Abstract
The process of CO2 euthanasia on mouse, rat, guinea pig and rabbit was observed using a CO2 euthanasia cabinet. The cabinet was filled with CO2 gas and the caged animal was placed into the cabinet. These animals quietly collapsed and their respiratory movement ceased within 25-225 seconds. A-V block was the first arrhythmia recognized on ECG in all cases. The arrhythmia recorded on ECG included complete A-V block, A-V dissociation, ventricular escape rhythm, atrial fibrillation, ventricular flutter and ventricular fibrillation. It could be concluded that euthanasia was satisfactorily performed on these species by means of the CO2 euthanasia cabinet.