The Pros & Cons Of Ovary Sparing Spay

Updated November 21, 2023

We are commonly asked to perform an ovary sparing spey in dogs. Here we explain the difference with other procedures.

I hope after reading this you will see why we do not offer the service.

What Is Ovary Sparing Spay?

Also called Partial Spay, an ovary sparing spay is essentially a hysterectomy where only the uterus and one ovary is removed and the other ovary is left in the dog. Unlike in a regular ovariohysterectomy, it is vital that the entire uterus is removed with no remnant tissue.

Why? Prolonged hormonal stimulation of the uterus in dogs often leads to an infection called pyometra or pyometron. Traditionally, spaying female dogs has been as much about preventing this as it has about pregnancy. Even a small amount of uterus left behind can lead to what is called a ‘stump pyometra’.

Advantages of Partial Spay

There are several known benefits of ovarian stimulation

Thanks to more recent studies, we now know that we can prevent almost all of this risk by careful choice of the age of desexing. By performing the spey later in selected breeds, their risks of joint diseases, cancer and incontinence approach zero. You can read the research on desexing age for each breed here.

Weight gain remains a higher risk after desexing in both sexes, but only where there is inadequate control of their food intake.

Disadvantages of Partial Spay

There are four disadvantages that may affect all dogs.

  • Larger surgery wound and surgery time (the entire uterus and cervix needs removal)
  • Dogs will continue to show 1 to 2 heats per year, where they bleed for around three weeks and may not be able to socialise
  • False pregnancy (pseudopregnancy) may occur after heats
  • Lifespan increases seen with desexing/neutering may be lost

Additionally, there are three serious disadvantages that might affect some dogs:

  • Mammary tumours can be expected in many bitches
  • Ovarian granulosa cell tumours are also documented
  • Mating with entire males can in rare cases lead to ‘sperm peritonitis’

Of these, mammary tumours are common. From the age of two you will need to check the mammary tissue throughly on a monthly basis which your vet can demonstrate. There is usually no danger if lumps are removed when small.

Granulosa cell tumours typically secrete oestrogen. Therefore, they are often found after investigation of a persistent vaginal discharge or attractiveness to male dogs. Howver, they can also grow silently.

Other Spay Options

Let’s compare other ways to desex or neuter female dogs. All of these should meet the requirements of the Dog & Cat Management Board in South Australia and other compulsory desex neuter schemes.

Tubal Ligation

Tubal ligation means preventing pregnancy by cutting and tying the fallopian tubes, therefore leaving the entire uterus and ovaries intact. Here are my views:

  • There is no published surgical method for tubal ligation
  • It’s not as reliable as surgeries where the organ is removed
  • The only benefit is contraception; dogs remain at risk of all the reproductive diseases
  • It makes a lot of sense as a short-term measure done by the breeder if desexing is planned later but otherwise we do not support the procedure

Ovariectomy or Ovary removal

Removal of the ovaries alone is almost identical in effect to the traditional ovariohysterectomy spay. The advantage is in reduced tissue trauma, wound size and surgical time.

Dogs after ovariectomy will not have seasons, and the risks of pyometra and mammary cancer should remain low, owing to the lack of hormonal stimulation. Just like traditional spays, ovariectomy can (and should) be performed early or late depending on the patient’s best interests.

We are happy to offer ovariectomy, as there do not appear to be negative consequences to dogs.

Late Desexing/Neutering

A valid third alternative is to still remove the ovaries, but wait until the dog is at or near full skeletal maturity. By doing this you should retain most of the benefits of oestrogen without much risk of harm. This is the later desexing option mentioned above.

  • Your dog still achieves full female development, including reduced adult female size (oestrogen causes earlier growth plate closure).
  • You should retain all the benefits of early desexing including increased lifespan, reduced mammary cancer, prevention of pyometra, no heats.
  • The risk of incontinence is only 3% and is usually easily treated
  • Other effects of loss of female hormones are unproven or speculative
  • Late desexing generally means over one year of age.

