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

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 trials. In the first trial a total of 45 ostriches were stunned with a voltage of 200V (spiked electrodes) during 1s. Unfortunately, in 10 animals the electrodes 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±10s. The measured current was 463±120mA. In the second trial a constant current of 400mA 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 characteristics of a general epileptiform insult. The total duration of the insult on the EEG was 21±8s. The measured current was 365±91mA and the voltage 191±27V. During the second stunning procedure four and seven ostriches were stunned with 200V (spiked electrodes) and 48V (blunt electrodes), respectively, during approx. 6s. 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 500mA 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.

[1]  E. Lambooij.  Electrical stunning by direct brain stimulation in pigs. , 1994, Meat science.

[2]  A. Forslid.  Transient neocortical, hippocampal and amygdaloid EEG silence induced by one minute inhalation of high concentration CO2 in swine. , 1987, Acta physiologica Scandinavica.

[3]  C H Veerkamp,et al.  The effects of alternative electrical and mechanical stunning methods on hemorrhaging and meat quality of broiler breast and thigh muscles. , 1996, Poultry science.

[4]  M. Raj,et al.  An evaluation of humane gas stunning methods for turkeys , 1994, Veterinary Record.

[5]  E. Lambooy,et al.  Electrical stunning of veal calves. , 1982, Meat science.

[6]  S. Wotton,et al.  Changes in the somatosensory evoked potentials and spontaneous electroencephalogram of hens during stunning with a carbon dioxide and argon mixture. , 1992, The British veterinary journal.

[7]  S. Wotton,et al.  The design of pig stunning tong electrodes-A review. , 1997, Meat science.

[8]  S. Wotton,et al.  Effect of electrical stunning on somatosensory evoked responses in the turkey's brain. , 1991, The British veterinary journal.

[9]  N. Gregory,et al.  Wefare implications of gas stunning pigs 1. Determination of aversion to the initial inhalation of carbon dioxide or argon , 1995 .

[10]  D. Blackmore,et al.  Slaughter of stock , 1988 .

[11]  J. Sales,et al.  Ostrich meat : a review , 1996 .

[12]  J. McKinstry,et al.  Electrical stunning in commercial rabbits: Effective currents, spontaneous physical activity and reflex behaviour. , 1998, Meat science.

[13]  W. Yasaka,et al.  Postdecapitation convulsions and their inhibition by drugs , 1975, Experimental Neurology.

[14]  D. S. Hale,et al.  Ostrich Slaughter and Fabrication.2. Carcass Weights, Fabrication Yields, and Muscle Color Evaluation , 1995 .