Spaying and neutering are cornerstones of responsible pet ownership: reducing unwanted litters, certain cancers, and some behavior problems. But over the past decade a growing body of veterinary research has shown that timing matters. For some breeds, especially large and giant breeds, delaying gonadectomy (spay/neuter) until after skeletal maturity can reduce the risk of certain joint disorders. This post explains why, which breeds are most affected, what early spay/neuter prevents, and what risks come with waiting; with references to the scholarly literature so you can dig deeper.
Quick summary (if you just want the bottom line)
Why delay?
Sex hormones influence growth-plate closure and bone/joint geometry; removing them too early can prolong bone growth and change joint biomechanics, increasing risk of hip dysplasia, cranial cruciate ligament (CCL) disease and elbow problems in some breeds.
Which breeds most often recommended to wait?
Many large and giant-breed dogs (e.g., Labradors, Golden Retrievers, German Shepherds, Rottweilers, Mastiffs and similar) but recommendations are breed- and sex-specific. Consult breed-specific tables from veterinary studies
What early spay/neuter prevents:
Unwanted pregnancies, much lower mammary tumor risk if spayed before first heat (female dogs), reduced roaming and some hormonally driven behaviors in males and females.
Risks of waiting:
Chance of unwanted pregnancy, pyometra (uterine infection) in intact females, some sex-hormone-related cancers and behavioral changes, and shelter/public policy issues. There is also increased cost as larger animals need more time and resources when it comes to surgery (Though not as much as a knee surgery later on).
1) How sex hormones affect bones and joints: The basic biology
Sex hormones (estrogens and androgens) help trigger growth-plate (physeal) closure during puberty. If a dog is spayed or neutered before those plates close, the bones can grow for a longer period of time, often resulting in slightly longer limbs and altered joint angles (for example, changes to the tibial plateau angle). Those geometric changes can increase mechanical stress on joints and soft tissues (like the cranial cruciate ligament (ACL in humans)), raising the risk for injuries and degenerative joint disease later in life. This mechanism is documented in veterinary reviews and experimental studies of growth-plate timing.
2) Which breeds are most commonly advised to delay spay/neuter?
Research shows the effect is not uniform across all dogs. It’s most pronounced in medium-to-large and giant breeds that naturally have longer growth periods and higher adult body mass. Key breed groups that studies highlight include:
- Labrador Retrievers and Golden Retrievers: several studies found increased joint disorder risks after early gonadectomy in these breeds.
- Large/giant breeds (e.g., German Shepherds, Rottweilers, Mastiffs, Great Danes and many hunting breeds): Breed-specific research and pooled analyses (Frontiers/UC Davis work) identified greater orthopedic risk associated with neutering before skeletal maturity in many of these heavier breeds.
Important caveat: the exact “best age” varies by breed and by sex. Recent large breed-specific analyses and breed tables (for 40+ varieties) are available in the veterinary literature and on the UC Davis/Frontiers summaries; they recommend individualized timing rather than one blanket age for all dogs. Always review breed-specific evidence with your veterinarian.
3) What joint problems are linked to early spay/neuter?
Studies connect early gonadectomy (commonly defined in research as before 6–12 months) to a higher incidence of:
- Cranial cruciate ligament disease (CCL / CCLD): ligament rupture or degeneration.
- Hip dysplasia / osteoarthritis: altered hip joint development and earlier degenerative changes.
- Elbow dysplasia in some breeds.
Multiple cohort and epidemiologic studies show that younger age at gonadectomy is associated with increased odds of some of these conditions, though, effect sizes vary by breed and sex. Recent reviews urge breed-tailored decisions rather than universal early-neuter policies.
4) What does early spaying/neutering prevent?
It’s important to weigh the joint-development trade-offs against the real benefits of early gonadectomy:
- Population control: prevents unplanned litters (a key shelter and public-health goal).
- Greatly reduced mammary (breast) cancer risk in females when spayed before the first heat. Long-standing evidence supports early spay for cancer prevention in many contexts.
