The establishment of guidelines and protocols for the use of firearms in the euthanasia of cattle is essential because unsuccessful attempts at euthanasia are inhumane and demoralizing. Failure of euthanasia by gunshot can lead to operator reticence1; however, delaying the decision to euthanize an animal prolongs its suffering and, in regard to euthanasia for control of a catastrophic infectious or foreign animal disease outbreak, can slow depopulation efforts and thus potentially exacerbate the risk of infection for other animals.
The use of firearms for the euthanasia and depopulation of cattle has precedence and is approved by both the AVMA2,3 and the American Association of Bovine Practitioners.4 Nevertheless, studies conducted to establish recommendations on which firearm and ammunition combinations routinely result in satisfactory euthanasia as well as minimize the risk of harm to operators and bystanders are lacking. The amount of energy that must be carried by a projectile to penetrate the skulls of various livestock species varies greatly.5 The caliber of the firearm and the various properties associated with the round being fired play a major role in whether the projectile achieves sufficient penetration of the skull and produces lethal brain damage.6 In 1 study,6 6 firearms and 11 types of ammunition were assessed to determine the effectiveness of the projectile to penetrate and cause brain tissue destruction in cattle; however, only 3 of the 11 trials performed had > 1 replicate, and there were insufficient data available for a valid statistical analysis. Effective skull penetration was not achieved in any of the trials that involved a .22-caliber long rifle in that study.6 Results of other studies7–9 indicate that the use of firearms for the euthanasia of sheep, cattle, and pigs is safe.
Novel approaches for the euthanasia of cattle in the field are necessary for many reasons. In the event of a catastrophic infectious or foreign animal disease outbreak in a geographic region densely populated with cattle, results of a simulation modeling study10 suggest that the required euthanasia rate is approximately 3 times as great as the available capacity to perform euthanasia, which will exacerbate the magnitude of the epidemic. Estimates of the time required to depopulate a typical Midwestern beef feedlot by use of a conventional captive bolt range up to 80 days,a which is unacceptably slow in the event of an infectious disease outbreak. The use of firearms for euthanasia could help decrease the time required for depopulation of large numbers of cattle. Cattle populations are growing increasingly concentrated both by geographic region and the number of cattle per premises. This consolidation results in a high number of cattle having intimate contact with each other and their human caretakers, thus increasing the potential for foreign animal and zoonotic disease transmission. The consolidation of a greater number of cattle on fewer premises also increases the number of cattle per premises that will require euthanasia under normal production conditions. On a per-premises basis, approximately 0.4% of beef and dairy cattle will become nonambulatory at some time,11 which means that large operations will likely have cattle with debilitating conditions that require euthanasia on a continuous basis, whereas smaller operations may rarely or only intermittently have a small number of cattle that require euthanasia.
The ban on the slaughter of nonambulatory cattle at commercial abattoirs has likely resulted in an increase in the number of cattle euthanized in the field.8 In a survey12 of 19 abattoirs and 3 auction markets in Canada, it was estimated that of the nonambulatory cattle that arrived at those facilities, < 1% (74/7,382) became debilitated during transit, which suggests that most cattle become nonambulatory on the farm. Although it is important to educate cattle producers on methods to prevent and care for nonambulatory cattle, it is equally important to provide them with evidence-based recommendations for proper equipment and procedures for euthanasia of such cattle when necessary.
The use of firearms for euthanasia of cattle is practical because nearly every cattle operation has access to firearms directly (owner or manager) or indirectly (employees or neighbors). However, published research regarding which firearms and ammunitions are appropriate for euthanasia of cattle is lacking, and replication and statistical analyses are limited in the research that is available. Moreover, imaging methods for the heads of cattle have improved such that in situ evaluation of the cranial cavity, brain, and projectile location following a gunshot can be performed. The purpose of the study reported here was to determine, by the use of CT, the efficacy of various combinations of commonly available firearms and ammunitions to penetrate and disrupt the brain tissue of cadaveric heads of feedlot steers.
Automatic Colt pistol
Rooney JA. Response to an FMD outbreak: use of vaccination in control strategies (oral presentation). 4th Annu Cross Border Livest Health Conf, Portland, Ore, July 2011. Available at: www.cblhconference.com/pdf/2011-pres-Response-FMD-outbreak.pdf. Accessed Jun 27, 2013.
Marlin Model 60, Marlin Firearms Co, Madison, NC.
Aguila Super Maximum, Centurion Ordnance Inc, Helotes, Tex.
Bushmaster M4A3 Type Carbine, Bushmaster Firearms International, Madison, NC.
Hornady V-Max, Hornady Manufacturing Co, Grand Island, Nev.
Ruger P-89, Sturm, Ruger & Co Inc, Newport, NH.
Lawman Ammunition, Ammunition Accessories Inc, Lewiston, Ind.
M1911A1, Springfield Armory, Geneseo, Ill.
.45 ACP, Federal Cartridge Co, Anoka, Minn.
Remington 870 Wingmaster, Remington Arms Co, Madison, NC.
Federal Heavy Field Load, Federal Cartridge Co, Anoka, Minn.
Winchester Super-X Power Point, Winchester, East Alton, Ill.
Excel 2007, Microsoft Corp, Redmond, Wash.
Shooting Chrony Inc., Mississauga, ON, Canada.
General Electric CTI, GE Medical Systems, Milwaukee, Wis.
SAS, version 9.2, SAS Institute Inc, Cary, NC.
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