Tracy Turner, DVM, Dipl. ACVS, ACVSMR, of Turner Equine Sports Medicine and Surgery, in Stillwater, Minnesota, described alternative methods at the 2018 American Association of Equine Practitioners Convention, held Dec. 1-5 in San Francisco, California.
He said the current AVMA-recommended options each pose have associated risks.
Barbiturates are toxic to animals and the environment and don’t break down easily, even after a horse’s carcass has decomposed. “This stuff doesn’t seem to go away,” said Turner.
Therefore, it can end up in soil and groundwater and can poison wildlife and dogs that feed on carcasses that aren’t disposed of quickly. He pointed out that if you’re found to be responsible for an endangered or protected species’ death (say a bald eagle scavenges on your horse’s exposed carcass), you could be fined up to $25,000.
Barbiturate use also makes carcass disposal challenging, said Turner. Landfills, composting, and rendering facilities don’t always accept barbiturate-ridden carcasses due to the groundwater contamination risk. Cremation and digester facilities do but are very expensive.
“Gunshot and captive bolt are excellent euthanasia methods when done properly,” said Turner, but many vets aren’t trained to use them. This is not something veterinary students learn to do in school, he added.
Turner often does veterinary work with the Equitarian Initiative in developing countries, where he must get creative when it comes to euthanasia methods. When traveling in these regions, he typically doesn’t have access to powerful drugs or firearms. He said his goal then becomes devising an alternative method of euthanasia that is quick, reliable, and irreversible; induces loss of consciousness with minimal pain; and is safe for personnel to handle and possible predators to consume (sometimes, for instance, they feed the carcasses to starving dogs).
One way Turner said he achieves this is by administering an anesthesia drug, followed by a product that makes the horse’s heart stop.
“Anesthetics are good methods of euthanasia,” he said. “Drugs such as xylazine and ketamine are very reliable, readily available, easy to control, and quick,” and don’t pose an environmental issue, he added.
Turner said he anesthetizes the horse with these drugs to produce unconsciousness, then administers one of several other solutions or drugs, depending on availability, that will reliably result in death. Possible options include IV potassium chloride, magnesium chloride, or magnesium sulfate (all easy-to-acquire salts) and intrathecal (into the spinal canal) lidocaine. It takes only about three minutes for death to occur with the latter method, he said, while the others might cause physiologic responses such as muscle spasms and an agonal breath (an involuntary last gasping breath associated with nerve discharge to the diaphragm and breathing musculature).
In closing, Turner emphasized that the existing AVMA euthanasia guidelines have their problems. “Barbiturates create environmental and disposal problems, and gun and captive bolt require training,” he said. “Adjunctive techniques performed after inducing anesthesia offer a simple alternative that requires skills more typical of veterinary training and poses a lower risk of environmental toxicity.”