Animal euthanasia is the act of putting to death painlessly or allowing to die, as by withholding extreme medical measures, an animal suffering from an incurable, especially a painful, disease or condition.
EuthanasiaEuthanasia refers to the practice of intentionally ending a life in order to relieve pain and suffering....
methods are designed to cause minimal pain and distress. Euthanasia is distinct from
animal slaughterSlaughter is the term used to describe the killing and butchering of animals, usually for food. Commonly it refers to killing and butchering of domestic livestock ....
and
pest controlPest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy.-History:...
, which are performed for purposes other than an act of mercy, although in some cases the killing procedure is the same.
In domesticated animals, this process is commonly referred to by
euphemismA euphemism is the substitution of a mild, inoffensive, relatively uncontroversial phrase for another more frank expression that might offend or otherwise suggest something unpleasant to the audience...
s such as "lay down", "put down", "put to sleep", or "put out of its/his/her misery".
Intravenous anesthetic
Pets are almost always euthanized by intravenous injection, typically a very high dose of
pentobarbitalPentobarbital is a short-acting barbiturate that was first synthesized in 1928. Pentobarbital is available as both a free acid and a sodium salt, the former of which is only slightly soluble in water and ethanol....
or
sodium thiopentalSodium thiopental, better known as Sodium Pentothal , thiopental, thiopentone sodium, or Trapanal , is a rapid-onset short-acting barbiturate general anaesthetic...
. Unconsciousness,
respiratoryRespiratory arrest is the cessation of breathing. It is a medical emergency and it usually is related to or coincides with a cardiac arrest. Causes include opiate overdose, head injury, anaesthesia, tetanus, or drowning...
then
cardiac arrestCardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
follow rapidly, usually within 30 seconds. Observers generally describe it as a quick and peaceful death.
Some veterinarians perform a two-stage process: An initial injection that simply renders the pet unconscious and a second shot that causes death. 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 (i.e., the pet's 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 United States. 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 (
SecobarbitalSecobarbital sodium is a barbiturate derivative drug that was first synthesized in 1928 in Germany. It possesses anaesthetic, anticonvulsant, sedative and hypnotic properties...
/
CinchocaineCinchocaine is an amide local anesthetic. It is the active ingredient in some topical hemorrhoid creams such as Proctosedyl...
) and
Tributame (
EmbutramideEmbutramide is a potent sedative drug developed by Hoechst A.G. in 1958. It was developed as a general anaesthetic agent, but was found to have a very narrow therapeutic window, with a 50mg/kg dose producing effective sedation, but a 75mg/kg dose was fatal. Along with strong sedative effects,...
/
ChloroquineChloroquine is a 4-aminoquinoline drug used in the treatment or prevention of malaria.-History:Chloroquine , N'--N,N-diethyl-pentane-1,4-diamine, was discovered in 1934 by Hans Andersag and co-workers at the Bayer laboratories who named it "Resochin". It was ignored for a decade because it was...
/
LidocaineLidocaine , Xylocaine, or lignocaine is a common local anesthetic and antiarrhythmic drug. Lidocaine is used topically to relieve itching, burning and pain from skin inflammations, injected as a dental anesthetic or as a local anesthetic for minor surgery.- History :Lidocaine, the first amino...
), which cause 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
seizureAn epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
activity before death. This may be due to premature cardiac arrest. However, if normal precautions (e.g.,
sedationSedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure...
with
detomidineDetomidine is an imidazole derivative and α2-adrenergic agonist, used as a large animal sedative, primarily used in horses. It is usually available as the salt detomidine hydrochloride...
) are taken, this is rarely a problem. Anecdotal reports that long term use of
phenylbutazonePhenylbutazone, often referred to as bute, is a non-steroidal anti-inflammatory drug for the short-term treatment of pain and fever in animals. In the United States, it is no longer approved for human use.-In humans:...
increase the risk of this reaction are unverified.
