Gasstunning

Gasstunning, often written as gas stunning, is the practice of rendering animals insensible prior to slaughter by exposing them to specific gas mixtures. It is used in some abattoirs to handle large numbers, with pigs and poultry among the primary species, though other livestock may be stunned in this way.

Gases and approaches involve carbon dioxide, nitrogen, argon, or blends. Configurations vary from rapid exposure to high CO2 concentrations to progressive or partial exposure using inert gas to induce hypoxia. The choice of gas and timing influences the onset of unconsciousness and the welfare outcomes for the animals.

Welfare and regulation are central considerations. CO2 exposure can cause aversive sensations or distress before loss of consciousness in some cases, so protocols aim to minimize suffering and ensure uniform insensibility before bleeding. Regulations in many regions specify that animals must be effectively stunned prior to slaughter and often set standards for monitoring, ventilation, and worker safety.

Advantages and challenges include high throughput and reduced handling and physical injuries, especially in large operations. However, gas systems require significant capital investment, ongoing gas consumption, and robust safety and maintenance programs. Not all species respond equally to gas stunning, and gas handling logistics can complicate facility design.

Context and developments place gasstunning among the range of humane slaughter methods, alongside electrical and mechanical stunning. Ongoing research seeks to refine gas formulations and protocols to improve welfare outcomes, process efficiency, and cost-effectiveness.