Further Examination of the Performance of Blank Cartridges Used in Captive Bolt Devices for the Pre-Slaughter Stunning of Animals

Simple Summary Since their advent in 1904, captive bolt devices have been used in abattoirs in Europe to produce an unconscious state in cattle prior to bleeding, to ensure that they suffer no pain during the process. These devices employ a single-use cartridge containing a propellant and no bullet (known as a blank cartridge) to rapidly provide a large quantity of gas through chemical combustion. This gas propels a piston (captive bolt) onto the head of the animal to produce a concussion that is severe enough to produce rapid brain dysfunction, preventing the brain from operating at a state where pain can be perceived by the animal. Subsequent penetration of the bolt is designed to prevent recovery from the stunned state by producing further mechanical damage to the brain. This paper examines and discusses variations in the performance of some blank cartridges in producing sufficient velocity and therefore energy to stun animals, thereby affecting animal welfare at slaughter. Blank cartridges produce gas through deflagration and are used as the main power source in captive bolt devices used within abattoirs and on farms in Europe. The European legislation recognises this and requires users to follow manufacturers' recommendations in terms of which power cartridge to use. Variation in cartridge performance of Eley (E) cartridges was found in previous research, which was published before Accles and Shelvoke (AS) started full production of their own cartridges. This work examined cartridge performance, structural integrity and dimensional tolerances, and found that the new AS cartridges that varied more greatly in performance in terms of velocity, kinetic energy and mechanical stability of casing than the more established E cartridges. In this study, 15% of the cartridges split at the primer flange on firing, resulting in less kinetic energy, which could impact the ability of the captive bolt to produce a successful stun. This, combined with the variation in performance in a primary component of a device that should have a uniform performance, could lead to animal welfare issues as this variation cannot be predetermined by examination of the cartridge pre firing.