Summary of Conditionally Acceptable Agents and Methods of Euthanasia - Characteristics and Modes of Action |
| Agents |
Classification |
Mode of action |
Rapidity |
Ease of performance |
Safety |
Species suitability |
Efficacy and comments |
| Blow to head |
Physical damage to brain |
Direct concussion of brain tissue |
Rapid |
Requires skill, adequate restraint, and appropriate force |
Safe |
Young pigs < 3 weeks old |
Must be properly applied to be humane and effective |
| Carbon dioxide (bottled gas only) |
Hypoxia due to depression of vital centers |
Direct depression of cerebral cortex, subcortical structures and vital centers; direct depression of heart muscle |
Moderately rapid |
Used in closed container |
Minimal hazard |
Nonhuman primates, free ranging wildlife |
Effective, but time required may be prolonged in immature and neonatal animals |
| Carbon monoxide (bottled gas only) |
Hypoxia |
Combines with hemoglobin, preventing its combination with oxygen |
Moderate onset time, but insidious so animal is unaware of onset |
Requires appropriately maintained equipment |
Extremely hazardous, toxic and difficult to detect |
Nonhuman primates, free ranging wildlife |
Effective, acceptable only when equipment is properly designed and operated |
| Cervical dislocation |
Hypoxia due to disruption of vital centers |
Direct depression of brain |
Moderately rapid |
Requires training and skill |
Safe |
Poultry, birds, lab mice, and rats (< 200 g) or rabbits (<1 kg) |
Irreversible. Violent muscle contractions can occur after cervical dislocation |
| Chloral hydrate |
Hypoxia from depression of respiratory center |
Direct depression of brain |
Rapid |
Personnel must be skilled perform IV injection |
Safe |
Horses, ruminants and swine |
Animals should be sedated prior to administration |
| Decapitation |
Hypoxia due to disruption of vital centers |
Direct depression of brain |
Rapid |
Requires training and skill |
Guillotine pose potential employee injury hazard |
Laboratory rodents, small rabbits, birds, some fish, amphibians, and reptiles (latter 3 with pithing) |
Irreversible. Violent muscle contraction can occur after decapitation |
| Electrocution |
Hypoxia |
Directdepression of brain and cardiac fibrillation |
Can be rapid |
Not easily performed in all instances |
Hazardous to personnel |
Used primarily in foxes, sheep, swine, mink (with cervical dislocation), ruminants, animals <5 kg |
Violent muscle contractions occur at same time as loss of unconsciousness |
| Gunshot |
Hypoxia due to disruption of vital centers |
Direct concussion of brain tissue |
Rapid |
Requires skill and appropriate firearm |
May be dangerous |
Large domestic and zoo animals, reptiles, amphibians, wildlife, cetaceans (<4 meters long) |
Instant unconsciousness, but motor activity may continue |
| Inhalant anesthetics |
Hypoxia due to depression of vital centers |
Direct depression of cerebral cortex, subcortical structures, and vital centers |
Moderately rapid onset of anesthesia; excitation may develop during induction |
Easily performed with closed container; can be administered to large animals by means of a mask |
Must be properly scavenged or vented to minimize exposure to personnel |
Nonhuman primates, swine |
Highly effective provided that subject is sufficiently exposed |
| Nitrogen, Argon |
Hypoxia |
Reduces partial pressure of oxygen available to blood |
Rapid |
Use closed chamber with rapid filling |
Safeif used with ventilation |
Cats, small dogs, birds, rodents, rabbits, other small species, mink, zoo animals, nonhuman primates, free ranging wildlife |
Effective except in young and neonates; an effective agent, but other methods preferable |
| Penetrating captive bolt |
Physical damage to brain |
Direct concussion of brain tissue |
Rapid |
Requires skill, adequate restraint, and proper placement of captive bolt |
Safe |
Dogs, rabbits, zoo animals, reptiles, amphibians, free ranging wildlife |
Instant loss of consciousness but motor activity may continue |
| Pithing |
Hypoxia due to disruption of vital centers, physical damage to brain |
Trauma of brain and spinal cord tissue |
Rapid |
Easily performed, but requires skill |
Safe |
Some ectotherms |
Effective, but death not immediate unless brain and spinal cord are pithed |
| Thoracic compression |
Hypoxia and cardiac arrest |
Physical interference with cardiac and respiratory function |
Moderately rapid |
Requires training |
Safe |
Small to medium sized free ranging birds |
Apparently effective |
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