That risk isn’t evenly spread either. Some dogs are much more likely to tear an ACL than others. Two of those four risks are under your control.

Risk Factors For ACL Injuries In Dogs

Let’s take a tour through what we know. I’ll start with the risks you can’t control.

1. Breed

Every vet knows that some breeds are more likely to ‘do a cruciate’ than others. We don’t understand the mechanism, but it’s probably related to the shape of their joints and their tendency for arthritis.

This is a good time to explode a particular myth about dog ACLs. They almost never tear during sporting activities. Most dog cruciate ligaments which rupture have been slowly degenerating for some time until they finally go ‘pop’. This might happen on a walk or a trip to the toilet.

When many owners of affected dogs look back, their dog has been getting little twinges for some time before the failure occurs. The reason for this is that there has been something wrong with the joint for a while. It’s rare for me to operate on a cruciate ligament and not to see pre-existing arthritis for example.

Breeds At Higher Risk Of A Torn ACL

So what are those breeds? The following table comes from a recent Swedish study. Although it’s missing the common Australian breeds, my impressions are that these breeds are rarely affected anyway.

2. Age

The average age for a dog to rupture a cruciate ligament is seven. In other words, they are neither young nor old. But this average hides important differences between breeds too.

There are those that go early.

And those that go late.

Of course, there’s nothing you can do about this once you’ve chosen a dog. The next two are where you can really make a difference.

3. Body Condition

Excess body condition has a significant effect on the risk of cruciate rupture. In the study referenced below, a dog with a torn ACL was around twice as likely to be overweight as an average member of the same breed.

It’s hard to say what this means for the risk of tearing the ACL in the first place, but it also probably also doubles.

Body condition is not the same as body weight. Within a breed, dogs of different sizes but the same body condition do not have a different risk.

4. Desexing Age

The most recently understood risk factor is the age at which a dog is desexed or neutered. Neutering itself does not increase the risk as long as the right time is chosen.

The big message to come out of 2020 is that this risk is unpredictable, and varies greatly between dogs (those pesky breeds again!).

You can imagine my mood when I read the paper and realised I had to write 40 web pages to properly explain the risk for each breed. Let’s just say that you get to reap the benefit and I’m glad it’s over.

There are also some general guidelines for dogs of different sizes. Personally, I would also delay desexing for any of the higher risk breeds shown above.

What About Exercise?

What doesn’t increase the risk is the type of activity of your dog. This fits with my experience; we almost never see Greyhounds with ruptured cruciates for example.

When a dog tears their ACL it’s usually no one’s fault. Not even their own!

If this has happened to your dog, don’t despair. Repair techniques only get better, and after the recovery, a normal life awaits.

You might also like: How To Fix A Torn ACL In Dogs

References

Engdahl, K., Emanuelson, U., Höglund, O., Bergström, A., & Hanson, J. (2021). The epidemiology of cruciate ligament rupture in an insured Swedish dog population. Scientific reports, 11(1), 1-11

Lampman, T. J., Lund, E. M., & Lipowitz, A. J. (2003). Cranial cruciate disease: current status of diagnosis, surgery, and risk for disease. Veterinary and Comparative Orthopaedics and Traumatology, 16(03), 122-126

Terhaar, H. M., Muir, P., Baker, L. A., Binversie, E. E., Chi, J., & Sample, S. J. (2020). Contribution of habitual activity to cruciate ligament rupture in Labrador Retrievers. Veterinary and comparative orthopaedics and traumatology: VCOT, 33(2), 82

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

While the paper isn’t perfect (more on that later), it does provide the first evidence for Yorkies on choosing a time of desexing with the fewest health problems. The study compared dogs neutered at different ages for their rates of:

• hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

UI was not reported in any of the spayed females.

If this table makes no sense, it’s mostly because there are no abnormal findings. Have a look at this one for Golden retrievers as a comparison. 

Summary: The Best Yorkshire Terrier Spay & Neuter Times

There is minimal evidence that Yorkie health problems are influenced by the age of neutering. Owners of either sex are therefore free to choose the age of desexing that suits them best.

Recommendation: 6 months for both sexes.

This is so far the only science we have for the best desexing age in Yorkies. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

Problems With This Study

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers. The following comment in the paper is a clue that it might also have been true for this population:

Across all breeds the mean age of last entry in the record for neutered males was 5.5 years (range 3.71–6.54), for neutered females 5.7 years (range 4.21–6.97), for intact males 4.9 (range 4.15–7.11), and intact females 4.7 (range 3.41–6.32)

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Yorkshire Terrier at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 35 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

While the paper isn’t perfect (more on that later), it does provide the first evidence for Westies on choosing a time of desexing with the fewest health problems. The study compared dogs neutered at different ages for their rates of:

• hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

There was a single case of UI in the females spayed < 6 months and in those spayed 6-11 months.

