Editing Neutering (section)

===Advantages===
Besides being a birth control method, and being convenient to many owners, castrating/spaying has the following health benefits:
* [[Sexual dimorphism|Sexually dimorphic]] behaviors such as [[copulation|mounting]] and [[urine spraying]] are reduced due to the decrease in hormone levels brought about by neutering.  In species other than dogs, certain forms of male [[aggression]] are also reduced.<ref>{{cite journal |last1=Farhoody |first1=Parvene |title=Aggression toward Familiar People, Strangers, and Conspecifics in Gonadectomized and Intact Dogs |journal=Frontiers in Veterinary Science |date=26 February 2018 |volume=5 |page=18 |doi=10.3389/fvets.2018.00018 |pmid=29536014 |pmc=5834763 |doi-access=free }}</ref>  Sexual behavior in cats seems to make them especially undesirable to pet owners.<ref name="Kustritz">{{cite journal |title=Determining the Optimal age for Gonadectomy of Dogs and Cats | doi=10.2460/javma.231.11.1665 |date= 2007 |last1= Kustritz |first1= Margaret V. Root |journal= Journal of the American Veterinary Medical Association |volume= 231 |issue= 11 |pages= 1665–75 |pmid= 18052800| s2cid=4651194 | url=https://semanticscholar.org/paper/0d15d47bace395843f23fc8eef127dcbfc22bf82 |doi-access= free }}</ref>
* Early spaying significantly reduces the risk of development of mammary tumours in female dogs. The incidence of mammary tumours in un-spayed female dogs is 71% (of which approximately 50% will be malignant and 50% will be benign), but if a dog is spayed before its first heat cycle, the risk of developing a mammary tumour is reduced to 0.35%—a 99.5% reduction.  The positive effects of spaying on reduction of later mammary tumours decreases with each heat the dog has (backing up the contention that the greatest benefit to reduce future mammary tumour development is to spay before the first heat), and there is no added benefit to spaying to reduce recurrence of a mammary tumour once it has been diagnosed.<ref>{{cite web|last1=Poulton|first1=Gerry|title=Mammary Tumours in Dogs|url=http://www.vef.unizg.hr/org/kirurgija/wp-content/uploads/2010/04/CESA_January_2009.pdf.pdf|publisher=Irish Veterinary Journal|url-status=live|archive-url=https://web.archive.org/web/20150402120904/http://www.vef.unizg.hr/org/kirurgija/wp-content/uploads/2010/04/CESA_January_2009.pdf.pdf|archive-date=2 April 2015}}</ref>
* Neutering increases life expectancy in cats: one study found castrated male cats live twice as long as intact males, while spayed female cats live 39% longer than intact females.<ref> [https://www.humanesociety.org/resources/why-you-should-spayneuter-your-pet The Humane Society of the United States]</ref> Non-neutered cats in the U.S. are three times more likely to require treatment for an animal bite. Having a cat neutered confers health benefits, because castrated males cannot develop testicular cancer, spayed females cannot develop uterine, cervical or ovarian cancer, and both have a reduced risk of mammary cancer.{{Citation needed|date=February 2023}}
* Without the ability to reproduce, a female necessarily has zero risk of pregnancy complications, such as [[Metrorrhagia|spotting]] and [[false pregnancy]], the latter of which can occur in more than 50% of unspayed female dogs.<ref>{{cite web |url=http://www.ivis.org/advances/concannon/gobello/ivis.pdf |title=Canine Pseudopregnancy: A Review |first=C. |last=Gobello |date=23 August 2001 |work=IVIS.org |publisher=International Veterinary Information Service |access-date=13 April 2010 |display-authors=etal |url-status=dead |archive-url=https://web.archive.org/web/20110419121323/http://www.ivis.org/advances/concannon/gobello/ivis.pdf |archive-date=19 April 2011  }}</ref>
* [[Pyometra]], [[endometrial cancer|uterine cancer]], [[ovarian cancer]], and [[testicular cancer]] are prevented, as the susceptible organs are removed, though [[Pyometra#Stump pyometra|stump pyometra]] may still occur in spayed females.
* Pyometra (or a pus filled womb) ('Pyo' = pus; 'metra' = uterus or womb) is a life-threatening condition that requires emergency veterinary treatment. The risk of a non-spayed female dog developing pyometra by age 10 is 25% across all breeds, but can be as high as 54% in some breeds.<ref>{{cite journal|title=Breed Risk of Pyometra in Insured Dogs in Sweden|journal=Journal of Veterinary Internal Medicine| doi=10.1111/j.1939-1676.2001.tb01587.x|volume=15|issue=6|pages=530–538|year=2001|last1=Egenvall|first1=Agneta|last2=Hagman|first2=Ragnvi|last3=Bonnett|first3=Brenda N.|last4=Hedhammar|first4=Ake|last5=Olson|first5=Pekka|last6=Lagerstedt|first6=Anne-Sofie|pmid=11817057|doi-access=}}</ref> The treatment of choice for a closed-pyometra (where the cervix is closed and the pus cannot drain) is admission to hospital, commencement on intravenous fluids and appropriate antibiotics and, once stable enough for the anaesthetic and surgery, emergency removal of the infected pus-filled uterus. Medical management can be attempted if the animal's condition allows (for example in the case of an 'open' pyometra where the pus drains per-vaginum from the uterus via the open cervix) or dictates (where the animal is too old or otherwise unwell to withstand surgery), if the owner wishes to keep the dog entire to breed or if the owner is unable to afford the veterinary fees associated with surgery. Emergency removal of the infected uterus carries a much higher degree of risk of death than a routine 'spay' operation. The risk of death from in dogs undergoing surgical treatment for pyometra is up to 17%.<ref>{{cite journal|title=Results and complications of surgical treatment of pyometra: a review of 80 cases|journal=[[Journal of the American Animal Hospital Association]]|url=http://cel.webofknowledge.com/InboundService.do?product=CEL&SID=T2VUDVHmOxrj332hibj&UT=WOS%3AA1989AR48200015&SrcApp=Highwire&action=retrieve&Init=Yes&SrcAuth=Highwire&Func=Frame&customersID=Highwire&IsProductCode=Yes&mode=FullRecord|archive-url=https://archive.today/20150319014740/http://cel.webofknowledge.com/InboundService.do?product=CEL&SID=T2VUDVHmOxrj332hibj&UT=WOS:A1989AR48200015&SrcApp=Highwire&action=retrieve&Init=Yes&SrcAuth=Highwire&Func=Frame&customersID=Highwire&IsProductCode=Yes&mode=FullRecord|url-status=dead|archive-date=2015-03-19}}</ref> Thus the risk of death in entire female dogs from a pyometra, even if given correct veterinary attention can be up to 9% by 10 years of age (17% of 54%). This risk is reduced to virtually zero if spayed.