve the judgment of the quality of life in foals, but it needs modifications based on these preliminary findings. Consequently, further studies on a larger sample size are needed to test the feasibility and validity of the refined FCPS.