TIME TO LOSS OF SOMATOSENSORY-EVOKED POTENTIALS AND ONSET OF CHANGES IN THE SPONTANEOUS ELECTROENCEPHALOGRAM OF TURKEYS DURING GAS STUNNING

The times to the loss of somatosensory evoked potentials (SEPs) and th e onset of suppressed and isoelectric electroencephalogram (EEG) were investigated in turkeys as they were stunned with gas mixtures consist ing of one of three mixtures: (A) 30 per cent carbon dioxide and 60 pe r cent argon in air (2 per cent residual oxygen and 8 per cent residua l nitrogen); (B) 90 per cent argon in air (2 per cent residual oxygen and 8 per cent residual nitrogen); (C) 65 per cent carbon dioxide in a ir (7 per cent residual oxygen and 28 per cent residual nitrogen). The time to the loss Of SEPS, EEG suppression and the onset of an isoelec tric EEG, respectively, were 22, 16 and 35 seconds in mixture A, 44, 4 1 and 101 seconds in mixture B, and 15, 15 and 67 seconds in mixture C . Stunning turkeys with mixture A or B would be suitable under commerc ial conditions. Mixture C, containing 65 per cent carbon dioxide in ai r, is considered on humanitarian grounds to be unacceptable for stunni ng turkeys owing to the pungency of the carbon dioxide at this concent ration.