Editing Neutering (section)

==Methods of sterilization==
{{anchor|Methods}}
===Females (spaying)===
{{see also|Pediatric spaying}}
[[File:Spay 1.JPG|thumb|Feline uterus]]
[[File:Female dog spay incision.jpg|thumb|Closed spaying incision on a female dog, taken 24 hours after surgery]]
Spaying is the surgical removal of the ovaries and sometimes uterus in female animals. It is commonly performed as a method of birth control and [[behavior modification]].<ref name="pmid8226251">{{Cite journal
| author = Hooper R. N.
| author2 = Taylor T. S.
| author3 = Varner D. D.
| author4 = Blanchard T. L.
| title = Effects of bilateral ovariectomy via colpotomy in mares: 23 cases (1984–1990)
| journal = Journal of the American Veterinary Medical Association
| volume = 203
| issue = 7
| pages = 1043–6
|date=October 1993
| doi = 10.2460/javma.1993.203.07.1043
| pmid = 8226251
}}</ref>

In non-human animals, the technical term is an '''ovo-[[hysterectomy]]''' or '''ovariohysterectomy'''; while in humans, this is called a hystero-[[oophorectomy]]. One form of spaying is to remove only the ovaries (oophorectomy or ovariectomy), which is mainly done in [[cat]]s and young [[dog]]s as well as in laparoscopic procedures. Another, less commonly performed method is an "ovary-sparing spay"<ref>{{cite web|url=http://www.parsemusfoundation.org/ovary-sparing-spay/|title=Ovary-Sparing Spay – Parsemus Foundation|url-status=live|archive-url=https://web.archive.org/web/20151008060139/http://www.parsemusfoundation.org/ovary-sparing-spay/|archive-date=8 October 2015}}</ref> in which the uterus is removed but one (or both) ovaries are left. A '''complete ovariohysterectomy''' may involve removal of the ovaries, uterus, [[oviduct]]s, and [[uterine horns]].

[[File:Cat spay scar.jpg|thumb|Surgical incision site of a female cat]]
The surgery can be performed using [[Open surgery|a traditional open approach]] or by [[Laparoscopic surgery|laparoscopic "keyhole" surgery]]. Open surgery is more widely available, as laparoscopic surgical equipment costs are expensive. Traditional open surgery is usually performed through a ventral midline incision below the [[Navel|umbilicus]]. The incision size varies depending upon the surgeon and the size of the animal. The uterine horns are identified and the ovaries are found by following the horns to their ends.

There is a ligament that attaches the ovaries to the body wall, which may need to be broken down so the ovaries can be identified. The ovarian arteries are then ligated with resorbable [[suture material]] and then the arteries transected. The uterine body (which is very short in litter-bearing species) and related arteries are also tied off just in front of the [[cervix]] (leaving the cervix as a natural barrier). The entire uterus and ovaries are then removed. The abdomen is checked for bleeding and then closed with a three-layer closure. The [[Linea alba (abdomen)|linea alba]] and then the subcutaneous layer are closed with resorbable suture material. The skin is then stapled, sutured, or glued closed. For suturing the feline linea alba, the most appropriate suture bite and stitch interval size was suggested to be 5 mm.<ref>{{cite journal |last1=Bartier |first1=Amanda L. |last2=Atilla |first2=Aylin |last3=Archer |first3=Rebecca |last4=Kwong |first4=Grace P. S. |title=Optimal Suture Bite Size for Closure of Feline Linea Alba—A Cadaveric Study |journal=Frontiers in Veterinary Science |date=10 December 2019 |volume=6 |page=441 |doi=10.3389/fvets.2019.00441|pmid=31921902 |pmc=6914685 |doi-access=free }}</ref>

Laparoscopic surgery is performed using a camera and instruments placed through small incisions (ports) in the body wall. The patient is under anaesthesia and lying on the back. The incisions are between {{convert|5|and|10|mm}} and the number varies according to the equipment and technique used. The surgeon watches on a screen during the operation. The first port is made just behind the umbilicus and the camera is inserted. The abdomen is inflated with carbon dioxide gas to create a space in which to operate. A second port is introduced a few centimeters in front of the navel and a long grasping instrument called a Babcock forceps is inserted. The surgeon finds the ovary with the instrument and uses it to suspend the ovary from a needle placed through the abdominal wall. This lifts the ovary and uterus safely away from other organs. The surgeon then removes the grasping instrument and replaces it with an instrument that cauterizes and cuts tissue. This instrument uses electricity to heat the blood vessels to seal them and to cut them. No sutures are placed inside. The ovary is separated from the uterus and round ligament. The cautery instrument is removed and replaced by the grasping instrument, which is used to pull the ovary out through the small abdominal incision (port). This is repeated on the other side and the small holes are closed with a few sutures. Another method uses ligatures and even the uterus is removed. 

