For female dogs, the situation is more complex. The number of health benefits associated with spaying may
exceed the associated health problems in some (not all) cases. On balance, whether spaying improves the
odds of overall good health or degrades them probably depends on the age of the female dog and the
relative risk of various diseases in the different breeds.
On the positive side, spaying female dogs
* if done before 2.5 years of age, greatly reduces the risk of mammary tumors, the most common
malignant tumors in female dogs
* nearly eliminates the risk of pyometra, which otherwise would affect about 23% of intact female
dogs; pyometra kills about 1% of intact female dogs
* reduces the risk of perianal fistulas
* removes the very small risk (0.5%) from uterine, cervical, and ovarian tumors
On the negative side, spaying female dogs
* if done before 1 year of age, significantly increases the risk of osteosarcoma (bone cancer); this is a
common cancer in larger breeds with a poor prognosis
* increases the risk of splenic hemangiosarcoma by a factor of 2.2 and cardiac hemangiosarcoma by
a factor of >5; this is a common cancer and major cause of death in some breeds
* triples the risk of hypothyroidism
* increases the risk of obesity by a factor of 1.6-2, a common health problem in dogs with many
associated health problems
* causes urinary "spay incontinence" in 4-20% of female dogs
* increases the risk of persistent or recurring urinary tract infections by a factor of 3-4
* increases the risk of recessed vulva, vaginal dermatitis, and vaginitis, especially for female dogs
spayed before puberty
* doubles the small risk (<1%) of urinary tract tumors
* increases the risk of orthopedic disorders
* increases the risk of adverse reactions to vaccinations
From:
http://www.naiaonline.org/pdfs/LongTermHealthEffectsOfSpayNeuterInDogs.pdfThere is some pretty interesting reading at these as well:
http://www.naiaonline.org/pdfs/LongTermHealthEffectsOfSpayNeuterInDogs.pdfLong-Term Health Risks and Benefits Associated with Spay / Neuter in Dogs
Laura J. Sanborn, M.S.
May 14, 2007
http://avmajournals.avma.org/doi/pdf/10.2460/javma.231.11.1665Determining the optimal age for gonadectomy of dogs and cats,
Margaret V. Root Kustritz, dvm, phd, dact
http://www.savethedals.org/earlyneuter.htmVeterinary "Review" Article on Neutering, with Implications for Dalmatian Stone-Formers Abstracted by Carroll H. Weiss
Study Group on Urinary Stones
Research Committee
Dalmatian Club of America
http://www.showdogsupersite.com/kenlclub/breedvet/neutr.htmlNEUTERING MALE AND FEMALE DOGS
Mary C. Wakeman, D.V.M.
©2003 for BREEDERVET
http://www.littleriverlabs.com/neuter.htmThe Question Of Neutering and at what age
(Put together by Gregg Tonkin, Little River Labradors from postings by Pam Davol PHD and Chris Zink DVM, PhD, DACVP)
http://leerburg.com/pdf/neutering.pdfShould You Neuter Your Dog?
Ed Frawley, Leerburg Kennels * words are l e e r b u r g.com and L e e r b u r g Kennels
http://www.traciehotchner.com/dt/files/WillWeChangeOnEarlySpay-Neuter_Villalobos.pdfThe Bond and Beyond for VPN December 2008
by Alice Villalobos
Will We Change on Early Spay-Neuter?
http://www.showdogsupersite.com/kenlclub/breedvet/castrationindogs.htmlISSUES REGARDING CASTRATION IN DOGS
Mary C. Wakeman, D.V.M.
©2003 for BREEDERVET
http://www.petresource.com/Articles%20of%20Interest/new_views_on_neutering.htmNew Views On Neutering
By Ruth Marrion, DVM
http://www.acc-d.org/2006%20Symposium%20Docs/Session%20I.pdfNon-reproductive Effects of Spaying and Neutering
Proceedings of the Third International Symposium on Non-Surgical
Contraceptive Methods for Pet Population Control * www.acc-d.org
SESSION OVERVIEW - Dr. John Verstegen
http://www.peptech.com/HTML/Animal_Health/Superlorin_general.htmlA non-surgical method to suppress testosterone
http://prdupl02.ynet.co.il/ForumFiles_2/23999370.pdfPros and Cons of Neutering
E. Hardie
Department of Clinical Sciences, North Carolina State University, Raleigh, NC, USA.
http://www.doglistener.co.uk/neutering/rspca.shtmlRSPCA Admit to Spaying and Castrating Puppies AT SIX WEEKS OLD
Stan Rawlinson MTCBPT.MPAACT
Doglistener Behaviourist and Obedience Trainer
http://users.lavalink.com.au/theos/Spay-neuter.htm#vaccShould I spay or should I no..? -- pros and cons of Spay-neuter
Hungarian Vizsla Health Resource
http://www.doglistener.co.uk/neutering/spaying_neutering.shtmlSpaying and Castration (Neutering) Dogs and Cats A Stark Warning
Stan Rawlinson, a full time Dog Behaviourist and Obedience Trainer.
http://www.wholedognews.com/Spay, Neuter, and Cancer: Revisiting and Old Trinity
Myrna Milani, BS, DVM
http://www.caninesports.com/SpayNeuter.htmlEarly Spay-Neuter Considerations for the Canine Athlete One Veterinarian's Opinion
© 2005 Chris Zink DVM, PhD, DACVP
http://www.columbusdogconnection.com/Documents/PedRebuttal%20.pdfRebuttal to "Early Spay-Neuter Considerations for the Canine Athlete"
Lisa M Howe, DVM, PhD, Dipl. ACVS Associate Professor, Small Animal Surgery Co-Chief
Surgical Sciences Sect Dept of Vet Small Animal Clinical Sci
College of Vet Med and Biom Sciences Texas A&M Univ College Station TX 77843
http://www.pluggd.tv/audio/channels/dog_talk_the_radio_show/episodes/4njnhDog Talk Show #96 Tracie Hotchner (10-18-2008)
Early spay/neuter may be harming our dogs! Hear Dr. Christine Zink, DVM, PhD, DAVCP on the physical benefits of delaying neutering and trainer Parvene Farhoody on how it can reduce aggression.
