The Latest Research and Studies
Up to date research references, articles and links
While these resources represent a broad range of studies and points of view, most of them strongly suggest that preserving sex hormone production in dogs leads to greater health and higher quality of life in general.
Scientific Articles and Studies
WSAVA Guidelines for the Control of Reproduction in Dogs and Cats
Conclusion: Emphasizes ethical, health-balanced control.
Romagnoli, S., et al. (n.d.). WSAVA guidelines for the control of reproduction in dogs and cats. Journal of Small Animal Practice.
Conclusion: Gonad-sparing alternatives could mitigate these risks by preserving natural hormone balance.
Zwida, K., & Kutzler, M. A. (2016). Non-reproductive long-term health complications of gonad removal in dogs as well as possible causal relationships with post-gonadectomy elevated luteinizing hormone (LH) concentrations. Parsemus Foundation.
Neutering of German Shepherd Dogs: Associated Joint Disorders, Cancers and Urinary Incontinence
Conclusion: Delaying neutering until after one year minimizes orthopedic and incontinence risks without elevating other cancers.
Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (n.d.). Neutering of German Shepherd dogs: Associated joint disorders, cancers, and urinary incontinence. Veterinary Medicine and Science.
Reproductive Capability Is Associated with Lifespan and Cause of Death in Companion Dogs
Conclusion: Hormonal retention may enhance overall longevity by reducing disease susceptibility.
Hoffman, J. M., Creevy, K. E., & Promislow, D. E. L. (n.d.). Reproductive capability is associated with lifespan and cause of death in companion dogs. PLOS ONE.
Demographic Risk Factors for Lymphoma in Australian Dogs: 6201 Cases
Conclusion: Neutering contributes to oncologic vulnerabilities, calling for targeted risk assessments.
Tonomura, N., et al. (2018). Demographic risk factors for lymphoma in Australian dogs: 6201 cases. Veterinary and Comparative Oncology.
The Effect of Neutering on the Risk of Mammary Tumours in Dogs - A Systematic Review
Conclusion: Early intervention provides strong cancer protection, a key benefit of the procedure.
Beauvais, W., Cardwell, J. M., & Brodbelt, D. C. (2012). The effect of neutering on the risk of mammary tumours in dogs—a systematic review. Journal of Small Animal Practice.
Conclusion: Further studies on LH mitigation could transform safer sterilization practices.
Kutzler, M. A. (2023). Understanding the effects of sustained supraphysiologic concentrations of luteinizing hormone in gonadectomized dogs: What we know and what we still need to learn. Theriogenology.
Conclusion: Breed-tailored neutering ages, often post-maturity, lower complication rates.
Hart, B. L., et al. (2024). Assisting decision-making on age of neutering for German Short/Wirehaired Pointer, Mastiff, Newfoundland, Rhodesian Ridgeback, Siberian Husky: Associated joint disorders, cancers, and urinary incontinence. Frontiers in Veterinary Science.
Conclusion: Individualized timing based on breed genetics optimizes health outcomes.
Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2020). Assisting decision-making on age of neutering for 35 breeds of dogs: Associated joint disorders, cancers, and urinary incontinence. Frontiers in Veterinary Science.
Association Between Lifespan and Body Condition in Dogs
Conclusion: Post-neuter weight management is vital for extending dog longevity.
Salt, C., Morris, P. J., Wilson, D., Lund, E. M., & German, A. J. (n.d.). Association between life span and body condition in dogs. Journal of Veterinary Internal Medicine.
Long-Term Health Risks and Benefits Associated with Spay/Neuter in Dogs
Conclusion: Case-specific evaluation, including alternatives, balances welfare needs.
Sanborn, L. J. (n.d.). Long-term health risks and benefits associated with spay/neuter in dogs. NAIA Online.
Gonadectomy Effects on the Risk of Immune Disorders in the Dog: A Retrospective Study
Conclusion: Hormonal disruption post-procedure compromises immune function.
Sundburg, C. R., et al. (2016). Gonadectomy effects on the risk of immune disorders in the dog: A retrospective study. BMC Veterinary Research.
Non-Surgical Methods of Contraception and Sterilization
Conclusion: These methods preserve health while achieving sterility.
Kutzler, M., & Wood, A. (2006). Non-surgical methods of contraception and sterilization. Theriogenology.
A Population Study of Neutering Status as a Risk Factor for Canine Prostate Cancer
Conclusion: Intact status offers protective effects against prostate issues.
Bryan, J. N., et al. (2007). A population study of neutering status as a risk factor for canine prostate cancer. The Prostate.
Urethral Sphincter Mechanism Incompetence in Male Dogs: A Retrospective Analysis of 54 Cases
Conclusion: Early neutering worsens sphincter incompetence.
Aaron, A., et al. (1996). Urethral sphincter mechanism incompetence in male dogs: A retrospective analysis of 54 cases. The Veterinary Record.
New Aspects of Canine Pyometra
Conclusion: This underscores a primary reproductive health benefit of neutering.