The benefits of laparoscopic surgery are less pain, faster recovery, and smaller wounds to heal. A study has shown that patients are 70% more active in the first three days post-surgery compared to open surgery. The reason open surgery is more painful is that larger incisions are required, and the ovary needs to be pulled out of the body, which stretches and tears tissue in the abdomen (it is not uncommon for patients to react under anaesthesia by breathing faster at this point).

Removing the ovaries in female dogs removes the production of [[progesterone]], which is a natural calming [[hormone]] and a [[serotonin]] uplifter. Spaying may therefore escalate any observable aggressive behaviour, either to humans or other dogs.<ref name="Polsky" /><ref name="Blackshaw" /><ref name="Wright" /><ref name="Crowell" />

The risk of infections, bleeding, ruptures, inflammation and reactions to the drugs given to the animal as part of the procedure are all possibilities that should be considered.

===Males (castration)===
{{Main|Castration#Other animals}}
{{See also|Gelding}}
[[File:Neutering incision on a dog.jpg|thumb|Closed castration incision on a male dog, taken 12 hours after surgery]]
In male animals, [[castration]] involves the removal of the [[testes]] (testicles), and is commonly practiced on both household pets (for birth control and behaviour modification) and on livestock (for birth control, as well as to improve commercial value). Often the term ''neuter[ing]'' is used to specifically mean castration, e.g. in phrases like "spay and neuter".


===Sterilization alternatives===

====Hormone-Sparing Surgery====
[[Vasectomy]]: In a more delicate procedure than castration, the [[Vas deferens|vasa deferentia]] – ducts that run from the testes to the [[penis]] – are cut then tied or sealed, to prevent [[sperm]] from entering into the [[urethra]]. Failure rates are insignificantly small. [[Animal breeding|Breeders]] routinely have this procedure carried out on male [[ferret]]s and [[sheep]] to manipulate the estrus cycles of in-contact females. It is uncommon in other animal species. Because a vasectomy is usually a more expensive procedure, among pet-keepers it is more often performed on [[Animal show|show animals]], to cosmetically preserve their appearance (though depending upon the [[Animal fancy|fancier organization]], the procedure may invalidate the animal's candidacy for certain awards, or relegate it to a non-[[Pedigree (animal)|pedigree]], generic "household pet" competition division, just as with full castration).

[[Tubal ligation]]: Snipping and tying of [[oviduct]]s as a sterilization measure can be performed on female cats, dogs, and other species; it is essentially the female equivalent of vasectomy, but a more invasive procedure. Risk of unwanted pregnancies is insignificantly small. Only a few veterinarians perform the procedure.

Like other forms of neutering, vasectomy and tubal ligation eliminate the ability to produce offspring. They differ from neutering in that they leave the animal's levels and patterns of [[sex hormone]] unchanged. Both sexes will retain their normal reproductive behavior, and other than birth control, none of the advantages and disadvantages listed below apply. This method is favored by some people who seek minimal infringement on the natural state of companion animals to achieve the desired reduction of unwanted births of cats and dogs.