If this table makes no sense, it’s mostly because there are no abnormal findings. Have a look at this one for Golden retrievers as a comparison. 

Summary: The Best Westie Spay & Neuter Times

There is minimal evidence that Westie health problems are influenced by the age of neutering. Females spayed early had a higher incidence of urinary incontinence but the numbers are far too small to be meaningful.

Recommendation: 6 months for both sexes

This is so far the only science we have for the best desexing age in Westies. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

Problems With This Study

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers. The following comment in the paper is a clue that it might also have been true for this population:

Across all breeds the mean age of last entry in the record for neutered males was 5.5 years (range 3.71–6.54), for neutered females 5.7 years (range 4.21–6.97), for intact males 4.9 (range 4.15–7.11), and intact females 4.7 (range 3.41–6.32)

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the West Highland White Terrier at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 35 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

While the paper isn’t perfect (more on that later), it does provide the first evidence for Shi Tzus on choosing a time of desexing with the fewest health problems. The study compared dogs neutered at different ages for their rates of:

• hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

UI was not reported in any of the spayed females.

Summary: The Best Shi Tzu Spay & Neuter Times

There is minimal evidence that Shi Tzu health problems are influenced by the age of neutering other than an increase in cancer noted in females spayed over 12 months of age.

Recommendation: 6 months for both sexes.

This is so far the only science we have for the best desexing age in Shi Tzus. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

Problems With This Study

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers. The following comment in the paper is a clue that it might also have been true for this population:

Across all breeds the mean age of last entry in the record for neutered males was 5.5 years (range 3.71–6.54), for neutered females 5.7 years (range 4.21–6.97), for intact males 4.9 (range 4.15–7.11), and intact females 4.7 (range 3.41–6.32)

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Shi Tzu at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 35 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

While the paper isn’t perfect (more on that later), it does provide the first evidence for Pugs on choosing a time of desexing with the fewest health problems. The study compared dogs neutered at different ages for their rates of:

• hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

UI was not reported in any of the spayed females.

If this table makes no sense, it’s mostly because there are no abnormal findings. Have a look at this one for Golden retrievers as a comparison. 

Summary: The Best Pug Spay & Neuter Times

There is minimal evidence that Pug health problems are influenced by the age of neutering. Owners of either sex are therefore free to choose the age of desexing that suits them best.

Recommendation: 6 months for both sexes.

This is so far the only science we have for the best desexing age in Pugs. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

Problems With This Study

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers. The following comment in the paper is a clue that it might also have been true for this population:

Across all breeds the mean age of last entry in the record for neutered males was 5.5 years (range 3.71–6.54), for neutered females 5.7 years (range 4.21–6.97), for intact males 4.9 (range 4.15–7.11), and intact females 4.7 (range 3.41–6.32)

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Pug at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 35 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

While the paper isn’t perfect (more on that later), it does provide the first evidence for Shelties on choosing a time of desexing with the fewest health problems. The study compared dogs neutered at different ages for their rates of:

• hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

One female spayed at 6-11 months and two spayed at 1 year developed UI.

If this table makes no sense, it’s mostly because there are no abnormal findings. Have a look at this one for Golden retrievers as a comparison. 

Summary: The Best Sheltie Spay & Neuter Times

There is minimal evidence that Sheltie health problems are influenced by the age of neutering. Owners of either sex are therefore free to choose the age of desexing that suits them best.

Recommendation: 6 months for both sexes.

This is so far the only science we have for the best desexing age in Shelties. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

Problems With This Study

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers. The following comment in the paper is a clue that it might also have been true for this population:

Across all breeds the mean age of last entry in the record for neutered males was 5.5 years (range 3.71–6.54), for neutered females 5.7 years (range 4.21–6.97), for intact males 4.9 (range 4.15–7.11), and intact females 4.7 (range 3.41–6.32)

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Sheltie at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 35 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

Firstly, what are the reasons why we desex male and female dogs? Here is what we know regarding neutering.

Why Desex Male Dogs

• Lifespan is increased
• Aggression between dogs and aggression towards family members are reduced (read here for a full discussion of the effects of desexing on aggression)
• Urine marking and roaming are reduced
• Medical conditions such as prostatic enlargement, cystine bladder stones, perineal hernia, testicular tumour & perianal tumour are reduced or eliminated.

Why Desex Female Dogs

• Lifespan is significantly increased
• Heat periods and unwanted pregnancy are eliminated
• Pyometra (uterine infection) is prevented

To help dog owners I tell them:

Desex males for behaviour; Desex females for health. References can be found below.

Why NOT Desex A Dog?