Hagman, R. (1970). New aspects of canine pyometra. Swedish University of Agricultural Sciences.
Tumors in Domestic Animals, 4th Edition
Conclusion: Hormones influence overall cancer epidemiology in pets.
Allen, A. (2003). Tumors in domestic animals, 4th edition. The Canadian Veterinary Journal.
Evaluation of the Risk and Age of Onset of Cancer and Behavioral Disorders in Gonadectomized Vizslas
Conclusion: Delaying procedure supports behavioral and oncologic health.
Zink, M. C., et al. (2014). Evaluation of the risk and age of onset of cancer and behavioral disorders in gonadectomized Vizslas. Journal of the American Veterinary Medical Association.
Evaluation of the Prevalence of Urinary Incontinence in Spayed Female Dogs: 566 Cases (2003–2008)
Conclusion: This frequent issue requires proactive management strategies.
Forsee, K. M., et al. (2013). Evaluation of the prevalence of urinary incontinence in spayed female dogs: 566 cases (2003–2008). Journal of the American Veterinary Medical Association.
Effect of Age at Gonadectomy on the Probability of Dogs Becoming Overweight
Conclusion: Dietary vigilance is essential post-procedure.
Lefebvre, S. L., et al. (2013). Effect of age at gonadectomy on the probability of dogs becoming overweight. Journal of the American Veterinary Medical Association.
Conclusion: Neutering could predispose to ligament injuries.
Light, V. A., et al. (2012). Sex hormone regulation of collagen concentrations in cranial cruciate ligaments of sexually immature male rabbits. American Journal of Veterinary Research.
Conclusion: Non-hormonal therapies offer viable alternatives.
De, C. E., et al. (2014). Gonadotropin-releasing hormone immunization for the treatment of urethral sphincter mechanism incompetence in ovariectomized bitches. Theriogenology.
Long-Term Outcome of Gonadectomy Performed at an Early Age or Traditional Age in Dogs
Conclusion: Traditional age may better suit health preservation.
Howe, L. M., et al. (2001). Long-term outcome of gonadectomy performed at an early age or traditional age in dogs. Journal of the American Veterinary Medical Association.
Short-Term Results and Complications of Prepubertal Gonadectomy in Cats and Dogs
Conclusion: Surgical safety is high, but long-term effects need scrutiny.
Howe, L. M. (1997). Short-term results and complications of prepubertal gonadectomy in cats and dogs. Journal of the American Veterinary Medical Association.
Gonadectomy in Immature Dogs: Effects on Skeletal, Physical, and Behavioral Development
Conclusion: Maturity delay affects holistic development.
Salmeri, K. R., et al. (1991). Gonadectomy in immature dogs: Effects on skeletal, physical, and behavioral development. Journal of the American Veterinary Medical Association.
Behavioral and Physical Effects of Spaying and Neutering Domestic Dogs (Canis familiaris)
Conclusion: Hormone loss impacts physique and psyche.
Farhoody, P., & Zink, C. M. (2010). Behavioral and physical effects of spaying and neutering domestic dogs (Canis familiaris). American Temperament Test Society.
Endogenous Gonadal Hormone Exposure and Bone Sarcoma Risk
Conclusion: Natural hormones provide oncologic protection.
Cooley, D. M., et al. (2002). Endogenous gonadal hormone exposure and bone sarcoma risk. Cancer Epidemiology, Biomarkers & Prevention.
Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers
Conclusion: Breed-specific delays are advisable.
de la Riva, G. T., et al. (2013). Neutering dogs: Effects on joint disorders and cancers in Golden Retrievers. PLOS ONE.
Effects of Ovariohysterectomy on Reactivity in German Shepherd Dogs
Conclusion: Behavioral shifts follow hormonal changes.
Kim, H. H., et al. (2005). Effects of ovariohysterectomy on reactivity in German Shepherd dogs. The Veterinary Journal.
Long-Term Health Effects of Neutering Dogs: Comparison of Labrador Retrievers with Golden Retrievers
Conclusion: Breed variations demand customized approaches.
Hart, B. L., et al. (2014). Long-term health effects of neutering dogs: Comparison of Labrador Retrievers with Golden Retrievers. PLOS ONE.
Effect of Gonadectomy on Subsequent Development of Age-Related Cognitive Impairment in Dogs
Conclusion: Hormones aid neurological maintenance.
Hart, B. L. (2001). Effect of gonadectomy on subsequent development of age-related cognitive impairment in dogs. Journal of the American Veterinary Medical Association.
Conclusion: Less invasive sterilization is adequate.
DeTora, M., & McCarthy, R. J. (2011). Ovariohysterectomy versus ovariectomy for elective sterilization of female dogs and cats: Is removal of the uterus necessary? Journal of the American Veterinary Medical Association.
Determining the Optimal Age for Gonadectomy of Dogs and Cats
Conclusion: No one-size-fits-all; consult professionals.
Root Kustritz, M. V. (2007). Determining the optimal age for gonadectomy of dogs and cats. Journal of the American Veterinary Medical Association.
Conclusion: Structural changes contribute to injuries.
