Determining the efficacy and safety of differing caliber/ammunition combinations for the humane euthanization and subsequent mass depopulation of market weight pigs.

The global pandemic attributable to the COVID-19 virus has severely disrupted the U.S. pork supply chain over the past few months as many packer/processors have closed and(or) restricted their scope of operations due to a limited labor force. As a consequence, the production flow of millions of market weight pigs has been stymied as producers now have few to no options for marketing animals that are quickly outgrowing their finishing barns and(or) taking the place of young pigs intended to move into these facilities. Tragically, producers are now faced with the decision of mass euthanasia and the subsequent depopulation of their finishing barns. Knowing this, it is imperative that producers are provided with a number of viable options for the safe and efficacious euthanization of market weight pigs, one of which is gunshot.

As on-farm mass depopulation of market weight pigs increases, many producers are turning to the use of a firearm as an approved method of euthanasia.1 There is an abundance of historical information on the general considerations of humane euthanasia, human safety considerations, and proper firearm placement.1,2 More recently, scientific data has been generated to further define proper caliber and ammunition selection to achieve a minimum of 300 feet-pound (ft-lb) for predictable humane euthanasia by gunshot (for animals up to 400 pounds).3 Nevertheless, there is little to no information illustrating both the efficacy and safety of the use of a firearm when using the multiple caliber/ammunition combinations currently available (.22 LR, .22 Mag, .38 Special, 9mm) nor is there a definitive methodology for assessing said efficacy and safety concerns. This lack of information has been exacerbated by a recent yet unpredictable increase in consumer demand for the lead round nose (LRN) and jacketed hollow point (JHP) bullets leaving the full metal jacket (FMJ) bullet as the only readily available option in each of the aforementioned calibers. Hence, a “proof of concept” exercise predicated upon the ability to conceptualize and subsequently evaluate the effectiveness and safety of multiple caliber/ammunition combinations is in fact warranted and of need to the swine industry now and in the event of a future foreign animal disease outbreak.

Key Findings:

1) Application of the novel methodologies described within this report generated valid data to define efficacy and safety considerations when using a firearm to euthanize market weight pigs.

2) The measurable trauma area of the brain was greater for the 9mm and .38 Special bullets when compared to both the .22 LR or .22 Mag bullets.

3) The .22 LR FMJ bullet fired from a 16-inch barrel (at ~140 ft-lb energy) can provide predictable humane euthanasia by gunshot in market weight pigs with minimal risk of contralateral emergence.

4) .38 Special and 9mm FMJ bullets (at >300 ft-lb energy) created saftey concerns as bullets emerged from the contralateral side of the head.

5) Under ideal conditions in which each head was securely fastend to a solid surface, anatomical anomalies and subtle differences in bullet placement resulted in a 95% success rate of brain penetration.

Conclusions:

The information obtained from this proof of concept exercise illustrates the ability to consistently evaluate and subsequently quantify the effectiveness of a FMJ bullet fired into the forehead of a market weight pig using each of four caliber rifles (.22 LR, .22 Mag, 0.38 Special, 9mm). Moreover, these findings demonstrate 1) the variation in penetrative depth and bullet conformational change both among and within a given caliber/ammunition combination and 2) the relative safety or lack thereof when using firearms as a means of mass euthanization. Further work is needed to ascertain differences in euthanization efficacy and safety when using not only the full metal jacket (FMJ) but also the lead round nose (LRN) and jacketed hollow point (JHP) bullets. Of note, the observed anatomical differences in brain size and location would suggest that proper placement of a firearm and(or) captive bolt gun as directed using current scientific literature and industry recommendations may in fact not render an animal unconscious and insensible to pain one hundred percent of the time (95% effectiveness under the ideal conditions of this study).