Editing Animal euthanasia (section)

== Methods ==
The methods of euthanasia can be divided into pharmacological and physical methods. Acceptable pharmacological methods include injected drugs and gases that first depress the central nervous system and then cardiovascular activity. Acceptable physical methods must first cause rapid loss of consciousness by disrupting the [[central nervous system]]. The most common methods are discussed here, but there are other acceptable methods used in different situations.<ref name=Recommendations>{{cite journal|title=Recommendations for euthanasia of experimental animals: Part 1|pmid=8938617|pages=293–316 (295)|year=1996|vauthors=Close B, Banister K, Baumans V, Bernoth EM, Bromage N, Bunyan J, Erhardt W, Flecknell P, Gregory N, Hackbarth H, Morton D, Warwick C |volume=30|issue=4|journal=[[Laboratory Animals (journal)|Laboratory Animals]]|doi=10.1258/002367796780739871|doi-access=}}</ref>

=== Intravenous anesthetic ===
[[File:Cat euthanasia 20230228.jpg|Dying cat with arm shaved for injections|thumb]]
Upon administration of intravenous anesthetic, unconsciousness, [[respiratory arrest|respiratory]] then [[cardiac arrest]] follow rapidly, usually within 30&nbsp;seconds.<ref>UK Veterinary Medicines Directorate Product Notes for 20% Pentobarbital solution. [https://web.archive.org/web/20070610225659/http://www.vmd.gov.uk/espcsite/Documents/128787.DOC]</ref>

The two-stage process that some veterinarians use includes a first shot that is a [[sedative]] to make the animal more comfortable and then a second shot that euthanizes the animal.<ref>{{Cite web |last=Contributors |first=WebMD Editorial |title=What Happens When You Put Your Pet to Sleep? |url=https://www.webmd.com/pets/what-happens-put-pet-to-sleep |access-date=2024-05-05 |website=WebMD |language=en}}</ref> This allows the owner the chance to say goodbye to a live pet without their emotions stressing the animal. It also greatly mitigates any tendency toward spasm and other involuntary movement which tends to increase the emotional upset that the pet's owner experiences.{{cn|date=February 2024}}

{{anchor|Tributame}}For large animals, the volumes of [[barbiturates]] required are considered by some to be impractical, although this is standard practice in the United States.<ref>{{cite web |url=https://www.aaep.org/images/files/2007_%20Euthanasia%20Guidelines.pdf |title=Euthanasia Guidelines |access-date=19 June 2008 |work=AAEP |date=207 | archive-url= https://web.archive.org/web/20080626105724/https://www.aaep.org/images/files/2007_%20Euthanasia%20Guidelines.pdf| archive-date= 26 June 2008 | url-status= dead}}</ref> 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 cause deep unconsciousness and cardiac arrest independently with a lower volume of injection, thus making the process faster, safer, and more effective.<ref>[https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/11303&ved=2ahUKEwirjfu95vSLAxWLh1YBHe1nANYQFnoECCMQAQ&usg=AOvVaw1xEi51ZVFjZCb1V7-ZIvZd fda.gov]{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}</ref>

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.<ref>NOAH Compendium of Data Sheets for Animal Medicines 2005</ref> Anecdotal reports that long-term use of [[phenylbutazone]] increases the risk of this reaction are unverified.<ref>{{cite web | url=https://veterinarypartner.vin.com/default.aspx?pid=19239&catId=102906&id=10307798&ind=1379&objTypeID=1007 | title=Veterinary Partner | work=VIN.com | date=8 August 2017 | last2=Spadafori | first2=Gina }}</ref>

After the animal has died, it is not uncommon for the body to have posthumous body jerks or a sudden bladder or bowel outburst. This is caused by the muscles of the deceased animal's body relaxing.{{cn|date=February 2024}}

