What Is The Best Age To Desex A Dog?

I’m going to lead you through the evidence we have for the age to desex a dog. I’m not going to give you the ‘right’ answer, but instead the tools so you can make the best decision for your dog. With the new mandatory 6-month desexing in Adelaide, this is the evidence you may need to ask your vet for a postponement.

Beware simple answers. The real world is frustratingly not in black and white; anyone who claims otherwise is either misleading themselves or others. The job of science is to get as close to the truth as is humanly possible.

Firstly, let’s establish the reasons why we desex male and female dogs. Here’s the evidence we have in favour of 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:

Although they sound scary, we shouldn’t be 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.

When To Desex Dogs

There are four times advised by different groups:

  1. Early age desexing as advocated by rescue shelters and some breeders
  2. 6-month desexing as advocated by most vets
  3. Late age desexing, typically over 12 months of age
  4. or Not at all, which from 2018 is no longer an easy option in SA

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.

Now have a look at this chart, in which I’ve summarised the results of three large studies from the University of California-Davis. Feel free to focus on the details but I’ll explain the main points later. These are the only big studies that compare outcomes at different desexing ages.

desex neuter problems
Age of Desexing vs Risk of Cruciate or Hip Problems

The Problem With The Evidence

Striking isn’t it? It’s clear that early desexing increases the risk of joint diseases in susceptible dogs. 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…

The Best Age To Desex A Dog

Our recommendations to 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 smaller dog breeds. This avoids a heat period in females and pre-empts most behaviour change in males.

Late desexing

Neutering at over 12 months is recommended for breeds prone to hip dysplasia and cruciate disease. It may also be helpful for males with anxiety and females with urinary incontinence.

There is no evidence available for medium-sized breeds, but 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.

For dog owners wanting to preserve female hormones through life, Ovary Sparing Spay is another alternative. Follow the link to learn more or 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

From July 2018, with compulsory 6-month desexing in South Australia, vets will need to register an exemption of some dogs until maturity. The period can be up to 18 months. It will apply 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. It’s then up to owners if they want to exercise this option.

Up to now, there’s not enough evidence to extend this advice to other breeds but you can rely on us to keep you informed as new facts emerge.

Further Reading

References & more studies showing health effects of desexing can be found at our page on Desexing Male Dogs. The three 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

By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. These blogs are from a series regularly posted on email and Twitter. Subscribe via email here to never miss a story!
Have something to add? Comments are welcome below and will appear within 24 hours of lodging.


57 Replies to “What Is The Best Age To Desex A Dog?”

  1. Hi Andrew, our 6month old staffy boy has had a fractured tibia pinned and the pins have now been removed. We had been considering getting him desexed soon but was suggested by a vet that may be best to wait til approx. 12months due to hormones effecting growth plates. Thanks

    1. Hi Jess. By now the fracture doesn’t sound relevant to the decision. I advise 9 months for medium-sized dogs but there’s no data to support any specific age except for large breeds.

  2. Hi – we have rehomed a 9yo female yellow lab that has not been desexed. We’re struggling with taking her in for the procedure. What is your recommendation? I guess she will have a longer recovery time being an older dog, and I’m not keen on putting her through this unnecessarily.

    1. Hi Andrew. There’s a clear and proven health benefit with desexing female dogs. Put your trust in a vet and your dog should only benefit.

  3. I have a 5 and 1/2 month old Japanese Spitz, what age should I have him desexed ? Initially I wanted to wait 12months but we find that we need to keep an eye on him in the house now as he is starting to mark furniture. (Only sporadically at this stage)

    1. Hi Steph. There is no reason to change the previous advice of six months for such a small breed. If you are starting to notice behavioural issues this is all the more reason to act quickly.

  4. Hi Andrew, I have a 3 and a half year old female Staffy X. What are the pros and cons of desexing her at this age and should I at all, even if I’m not breeding her?

    1. Hi Kellie. There is a compelling argument for desexing mature female dogs. The only serious drawback is the loss of fertility. In contrast to this, the advantages are: a significantly longer life span, elimination of the risk of pyometra, a reduction in mammary carcinoma.

  5. Hello, I am on a waiting list for a Shetland sheep dog puppy from a reputable breeder. She is saying she sends the puppy to their new owner at 12 weeks of age after being desexed. Is it too young to be desexed prior to 12 weeks of age and lead to potential urinary incontinence & hip dysplasia? Also, is it better to have your puppy around 8 weeks so you can bond and train? Just not sure how to bring my concern to the breeder.

  6. Hi Andrew,
    Thanks for your informative and evidence-based article – really helpful. I am looking at a medium groodle (around 15kg and 45cm at the withers, considering boys and girls but probably will go with boy) from a breeder who insists on desexing at 7 weeks based on population control, lower impact of the operation as a puppy and apparently ‘no evidence that there is any negative impact for dogs this size’. What are your thoughts here? I’m going to try and negotiate (my preference would be to wait until 6months) but as the breeder has had problems with people not honouring desexing commitments before they are unlikely to say yes.

