Editing Neutering (section)

===Disadvantages===
* As with any surgical procedure, immediate complications of neutering include the usual [[Veterinary anesthesia|anesthetic]] and [[Veterinary surgery|surgical]] complications, such as bleeding, infection, and death. These risks are relatively low in routine neutering; however, they may be increased for some animals due to other pre-existing health factors. In one study the risk of anesthetic-related death (not limited to neutering procedures) was estimated at 0.05% for healthy dogs and 0.11% for healthy cats. The risks for sick animals were 1.33% for dogs and 1.40% for cats.<ref>{{Cite journal|pmid=18466167 |date=2008 |author1=Brodbelt |first2=K. J. |first3=R. A. |first4=P. J. |first5=L. E. |first6=D. U. |first7=J. L. |title=The risk of death: the confidential enquiry into perioperative small animal fatalities |volume=35 |issue=5 |pages=365–73 |doi=10.1111/j.1467-2995.2008.00397.x |journal=Veterinary Anaesthesia and Analgesia |last2=Blissitt |last3=Hammond |last4=Neath |last5=Young |last6=Pfeiffer |last7=Wood|s2cid=22017193 |url=https://researchonline.rvc.ac.uk/id/eprint/1370/1/1370.pdf }}</ref>
* Spaying and castrating cats and dogs may increase the risk of [[obesity]] if nutritional intake is not reduced to reflect the lower metabolic requirements of neutered animals.<ref name="PMID18774325">{{cite journal | pmid = 18774325 | doi=10.1016/j.jfms.2008.07.002 | volume=11 | issue=2 | title=Prevalence and risk factors of obesity in an urban population of healthy cats |date=February 2009 | journal=Journal of Feline Medicine and Surgery | pages=135–40 | author=Colliard L. | author2=Paragon B. M. | author3=Lemuet B.| author4=Bénet J. J. | author5=Blanchard G.| s2cid=25617418 | doi-access=free | pmc=10832791 }}</ref> In cats, a decrease in sex hormone levels seems to be associated with an increase in food intake.<ref name="PMID17845247">{{cite journal | pmid = 17845247 | doi=10.1111/j.1439-0396.2006.00667.x | volume=91 | issue=9–10 | title=Oestradiol, but not genistein, inhibits the rise in food intake following gonadectomy in cats, but genistein is associated with an increase in lean body mass |date=October 2007 | journal=Journal of Animal Physiology and Animal Nutrition | pages=400–10 | author=Cave N. J. | author2=Backus R. C. | author3=Marks S. L.| author4=Klasing K. C.}}</ref> In dogs, the effects of neutering as a risk factor for obesity vary among breeds.<ref name="PMID15923551">{{cite journal | pmid = 15923551 | volume=156 | issue=22 | title=Prevalence of obesity in dogs examined by Australian veterinary practices and the risk factors involved |date=May 2005 | journal=Veterinary Record | pages=695–702 | author=McGreevy P. D. | author2=Thomson P. C. | author3=Pride C.| author4=Fawcett A. | author5=Grassi T.| author6=Jones B. | doi=10.1136/vr.156.22.695| s2cid=36725298 }}</ref>
* Neutered dogs of both sexes are at a twofold excess risk to develop [[osteosarcoma]] (bone cancer) as compared to intact dogs. The risk of osteosarcoma increases with increasing breed size and especially height.<ref name=Priester>{{Cite journal|pmid=7254313 |date=1980 |author1=Priester |first2=F. W. |title=The Occurrence of Tumors in Domestic Animals |issue=54 |pages=1–210 |journal=National Cancer Institute Monograph |last2=McKay}}</ref><ref name=Ru>{{Cite journal|doi=10.1016/S1090-0233(98)80059-2 |title=Host related risk factors for canine osteosarcoma |date=1998 |last1=Ru |first1=G. |first2=B. |first3=L. |journal=The Veterinary Journal |volume=156 |pages=31–9 |pmid=9691849 |issue=1 |last2=Terracini |last3=Glickman}}</ref><ref name=Cooley>{{Cite journal|author=Cooley, D. M.|author2=Beranek, B. C.|date=1 November 2002|title=Endogenous gonadal hormone exposure and bone sarcoma risk|journal=Cancer Epidemiology, Biomarkers & Prevention|url=http://cebp.aacrjournals.org/cgi/content/full/11/11/1434|pmid=12433723|volume=11|issue=11|pages=1434–40|display-authors=etal|url-status=live|archive-url=https://web.archive.org/web/20030825175957/http://cebp.aacrjournals.org/cgi/content/full/11/11/1434|archive-date=25 August 2003}}</ref>
