UK: End to CO₂ use in slaughter recommended by Animal Welfare Committee

The Animal Welfare Committee has recommended that CO₂ be phased out as a method for stunning pigs pre-slaughter within five years.

The independent advisory body, which advises Defra and the devolved administrations, has published an Opinion on the ‘welfare impacts on pigs of high concentration CO₂ gas stunning and of potential alternative stunning methods’.

The report states that exposure of conscious pigs to high concentrations of CO₂ is associated with three major welfare concerns: pain, respiratory distress and fear. The reports looks into the viability of other methods of stunning, including exposure to an inert gas mixture such as argon or nitrogen. It notes that there are ‘technical challenges’ to using inert gases in current CO₂ systems or with modification.

But it says immersion in argon ‘causes minimal immediate visible reaction, since these gases cannot be sensed directly by the pig’. “However, the induction of unconsciousness remains gradual, and it should be noted that all lethal Controlled Atmosphere Stunning mixtures are associated with some degree of welfare compromise,” the report says.

It adds that there is no welfare benefit of adding CO₂ to inert gases. The report also covers electrical stunning, captive bolt devices, pre-stun handling and considers issues around meat quality and costs and discusses the ethics of the different methods.

It makes a number of recommendations to government and industry, including:

• The use of CO₂, including in combination with inert gases, as a method of stunning for pigs should be prohibited to prevent pigs experiencing avoidable pain, distress or suffering at slaughter associated with high concentration.
• Any transition period given to industry to enable the change to alternative methods of slaughter should be as short as possible and in any case within five years. Industry should seek to implement the changes as quickly as possible.
• Slaughter lines should be approved to slaughter no more than a specified number of animals per hour, such that each animal has time to move through the system without the need for physical coercion.
• Legislation should be amended to require pigs to be kept in a small social group, preferably with animals from their rearing group, during lairaging and slaughter.
• Government and industry should encourage research into technologies, such as automated video monitoring systems, to assess animal welfare and to detect harms in animal handling, stunning and slaughter processes in the abattoir.