=====Injectable=====
* Male dogs – Two intratesticular injectable formulations are known to sterilize male dogs. [[Zeuterin]] was approved by the United States [[Food and Drug Administration]] (FDA) for permanent sterilization of male dogs ages three months and older by causing [[necrosis]] of the testicle.<ref>{{Cite web|url=https://www.acc-d.org/available-products/zeuterin-esterilsol|title=Zeuterin|date=5 January 2019|website=www.acc-d.org|access-date=5 January 2019}}</ref> It is not currently available commercially. Calcium chloride dissolved in a variety of diluents have also been studied, with the majority of research and most promising results using calcium chloride dissolved in ethyl alcohol. Calcium chloride formulations can be purchased for use in animals from compounding pharmacies, but the use of calcium chloride for sterilization of males is not approved by the FDA or any other international regulatory agency.<ref>{{Cite journal|last=Leoci|first=Raffaella|date=14 October 2014|title=Alcohol diluent provides the optimal formulation for calcium chloride non-surgical sterilization in dogs|journal=Acta Veterinaria Scandinavica|volume=56|issue=1 |pages=62|doi=10.1186/s13028-014-0062-2|pmid=25317658|pmc=4195956 |doi-access=free }}</ref>
* Male cats – Calcium chloride formulations have also been studied in male cats.<ref>{{Cite journal|last=Jana|first=Kuladip|date=2011|title=Clinical Evaluation of Non-surgical Sterilization of Male Cats with Single Intra-testicular Injection of Calcium Chloride|journal=BMC Vet Res|volume=7|pages=39|pmc=3152893|pmid=21774835|doi=10.1186/1746-6148-7-39 |doi-access=free }}</ref> 
* Male rats – [[Adjudin]] ([[Analog (chemistry)|analogue]] of indazole-carboxylic acid), induces reversible germ cell loss from the [[Seminiferous tubules|seminiferous epithelium]] by disrupting cell adhesion function between [[Sertoli cell|nurse cells]] and [[Spermatogonium|immature sperm cells]], preventing [[Spermatogenesis|maturation]].
* Male mice – injection of a solution of the JQ1 molecule to bind to a pocket of BRDT necessary for chromatin remodeling, which gives the proteins that regulate how genes act access to the genetic material<ref>{{Cite journal| first1= Martin M. |last1= Matzuk |first2= Michael R. |last2= McKeown|first3= Panagis |last3= Filippakopoulos |first4= Qinglei |last4= Li |first5= Lang |last5= Ma |first6= Julio E. |last6= Agno |first7= Madeleine E. |last7= Lemieux |first8= Sarah |last8= Picaud |first9= Richard N. |last9= Yu |first10= Jun |last10= Qi |first11= Stefan |last11= Knapp |first12= James E. |last12= Bradner | title=Small-Molecule Inhibition of BRDT for Male Contraception | journal=Cell | date=2012-08-17 | volume=150 | issue=4 | pages=673–684 | url= | doi=10.1016/j.cell.2012.06.045 | pmid=22901802 | pmc=3420011}}</ref>
* Male sheep and pigs – Wireless Microvalve.<ref>{{Cite journal |last1= Jones |first1= Inke |first2= Lucas |last2= Ricciardi |first3= Leonard |last3= Hall |first4= Hedley |last4= Hansen |first5= Vijay |last5= Varadan |first6= Chris |last6= Bertram |first7= Simon |last7= Maddocks |first8= Stefan |last8= Enderling |first9= David |last9= Saint |first10= Said |last10= Al-Sarawi |author-link11= Derek Abbott |first11= Derek |last11= Abbott |url= http://www.eleceng.adelaide.edu.au/personal/dabbott/publications/SMS_jones2008.pdf |title= Wireless RF communication in biomedical applications |journal= Smart Materials and Structures |volume= 17 |issue= 1 |date= 17 January 2008 |pages= 8–9 |doi= 10.1088/0964-1726/17/1/015050 |access-date= 2008-06-25 |url-status= live |archive-url= http://archive.wikiwix.com/cache/20110825090935/http://www.eleceng.adelaide.edu.au/personal/dabbott/publications/SMS_jones2008.pdf |archive-date= 25 August 2011 |df= dmy-all |bibcode= 2008SMaS...17a5050J |s2cid= 31682313 }}</ref> A proposed non-chemical, reversible sterilization method using a [[Piezoelectricity|piezoelectric]] [[polymer]] that will deform when exposed to a specific electric field broadcast from an emitter.  The valve will then open or close, preventing the passage of sperm, but not [[seminal fluid]]. Located in a section of the [[vas deferens]] that occurs just after the [[epididymis]], the implantation can be carried out by use of a hypodermic needle.
* Female mammals – Vaccine of antigens (derived from purified [[porcine zona pellucida]]) encapsulated in liposomes (cholesterol and lecithin) with an adjuvant, latest US patent [https://web.archive.org/web/20061027161320/http://www.pharmcast.com/Patents/Yr2001/June2001/061201/RE37224_Fertilization061201.htm RE37,224] (as of 2006-06-06), CA patent [https://web.archive.org/web/20071029225337/http://patents1.ic.gc.ca/details?patent_number=2137363 2137263] (issued 1999-06-15). Product commercially known as SpayVac,<ref>[https://web.archive.org/web/20031214053009/http://www.spayvac.org/ SpayVac]. Retrieved on early 2003.</ref> a single injection causes a treated female mammal to produce antibodies that bind to [[Zona Pellucida|ZP3]] on the surface of her ovum, blocking sperm from fertilizing it for periods from 22 months up to 7 years (depending on the animal<ref>{{cite conference |url=https://www.aphis.usda.gov/wildlife_damage/nwrc/publications/06pubs/miller062.pdf |title=Long-term Efficacy of Three Contraceptive Approaches for Population Control of Wild Horses |first1=Gary |last1=Killian |first2=Nancy K. |last2=Diehl |first3=Lowell |last3=Miller |first4=Jack |last4=Rhyan |first5=David |last5=Thain |date=2007 |conference=22nd Vertebrate Pest Conference |editor1-last=Timm |editor1-first=R. M. |editor2-last=O'Brien |editor2-first=J. M. |book-title=Proceedings, Twenty-Second Vertebrate Pest Conference |publisher=University of California, Davis |pages=67–71 |url-status=live |archive-url=https://web.archive.org/web/20170213013356/https://www.aphis.usda.gov/wildlife_damage/nwrc/publications/06pubs/miller062.pdf |archive-date=13 February 2017  }}</ref><ref>{{cite web| last1=DeNicola | first1=Anthony | first2= Lowell A. |last2= Miller | first3= James P. |last3= Gionfriddo | first4= Kathleen A. |last4= Fagerstone  | publisher=Northeast Association of Fish and Wildlife Agencies | url=http://www.neafwa.org/html/wildlifeabs.shtml#d | title=Status of Present Day Infertility Technology | date=2007-03-16 | access-date=2007-03-16 |archive-url = https://web.archive.org/web/20070829131847/http://www.neafwa.org/html/wildlifeabs.shtml#d |archive-date = 29 August 2007}}</ref>). This will not prevent the animal from going into heat (ovulating) and other than birth control, none of the  advantages or disadvantages mentioned below apply.