=== Inhalants ===
{{main|Controlled-atmosphere killing}}
Gas anesthetics such as [[isoflurane]] and [[sevoflurane]] can be [[controlled-atmosphere stunning|used for euthanasia]] of very small animals. The animals are placed in [[gas chamber|sealed chambers]] where high levels of anesthetic gas are introduced. Death may also be caused using [[carbon dioxide]] once unconsciousness has been achieved by inhaled anesthetic.<ref name=ANU>{{cite web |work=Australian National University |title=Laboratory Animal Euthanasia |format=DOC |url=http://www.anu.edu.au/ro/ORI/HumaneEuthanasia.doc |access-date=30 November 2007 |archive-url=https://web.archive.org/web/20070819094116/http://www.anu.edu.au/ro/ORI/HumaneEuthanasia.doc |archive-date=19 August 2007 |url-status=dead }}</ref> Carbon dioxide is often used on its own for euthanasia of wild animals.<ref>{{Cite web |url=http://icwdm.org/wildlife/euthanasia/carbondioxide.asp |title=Animal Euthanasia Information - Carbon doxide gas (Internet Center for Wildlife Damage Management |access-date=17 February 2011 |archive-url=https://web.archive.org/web/20161001201251/http://icwdm.org/wildlife/euthanasia/carbondioxide.asp |archive-date=1 October 2016 |url-status=dead }}</ref> 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.<ref name="pmid15901358">{{cite journal |vauthors=Conlee KM, Stephens ML, Rowan AN, King LA |title=Carbon dioxide for euthanasia: concerns regarding pain and distress, with special reference to mice and rats |journal=[[Laboratory Animals (journal)|Laboratory Animals]] |volume=39 |issue=2 |pages=137–61 |date=April 2005 |pmid=15901358 |doi=10.1258/0023677053739747 |s2cid=14005155 |url=https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1015&context=acwp_lab|doi-access=free }}</ref> In 2013, the American Veterinary Medical Association (AVMA) issued new guidelines for carbon dioxide induction, stating that a flow rate of 10% to 30% volume/min is optimal for the humane euthanasia of small rodents.<ref name="2013 AVMA Guidelines for the Euthanasia of Animals: 2013 Edition">[https://www.avma.org/kb/policies/documents/euthanasia.pdf 2013 AVMA Guidelines for the Euthanasia of Animals]</ref>

[[Carbon monoxide]] is often used, but some states in the US have banned its use in animal shelters:<ref>{{cite web |last1=Purtill |first1=Corinne |title=The gas chamber is being officially retired in California as a method of execution—for animals |url=https://qz.com/700599/the-gas-chamber-is-being-officially-retired-in-california-as-a-method-of-execution-for-animals |website=QZ |date=7 June 2016 |access-date=26 February 2024}}</ref><ref>{{cite web |title=Banned In 19 States, Animal Gas Chamber Still Legal In Pennsylvania |url=https://www.wtae.com/article/banned-in-19-states-animal-gas-chamber-still-legal-in-pennsylvania/7455400 |website=WTAE |date=2 February 2012 |access-date=26 February 2024}}</ref> although carbon monoxide poisoning is not particularly painful, the conditions in the gas chamber are often not humane.<ref>{{Cite web |url=http://news.nationalgeographic.com/news/2005/04/0411_050411_peteuthanasia.html |title=Animal Gas Chambers Draw Fire in U.S. - National Geographic |access-date=17 February 2011 |archive-url=https://web.archive.org/web/20110629001053/http://news.nationalgeographic.com/news/2005/04/0411_050411_peteuthanasia.html |archive-date=29 June 2011 |url-status=dead }}</ref> [[Nitrogen]] has been shown to be effective, although some young animals are more resistant to the effects,<ref name="pmid17423118">{{cite journal |vauthors=Quine JP, Buckingham W, Strunin L |title=Euthanasia of small animals with nitrogen; comparison with intravenous pentobarbital |journal=The Canadian Veterinary Journal |volume=29 |issue=9 |pages=724–6 |date=September 1988 |pmid=17423118 |pmc=1680841 }}</ref> and it currently is not widely used.{{cn|date=February 2024}}

The use of gas chambers is not the most humane form of euthanasia as it can take up to 20 minutes to fully euthanize the animal. If the chambers are not calibrated correctly or the animal is ill, the process is only delayed further which can cause more harm to the animal.<ref>{{Cite web |title=Bringing an end to inhumane euthanasia {{!}} The Humane Society of the United States |url=https://www.humanesociety.org/resources/bringing-end-inhumane-euthanasia |access-date=2024-05-05 |website=www.humanesociety.org |language=en}}</ref>

