Behavioural signs of pain
It can be challenging to recognise pain in ferrets purely through behavioural changes , as the changes can be subtle and there is a scarcity of available information .
In an article on ferret pain and distress written by a ferret owner , the author describes how he identified a change in the behaviour of his ferret , which ‘ suddenly started to hide ’, as being a sign of pain caused by a fractured canine tooth . Another of his ferrets became ‘ very subdued ’, with a slight limp , and radiographs later revealed it had a fractured hip [ 20 ] .
This ferret moved away on palpation of the surgical site , but ferrets are known to often move when touched , especially by someone unfamiliar , so the response to palpation should be repeatable and reliable . It is hard to assess pain in animals recovering from anaesthesia , particularly when unfamiliar with the species . The grimace scale needs to be taken into account alongside all other parameters and behavioural indices , and never used as a stand-alone scoring method .
Jaw clenching and teeth grinding are behaviours that could indicate pain and may also be easily missed . Teeth grinding may manifest as a ferret that ‘ holds its head down and rhythmically moves its facial muscles back and forth and wriggles its ears in response to painful stimuli ’. This may be a sign of abdominal pain [ 11 ] .
Ferrets are generally quiet animals , but they do make vocalisations associated with pain , fear or distress , which include grunting ( especially when handled ), crying , whimpering , screaming or hissing [ 11 , 17 ] .
Figure 9 . The Case 1 ferret showing facial grimacing and a slightly hunched , head-down posture .
The ferret grimace scale
Pain scales were developed in human medicine to assess pain in non-verbal infants and are now also used in veterinary practice . A grimace scale has been developed to help assess pain in ferrets ( Appendix 1 [ 21 ] , page 31 ). Recent investigations into the validity of the ferret grimace scale found that it shows promise [ 22 ] .
Pain consists of nociception ( the detection of painful stimuli ), a physiological response (‘ it hurts ’), and an emotional response (‘ it makes me feel bad ’). Studies on mice indicate that facial grimacing correlates with the emotional response to pain [ 23 ] . While facial expressions are crucial for communication across various species , grimacing is considered a coping mechanism that may reduce sensory input but also communicate pain to conspecifics . Fisher [ 11 ] notes : ‘ it is amazing to watch the change in behavioural attitude and facial relaxation [ in ferrets ] once pain medication is administered ’.
Case studies using the ferret grimace scale Case 1
A female ferret post ovariohysterectomy with an intramuscular ( IM ) anaesthesia protocol of midazolam , ketamine , medetomidine and buprenorphine , alongside meloxicam and splash-block bupivacaine . The medetomidine was reversed . Figure 9 shows the patient 2 hours after surgery , with normal basic postoperative parameters . Note the facial grimacing and slightly hunched , head-down posture .
Case 1 ' s ferret grimace score
Orbital tightening 2 Nose bulging 2 Cheek bulging 0.5 Ear changes 1 Whisker retraction 2 Score ( out of possible 10 ) 7.5
Case 2
A hospitalised male ferret that was exhibiting signs of pain and sickness associated with chronic hepatopathy , having previously undergone two exploratory surgeries some weeks before . The patient was minimally interactive and rarely left his bed ; he slept a lot and was completely anorexic and showed facial grimacing ( Figure 10 , page 21 ). The patient tensed in response to abdominal palpation . It is difficult to differentiate between pain , sickness and stress behaviours as these overlap . In such cases , analgesia can be given at a dose appropriate to the perceived level of pain and the patient closely monitored to evaluate its response to the analgesic agent .
20 Veterinary Nursing Journal