Computed tomographic assessment of brain tissue disruption and skull damage in equine cadaveric heads caused by various firearm-ammunition combinations applied as potential gunshot methods for euthanasia of horses.

The study conducts a computed tomographic evaluation of the brain tissue disruption and skull damage in adult horse cadaver heads using different firearm-ammunition combinations. The research then examines the effectiveness of the said combinations when applied at a novel anatomic aiming point, to determine their suitability for equine euthanasia.

Research Design and Methodology

• The research used 53 cadaveric heads of adult horses and applied six different firearm-ammunition combinations at a novel anatomical aiming point. This point was defined along the external sagittal crest of the head where the two temporalis muscles form an inverted V.
• The different firearm-ammunition combinations used were a .22-caliber long rifle pistol (firing a 40-grain, plated lead, solid-core or hollow-point bullet); a semiautomatic 9-mm pistol firing a 115-grain, jacketed hollow-point bullet; a semiautomatic .223-caliber carbine firing a 55-grain, jacketed hollow-point bullet; a semiautomatic .45-caliber automatic Colt pistol; and a 12-gauge shotgun firing a 1-oz rifled slug.
• For some tests, additional cadaveric heads were placed in a sideways recumbent position and shot with the semi-automatic 9-mm pistol-hollow-point bullet combination.
• All the cadaveric heads were assessed using CT before and after being shot. The resulting images were then evaluated for fragmentations of the shot, skull fractures, and disruptions in the cerebrum, cerebellum, and brainstem.

Findings and Conclusions

• The CT evaluations revealed that all firearm-ammunition combinations caused sufficient disruption in the cerebrum, cerebellum, and brainstem that was comparable to the immediate death of a live horse.
• The study also found that hollow-point ammunition was as effective as solid-core ammunition in terms of causing brain tissue disruption. The position of the head at the time of the shots did not affect the level of brain tissue disruption.
• The research concluded that, when applied at the novel anatomical aiming point, all the tested firearm-ammunition combinations would be suitable for the euthanasia of horses.