=== Cervical dislocation ===
[[Cervical dislocation]], or displacement (breaking or fracturing) of the neck, is an older and less common method of killing small animals such as mice. When performed properly, it is intended to cause a death that is as painless as possible and has no cost or equipment involved. The handler must know the proper method of executing the movement which will cause the cervical displacement and without proper training and method education there is a risk of not causing death and can cause severe pain and suffering. It is unknown how long an animal remains conscious, or the level of suffering it goes through after a correct snapping of the neck, which is why it has become less common and often substituted with inhalants.{{cn|date=February 2024}}

=== 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.{{cn|date=February 2024}} With regard to state and federal laws, one of the most humane forms of euthanizing animals is through the injection Sodium Pentobarbital. This is typically the second shot that is followed after a sedative when euthanizing animals.<ref>{{Cite web |title=Sodium Pentobarbital {{!}} Internet Center for Wildlife Damage Management |url=https://icwdm.org/management/euthanasia/sodium-pentobarbital/ |access-date=2024-05-05 |language=en}}</ref>

While [[intraperitoneal injection]] is fully acceptable (although it may take up to 15 minutes to take effect in dogs and cats<ref name=ANU/>), an [[intracardiac injection|intracardiac (IC) injection]] may only be performed on an unconscious or deeply sedated animal. Performing IC injections on a fully conscious animal in places with humane laws for animal handling is often a criminal offense.<ref>Calif. Penal Code 597u (a)(2)</ref>

=== Shooting ===
[[File:Kill your Ponies with the Greener Killer - 1912 - press advertisement.jpg|thumb|1912 press advertisement for "The Greener Killer", a firearm for euthanising ponies and horses]]
[[File:TED Stunner Captive Bolt Technology.jpg|thumb|right|Captive bolt gun]]

This can be a means of euthanasia for large animals—such as horses, cattle, and deer—if performed properly.<ref name="canadian-guidelines">{{cite journal |last1=Longair |first1=JA |last2=Finley |first2=GG |last3=Laniel |first3=MA |last4=Mackay |first4=C |last5=Mould |first5=K |last6=Olfert |first6=ED |last7=Rowsell |first7=H |last8=Preston |first8=A |title=Guidelines for euthanasia of domestic animals by firearms |journal=The Canadian Veterinary Journal |date=December 1991 |volume=32 |issue=12 |pages=724–6 |pmid=17423912 |pmc=1481111 }}</ref><ref name="iowa-state">{{cite web |title=Gunshot or Penetrating Captive Bolt |url=https://vetmed.iastate.edu/vdpam/about/production-animal-medicine/dairy/dairy-extension/humane-euthanasia/humane-euthanasia/gunshot-or-penetrating-captive-bolt |publisher=[[Iowa State University]] |access-date=24 August 2022}}</ref>
This may be performed by means of:

; [[Firearms]]:<ref name="iowa-state"/> Traditionally used in the field for euthanizing horses, deer or other [[game animals|large game animals]]. The animal is shot in the forehead with the bullet directed down the spine through the [[medulla oblongata]], resulting in instant death.<ref>Tom J. Doherty, Alex Valverde, ''Manual of Equine Anaesthesia and Analgesia'', Blackwell Publishing 2006 (p. 352)</ref> The risks are minimal if carried out by skilled personnel in a suitable location.

; [[Captive bolt gun]]:<ref name="iowa-state"/> Commonly used by the [[meat packing industry]] to slaughter cattle and other livestock. The bolt is fired through the forehead causing massive disruption of the [[cerebral cortex]]. In cattle, this stuns the animal, though if left for a prolonged period it will die from [[cerebral oedema]]. Death should therefore be rapidly brought about by [[pithing]] or [[exsanguination]]. Horses are killed outright by the captive bolt, making pithing and exsanguination unnecessary.<ref>{{Cite journal |doi=10.20506/rst.21.3.1382 |doi-access=|title=Animal welfare consequences in England and Wales of the 2001 epidemic of foot and mouth disease |year=2002 |last1=Laurence |first1=C.J. |journal=Revue Scientifique et Technique de l'OIE |volume=21 |issue=3 |pages=863–868 |pmid=12523721 }}</ref>