[The use of T61 for the humane killing of pets and laboratory animals]

Experiments were carried out to determine the onset of loss of consciousness and muscle relaxation following administration of the euthanising agent T61. Simultaneous recordings of EMG, EEG, ECG and capnogram (dogs only) were obtained in acutely instrumented rabbits and dogs. The results showed that loss of consciousness and muscle activity occurred simultaneously following administration of T61. Vocalisation and increased muscle movement occurred both when T61 and butyramide were used in the initial phase of the injection in three out of eight dogs. From this study, it was concluded that the presence of the muscle relaxant does not pose an ethical problem for the use of T61 as euthanising agent, though the results suggested that the use of T61 may have some emotionally unpleasant side-effects.