Evaluation of the tranquilliser trap device (TTD) for improving the humaneness of dingo trapping

Abstract

Predation of sheep and cattle by the dingo (Canis lupus dingo) is implicated in significant stock losses throughout much of mainland Australia. Leg-hold traps are commonly used for dingo control and ways are sought to improve the humaneness of these devices. We evaluated the performance of the tranquilliser trap device (TTD) attached to Victor Soft-Catch® traps for their ability to deliver a sedative and anxiolytic drug to trapped dingoes. A trapping programme was conducted in south-west Queensland where traps were set alternatively with a TTD containing either 800 mg of diazepam (drug TTD) or a placebo (placebo TTD). All TTDs included 20 mg of the bait marker iophenoxic acid (IPA) to ascertain dosing success. Each trap was fitted with an activity-monitoring data logger that recorded time of capture and subsequent dingo activity. In 41 out of 48 (85.4%) captures the TTD was ruptured and released its contents. No elevation in serum iodine levels above I mg ml-1 resulting from the ingestion of IPA occurred in 8 out of 36 (22.2%) captures, which suggests a higher rate of dosage failure. Dingo activity was highest in both groups immediately after capture, but declined after the first hour in each. The activity of dingoes that accepted a drug TTD was significantly reduced compared to those that took the placebo. However, tooth and limb damage scores did not differ significantly between the drug and placebo group. Much of the physical trauma may have occurred within the first hour of capture when activity was intense and before drug onset in the TTD drug group. The use of TTDs containing sedative and anxiolytic drugs has the potential to reduce anxiety and distress associated with prolonged captivity, but the delivery of a lethal agent that is rapidly acting and humane may result in better welfare outcomes.