* Studies of cardiac tumors in dogs showed that there was a 5 times greater risk of [[hemangiosarcoma]] (cancer of blood vessel lining), one of the three most common cancers in dogs, in spayed females than intact females and a 2.4 times greater risk of hemangiosarcoma in castrated dogs as compared to intact males.<ref name=Prymak>{{Cite journal |author=Prymak C. |author2=McKee L. J. |author3=Goldschmidt M. H.|author4=Glickman L. T. |date=1988 |title=Epidemiologic, clinical, pathologic, and prognostic characteristics of splenic hemangiosarcoma and splenic hematoma in dogs: 217 cases (1985) |journal= Journal of the American Veterinary Medical Association |volume=193 |issue=6 |pages=706–712 |doi=10.2460/javma.1988.193.06.706 |pmid=3192450}}</ref><ref name=Ware>{{Cite journal|doi=10.1892/0891-6640(1999)013<0095:CTID>2.3.CO;2 |pmid=10225598 |title=Cardiac Tumors in Dogs: 1982–1995 |date=1999 |last1=Ware |first1=Wendy A. |last2=Hopper |first2=David L. |journal=Journal of Veterinary Internal Medicine |volume=13 |issue=2 |pages=95–103|doi-broken-date=4 January 2025 }}</ref>
* Spaying and castrating is associated with an increase in urinary tract cancers in dogs, however the risk is still less than 1%.<ref name=Sanborn>{{cite web |author=Sanborn, L. J. |title=Long-Term Health Risks and Benefits Associated with Spay / Neuter in Dogs |url=http://www.naiaonline.org/pdfs/LongTermHealthEffectsOfSpayNeuterInDogs.pdf |date=14 May 2007 |access-date=13 April 2010 |url-status=live |archive-url=https://web.archive.org/web/20100107141430/http://www.naiaonline.org/pdfs/longtermhealtheffectsofspayneuterindogs.pdf |archive-date=7 January 2010  }}</ref>
* Neutered dogs of both sexes have a 27% to 38% increased risk of adverse reactions to vaccinations. However, the incidence of adverse reactions for neutered and intact dogs combined is only 0.32%.<ref name=Moore>{{Cite journal |author=Moore G. E. |author2=Guptill L. F. |author3=Ward M. P.|author4=Glickman N. W. |author5=Faunt K. F.|author6=Lewis H. B. |author7=Glickman L.T. |date=2005 |title=Adverse events diagnosed within three days of vaccine administration in dogs|journal= Journal of the American Veterinary Medical Association |volume=227 |issue=7 |pages=1102–1108 |doi=10.2460/javma.2005.227.1102 |pmid=16220670|s2cid=8625559 |doi-access=free }}</ref>
* Neutered dogs have been known to develop hormone-responsive [[alopecia]] (hair loss).<ref>{{Cite web|url=https://m.petmd.com/dog/conditions/endocrine/c_dg_hormone_responsive_dermatoses|title=Baldness and Hormone-Related Skin Disorders in Dogs|website=m.petmd.com|access-date=2019-12-28}}</ref>
* A 2004 study found that neutered dogs had a higher incidence of cranial cruciate ligament (CCL) rupture, a form of anterior cruciate ligament (ACL) injury.<ref>{{cite journal |last1=Slauterbeck |first1=J. R. |author2=Pankratz, K. |author3=Xu, K. T. |author4=Bozeman, S. C. |author5= Hardy, D. M.  |title=Canine Ovariohysterectomy and Orchiectomy Increases the Prevalence of ACL Injury |journal=Clinical Orthopaedics and Related Research |date=Dec 2004 |volume=429 |issue=429 |pages=301–5|doi=10.1097/01.blo.0000146469.08655.e2 |pmid=15577502 |s2cid=23047078 }}</ref>
* A study of [[golden retrievers]] found that castrated males were 3 times more likely than intact males to be diagnosed with [[lymphoma in animals|lymphoma]] and 2 times more likely to have [[Hip dysplasia (canine)|hip dysplasia]].<ref>{{cite journal|last=Torres de la Riva|first=Gretel|title=Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers|doi=10.1371/journal.pone.0055937|pmid=23418479|pmc=3572183|journal=PLOS ONE|volume=8|issue=2|pages=e55937|year=2013|bibcode=2013PLoSO...855937T|doi-access=free}}</ref>
* Castration and spaying can increase the risk of geriatric cognitive impairment.<ref name=Sanborn />