Apart from infertility, proven negatives associated with desexing include:

• Increased risk of dogs being overweight or obese
• Higher incidence of hip dysplasia and cruciate ligament problems
• Increased rate of certain cancers such as lymphosarcoma, haemangiosarcoma, mast cell tumour
• Prostate and bladder cancer are more common in males
• Urinary incontinence is more common in females

Although they sound scary, we shouldn’t be overly concerned about the cancers associated with desexing. That’s because there’s clearly a trade-off in lower rates of other diseases: neutering gives a moderate increase in lifespan to both sexes of 9 to 12 months. In other words, although some causes of death become more common, other causes of death must become less common.

I’m much more concerned about accidentally increasing the rate of debilitating non-life-threatening diseases. That’s the information I use to decide when to desex.

Best Desexing Age: 39 Dog Breeds

The following data come from two 2020 studies of purebreeds and mixed breeds of different sizes. They looked at the rate of joint problems, cancers, and urinary incontinence at different desexing ages.

In this chart I have chosen a time for neutering that reduces any problems found for each breed. When possible, I have matched it to our general advice below. You can read the raw data and my reasoning by clicking on each breed’s name.

Take away messages:

• small breeds suffer few or no known problems
• many medium-sized and large breeds benefit from a modest delay
• giant breeds do not appear to need later desexing

Now also have a look at the chart featured at the beginning, in which I’ve summarised the results of three older studies from the University of California-Davis. Feel free to focus on the details but I’ll explain the main points later.

This is so far the only science we have for the best desexing age in these breeds. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

The Problem With The Evidence

From reading these studies it’s clear that early desexing increases the risk of joint diseases in certain dog breeds. The argument regarding cancers is less certain. The theory is that hormones influence normal development of joints in some breeds. Once a joint is fully grown, hormones shouldn’t make much of a difference. But there’s still a small problem: body weight.

Not one of these observational studies is controlled for weight. The desexed groups are almost certainly heavier, and we know that weight is a significant risk factor for cranial cruciate ligament disease (CCLD) and hip dysplasia (HD). This is a quote from one study:

…the occurrence of HD and CCL in early-neutered dogs is a combined function of the effect of neutering on growth plates, as well as the increase in weight on the joints brought on by neutering. Reference 1

This doesn’t change the findings, which are statistically significant for most of the large differences. However, the question remains: if an owner can control their desexed dog’s weight, is there still a risk of joint problems? Until this is answered (if ever!), it’s safest to follow these guidelines…

When To Desex A Dog

Apart from specific breed advice above, our general recommendations to all dog owners are below. Prices for the desexing options can be found here.

6 month desexing

The earlier age is still likely to be the best time for most smaller dog breeds. This avoids a heat period in females and pre-empts most behaviour change in males.

Late desexing

Neutering at 12 months is recommended for breeds prone to hip dysplasia and cruciate disease (though the newer data suggests that 6 months is OK for male Labradors and even giant breeds). Later desexing may also be helpful for females with urinary incontinence.

For medium-sized breeds, we recommend waiting until at least 9 months in dogs from 15 kg adult bodyweight. Dachshunds should also be desexed later to reduce the risk of IVDD.

Females with a deeply recessed vulva should also be allowed to have a season to reduce the risk of perivulval dermatitis as adults. After a season in females, it’s best to wait at least 2 months for everything to settle down prior to surgery.

Early age desexing

Early age desexing is important for rescue shelters to avoid overpopulation but otherwise is best avoided. There have been very few good studies looking at 8 week desexing but in my opinion it’s likely that any effects on joints will be magnified by taking desexing even earlier. Read here about the risks of incontinence associated with early age desexing.

Read about the choices available for dog desexing here.

Many owners of male dogs who opt for late desexing find problem behaviours develop that can be quite hard to manage. To these owners, we say: go as far as you can but don’t feel guilty to give up early. Bad habits can be very hard to stop once they start, and the evidence isn’t ironclad. Any delay should help.

When Desexing Exemptions Will Apply

Since July 2018, with compulsory 6-month desexing in South Australia, vets need to register a temporary exemption of some dogs until maturity. The period can be up to 18 months. It can be applied to any breed shown to be at higher risk of hip dysplasia or cruciate disease, not just the ones featured in these studies. This is speaking to the evidence in the safest way and it’s only right.

Just ask us if you want this done; it’s quick and easy. Note that to comply with SA law we will not provide permanent exemptions unless there are compelling health reasons.

In Australia, there is a strong push from society for all dogs to be desexed. I think an impartial reading of the pros and cons of desexing male dogs will lead most people to decide it’s also in their pet’s best interests. Female dogs, who get a comparatively greater lifespan advantage, present an even more compelling case. Although you are welcome to disagree, to me the only decision is when to do it.

