Achieving humane outcomes in killing livestock by free bullet I: Penetrating brain injury.

Humane killing of farm animals by free bullet is a commonly used second-best option in emergency situations and disease control operations. Theoretical justification has been weak in experimental reports of firearm system use in the field. Veterinarians require an in-depth understanding of killing with free bullet to take corrective action when systems fail under field application. This review describes the technical considerations in choosing safe, effective firearm systems to effectively kill minimally restrained livestock at close range. Frequently referenced firearm/bullet recommendations are excessively powerful and unnecessarily hazardous. Based on ballistic energetic performance and mechanical design, the rifle chambered for low energy pistol ammunition, using non-toxic controlled expanding bullets, has the technical capability to deliver immediate insensibility and death at a distance of 5 m or less. At 1 m distance, the .410 shotgun with steel or porcelain shot meets the environmental safety, ballistic, and mechanical challenges and has workplace safety advantages over rifle-based systems.