Insensibility during slaughter of pigs in comparison to other domestic stock

Authors: Blackmore DK, Newhook J
Publication: New Zealand Veterinary Journal, Volume 29, Issue 12, pp 219-222, Dec 1981
Publisher: Taylor and Francis

Animal type: Livestock, Pig, Production animal
Subject Terms: Animal welfare, Animal handling, Nervous system/neurology, Slaughter
Article class: Scientific Article

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Abstract: The onset of insensibility during slaughter was studied in five, 31-day-old pigs. The state of sensibility was determined from the study of electroencephalograms (EEC) which were of a bipolar transhemispheric derivation. In 3 pigs slaughtered by bilateral severance of both common carotid arteries and jugular veins, it was judged that insensibility occurred within 25s and there was no resurgence of cerebrocortical activity following subsequent respiratory gasps. The EEGs became isoelectric within 115s. These results are compared with previous findings by the authors that adult sheep and lambs slaughtered by similar techniques became insensible within 7s whereas, in calves, the onset of insensibility was delayed for up to 85s and there were resurgences of cerebrocortical activity, following a respiratory gasp, for more than 300s. These differences in the apparent onset of insensibility in the 3 species of animal are discussed in relation to the anatomical features and possible dynamics of the blood supply to the brain during slaughter. It is concluded that for humane reasons, “head-to-back” electrical stunning of pigs is preferable to a “head-only” method.

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