Evaluation of Oral Transmucosal Administration of Pentobarbital for Euthanasia of Conscious Wild Birds

This prospective study evaluated oral transmucosal pentobarbital sodium at three doses in 110 wild-caught wild birds requiring euthanasia. Birds received transmucosal pentobarbital at five (430 mg/kg), six (516 mg/kg), and seven times (602 mg/kg) the intravenous dose for mammals. Time to first effects and loss of consciousness, presence of pupillary light and corneal reflexes, apnea, and asystole were recorded each minute. When asystole was not achieved at 5 minutes, IV pentobarbital was administered. Combining data for all doses, loss of consciousness occurred at a median (range) of 2 minutes (0-4.75 min), apnea at 3 minutes (0-6 min), and asystole at 4 minutes (0.5-5 min). Loss of consciousness and apnea occurred significantly faster in the 602 mg/kg dose group than in the 430 mg/kg group (p = 0.009, difference of 0.6 ± 0.2 min; p = 0.024, difference of 0.7 ± 0.3 min), respectively. Apnea and asystole were achieved in 80/110 birds within 5 minutes. Oral transmucosal pentobarbital results in rapid loss of consciousness and respiratory arrest and provides a reliable alternative euthanasia method compared to intravenous administration.