Equine Gunshot Euthanasia: Creation of a 3D-Printed Model with Integrated Sensors for Training

SIMPLE SUMMARY: When conditions make it necessary to end a horse’s life, it must be accomplished in a humane manner. Intravenous administration of an overdose of a concentrated barbiturate anesthetic agent has been the most common method for providing a humane ending in horses. However, due to emerging public safety, barbiturate supply constraints, and environmental reasons, alternative methods for providing humane endings for horses and other large animals are required today. A gunshot correctly delivered to the brain has been shown to be an effective option. It is critical the gun be aimed correctly for the gunshot to destroy specific structures in the brain ensuring instantaneous, permanent unconsciousness and death. Despite the availability of aiming guidelines, studies examining bullet trajectories in animals euthanized by gunshot have identified issues related to incorrect aiming leading to unreliable disruption of the brain structures to ensure a quick and humane death. The availability of a training model and establishment of training guidelines for practitioners to gain proficiency with gunshot euthanasia prior to performing the procedure on animals in the field would correct this welfare issue. This paper describes the development of a 3D-printed, anatomically accurate, economically scalable, and portable model for training in successful humane gunshot euthanasia. ABSTRACT: Challenges and issues related to the use of pentobarbital euthanasia and disposal of animal remains within the US have recently been reviewed. Environmental and public health challenges increasingly necessitate consideration of alternative methods such as gunshots, an American Veterinary Medical Association (AVMA) “acceptable with conditions” method, for the humane euthanasia of horses. A recent study reported a correctly aimed gunshot provides a humane option for euthanizing horses. However, although aiming guidelines exist, studies examining bullet trajectories in animals euthanized by gunshot have reported that inadequate disruption of the brain is a serious welfare issue. Here, we report the development and production of a portable, reusable, equine gunshot euthanasia training model. Using 3D printing, an anatomically accurate model of an equine head has been developed, with external aiming landmarks and equipped with integrated laser sensors and LED eyes. The laser sensors are embedded in two specific anatomical tracts (pons and medulla) with aiming paths associated with the aiming landmarks to train correct aiming angle. The LED eyes are linked to the laser sensors to provide instant feedback on aiming accuracy. When a beam from a commercially available blue training gun laser travels along the correct aiming path and strikes the sensor inside the head, the lights in the model’s eyes go out and there is an audible signal, providing immediate feedback on the accuracy of the shot. The model facilitates the training of veterinary personnel and first responders in successful gunshot euthanasia, providing instantaneous feedback on the likelihood of a shot causing immediate, humane death in a live animal.