The efficacy of two analgesics as potential fox bait additives

Baiting of foxes with fluoroacetic acid (1080) is a common practice, however there are concerns about the possible perception of pain during the latter stages of the toxicosis. By adding an effective analgesic to bait, the possibility of a painful death may be mitigated. While little is known about analgesics in foxes it is likely that non-steroidal anti-inflammatory (NSAID) analgesics would be the product of choice because of low cost and ready availability. One way of testing the effectiveness of an analgesic is by measuring Evoked Response Potentials (ERP), which are part of the EEG. These measure the animal’s ability to feel pain on the basis that they reflect the electrical activity associated with the generation of pain perception in the brain. Compounds with high analgesic effects should result in a large or total suppression of ERP. This technique was used to evaluate the effectiveness of carprofen and a second non steroidal anti-inflammatory (NSAID II) as an analgesic that may be added to 1080 bait for foxes. The effects on ERP of these two non-steroidal anti-inflammatory compounds were compared to the effect of butorphanol (a narcotic) as a positive control. A control group without analgesic was also included to monitor changes in ERP over time. A pulse of 15 electric stimuli just above the pain threshold (around 11 Volts) was administered while the foxes were under general anaesthesia. The resulting changes in brain activity were recorded as the ERP and were analysed following fast Fourier transformation. A total of 12 foxes were used, with 3 foxes per treatment. The results indicate that NSAID II shows some promise as an effective analgesic and 1080 bait additive for fox baiting.

Author Jongman, E.C.
Date null
Year 2001
Secondary title 12th Australasian Vertebrate Pest Conference
Place published Conference Location
Publisher Department of Natural Resources and Environment, M
Pages 322-325
Notes Notes
Control method Baiting
Region VIC