Some neural and behavioural aspects of electrical and mechanical stunning in ostriches

摘要

Different electrical and mechanical stunning procedures were studied in ostriches to determine the effectiveness of the method. Fifty-eight South-African Black ostriches were equipped with EEG electrodes and stunned with three different electrical head-only methods and with a new captive needle pistol, using air pressure. The first stunning procedure consists of two tnals. In the first trial a total of 45 ostriches were stunned with a voltage of 200V (spiked electrodes) during 1 s. Unfortunately, in 10 animals the elec- trodes were disconnected. A general epileptiform insult on the EEG followed by recovery was observed in 20 ostriches. Another eight animals died after recovery and five showed an iso-electric line and were dead. The total duration of the insult was 25 ± 10 s. The measured current was 463 ± 120 mA. In the second trial a constant current of 400 mA was administered to 13 ostriches. In one animal the electrodes were disconnected. Eight out of 12 animals showed a general epileptiform insult, two of them showed an iso- electric line and two did not show the charactenstics of a general epileptiform insult. The total duration of the insult on the EEG was 21　± 8 s. The measured current was 365 ± 91 mA and the voltage 191 ± 27 V. During the second stunning procedure four and seven ostriches were stunned with 200 V (spiked electrodes) and 48 V (blunt electrodes), respectively, during approx. 6 s. They all died. In addition, a group of 20 ostriches stunned with captive needle pistol using air pressure showed unconsciousness after stunning by the appearance of theta and delta waves tending to an iso-electric line on the EEG trace. It is recommended to use at least 500 mA to stun ostriches effectively and to use a short stun-stick interval or to kill them by a long stunning duration. The captive needle pistol, using air pressure, can be an alternative for electrical head-only stunning.