====Other====
* Male mice – reversible regulation of the KATNAL1 gene in the Sertoli cell microtubule dynamics of the testes.<ref>{{Cite journal |first1= Lee B. |last1= Smith |first2= L. |last2= Milne |first3= N. |last3= Nelson |first4= S. |last4= Eddie |first5= P. |last5= Brown |first6= N. |last6= Atanassova |first7= M. K. |last7= O’Bryan |first8= L. |last8= O’Donnell |first9= D. |last9= Rhodes |first10= S. |last10= Wells |first11= D. |last11= Napper |first12= P. |last12= Nolan |first13= Z. |last13= Lalanne |first14= M. |last14= Cheeseman |first15= J. |last15= Peters |title= KATNAL1 Regulation of Sertoli Cell Microtubule Dynamics is Essential for Spermiogenesis and Male Fertility |date= May 2012 |url= http://www.eurekalert.org/pub_releases/2012-05/uoe-gdp052412.php |journal= PLOS Genetics |doi= 10.1371/journal.pgen.1002697 |volume= 8 |issue= 5 |pages= e1002697 |pmid= 22654668 |pmc= 3359976 |url-status= live |archive-url= http://archive.wikiwix.com/cache/20120526133105/http://www.eurekalert.org/pub_releases/2012-05/uoe-gdp052412.php |archive-date= 26 May 2012 |df= dmy-all |doi-access= free }}</ref>
* Female mammals – orally administered phosphodiesterase 3 inhibitor ORG 9935 daily before and during ovulation, which blocks the resumption of meiosis resulting in ovulation of a non-fertilizable, immature oocyte without rupturing the follicle.<ref>{{Cite journal| first1= Jeffrey T. |last1= Jensen |first2= Mary B. |last2= Zelinski |first3= Jessica E. |last3= Stanley |first4= John W. |last4= Fanton| first5=  Richard L. |last5= Stouffer | title=The phosphodiesterase 3 inhibitor ORG 9935 inhibits oocyte maturation in the naturally selected dominant follicle in Rhesus macaques | journal=Contraception |date=April 2008 | pages=303–7 | volume=77 | issue=4 | doi=10.1016/j.contraception.2008.01.003 | pmc=2505347| pmid=18342656 }}</ref>


"'''{{vanchor|Gomerization|reason=Redirects here. So do other terms boldfaced in this section.}}'''" is breeders' informal term for surgical techniques by which male livestock, such as bulls, retain their full [[libido]] (and related effects like sex [[pheromones]] that would be lost through castration), but are rendered incapable of [[copulation (zoology)|copulation]]. This is done to stimulate and identify [[estrous]] females without the risk of transmitting [[Sexually transmitted disease|venereal diseases]] or causing a pregnancy by a male other than the one intended for [[selective breeding]]. Animals altered for this purpose are referred to as '''teasers''' (teaser bulls, etc.), or '''gomers'''. Several methods are used. '''Penile translocation''' surgically alters the penis to point far enough away from its normal direction that it cannot manage [[vagina]]l penetration. '''Penile fixation''' permanently attaches the penis to the abdomen so that it cannot be lowered for penetration. [[Penectomy]] is the partial or complete removal of the [[penis]].<ref>{{cite web|url=http://www.drostproject.org/en_bovrep/2-8/itemtop56.html|title=Penectomized Teaser Bull|publisher=The Drost Project|access-date=2011-08-24|url-status=live|archive-url=https://web.archive.org/web/20120331044336/http://www.drostproject.org/en_bovrep/2-8/itemtop56.html|archive-date=31 March 2012}}</ref>