Determining a cut-off point for intervention analgesia in rabbits using the Bristol Rabbit Pain Scale

BackgroundThe objective of this study was to determine the threshold of the Bristol Rabbit Pain Scale (BRPS) indicating the need for intervention analgesia. MethodsFourteen members of veterinary staff were recruited to rate rabbits (n = 71) in acute pain. Observers in group A (n = 7) were asked to score each rabbit using the BRPS, while observers in group B (n = 7) independently answered the question 'In your clinical capacity, do you think this animal requires analgesia?' with either 'Yes' or 'No'. The answers from the two groups were then compared. ResultsRabbits for which group B answered 'No' (n = 36) had a median BRPS score (range) of 4 (0-10), while those for which group B answered 'Yes' (n = 42) had a median BRPS score of 9 (1-18; Z = -7.48; p < 0.001). The area under the receiver operating characteristic curve was 0.85 (95% confidence interval: 0.77-0.93; p < 0.001), indicating excellent discrimination of the BRPS with a cut-off score of 5.5 (sensitivity 88.1% and specificity 69.4%). However, for practicality, a score of 5 was deemed a feasible cut-off. LimitationsThe main limitations of this study are the small rabbit sample size and the subjective nature of pain scoring in animals. ConclusionsAnalgesic intervention should be considered in rabbits with a pain score equal to or greater than 5 on the BRPS.