Euthanasia of young pigs with carbon monoxide

In experiments with carbon monoxide euthanasia in 30 piglets, carbon monoxide was administered rapidly (five to 10 minutes), slowly (45 minutes) or in combination with nitrous oxide (15 minutes). When carbon monoxide was administered at a fast flow rate, visual signs of severe excitation were observed (sometimes before unconsciousness). With low carbon monoxide flow rates, and in particular, when carbon monoxide was combined with nitrous oxide, excitation was less evident and only occurred after unconsciousness.