- Reduced roaming, marking, and some aggressive/sexual behaviors that are hormonally driven (particularly intact males).
So: for many small or mixed-breed dogs, the advantages of early neutering (particularly in population control and behavior) may still outweigh the orthopedic concerns. For some large/giant breeds, the orthopedic risks push the balance the other way.
5) What are the risks if you do wait to spay/neuter?
Delaying gonadectomy to protect joints is not risk-free. Potential downsides include:
- Unwanted pregnancies and the burden of managing intact females in heat.
- Pyometra (potentially life-threatening uterine infection) risk increases with age and every heat-cycle or attempted breeding in intact females.
- Certain hormone-linked cancers (in some studies the relationships are complex and breed-dependent). For example, breed-specific cancer risks have been reported and must be weighed alongside orthopedic risk.
- Behavioral or management issues such as roaming, marking, and intact male aggression/territorial behaviors, which may affect quality of life and public safety.
- Increased cost of the surgery. Many veterinary centers charge more for larger animals. Larger animals require longer surgery time, materials (suture, drugs, etc), more people to lift and care for patients safely.
Additionally, shelter and clinic policies sometimes require early neuter for animals adopted from rescues. So, owners should plan and discuss timing early if they adopt a puppy.
6) How veterinarians and researchers recommend deciding
Current expert guidance increasingly favors a personalized, evidence-based approach:
- Assess breed and sex: consult breed-specific data (e.g., the Frontiers / UC Davis research summaries that examined dozens of breeds).
- Consider weight and growth patterns: heavier adult weight is a risk factor for osteoarthritis and some joint injuries.
- Factor in lifestyle and household risk: risk of roaming, likelihood of accidental breeding, ability to manage an intact animal, and owner capacity to monitor for heat cycles or mating.
- Talk to your vet about timing: many vets now recommend delaying to ~12-18 months (or until growth plate closure) for large and giant breeds; however, exact ages vary by breed and sex and by the specific risk profile. Recent large-scale breed tables (UC Davis / Frontiers) are a useful starting point.
7) Practical steps for owners considering a delayed spay/neuter
- Ask your veterinarian for breed-specific evidence: You can also find your own online with UC Davis and Frontiers.
- Monitor weight and condition: Maintain an optimal body condition score to reduce orthopedic stress.
- Plan for reproductive management: If you delay spay, prepare to manage heat cycles and prevent accidental matings. Also plan for increased cost due to size difference.
- Consider alternative timing for females: If mammary tumor prevention is a high priority discuss tradeoffs with your vet.
8) Bottom line (evidence-based takeaways)
- The relationship between spay/neuter age and joint health is well supported by multiple studies, but effects are breed- and sex-specific.
- Large and giant breeds are the group most likely to benefit from delaying gonadectomy until later (often until skeletal maturity), because of effects on growth plates and joint geometry.
- Delaying brings trade-offs (pregnancy risk, pyometra, some cancer risks, behavioral issues), so the decision must be individualized and discussed with your veterinarian.
References & Further Reading (scholarly sources)
- Hart BL, Hart LA, Thigpen AP, Willits NH. Assisting decision-making on age of neutering for 35 breeds of dogs: associated joint disorders, cancers, and urinary incontinence. Frontiers in Veterinary Science. 2020.
- Kutzler MA, Wehrend A. Possible relationship between long-term adverse health effects and gonadectomy in dogs. (Review). 2020. (PMC).
- Simpson M, et al. Age at gonadectomy and risk of overweight/obesity and orthopaedic injuries in dogs. PLOS ONE. 2019.
- Graves JL, et al. Body weight, gonadectomy, and other risk factors for osteoarthritis and joint disorders in dogs. Frontiers in Veterinary Science. 2023.
- Howe LM, Slater MR, et al. Optimal age to spay/castrate: evidence review. 2015 (veterinary literature).
- UC Davis / Veterinary Medicine summaries and breed tables. Updated guidance on breed-specific timing. (University of California, Davis; Frontiers updates).
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