The aversiveness of carbon dioxide stunning in pigs and a comparison of the CO2 stunner crate vs. the V-restrainer

Abstract

Using aversion learning techniques, the relative aversiveness of CO2 to pigs in comparison to a shock with an electric prodder, and the aversiveness of a CO2-stunner crate in comparison to the aversiveness of a V-belt restrainer used for electric stunning were examined. The results showed that 90% CO2 was considerably less aversive than an electric shock with a prodder. However, during exposure to 90% CO2 all pigs lost conscious, which may have affected their memory of the procedure. The pigs remained conscious after exposure to 60% CO2 and again showed virtually no aversion towards the stunner crate, while an electric shock with a prodder appeared highly aversive. The aversion to the V-rest..