Wefare implications of gas stunning pigs 1. Determination of aversion to the initial inhalation of carbon dioxide or argon

Abstract

The aversive effects of 90% argon in air, 30% carbon dioxide in air or 90% carbon dioxide in air were investigated in 16 slaughter weight pigs. Aversion was assessed from their reluctance to enter the 3 gaseous atmospheres to obtain a reward (apples). The pigs did not show any aversion to the inhalation of 90% argon in air. The majority of the pigs did not show aversion to the presence of 30% carbon dioxide in air. However, the inhalation of 90% carbon dioxide was aversive to most pigs. Deprivation of food for 24 h prior to testing did not overcome the pigs' reluctance to enter an atmosphere containing 90% carbon dioxide.