If there is one take-home message it is this: despite the risks of some diseases being higher in desexed dogs, population level evidence supports desexed dogs having a longer lifespanIn large studies, the lifespan of neutered or spayed female dogs is 0.8 to 1 year greater than entire females. It is unproven and unlikely that this benefit will persist by just removing the uterus.

Related: A Comparison Of Male & Female Dog Desexing & Contraception

Thrusfield, M. V., Holt, P. E., & Muirhead, R. H. (1998). Acquired urinary incontinence in bitches: its incidence and relationship to neutering practices. Journal of small animal practice, 39(12), 559-566.

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.

32 Replies to “The Pros & Cons Of Ovary Sparing Spay”

  1. Hi Andrew
    I have an 18 mth old female Airedale. She is intact and she did not have her first season until she was 16 mths old. She is my 5th Airedale but my first female. All my previous boys were not desexed. Back in the day, dogs, male and female were not desexed unless there was a medical reason to do so, or the owner specifically requested it. How times have changed. I had not planned on getting her desexed either until I read your articles on desexing and OSS. Yes, the laws here in SA have changed re desexing but if you have a pedigree dog with papers and ownership you can become a member of Dogs SA and be exempt from DACO desexing laws. I am very grateful to read about the the options you provide and are now considering OSS. I am unclear about one thing though. You say after OSS she will still go on heat. What do you exactly mean by this? I am assuming since she doesn’t have a uterus she will no longer bleed, yet she will still ovulate due to her retained ovary. So are you talking about a “scent thing” in regards to being attractive to males? If so, then how will I know as her owner when she is ovulating ? I do not have an intact male at home. You also discuss late desexing, older than a year old. What are your views on desexing after the age of 5 /6 years since the majority of cases of pyometra occurs later in life. I guess the big question is, why desex at all? There are countries in Europe where desexing is against the law as desexing is regarded as mutilation along with tail docking etc. It seems to me that only the USA and Australia have taken the view that desexing your dog is a good thing. Maybe compulsory desexing laws are not the answer to lowering the number of unwanted dogs in Australia. Maybe we need new laws making owners more accountable and responsible in regards to unwanted breeding. This would allow our dogs to remain intact, control unwanted breeding and maintain a healthy dog gene pool in this country.

    1. Hi Glenys. There’s so much to unpack here. Firstly, as a second-generation veterinarian, I can assure you that back in the day dogs and cats were still desexed, as there have always been sound medical reasons to do so, which you can find from links within the article. Fundamentally though, they sum up to add one year of life to a female dog who is desexed and that is even with good veterinary care. Later desexing at 5 to 6 years of age will be somewhere in the middle, as you will almost certainly still face multiple mammary tumours, and pyometra is well known to occur even this early. As for coming into heat, the associated bloody discharge comes from the vagina, so it will still be produced when the uterus is removed.

  2. We are getting a border collie puppy in a few weeks. The breeder has told us she will have tubal ligation at 8 weeks prior to us getting her but that we can choose to have her fully desexed which would mean she wouldn’t have to have a second surgery later. We can chose not to have her fully desexed now (just tubal ligation) and have her fully desexed later which I am assuming you would recommend given the increased risk of incontinence and joint dysplasia. Is this correct? Is hip dysplasia common in border collies? Do we have to have her fully desexed or is tubal ligation enough? If we do have to have her fully desexed is removal of just ovaries preferred over traditional method of removing ovaries and uterus?

  3. Hi Andrew, Very interesting facts re desexing. At some point during the year I hope to be getting a mini schnauzer puppy. One breeder will sell me a puppy with having a tubal ligation procedure been done and another breeder who does not do this. I know I will still have to have the pup desexed at 6 months. My question is….. does having a tubal ligation procedure done at pre 10weeks of age have any downsides… ie anaesthetic, trauma etc. etc. Which is the better way to go – if any.