Further Reading

References & more studies showing health effects of desexing can be found at our page on Desexing Male Dogs. The five studies quoted here are:

1. de la Riva, G. T., Hart, B. L., Farver, T. B., Oberbauer, A. M., Messam, L. L. M., Willits, N., & Hart, L. A. (2013). Neutering dogs: effects on joint disorders and cancers in golden retrievers. PloS one, 8(2), e55937. Full Article.
2. Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2014). Long-term health effects of neutering dogs: comparison of Labrador Retrievers with Golden Retrievers. PloS one, 9(7), e102241. Full Article
3. Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2016). Neutering of German Shepherd Dogs: associated joint disorders, cancers and urinary incontinence. Veterinary Medicine and Science. Full Article
4. 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, 7, 388. Full Article
5. Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2020). Assisting decision-making on age of neutering for mixed breed dogs of five weight categories: associated joint disorders and cancers. Frontiers in veterinary science, 7, 472. Full Article

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

The study actually looked at 0-9kg crossbreeds but this data should be the closest match to a Cavoodle currently available.

This paper provides the first evidence for small dog breeds on choosing a time of desexing with the fewest health problems. The study compared the dogs neutered at different ages for their rates of:

• joint disorders: hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• cancers: lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

UI was not reported in early spayed females.

If this table makes no sense, it’s mostly because there are no abnormal findings. Have a look at this one for Golden retrievers as a comparison. 

Summary: The Best Cavoodle Spay & Neuter Times

As you can see, there is minimal evidence that health problems in small dogs like Cavoodles are influenced by the age of neutering. Owners of either sex are therefore free to choose the age of desexing that suits them best.

Recommendation: 6 months for both males and females.

This is so far the only science we have for the best desexing age in small dogs. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

The study authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Staffy at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 39 Breeds | Desexing Choices For Dogs | Costs Of Desexing

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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

English Staffordshire Terriers would probably be most similar to Kelpie desexing times.

This paper provides the first evidence for larger dog breeds on choosing a time of desexing with the fewest health problems. The study compared the dogs neutered at different ages for their rates of:

• joint disorders: hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• cancers: lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, my summary to follow):

UI was diagnosed in 3 percent of females spayed at less than 11 months.

Summary: The Best Staffy Spay & Neuter Times

Joint problems were more common in 20-29kg dogs desexed under 1 year of age. UI was also more common in females.

Recommendation: 1 year for both sexes, but the decision may be based on other factors such as:

• local neutering legislation
• risk of male dog aggression to children or unpleasant male behaviour such as urine marking
• risk of pregnancy or reluctance to manage a female in heat
• health problems associated with intact dogs

This is so far the only science we have for the best desexing age in dogs of this size. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

The study authors are to be applauded to bringing into focus one of the most common questions from dog owners. For the Staffy at least, they’ve made the decision a lot easier.

Related: Best Desexing Age For 39 Breeds | Desexing Choices For Dogs | Costs Of Desexing

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.

The study actually looked at 30+ kg crossbreeds but this data should be the closest match to a large breed currently available if it isn’t in covered this list.

While the paper isn’t perfect (more on that later), it does provide the first evidence for large-sized dog breeds on choosing a time of desexing with the fewest health problems. The study compared the dogs neutered at different ages for their rates of:

• joint disorders: hip dysplasia (HD), cruciate ligament injury (CCL) and elbow dysplasia (ED)
• cancers: lymphoma (LSA), mast cell tumour (MCT), haemangiosarcoma (HSA), osteosarcoma (OSA)
• urinary incontinence (UI)

All of these have been suspected to be linked with the age of neutering. Here’s what they found (only bold values are significant, after the four tables you will find my summary):

Dogs 30-39kg

Dogs 40+ kg

UI was only documented in females spayed under 6 months of age.

Summary: The Best Large Dog Spay & Neuter Times

Joint problems were more common in large dogs desexed under 1 year of age.

Recommendation: 1 year for both males and females.

This is so far the only science we have for the best desexing age in large breeds. Your vet, breeder or online group may have a different opinion based on their experience or personal beliefs. It’s perfectly reasonable to take their advice into consideration as well.

The decision may be based on other factors such as:

• local neutering legislation
• risk of male dog aggression to children
• risk of pregnancy or reluctance to manage a female in heat
• health problems associated with intact dogs

Problems With This Study

In the original paper, the authors appear to make some recommendations based on very limited evidence. I have published the original study data so you can see the actual numbers involved and decide for yourself.

The authors do not mention the well-known increase in lifespan associated with desexing male and female dogs, which tends to counteract most concerns about specific cancers.

The study tries to also look at the rates of mammary cancer & pyometra in females, but cannot give an accurate assessment for two reasons:

1. the mean ages listed above are far too young to pick up most cases
2. pyometra and mammary cancer are rarely referred to university hospitals

Regardless of any concerns, the authors are to be applauded to bringing into focus one of the most common questions from dog owners. For large breed dogs, they’ve made the decision a lot easier.

Related: Best Desexing Age For 39 Breeds | Desexing Choices For Dogs | Costs Of Desexing

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here.