Captive Bolt Euthanasia Advice

Iowa State University professor of veterinary medicine Jan Shearer says he takes seriously the portion of the Veterinary Oath that pledges one’s knowledge and skills for “the prevention and relief of animal suffering.”

“Unfortunately, there are things from which we cannot provide relief,” he states. “Euthanasia is a necessary reality of animal agriculture.”

Shearer, who also is past president of the Dairy Cattle Welfare Council (DCWC), recently presented a DCWC webinar on “Best practices and training for on-farm euthanasia.” He discussed the three approved methods of euthanasia for cattle included in the American Veterinary Medical Association (AVMA) and American Association of Bovine Practitioners (AABP) euthanasia guidelines.

Of the three methods, he said administration of a captive bolt to the skull is preferable in a number of ways. “It is safer to human handlers than using a firearm, and avoids the cost; animal disposal difficulties; and record-keeping challenges incurred when using intravenous anesthetics such as barbiturates,” he stated.

Shearer cautioned, though, that administration of penetrating or non-penetrating captive bolts must be done effectively to achieve the most humane outcome. His advice:

1. Restrain the animal. Even very sick cattle may be head-shy and move during the procedure. Always put a halter on the animal first.
2. Position the device correctly. Unlike a firearm, a captive bolt gun should be placed directly against the skull. Position the device perpendicular to the face, at the intersection of two imaginary lines drawn from the outside corner of the eye to the base of the opposite horn. Another way to explain the correct position is to aim directly between the ears.
3. Clean and maintain the device routinely. Research by noted animal behavior specialist Temple Grandin has found that the gun powder charged captive bolts on some farms may not be properly maintained (i.e. are rusty, dirty or otherwise impaired). This can slow the speed of the bolt and cause ineffective results and unnecessary animal suffering. Damp cartridges also can produce a softer shot, so store bolts in a cool, dry, clean environment. For pneumatic stunners, low air pressure can be a cause of soft shots. 
4. Follow up with a secondary method. A properly administered captive bolt will render an animal immediately unconscious, but may not cause death.  Complete euthanasia requires following up with exsanguination, pithing, rapid intravenous administration of saturated potassium chloride solution; or, a second or even third bolt shot with the captive bolt. Always be sure the animal is completely expired before leaving it by assuring the heart has stopped.  Note that the heart may beat for 7-8 minutes even when a good shot has been administered.  The heart beat is not controlled by the brain; rather the sino-atrial node in the right atrium of the heart, so the heart will continue to beat until anoxia (lack of oxygen) stops the heart muscle. 
5. Use non-penetrating captive bolts for young calves only.  This less-invasive method works well for young animals, but is not powerful enough to effectively do the job in adult cattle.

Shearer recommends working with your veterinarian to train farm employees on proper euthanasia techniques. For the captive bolt method, he advises that the person using the tool also should be responsible for cleaning it after every use.

He also is a strong proponent of recognizing individuals for their achievement of completing training in euthanasia. “Appreciation is a fundamental human need,” he said. “By recognizing workers’ completion of euthanasia training, you will create a source of pride for them, and likely improve their implementation.” Shearer noted that euthanasia training and documentation also are required in most animal welfare audits.

The Iowa State University College of Veterinary Medicine has a website on humane euthanasia that covers all of the steps of captive bolt administration and equipment maintenance. Also included are a number of helpful euthanasia resources and training tools in English and Spanish that can be downloaded for free.