Lethal chamber in the Royal London Institute and Home for Lost and Starving Cats

Animal euthanasia (from the Greek meaning "good death") is the act of humanely killing.^[1] Euthanasia methods are designed to cause minimal pain and distress.

In domesticated animals, this process is commonly referred to by the euphemisms "lay down," "put down," "put to sleep," "put out of its/his/her misery," or "sent away to the farm."

[edit] Methods

[edit] Intravenous anesthetic

Pets are almost always euthanized by intravenous injection,^{[citation needed]} typically a very high dose of a barbiturate such as pentobarbital. Unconsciousness, respiratory then cardiac arrest follow rapidly, usually within 30 seconds^[2]. Observers generally describe it as a quick and peaceful death. The animal almost always makes a gasping sound, and appears to suffer a mild fit due to muscle contraction.

Some veterinarians perform a two-stage process: An initial injection that simply renders the pet unconscious and a second shot that "puts it to sleep".^{[citation needed]} This allows the owner the chance to say goodbye to a live pet without their emotions stressing the pet. It also greatly mitigates any tendency toward spasm and other involuntary movement (ie, the pets facial or eye movement) which would tend to increase the emotional upset that the pet's owner is already experiencing.

For large animals, the volumes of barbiturates required are considered by some to be impractical, although this is standard practice in the US.^[3] In some cases, shooting (see below) is considered appropriate. Alternatively, for horses and cattle, other drugs may be available. Some specially formulated combination products are available such as Somulose (Secobarbital/Cinchocaine) and Tributame (Embutramide/Chloroquine/Lidocaine), which provide deep unconsciousness and cardiac arrest independently, with a lower volume of injection, thus making the process faster, safer and more effective.

Occasionally a horse injected with these mixtures may display apparent seizure activity before death. This may be due to premature cardiac arrest. However, if normal precautions (e.g. sedation with detomidine) are taken, this is rarely a problem^[4]. Anecdotal reports that long term use of phenylbutazone increase the risk of this reaction are unverified.

[edit] Inhalant (gas) anesthetic

Gas anesthetics such as isoflurane and sevoflurane can be used for euthanasia in very small animals. The animals are placed in sealed chambers where high levels of anesthetic gas are introduced. Death may also be caused by carbon monoxide once unconsciousness has been achieved by inhaled anaesthetic.^[5]

[edit] Cervical dislocation

Cervical dislocation, or snapping of the neck, is a simple and common method of killing small animals such as rabbits. Performed properly it causes instant death, and it requires no equipment other than a pair of gloves for protection while handling the animal.

[edit] Intracardiac or intraperitoneal injection

When intravenous injection is not possible, euthanasia drugs such as pentobarbital can be injected directly into a heart chamber or body cavity.

While intraperitoneal injection is fully acceptable (although it may take up to 15 minutes in dogs and cats^[5]), an intracardiac (IC) injection may only be performed on an unconscious or deeply sedated animal. In California, IC injection on a fully conscious animal is a crime.^[6]

[edit] Shooting

This can be an appropriate means of euthanasia for large animals (e.g. horses, cattle) if performed properly. This may be by means of:

Free bullet 

Traditionally used for shooting horses. The horse is shot in the forehead, with the bullet directed down the spine through the medulla oblongata, resulting in instant death.^[7] The risks are minimal if carried out by skilled personnel in a suitable location.

Captive bolt 

Commonly used for cattle and other livestock. The bolt is fired through the forehead causing massive disruption of the cerebral cortex. In cattle this merely stuns the animal, and death must be brought about by pithing or exsanguination. Horses are killed outright by the captive bolt, making pithing or exsanguination unnecessary^[8].

[edit] Reasons for euthanasia

• Terminal illness - e.g. cancer
• Rabies
• Behavioral problems - e.g. aggression
• Illness or broken limbs that would cause suffering for the animal to live with, or when the owner has insufficient financial reserves to pay for (or a moral objection to) treatment.
• Old age - Deterioration to loss of major bodily functions. Severe impairment of the quality of life.
• Lack of space - Some shelters simply do not have the available room to provide shelter for an abandoned animal.

Small animal euthanasia is typically performed in a veterinary clinic or hospital, or in an animal shelter, and is usually carried out by a veterinarian, or a veterinary technician working under the veterinarian's supervision. Often animal shelter workers are trained to do euthanasia as well. Some veterinarians will perform the euthanasia at the pet owner's home - this is virtually mandatory in the case of large animal euthanasia; except in the case of horse racing, where the injured animal is sometimes put down on the track.

[edit] Remains

Many pet owners choose to have their pet cremated or buried after they are euthanized,^[9] and there are pet funeral homes that specialize in animal burial or cremation.^[10]

Many animals euthanized at shelters or animal control agencies are sent to meat rendering facilities,^[11] to be processed for use in cosmetics, fertilizer, gelatin, poultry feed, pharmaceuticals and pet food.^[12] The amount of phenobarbital in dog food has caused dogs to become less responsive to the drug when being euthanized, though a 2002 FDA study found no dog or cat DNA in the foods they tested. They theorized that the drug found its way into dog food from euthanized cattle and horses. They also stated that the level of the drug found in the food was safe.^[13]

[edit] See also

• Animal chaplains
• Animal loss
• Animal welfare
• Rainbow Bridge (pets)
• Animal slaughter
• Pets

[edit] References

[edit] External links

• 2007 AVMA Guidelines on Euthanasia
• Euthanasia of Animals Used for Scientific Purposes at The University of Adelaide
• World Internet News WIN chronicles what happens to abandoned dogs.
• National Agricultural Library, United States Department of Agriculture
• No Kill Advocacy Center - "no kill" shelter advocacy organization
• Horse euthanasia information for the UK
• Recommendations for euthanasia of experimental animals: Part1 (lal.org.uk)
• Recommendations for euthanasia of experimental animals: Part2 (lal.org.uk)
• Pet Euthanasia Knowing when it's time for pet euthanasia.