Inhalants
Gas anesthetics such as
isofluraneIsoflurane is a halogenated ether used for inhalational anesthesia. Together with enflurane and halothane, it replaced the flammable ethers used in the pioneer days of surgery. Its name comes from being a structural isomer of enflurane, hence they have the same empirical formula...
and
sevofluraneSevoflurane , also called fluoromethyl hexafluoroisopropyl ether, is a sweet-smelling, nonflammable, highly fluorinated methyl isopropyl ether used for induction and maintenance of general anesthesia. Together with desflurane, it is replacing isoflurane and halothane in modern anesthesiology...
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 dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
once unconsciousness has been achieved by inhaled anaesthetic. Carbon dioxide is often used on its own for euthanasia of wild animals. There are mixed opinions on whether it causes distress when used on its own, with human experiments lending support to the evidence that it can cause distress, and equivocal results in non-humans.
Carbon monoxideCarbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
is often used, but some states in the US have banned its use in animal shelters: although carbon monoxide poisoning is not particularly painful, the conditions in the gas chamber are often not humane.
NitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
has been shown to be effective, although some young animals are rather resistant, and it currently is not widely used.
Cervical dislocation
Cervical dislocationCervical dislocation, "breaking the neck" or "snapping the spine" are terms used to describe this killing method intended to be quick and painless...
, or displacement of the neck, is a simple and common method of killing small animals such as mice. Performed properly it causes instant death, and it requires no equipment other than a pair of gloves for protection while handling the animal.
Intracardiac or intraperitoneal injection
When intravenous injection is not possible, euthanasia drugs such as
pentobarbitalPentobarbital is a short-acting barbiturate that was first synthesized in 1928. Pentobarbital is available as both a free acid and a sodium salt, the former of which is only slightly soluble in water and ethanol....
can be injected directly into a heart chamber or body cavity.
While
intraperitoneal injectionIntraperitoneal injection or IP injection is the injection of a substance into the peritoneum . IP injection is more often applied to animals than humans...
is fully acceptable (although it may take up to 15 minutes in dogs and cats), an
intracardiac (IC) injectionIntracardiac injections are injections that are given directly into the heart muscles or ventricles. They are used in emergencies.- Procedure :...
may only be performed on an unconscious or deeply sedated animal. In California, IC injection on a fully conscious animal is a crime.
Shooting
This can be an appropriate means of euthanasia for large animals (e.g., horses, cattle, deer) 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 oblongataThe medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
, resulting in instant death. 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 cortexThe cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
. In cattle this stuns the animal, though if left for a prolonged period it will die from cerebral oedema, though this is a huge welfare problem. Death should be rapidly brought about by
pithingPithing is a slaughtering technique in which the brain of the animal is destroyed by a tool called a pithing cane or rod, which is inserted into the hole which is created by captive bolt stunning. Trained slaughtermen will be experienced in the use of captive bolt weapons...
or
exsanguinationExsanguination is the fatal process of hypovolemia , to a degree sufficient enough to cause death. One does not have to lose literally all of one's blood to cause death...
. Horses are killed outright by the captive bolt, making pithing or exsanguination unnecessary.
Reasons for euthanasia
- Terminal illness
Terminal illness is a medical term popularized in the 20th century to describe a disease that cannot be cured or adequately treated and that is reasonably expected to result in the death of the patient within a short period of time. This term is more commonly used for progressive diseases such as...
– e.g. cancer
- Rabies
Rabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...
- Behavioral problems (that usually cannot be corrected) – e.g. aggression
In psychology, as well as other social and behavioral sciences, aggression refers to behavior between members of the same species that is intended to cause humiliation, pain, or harm. Ferguson and Beaver defined aggressive behavior as "Behavior which is intended to increase the social dominance of...
- Illness or broken limbs that would cause suffering for the animal to live with, or when the owner cannot afford (or has a moral
A moral is a message conveyed or a lesson to be learned from a story or event. The moral may be left to the hearer, reader or viewer to determine for themselves, or may be explicitly encapsulated in a maxim...
objection to) treatment.