    1. Hi Tom. I am completely against desexing at such a young age, and even 6 months is too soon. The only reason you don’t have breed-specific evidence is that it’s impossible to collect it for all breeds and sizes. The fact that one of the parent breeds is clearly disadvantaged by early desexing should be all the evidence your breeder needs. I would also ask why your breeder feels they need to be the one policing whether a dog is desexed or not. If they really must, then they should only get temporary tubal ligation (females) or vasectomy (males) if they are truly in it for the betterment of animals.

  7. Can you desex a retired 4 yr old male show dog without causing any new issues, behavioural or other. .?. All my previous dogs were desexed before 12 months.

    1. Hi Andrew
      We have a 8mo lab x cocker spaniel. We were trying to wait until he was 12 months but he is humping every night. Should we get him neutered now or try to wait another 4 months? Thanks

      1. Hi Louise. There’s no strong reason to wait given he is likely to be a smaller breed, but I also believe that temperament and behaviour should always take precedence in the decision.

  8. Hi Andrew,
    I’m so confused about what dry food to feed my 2yr German Shepherd male.
    Years ago we fed them on supermarket well known brand and the animals lived longer.
    Now there is all types on the market. I feel dogs/cats not living as long as they did. What do I feed him on? Unfortunately he has Hip Dysplasia too.

  9. Andrew

    I have a miniature spoodle. Very active and friendly. Hard to contain her jumping or standing up which she does with enthusiasm, I am worried about joint disease! I am being very stringent with her diet and regular exercise. I never allowed my old dog to get over weight. But I am worried about desexing. The vet says six months. What are your thoughts?

  10. Hello. My male mini groodle was desexed at 6 weeks by the vet breeder. Now I’m wonder what can I do to to help him not to have the bone related conditions that could arise from desexing so early. Keeping him fit and not allowing a lot of jumping and running around was mentioned to me. Is that right?

    1. Hi Maria. General advice for young puppies is to avoid encouraging running and jumping and especially stairs, and possibly also slippery surfaces. Weight control is also essential, as is good diet. We must also remember that puppies will always run and jump of their own accord and we would go crazy trying to stop them. We need breeders like yours to start asking for their puppies to have a vasectomy instead of a full desexing if they want to do it at six weeks of age. If you feel brave, send them a message!

    1. Hi Sonia. There’s nothing wrong with desexing a dog at two or three years old, it’s just that some of the habits they develop won’t go away completely.

  11. Hi Dr Andrew. I have a 5-month old female Mini Poodle who was born with an umbilical hernia. Our vet has suggested that he will remove the hernia at the same time he spays her. I have researched that poodles can be prone to hip dysplasia. One dog forum member recommends that females should go through one or two heat cycles before spaying to reduce the risk of spay incontinence or perivulval dermatitis as an adult. I am so worried that I’ll get this wrong, and value your input and advice on the best possible age to de-sex a Mini. Is an ovary-sparing spay something I ought to be considering too? Many grateful thanks!

    1. Hi Heather. The problem for all dog owners is this: it’s easy to base a decision on the advice of “One dog forum member“ instead of the evidence or an expert consensus. The information in this article is the best we have. I have never seen hip dysplasia in a miniature or toy poodle – that again shows the detriment of some online advice (it has no doubt occurred, but is so rare that one should not base any decisions around it when there are other more important factors). The best thing you can do is talk it over with your vet based on your individual dog – for example, I can’t comment on perivulval dermatitis without looking at your dog’s conformation and I’m sure your vet would be happy to do so.

  12. Thank you for this great article. I have a 6 month old fox terrier / border collie cross, male pup who will do agility. He seems to be developing much faster than my border collies. So 12 months might be old enough to de-sex him?

    1. Hi Brigette. The best age may depend partly on training needs, but if we look at joint health alone, that would be at over 12 months.

  13. Hello Andrew
    I have a five and a half month old Labrador puppy (girl). When she was four months old she got aspirated pneumonia and nearly died. One of the antibiotics she was put on has quite possibly effected her growth plates. I was warned of this but at the time there was no choice but to give it to her in my mind to save her life. My vet is saying to desex her at 6 months but I am concerned about joint problems for her if she’s desexed too early and I guess also another bout of anesthetic and surgery when she’s not long through being so sick. I also wander about the benefit of letting her have one heat before she’s desexed to let her body ‘normalise’ a bit. What do you think?
    Thankyou for your help.
    All the best

    1. Hi Chris. I’m sure your vet wouldn’t be recommending it if it wasn’t safe but there should be no harm in waiting a bit longer to desex her. The evidence we have is detailed above – it’s not perfect but in our clinic we would wait until 12 months of age.