* About 2% of castrated [[male dogs]] eventually develop [[prostate cancer]], compared to less than 0.6% of intact males.<ref name=Teske>{{Cite journal|doi=10.1016/S0303-7207(02)00261-7 |title=Canine prostate carcinoma: epidemiological evidence of an increased risk in castrated dogs |date=2002 |last1=Teske |first1=E. |journal=Molecular and Cellular Endocrinology |volume=197 |pages=251–5 |pmid=12431819 |first2=E. C. |first3=E. M. |first4=E. |first5=J. A. |issue=1–2 |last2=Naan |last3=Van Dijk |last4=Van Garderen |last5=Schalken|s2cid=7080561 }}</ref><ref name=Sorenmo>{{Cite journal|doi=10.1046/j.1476-5829.2003.00007.x |title=Immunohistochemical characterization of canine prostatic carcinoma and correlation with castration status and castration time |date=2003 |last1=Sorenmo |first1=K. U. |first2=M. |first3=F. |first4=C. |first5=J. |journal=Veterinary and Comparative Oncology |volume=1 |pages=48–56 |pmid=19379330 |issue=1 |last2=Goldschmidt |last3=Shofer |last4=Goldkamp |last5=Ferracone}}</ref> The evidence is most conclusive for [[Bouvier des Flandres|Bouviers]].<ref name=Sanborn/>
* In a study of 29 intact male dogs and 47 castrated males aged 11–14, the neutered males were significantly more likely to progress from one geriatric cognitive impairment condition (out of the four conditions – disorientation in the house or outdoors, changes in social interactions with human family members, loss of house training, and changes in the sleep-wake cycle) to two or more conditions. Testosterone in intact males is thought to slow the progression of cognitive impairment, at least in dogs that already have mild impairment.<ref>{{Cite journal|pmid=11439769 |doi=10.2460/javma.2001.219.51 |date=2001 |author1=Hart |title=Effect of gonadectomy on subsequent development of age-related cognitive impairment in dogs |volume=219 |issue=1 |pages=51–6 |journal=Journal of the American Veterinary Medical Association|s2cid=17565731 |doi-access=free }}</ref>
* As compared to intact males, castrated cats are at an increased risk for certain problems associated with [[feline lower urinary tract disease]]. They are much more likely to suffer from [[feline cystitis]] which can escalate into a life-threatening urethral blockage.<ref>{{Cite journal|pmid=11345305 |doi=10.2460/javma.2001.218.1429 |date=2001 |author1=Lekcharoensuk |first2=C. A. |first3=J. P. |title=Epidemiologic study of risk factors for lower urinary tract diseases in cats |volume=218 |issue=9 |pages=1429–35 |journal=Journal of the American Veterinary Medical Association |last2=Osborne |last3=Lulich|doi-access=free }}</ref>
* Neutering has been associated with an increased likelihood of urethral sphincter incontinence in male dogs.<ref>{{cite journal | last1 = Aaron | first1 = A. | last2 = Eggleton | first2 = K. | last3 = Power | first3 = C. | last4 = Holt | first4 = P. E. | title = Urethral sphincter mechanism incompetence in male dogs: a retrospective analysis of 54 cases | journal = Veterinary Record | volume = 139 | issue = 22 | pages= 542–6| year = 1996 | doi=10.1136/vr.139.22.542| pmid = 8961524 | s2cid = 5642622 }}</ref>
* There is evidence that spaying can increase the risk of [[urinary incontinence]] in dogs, especially when done before the age of three months. Up until 12 months of age, the risk decreases as the age at spaying increases.<ref name="Beauvais">{{Cite journal | last1 = Beauvais | first1 = W. | last2 = Cardwell | first2 = J. M. | last3 = Brodbelt | first3 = D. C. | doi = 10.1111/j.1748-5827.2011.01176.x | title = The effect of neutering on the risk of urinary incontinence in bitches - a systematic review | journal = Journal of Small Animal Practice | volume = 53 | issue = 4 | pages = 198–204 | year = 2012 | pmid =  22353203| url = https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1002&context=endoc }}</ref><ref>{{Cite web|url=https://www.merck-animal-health-usa.com/dp/49|title=Merck Animal Health USA|website=www.merck-animal-health-usa.com|access-date=2019-12-14}}</ref>
* Spayed female dogs are at an increased risk of [[hypothyroidism]].<ref name=Panciera>{{Cite journal |author=Panciera D. L. |date=1994 |title=Hypothyroidism in dogs: 66 cases (1987–1992) |journal= Journal of the American Veterinary Medical Association |volume=204 |issue=5 |pages=761–767|doi=10.2460/javma.1994.204.05.761 |pmid=8175472 }}</ref>