http://www.antrozoologisenteret.no/artikler/art_breed.pdfEffects of breed, sex, and neuter status on trainability in dogs
James A. Serpell* and Yuying Hsu+
http://users.skynet.be/fa242124/a-english/castration-dogs.htmlGonadectomy and behavior
Dr Joël Dehasse
http://homepage.psy.utexas.edu/homepage/faculty/Gosling/reprints/AABS05DogPersonalityReview.pdfTemperament and personality in dogs (Canis familiaris): A review and evaluation of past research
Amanda C. Jones *, Samuel D. Gosling
http://www.skeptvet.com/index.php?p=1_23_Benefits-Risks-of-NeuteringEvaluating the Benefits and Risks of Neutering
The SkeptVet - the owner of this blog is not identified but the articles referenced are searchable.
http://www.petfinder.com/for-shelters/pediatric-spay-neuter.htmlPediatric Spay/Neuter
Dr. Lila Miller, ASPCA
http://k9harmony.co.uk/spaying-and-castration/Spaying and Castration - What Your Vet and the Rescue Centres May Not Tell You
Pauline Waller, member #178 Professional Association of Applied Canine Trainers, - articles referenced and searchable
http://www.champdogsforum.co.uk/cgi-bin/board/topic_show.pl?pid=1123732;hl=castrate#pid1123732To Castrate or Not? - Interesting discussion regarding a young male targeted by an aggressive older male.
http://www.cdoca.org/downloads/files/Early%20SN%20and%20Behavior.pdfNon-reproductive Effects of Spaying and Neutering on Behavior in Dogs
Deborah L. Duffy, Ph.D., and James A. Serpell, Ph.D., Center for the Interaction of
Animals and Society, School of Veterinary Medicine, University of Pennsylvania
http://www.2ndchance.info/spayneuter.htmAt What Age Should I Spay or Neuter My Dog or Cat?
What Are The Advantages And Disadvantages Of Neutering My Pet?
Revisiting The Idea Of Early-Age Neutering
Ron Hines DVM PhD 10/05/09
http://saveourdogs.net/category/health/Articles and links to Veterinary organizations opposing mandatory spay/neuter
http://askdryin.com/blog/tag/dog-behavior-arousal-aggression-spay-neuter/Can Spaying Make Dog Behaviour Worse?
Sophia Yin, DVM, MS March 5, 2009
http://www.associationofanimalbehaviorprofessionals.com/effects_of_neutering.htmlThe Effects of Spaying and Neutering on Canine Behaviour
James O'Heare, Based on section from Aggressive Behavior in Dogs, 2006,
http://www.petfriendlyworld.com/chatforum/showthread.php?t=23096The Behavioural Effects of Canine Castration
Hazel Palmer, 1993 See post #8 in the chat forum at Pet Friendly World.
http://www.cdoca.org/downloads/files/Early%20SN%20and%20Behavior.pdfDoes Spaying and Neutering Reduce Aggression?
Dr. Polley DVM, 2001 American Dog Breeders Association
http://www.gpmcf.org/respectovaries.htmlA Healthier Respect for Ovaries (in dogs)
David J. Waters, DVM, PhD, Diplomate ACVS
Director, Center for Exceptional Longevity Studies
Gerald P. Murphy Cancer Foundation
http://news.uns.purdue.edu/x/2009b/091201OvarianResearch.htmlMessage for women and dogs: keeping ovaries is linked to longevity
To the Purdue Research Park,
http://www.purdueresearchpark.comhttp://www.rockllewellinsetters.com/OvaryExposureLongevityStudyfromAgingCellJournalbyDavidJWatersetalDec2009.pdfExploring mechanisms of sex differences in longevity: lifetime ovary exposure and exceptional longevity in dogs
David J. Waters,1,2 Seema S. Kengeri,1 Beth Clever,1 Julie A. Booth,1 Aimee H. Maras,1 Deborah L.
Schlittler1 and Michael G. Hayek3
http://www.avma.org/onlnews/javma/may09/090515j.aspAVMA: Mandatory spay/neuter a bad idea
Javma News, May 15, 2009
http://www.pet-informed-veterinary-advice-online.com/male-dog-neutering.htmlVeterinary Advice Online: Male Dog Neutering
http://www.pet-informed-veterinary-advice-online.com/dog-spaying.htmlVeterinary advice Online: Dog Spaying (Spaying a Female Dog)
Dr. Shauna O'Meara Pet Informed:
http://www.pet-informed-veterinary-advice-online.com/index.htmlhttp://www.journals.elsevierhealth.com/periodicals/applan/article/S0168-1591(08)00114-7/abstract
Breed differences in canine aggression 1, Dec. 2008
Deborah L. Duffy, Yuying Hsub, James A. Serpella
http://cebp.aacrjournals.org/content/11/11/1434.fullEndogenous Gonadal Hormone Exposure and Bone Sarcoma Risk
Dawn M. Cooley, Benjamin C. Beranek, Deborah L. Schlittler, Nita W. Glickman, Lawrence T. Glickman, and David J. Waters