  14. Hi Andrew,
    I am purchasing a female “Retrieverdor” (Golden Retriever x Labrador) who will be 9 weeks tomorrow and wondering what your suggested age to de-sex would be? I’ve called around to many vets and the receptionist always says “6 months” however the company we purchased from is suggesting to leave it as long as possible, but before she reaches sexual maturity. Im just concerned with the conflicting information and want to be confident that im doing the right thing by my girl. They are suggesting to register as a breeder for a small additional cost at time of registration to allow us to extend the age. I’d love to know your thoughts? Thanks mate

    1. Hi Brendan. Our standard recommendation is to desex at all over one year of age (i.e. after the first heat but before the second heat). You can easily get an exemption from your vet to cover this delay.

  15. Hi Andrew,
    Thank you for presenting the research so beautifully. I have a 6month old Lab pup who will not be allowed to become overweight. He is quite a big framed boy even for his breed and very active. Could you please clarify if the optimal time for desexing to avoid musculoskeletal issues is at 12 months or a specific time after? Thank you !

    1. Hi Anya. The research look at ‘less that 12 months’ vs ‘greater than 12 months’. The older group would have contained dogs desexed at all ages so it’s hard to say. Many breeders say 18 months, but I recommend 12 months as behaviour can become challenging if left too long.

  16. Hi Andrew,
    Thank you for your informative comments and answers.
    I have a female standard.poodle. She is about 17 weeks old. I had thought to get her desexed in a couple of weeks as I will be going overseas for 4 weeks and I am worried that she might come into season whilst my daughter is looking after her. Is this a valid concern of should I wait until she is 6 months old?

    1. Hi Cathy – you can certainly wait until you get back. The chances of a large dog coming into season before six months of age are exceedingly low.

  17. Hi Andrew,
    We have a nearly 1 year Male border collie not desexed yet ( the breeder suggested to wait untill he ll be 18 months) and soon we’ll have a second pup a husky cross kelpie female.
    To avoid issues between them we were thinking to have the new pup desexed pretty soon . She will be 10 weeks old when we ll get her . What’s your suggestion? Should we desexed both or just the female now and the Male when he ll be 18 months old?

    1. Hi Luca. There is no compelling reason to wait any longer to desex your male dog, and in fact there are distinct behavioural disadvantages (let’s not forget that dog breeders are much more willing to manage male dog behaviour and rarely have small children around). There are, however, compelling reasons to delay desexing your female (see this page on incontinence for example). Therefore, I would get the male done ASAP and leave the female to have one heat.

  18. I have a male border collie who zi would like to do agility with and wanting to know if getting him desexed at 6mths wont effect his bone growth.

  19. Hi Andrew
    Does sterilisation as opposed to desexing of a male dog satisfy the intent of South Australian legislation?
    Thank you

  20. Hi Andrew, I have just bought an 8 week old female Dalmatian. Is she classed as a large breed. Should I wait till she stops growing? I am contemplating a hysterectomy and leaving the ovaries.
    Thanks Marie

  21. Hi Andrew, I have just brought home a female Borzoi pup. The breeder has recommended a late desexing for her, as she is a giant breed and early desexing could disrupt her hormones causing excessive growth issues. As I want to do the best for her, I am interested in the veterinary point of view. Is this practise recommended?

    1. Hi Donna. This article sets out everything we know about the optimal desexing age. Therefore you are welcome to make up your own mind from the evidence! The short answer is: yes, we advise waiting until maturity in large breeds.

  22. We are looking to buy a labdradoodle later in the year. The problem is every breeder I have contacted across Australia , whether a member of the Australian Labradoodle association or not, only sells pups at 8 weeks that have already been desexed. As a GP and reading the evidence that concerns me. Are you aware of any Labradoodle breeders that either offer a contract to be desexed at 6 months or offer a tubal ligation instead ? We want our dog desexed just not at 6-7 weeks. Any advice appreciated.

    1. Hi Kylie- you raise a very good point. I do not know of any that do not desex early but I am almost certain they will exist. As for those that do it early, please add your voice to the evidence. It’s a strange culture this breed group have developed and it needs to change.

      1. Hi Andrew,
        My puppy was desexed when we bought her, but she appears to have come into ‘season’ at 7 months !-, is it ok to desex her whilst she’s now supposedly in ‘season’ ?

      2. Hi Gloria. It’s extremely rare for dogs to come into season after being spayed, and would make me wonder if she was spayed at all or if there’s something else wrong. If you haven’t already, please get a vet checkup. I always advise waiting until a season has finished before desexing.

    2. Hi Kylie,

      Same problem here exactly. I am biomedical researcher studying the effects of hormones on the brain. I find this early desexing practice quite uninformed and would hate to speculate about the real reasons behind it. Unless I find a reputable AL breeder who does not early desex I would go for a different breed. This great article has further reinforced me in that.

  23. Hi my name is Nellie and I have a cross Maltese Lhsa Apso male dog. He is ten years old and in the last couple of months after he has an
    erection the foreskin does not cover his penis. I took him to the vet and they said he needs to be desexed or he is going to have all sorts of problems. I have always had the impression that it was dangerous to desex them at such a late age. Is it ok to do or not.

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