Duerr, F. M., et al. (2007). Risk factors for excessive tibial plateau angle in large-breed dogs with cranial cruciate ligament disease. Journal of the American Veterinary Medical Association.
Luteinizing Hormone Receptor Expression by Nonneoplastic and Neoplastic Canine Lymphocytes
Conclusion: Explains post-neuter immune-oncology ties.
Ettinger, A. M. (2019). Luteinizing hormone receptor expression by non-neoplastic and neoplastic canine lymphocytes. American Journal of Veterinary Research.
Canine Splenic Hemangiosarcoma Cells Express and Activate Luteinizing Hormone Receptors In Vitro
Conclusion: Targets for anti-cancer interventions.
Zwida, K. H., & Kutzler, M. A. (2022). Canine splenic hemangiosarcoma cells express and activate luteinizing hormone receptors in vitro. American Journal of Veterinary Research.
Conclusion: Demonstrates reversibility of complications.
Brent, L., et al. (2021). Restoration of reproductive hormone concentrations in a male neutered dog improves health: A case study. Topics in Companion Animal Medicine.
Conclusion: Hormonal role in skeletal integrity.
Kiefel, C. A., & Kutzler, M. A. (2020). Assessment of luteinizing hormone receptor expression in structural support tissues of canine hip and femorotibial joints. American Journal of Veterinary Research.
Gonad-Sparing Surgical Sterilization in Dogs
Conclusion: Ideal for health preservation.
Kutzler, M. A. (2020). Gonad-sparing surgical sterilization in dogs. Frontiers in Veterinary Science.
Conclusion: Central to understanding complications.
Kutzler, M. A. (n.d.). Possible relationship between long-term adverse health effects of gonad-removing surgical sterilization and luteinizing hormone in dogs. Animals.
Conclusion: Individual assessment recommended.
Arroube, A., & Pereira, A. F. (2025). Dog neuter, yes or no? A summary of the motivations, benefits, and harms, with special emphasis on the behavioral aspect. Animals.
Conclusion: Post-maturity neutering advised.
Low, D., et al. (2025). The association between gonadectomy and timing of gonadectomy, and the risk of canine cranial cruciate ligament disease: A systematic review and meta-analysis. Veterinary Surgery.
Conclusion: Impacts personality traits.
Kolkmeyer, C. A., et al. (2024). Personality unleashed: Surveying correlation of neuter status and social behaviour in mixed-breed male dogs across weight classes. Animals.
Age of Neutering Contributes to Risk of Cruciate Ligament Rupture in Labrador Retrievers
Conclusion: Delay for joint health.
DeForge, T. L., et al. (2025). Age of neutering contributes to risk of cruciate ligament rupture in Labrador Retrievers. Journal of the American Veterinary Medical Association.
Resources and Reviews
Exploring How Spay/Neuter Impacts Long-Term Health in Dogs
Conclusion: Promotes informed owner decisions.
American Kennel Club Canine Health Foundation. (n.d.). Exploring how spay/neuter impacts long-term health in dogs. AKC CHF.
Rottweiler Study Links Ovaries with Exceptional Longevity
Conclusion: Ovaries contribute to extended lifespan.
American Veterinary Medical Association. (2010). Rottweiler study links ovaries with exceptional longevity. JAVMA News.
Conclusion: Evidence supports alternatives.
Dogs First. (n.d.). Dog neutering is an emotive subject for welfare and population reasons but let’s take a look at the facts. DogsFirst.ie.
Gonadectomy in Dogs: Considerations & Review
Conclusion: Holistic evaluation key.
Clinician's Brief. (2022). Gonadectomy in dogs: Considerations & review. Clinician's Brief.
Conclusion: Early for shelters, but risks apply.
Kislak, P. (n.d.). Early age spay/neuter. Coalition for Healthy Animals and Humans.
Conclusion: Healthier sterility path.
Parsemus Foundation. (n.d.). Hormone-sparing sterilization. Parsemus.org.
Restoring Hormone Levels in a Neutered Dog Leads to Health Improvements
Conclusion: Restoration aids recovery.
Phys.org. (2021). Restoring hormone levels in a neutered dog leads to health improvements. Phys.org.
Conclusion: Delay protects mobility.
Dogs Naturally Magazine. (n.d.). Spay/neuter and joint disease. DogsNaturallyMagazine.com.
Spaying and Castration (Neutering) Dogs
Conclusion: Explore options thoroughly.
Dog Listener. (n.d.). Spaying and castration (neutering) dogs. DogListener.co.uk.
Your Dog Needs To Be Spayed Or Neutered – Right?
Conclusion: Not universally required.
Veterinary Practice News. (n.d.). Sterilization effects worse for Golden Retrievers than Labs. VeterinaryPracticeNews.com.
Neutering: This Common Procedure Can Boost Cancer and Joint Problems As Much As Five-Fold
Conclusion: Weigh trade-offs carefully.
Illegal in Scandinavia, Surgical Sterilization Is Still Routine in America
Conclusion: Non-surgical alternatives viable.