Plus-Hex CLINICAL
Healthy ferrets alternate between high-energy activity and extended periods of sleep , often resting for up to 70 % of the day , according to studies of their brain activity [ 13 ] . In the authors ' experience , a healthy ferret remains alert when engaged in interesting activities , whereas an unwell ferret is lethargic , minimally interactive and hard to rouse ( Figure 5 ). If disturbed , an unwell ferret tends to return to sleep faster than a healthy ferret .
Figure 5 . This ferret was unwell , stayed curled up and was reluctant to be roused . Staying curled up could be perceived as a form of guarding behaviour against being disturbed or handled .
Assessing pain in research settings
A number of tests are available to assess pain ( mainly in rodents ) in research settings [ 14 ] . These include evaluating physiological signs ( such as levels of cortisol and other biochemical parameters ), behavioural signs ( using behavioural ethograms ) and emotional responses ( for example , cognitive bias ) to a painful stimulus [ 15 , 16 ] . Similar parameters are used in veterinary practice , although there is access to fewer tests in the practice setting .
Physiological signs of pain
Pain stimulates the sympathetic nervous system , increasing circulating adrenaline and noradrenaline . This leads to an increased heart rate , respiratory rate , temperature and blood pressure . Peripheral vasoconstriction , sweating and pupillary dilation are also seen in some species [ 17 ] .
Many physiological signs of pain , including changes in respiratory rate and heart rate , can be readily measured in ferrets . However , it is essential to recognise that these parameters may also be affected by stress , illness , handling or changes in the animal ' s environment .
Figure 6 . Blood pressure monitoring of an anaesthetised ferret .
Figure 7 . Temperature monitoring of a ferret distracted with a treat . This patient was unwell and had ascites .
The authors recommend establishing a baseline respiratory rate , heart auscultation and pain assessment , along with mucous membrane colour and rectal temperature , if a patient is cooperative . Hepps et al . [ 18 ] suggest that tympanic thermometry may be a useful and less stressful alternative to rectal temperature measurement , although further research is needed .
It is possible to achieve a blood pressure measurement in unwell , collapsed or anaesthetised ferrets , on the forelimb or tail , but care should be taken not to cause excessive stress . The cuff for use in this species is small , so the rule of thumb is to add 30 mmHg to any Doppler measurement [ 19 ] .
Monitoring physiological parameters such as heart rate , blood pressure and respiratory rate is crucial for assessing pain in anaesthetised patients . If these indicators show inadequate analgesia or light anaesthesia , supplemental analgesia or further anaesthesia should be administered .
It can be challenging to obtain blood pressure or rectal temperature measurements from healthy , conscious ferrets , as they do not stay still . Although it is easier to obtain readings of blood pressure ( Figure 6 ), rectal temperature ( Figure 7 ), or even an electrocardiogram ( ECG ) ( Figure 8 ) in an unwell or collapsed ferret , care should be taken not to cause excessive stress .
Figure 8 . Electrocardiography ( ECG ) of a ferret . This patient was very unwell so tolerated the ECG clips .
Volume 39 ( 6 ) • December 2024
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