The Impact of Early Spaying and Neutering on Dogs: What the Science Says

Published: September 27, 2025

For many dog owners, spaying or neutering is a standard choice to prevent unwanted litters and manage behavior. However, a recent study published in the Journal of Small Animal Practice (September 2023) suggests that the timing of these procedures can have significant health implications. Analyzing data from 20,590 dogs, the research indicates that early spaying (before ~3 years in females) and neutering (before ~2 years in males) may increase the risk of torn knee ligaments and joint issues. Let’s explore the findings and their relevance for your dog.

The Study: What Did It Find?

This UK-based study, led by Rachel Casey and colleagues from the University of Bristol, used the VetCompass database to track health outcomes across a diverse dog population. The key insight? Timing is critical. Dogs neutered before reaching skeletal maturity—typically around 1–2 years depending on size—showed a higher incidence of orthopedic problems, including cranial cruciate ligament (CCL) ruptures and hip dysplasia.

Females: Spaying before 12 months increased the odds of CCL rupture by 1.5–2.0 times. Delaying past 18–24 months reduced this risk, supporting the ~3-year threshold for safer outcomes.

Males: Neutering before 6 months raised the odds of joint disorders by up to 2.5 times, with risks dropping after 18 months (~2-year threshold).

Mechanism: Early removal of reproductive organs disrupts growth plate closure, altering joint development and stressing ligaments.

The study also highlighted behavioral benefits of early neutering but stressed weighing these against potential joint risks, especially in larger or more active dogs.

Beyond the Basics: Hormone-Sparing Alternatives

Veterinary reproduction specialists now recommend hormone-preserving sterilization methods, such as vasectomy for males or ovary-sparing spays for females. These prevent reproduction—stopping unwanted litters with 99% effectiveness—while retaining hormones that support joint health. The study suggests this approach could reduce CCL and joint issue risks by 20–50% compared to traditional methods.For dog owners, this opens a new avenue: delaying routine neutering until skeletal maturity (around 18–24 months) unless medically necessary, or exploring these alternatives. Consult your vet for tailored guidance.

Broader Context: Supporting the EvidenceThis finding aligns with other research. A 2020 UC Davis study of 35,000+ dogs and a 2014 PLoS One analysis of multiple breeds confirm that early gonadectomy increases joint disorder odds by 1.5–3x. These studies suggest delaying neutering, particularly in larger or active dogs, can mitigate risks without significantly raising cancer rates.

What This Means for You

Consider these steps for your dog:

Delay When Possible:

Aim for neutering after 18 months, aligning with skeletal maturity, to minimize joint risks.

This blog is based on the referenced study and related research as of September 27, 2025. Always consult a veterinarian for personalized advice.

Availability of Hormone-Sparing Sterilization in the UK

hormone-sparing alternatives like vasectomy for male dogs and ovary-sparing spay (also called ovary-sparing hysterectomy or OSH) for females are available in the UK, though they are not yet widely offered or routine procedures. These methods are gaining interest due to emerging research on the benefits of preserving natural hormones for joint health,behaviour, and overall well-being, while still preventing reproduction. However, availability depends on finding specialized veterinary practices, and they may cost more than traditional spay/neuter due to the specialized surgical techniques required.

Current Status and Recommendations

Ovary-Sparing Spay (for Females): This procedure removes the uterus and cervix but leaves the ovaries intact, allowing hormone production to continue. It prevents pregnancy and pyometra (uterine infection) but retains heat cycles. It's recognized in veterinary literature and performed by some UK vets, often laparoscopically for better access.

Local Vets (a UK-based chain) explicitly offers it, noting benefits like lower risks of urinary incontinence and joint issues compared to full spays.

Veterinary resources like Vetlexicon confirm it's an option for owners wanting prolonged hormonal exposure, though not frequently done.

Vasectomy (for Males): This cuts or blocks the vas deferens to stop sperm production, rendering the dog infertile while keeping the testicles and testosterone levels intact. It maintains male behaviors but avoids full castration's potential downsides. It's rarely performed in the UK and typically only under specific circumstances, such as for working dogs (e.g., police dogs) where hormone retention is desirable.

Some practices, like Hook Norton Veterinary Group, offer keyhole (laparoscopic) vasectomies as an alternative to full neutering.

These procedures align with the study's suggestion of reducing CCL and joint risks by 20–50%, as they preserve growth-supporting hormones without full gonad removal.

The American Veterinary Medical Association endorses them as valid alternatives, and UK vets are increasingly discussing them in light of similar European trends where neutering is less aggressively promoted.

How to Access Them in the UK

Finding Providers: Start with the "Ovary Sparing Spay and Vasectomy For Dogs UK" Facebook group, which has a directory of UK vets offering these services (over 1,000 members sharing experiences and recommendations).

A linked note in the group lists specific practices performing alternative altering procedures.

Search for "gonad-sparing sterilization UK vets" or contact referral services like the British Veterinary Association for specialists.

Considerations: Not all vets are trained in these (e.g., vasectomies require expertise to avoid complications like sperm granulomas).

Costs may range from £300–£800+ (similar to or higher than standard procedures), depending on location and method. Always discuss with your vet: They'll assess your dog's age, health, and lifestyle, as these aren't suitable for everyone (e.g., if behavior issues stem from hormones).

Explore Alternatives: Discuss hormone-sparing options with your vet to balance reproduction control with health.

Monitor Health: Watch for lameness or joint stiffness, especially if your dog was neutered young.

Advocate: Share this info with other dog lovers to encourage informed decisions.

Final Thoughts

The choice to spay or neuter is personal and should involve your veterinarian, considering your dog’s size, activity level, and local regulations. This study doesn’t oppose the procedures but underscores the importance of timing and alternatives. Preserving your dog’s joint health might be as simple as waiting a bit longer or opting for a modern approach. Check the full study (DOI: 10.1111/jsap.7023) for more details,