A Two-Step Process of Nitrous Oxide before Carbon Dioxide for Humanely Euthanizing Piglets: On-Farm Trials

The current approved method of using carbon dioxide (CO2) to euthanize newborn piglets is raising animal welfare concerns on whether the method is truly humane. A new form of euthanasia that is humane, practical, and socially acceptable is needed. Nitrous oxide (N2O), also known as laughing gas, has been shown to induce narcosis in piglets. We used a novel two-step system of exposing compromised piglets for six minutes to N2O followed by carbon dioxide and compared it to using CO2 alone. After exposure to nitrous oxide, all piglets lost posture, a sign of the onset of loss of consciousness, before being exposed to CO2 when they showed behavioral distress. On-farm use of a two-step method reduced the amount of time the piglets were exposed to CO2 but did not reduce the amount of distressful behaviors. Therefore, the results do not support the hypothesis that using N2O in a two-step system is more humane than CO2 alone