A composite scale to recognize abdominal pain and its variation over time in response to analgesia in rabbits

Comparison between Carprofen and Meloxicam for Post-Neutering Pain Management in Pet Rabbits

Surgical neutering in pet rabbits is common practice to prevent reproduction and associated health issues. Adequate postoperative pain management is crucial for recovery, yet effective methods in clinical settings remain underexplored. This study compared the analgesic effects of carprofen and meloxicam in pet rabbits undergoing surgical neutering. Fifty rabbits of varied demographics were included, with pain assessed using the Centro Animali Non Convenzionali Rabbit Scale (CANCRS). Rabbits were allocated to receive postoperative 2 mg kg-1 carprofen or 1 mg kg-1 meloxicam by subcutaneous injection. Anesthesia was induced with an intramuscular combination of ketamine (20 mg kg-1), medetomidine (0.4 mg kg-1), and butorphanol (0.2 mg kg-1), and ovariectomy or orchiectomy were performed. The CANCRS scale was used to assess pain by evaluating the rabbit preoperatively, 6 h postoperatively, and at three time points the following day. Times of return to spontaneous feeding and fecal production were also recorded. No statistically significant difference was found between treatment groups based on CANCRS scores and resumption of food intake and fecal output. No clinically detectable adverse effects were noted. While limitations include the use of a single pain assessment scale and the absence of a placebo control group, the results suggest that both carprofen and meloxicam can be viable options in clinical practice. Further research utilizing diverse pain assessment methods is warranted to enhance understanding and optimize pain management strategies for rabbits undergoing surgical procedures.

Effects of Intratesticular Lidocaine in Pet Rabbits Undergoing Orchiectomy

The use of local anesthetics for castration is both simple and cost-effective, and it may contribute to reducing the anesthetic requirements. Despite its common use in clinical practice, the literature regarding the effects of intratesticular lidocaine in rabbits is limited. In this study, nine rabbits per group were assigned to intratesticularly receive either 2% lidocaine (0.05 mL/kg into each testicle) or an equivalent volume of saline prior to elective orchiectomy. Anesthesia was induced by intranasal administration of ketamine, medetomidine, and butorphanol. During intraoperative assessment, no significant differences in vital parameters (heart rate, respiratory rate, and peripheral saturation of oxygen) were observed between the groups. However, rabbits receiving intratesticular saline displayed a higher incidence of responses to surgical stimuli. Postoperative pain was evaluated using the composite Centro Animali Non Convenzionali Rabbit Scale (CANCRS), revealing a significantly lower score at the initial post-surgery assessment in rabbits treated with intratesticular lidocaine. All subjects exhibited rapid resumption of food intake and fecal output. While all rabbits demonstrated satisfactory perioperative performances, the use of intratesticular lidocaine was associated with a diminished response to surgical stimuli. Consequently, this practice has the potential to reduce the requirement for additional anesthetics or analgesics, promoting faster recovery.

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

BACKGROUND

The objective of this study was to determine the threshold of the Bristol Rabbit Pain Scale (BRPS) indicating the need for intervention analgesia.

METHODS

Fourteen 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.

RESULTS

Rabbits 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.

LIMITATIONS

The main limitations of this study are the small rabbit sample size and the subjective nature of pain scoring in animals.

CONCLUSIONS

Analgesic intervention should be considered in rabbits with a pain score equal to or greater than 5 on the BRPS.

Pain Recognition in Rabbits

Rabbits typically undergo at least one painful procedure during their lifetime and appropriate methods of assessment are essential to reduce or alleviate pain. Various methods of assessing pain in rabbits have been investigated, with the validity of spontaneous behavior and grimace scale scoring being the most studied to date. Assessment of pain is challenging, compounded by rabbits being a prey species that display freezing behavior in the presence of unfamiliar caregivers. Here we discuss some key changes in rabbits that can be used in the assessment of pain and provide some practical suggestions to ensure that the assessment can be carried out effectively.