Assessment of acute pain in donkeys using the Donkey Composite Pain Scale (Do-CPS)

Abstract

Although there is shared heritage between the donkey and horse, they are remarkably different in their behaviour and physiological traits. Therefore, it is no longer acceptable to simply consider a donkey as a small horse and do donkeys need their own species-specific validated tools for the assessment of pain. In a composite pain scale (CPS), several putative pain-related parameters are evaluated concomitantly and are scored individually. This study investigates the clinical applicability, the validity and inter-observer variability for a refined CPS designed for donkeys; the Donkey Composite Pain Scale (Do-CPS). A total of 159 donkeys (n = 44 with acute pain, n = 115 healthy pain free controls) have been assessed by direct observations, using the Do-CPS. The patients were all suffering from acute pain caused by different medical conditions (lameness, facial pain, post-operative pain and colic) and were observed for at least two to three days. The Do-CPS scores showed high inter-observer reliability (R2 = 0.95, P < 0.001). The cut-off value for differentiation between healthy pain free and acute pain donkeys was 5. The Do-CPS showed statistical significant differences between patients and control donkeys for all patient subgroups. Sensitivity and specificity were good (sensitivity 73%, specificity 100%), in particular for the subgroup ‘lameness’ (sensitivity 92%, specificity 100%). After applying weighting factors to the individual parame- ters, sensitivity improved however specificity reduced for all patient subgroups. The use of the Do-CPS enabled repeated and objective scoring of pain in donkeys with acute pain, especially for the patient sub- groups ‘lameness’ and ‘colic’.