Vertebrate pests control still relies on the use of poisons that are linked with secondary poisoning or are considered inhumane. Stoat (Mustela erminea) control is conducted in New Zealand to protect kiwi chicks from predation. Para-aminopropiophenone (PAPP) is being investigated for more humane culling. Research to test the humaneness was undertaken in cage experiments followed by field efficacy trials. Fifteen individually housed stoats were presented with 5-10 grams of meat with PAPP (12.8 mg) added in the form a 40% PAPP paste. The PAPP paste was added prior to presenting the meat "bait" to the stoats. PAPP impregnated meat was palatable and eaten by stoats. All 15 stoats died after eating bait. Onset of symptoms occurred on average 17 minutes after eating the meat containing PAPP. Death occurred after a short period of lethargy and unconsciousness in an average time of 44 minutes, and symptoms demonstrated PAPP to be humane and effective. Subsequently field trials over two 1,500 hectare blocks of native bush PAPP paste produced 90% reductions in stoat populations. PAPP represents the first new active ingredient to be developed as a vertebrate pesticide for 30 years and the only one with humaneness as the primary consideration. The dose is optimised to reduce oxygen supply to the brain such that stoats become lethargic, sleepy and unconscious prior to death within 1 hour.
These pen and field studies were conducted with the approval of the Lincoln University Animal Ethics Committee. AEC approval numbers were 145 and 190 respectively.