Disentangling stress and pain in clinical pet rabbits: validated pain scales outperform salivary corticosterone

This study evaluated rabbit pain scales and salivary corticosterone (salCORT) within a longitudinal model designed to separate stress- and pain- related phases. Client-owned rabbits presenting for acute painful gastrointestinal disease were assessed across three phases: Pain (emergency admission), High-Stress (2 weeks post-recovery and discharge, hospital recheck) and Low-Stress (home environment). Video recordings and salivary samples were obtained at identical clock times in all phases to control for circadian variation. Videos were scored using the Rabbit Grimace Scale (RbtGS), Centro Animali Non Convenzionali Rabbit Scale (CANCRS), Bristol Rabbit Pain Scale (BRPS) and Rabbit Pain Behaviour Scale (RPBS). SalCORT was quantified using a multispecies ELISA kit. Phase effects and diagnostic discrimination (Pain vs High-Stress) were analysed using non-parametric repeated-measures tests and ROC curve analysis. Validated rabbit pain scales―particularly CANCRS and RbtGS―demonstrated superior ability to distinguish pain from stress, whereas salCORT primarily reflected physiological arousal (Kadlecova et al. 2023).