For decades, the advice was simple and rarely questioned: spay or neuter your dog at six months, before the first season, and don’t think about it again. Then the research caught up, and it turned out the timing of that decision matters far more than anyone appreciated — especially for large, athletic herding breeds. The honest answer today isn’t “yes or no”. It’s “when”, and the right “when” depends on your dog.
I want to walk through what the data actually shows, because there’s a lot of confident misinformation in both directions, and herding-breed owners deserve the real trade-offs.
Why the Old Advice Changed
The turning point was a body of breed-specific research from the University of California, Davis, which examined large numbers of dogs by breed and looked at how the age of neutering correlated with joint disorders and certain cancers. The findings were striking, and they varied enormously by breed — which is precisely why blanket advice was always doomed.
The headline for large herding breeds: neutering before the growth plates close raises the risk of certain joint disorders and some cancers, in some breeds by two to four times. This isn’t fringe opinion; it’s the pattern that keeps appearing across the breed-specific data.
The mechanism makes biological sense. Sex hormones do more than drive reproduction — they signal the growth plates at the ends of the long bones to close at the right time. Remove those hormones early and the plates stay open longer, so the bones grow slightly longer than nature intended. That subtly alters the angles and alignment of the joints, which loads structures like the knee and hip abnormally. In a breed already carrying orthopaedic risk, that’s a meaningful nudge in the wrong direction.
The Joint Risk: Cruciate and Hips
This is where it gets concrete for herding owners. Early neutering is associated with higher rates of cranial cruciate ligament disease and hip dysplasia in several large breeds. Given that a torn cruciate is already the most common career-ending injury I see in active shepherds, anything that raises that risk deserves serious weight in the decision.
The same logic touches the hips. The developmental nature of hip dysplasia in herding breeds means anything that alters how the growing joint forms can tip a borderline hip toward trouble. For a working dog whose whole life depends on sound joints, letting the skeleton finish maturing before removing the hormones that govern it is a defensible, evidence-based choice.
In practical terms, that’s why many vets now suggest waiting until somewhere around 12 to 18 months for large herding breeds — letting the growth plates close first — rather than the old six-month default.
The Cancer Picture Cuts Both Ways
Here’s where I have to be careful, because cancer is the area people most often hear half the story.
Some cancers are more common in dogs neutered early — certain breeds show raised rates of conditions like lymphoma, mast cell tumours and haemangiosarcoma associated with early sterilisation. That’s a genuine concern, and haemangiosarcoma in particular is one I’d never wave away in this breed group.
But neutering also reduces some cancer risks, and these are not trivial. Spaying a bitch dramatically cuts the risk of mammary cancer — the protection is strongest when done before the first or second season, and mammary tumours are common and frequently malignant. Spaying also entirely removes the risk of pyometra, a life-threatening infection of the uterus that affects a substantial proportion of intact older bitches and kills some of them. Neutering a male eliminates testicular cancer and reduces prostate problems.
So you cannot honestly say “neutering causes cancer” or “neutering prevents cancer”. It shifts the risk profile — down for some, up for others — and the balance differs by sex and breed. For a bitch, the pyometra and mammary protection are weighty arguments in favour that simply don’t exist for a male.
It’s About Timing, Not a Verdict
The thing I want owners to internalise is that this is a decision with trade-offs on every option — there’s no risk-free choice, only different risks.
- Neuter early (around six months): simplest behaviourally, strongest mammary-cancer protection in bitches, no pyometra risk — but the highest joint-disorder risk in large breeds and a raised profile for certain cancers.
- Delay to skeletal maturity (12–18+ months): lets the joints finish forming, lowering orthopaedic risk — but means managing a season or two, accepting a smaller window of mammary protection, and a period of intact behaviour.
- Leave entirely intact: preserves full hormonal development — but carries pyometra risk in bitches, mammary risk, unwanted-litter responsibility, and management of hormonal behaviours.
For most large herding breeds, my general steer is to wait until the dog is physically mature before neutering, because the joint argument is strong and the dogs are built for athletic work. But “general” is doing real work in that sentence. A bitch with a strong family history of mammary cancer, an owner who genuinely cannot manage a season safely, or a dog with behavioural issues that hormones are clearly driving — each of those can rightly shift the calculation.
Have the Conversation Properly
This is a decision to make with your vet, dog in front of you, not from a forum post or a breeder’s blanket rule. Bring the specifics: the breed, the sex, the family health history, your living situation, what the dog is actually for. A working Malinois headed for years of athletic demand has a different optimal answer from a companion dog in a household that can’t safely manage seasons.
The one thing I’d ask you to drop is the idea that there’s a single correct age that applies to every dog. The UC Davis work demolished that. What it gave us instead is better: the ability to make a timed, breed-aware decision that genuinely fits the dog in front of you.
The Bottom Line
Spaying and neutering still have real benefits — but for large herding breeds, when you do it changes the risk to the joints and to certain cancers, sometimes substantially. Treat it as a timing question, weigh the trade-offs honestly with your vet, and in most athletic herding dogs, give the skeleton time to finish before you remove the hormones that built it.