- Old age – Deterioration to loss of major bodily functions. Severe impairment of the quality of life.
- Lack of homes – Many shelters receive considerably more surrendered animals than they are capable of re-housing. This can be attributed to irresponsible owners who do not spay or neuter pets, causing unwanted litters. Most pets turned in to animal shelters are not adopted out.
- Animal testing
Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments. Worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million...
– After use in testing, most animals are euthanized.
Small animal euthanasia is typically performed in a veterinary clinic or hospital, or in an animal shelter, and is usually carried out by a
veterinarianA veterinary physician, colloquially called a vet, shortened from veterinarian or veterinary surgeon , is a professional who treats disease, disorder and injury in animals....
, or a
veterinary technicianIn North America, the principle paraveterinary workers are called veterinary technicians or veterinary technologists-Job description:Technical skills include:...
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. In the case of large animals which have sustained injuries, this will also occur at the site of the accident, for example on a racecourse.
Some
animal rightsAnimal rights, also known as animal liberation, is the idea that the most basic interests of non-human animals should be afforded the same consideration as the similar interests of human beings...
organizations, such as
People for the Ethical Treatment of AnimalsPeople for the Ethical Treatment of Animals is an American animal rights organization based in Norfolk, Virginia, and led by Ingrid Newkirk, its international president. A non-profit corporation with 300 employees and two million members and supporters, it claims to be the largest animal rights...
, support animal euthanasia in certain circumstances, and practice euthanasia at shelters that they operate.
Remains
Many pet owners choose to have their pet cremated or buried after the pet is euthanized, and there are pet
funeral homeA funeral home, funeral parlor or mortuary, is a business that provides burial and funeral services for the deceased and their families. These services may include aprepared wake and funeral, and the provision of a chapel for the funeral....
s that specialize in animal burial or cremation.
In some instances, animals euthanized at shelters or animal control agencies have been sent to meat rendering facilities, to be processed for use in
cosmeticsCosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...
,
fertilizerFertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
,
gelatinGelatin is a translucent, colorless, brittle , flavorless solid substance, derived from the collagen inside animals' skin and bones. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing. Substances containing gelatin or functioning in a similar...
,
poultry feedFodder or animal feed is any agricultural foodstuff used specifically to feed domesticated livestock such as cattle, goats, sheep, horses, chickens and pigs. Most animal feed is from plants but some is of animal origin...
, pharmaceuticals and
pet foodPet food is plant or animal material intended for consumption by pets. Typically sold in pet stores and supermarkets, it is usually specific to the type of animal, such as dog food or cat food...
. The amount of pentobarbital in dog food may have 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.
See also
- Animal chaplains
Animal chaplains community, including pet loss grief support, animal memorial services, praying for animals who are sick or injured, comforting bereaved family members, holding hands with pet owners during surgery or animal euthanasia at a veterinary clinic or animal hospital, and performing...
- Animal loss
The death of a pet or an animal to which one has become emotionally bonded can be an intense loss, comparable with the death of a human loved one, or even greater depending on the individual. The death can be felt more intensely when the owner has made a decision to end the pet’s life through ...
- Animal slaughter
Slaughter is the term used to describe the killing and butchering of animals, usually for food. Commonly it refers to killing and butchering of domestic livestock ....
- Animal welfare
Animal welfare is the physical and psychological well-being of animals.The term animal welfare can also mean human concern for animal welfare or a position in a debate on animal ethics and animal rights...
- Dysthanasia (animal)
Animal dysthanasia refers to the practice of prolonging the life of animals that are seriously or even terminally ill and that are potentially experiencing suffering...
- Pets
PETS may be an acronym for:* Pet Travel Scheme, which allows animals to travel internationally without quarantine* Pets Evacuation and Transportation Standards Act...
- Rainbow Bridge (pets)
The Rainbow Bridge is the theme of a work of poetic prose written some time between 1980 and 1992, whose original creator is unknown.The theme is of a mythological place to which a pet goes upon its death, eventually to be reunited with its owner...
External links