BEHAVIORAL AND CARDIOVASCULAR-RESPONSES OF RATS TO EUTHANASIA USING CARBON-DIOXIDE GAS

Our results showed more rapid falls in pulse rate and blood pressure i n rats euthanized in a chamber precharged with carbon dioxide (CO2), w hen compared with rats euthanized more slowly, but death still took ov er 5 min in the former group. There was no behavioural evidence of pai n or distress in either group during euthanasia. Initial ataxia and dy spnoea was punctuated by a lag before death, thus separating euthanasi a into three clearly defined phases.;All visual signs of death precede d complete vascular collapse by about 1 min in both groups, so we reco mmend that gas flow be maintained for at least 1 min after apparent de ath.