Evaluation of a protocol for determining the effectiveness of pretreatment with local analgesics for reducing experimentally induced articular pain in domestic fowl.

An experimental paradigm based on the microcrystalline sodium urate-induced arthritis model was developed for determining the effectiveness and optimum dose of drugs with potential local analgesic properties for the diagnosis and alleviation of musculoskeletal pain in birds. The optimum intra-articular injection of sodium urate was 6 mg in 0.2 ml diluent in 12-week-old male domestic fowl of 1.5 kg live weight. The response criteria were changes in behavioural profiles over 60 minutes commencing one hour after intra-articular injection. The testing system was used to determine the optimum rate of intra-articular application of the local anaesthetic bupivacaine hydrochloride. The behavioural profile of treated birds was restored to that of the controls at a minimal injection of 3 mg in 0.3 ml saline. It was concluded that the optimum intra-articular dose of bupivacaine for the treatment of musculoskeletal pain in the domestic fowl was 3 mg bupivacaine in 0.3 ml saline.