Spay / Neuter
When should I spay or neuter my dog?
There is no single right age. The evidence now points to size and breed-specific timing rather than the blanket six-month rule most of us grew up with.
By Dr. Elena Rowe, DVM · Reviewed by Dr. Priya Anand, DVM, DACVIM · Updated 2026-08-28 · 11 min read
Why the old six-month rule changed
Large retrospective studies at UC Davis examined dozens of breeds and found that in several large breeds, desexing before twelve months was associated with higher rates of cranial cruciate ligament rupture, hip dysplasia and some cancers. In small breeds, those associations largely disappear.
Sex hormones contribute to growth-plate closure. Desexing before the plates close produces slightly longer limbs and altered joint angles, which is the leading explanation for the orthopedic findings.
Timing by adult size
Use these as a starting point for a conversation with your vet, not a prescription:
- Under 20 lb adult: six to nine months is generally uncomplicated
- 20–50 lb: nine to twelve months for many breeds
- 50–90 lb (Golden Retriever, Labrador, Bernedoodle): often twelve to eighteen months, later for males
- Giant breeds: after eighteen months, once growth plates have closed
- Females: many vets recommend waiting until after the first season in large breeds, balancing mammary risk against orthopedic risk
Arthritis and orthopedic considerations
The orthopedic concern is not surgery itself but its timing relative to skeletal maturity. Dogs desexed very early in large breeds show higher cruciate rupture rates, and cruciate injury is a leading cause of secondary osteoarthritis later in life.
If early desexing is unavoidable — a rescue requirement or a breeder contract — you can offset a good deal of risk with lean body condition, controlled growth in the first year, avoiding repetitive high-impact exercise before eighteen months, and building sustained muscle support around the joints.
The whole picture
Weigh mammary tumour and pyometra prevention, unwanted litters, roaming and intrasexual aggression, household management of seasons, and the individual dog's breed data. A well-managed intact dog and a well-timed desexed dog are both reasonable outcomes; an unmanaged intact dog is not.
Frequently asked questions
- Does neutering calm a dog down?
- It reduces roaming, marking and some intrasexual aggression, but it does not reduce general excitability or fix fear-based behaviour, which is training and management territory.
- Does early neutering cause arthritis?
- It does not cause arthritis directly. It is associated with higher rates of joint disorders in some large breeds, and those injuries commonly lead to osteoarthritis later.