    1. Hi Carol. Tubal ligation should have no adverse affects other than any associated with surgery (and therefore none at all if everything goes to plan). I think it’s a good alternative if breeders insist on early Desexing so that we don’t lose the effects of hormones.

  4. Hello Andrew, I breed Griffons, dogs under 5kg. I desexed my first litter at 12 weeks and there have been no issues at all. The subsequent litters were not desexed after a lot of pressure from the other breeders, but I feel like the benefits of desexing my puppies will far outweigh the possible negatives. For larger breeds I certainly understand why you would delay desexing but Im not sure about the smaller breeds.

    1. Hi Michele. It’s fair to say that the problems we see with early spay are likely to be greater for the larger breeds of dogs, but they won’t disappear completely for small and toy breeds either. Therefore, the decision to spay before six months of age in any dog will come with some inherent disadvantage, even if it is small. It’s up to each breeder to make an argument that there is enough advantage with earlier desexing to offset this (I can only think of prevention of backyard breeding).

  5. Hello Andrew! Our two year old German Shepherd recently had a partial spay. She began spotting fairly heavily nine days ago and we are concerned. We knew that there was a chance of some spotting with a partial spay but this doesn’t seem right. What is your advice? Thank you!

    1. Hi Cathryn. Some spotting is normal during seasons but it’s best you get your vet to have a look given that the surgery was done so recently.

  6. Hi Andrew, We have a female standard poodle who is now 7 months old and we have delayed her desexing (removing both ovaries and uterus) until her growth plates are closed and skeletal development complete. We planned to review after her first season, and even consider waiting for her second season to be sure of avoiding joint issues in later life. We have a very caring and competent vet who is not in agreement with us on this issue, and mentioned that the risk of mammary tumors is increased if we wait until she had two seasons. We have researched as much as we can, including reading your excellent papers on the issue but are still confused. We really want to give her the best possible life free of preventable disease. We are both home with her all day and our home is well fenced, so management during her seasons is not an issue. Of course we would never repeat your advice to our vet, but are genuinely interested in your opinion of our particular situation. Thank you.

    1. Hi Malcolm. Your vet is right in that the risk of mammary cancer is likely to increase with each season. However, most vets would agree that even after two seasons the risk is still quite low. However, I would follow the advice in our page on the best age to desex a dog and do it at around one year of age. That’s probably the sweet spot in balancing risks and benefits.

  7. My nearly two year old first generation labradoodle had a one ovary sparing spay as a puppy by the breeder with removal of one ovary and uterus Our vet keeps wanting to remove her ovary that is left which I think will be a difficult operation as it will be floating around and harder to find and I’m not happy to put my dog through another surgery when the benefits and risks are similar. What are your thoughts on this. She does come into heat twice a year but so far no other problems.

    1. Hi Pam. It’s totally up to you, but I would probably go ahead and remove the second ovary. It’s true that the wound will probably need to be larger in order to find it, but that should be the only disadvantage. If you leave it, then the information on this page gives you a guide on what to expect (mainly ongoing seasons and later mammary tumours).

  8. Hi Andrew,

    Firstly a big thank you for your articles, I really appreciate the evidence based conclusions even if it happens to go against the norm.

    I’ve read your articles on desexing particularly delayed desexing. As a result of stumbling across it I did further research and had my vet write an exemption letter to the council for delaying the compulsory 6month desexing in our area (QLD)for
    our male English Mastiff ( until
    18 months – should I try to extend to 2 years?)

    After bringing this to their attention and the vet doing his own research they thanked me and are now recommending this to all of their giant breed clients.

    Now we are picking up a 5mo female British Bulldog pup as a companion this weekend. Although we are aware of the array of health issues (I still question this decision ethically) my husband has wanted one since he was a kid.

    We have done our research on her lines and have undertaken a health check with the most experienced vet we could find in the area, asking specifically to check on conditions bulldogs are prone to on top of the standard checks.

    Anyhow, given that they are prone to displaysia and ACL’s (and pretty much everything!) what age would you recommend getting her desexed?

    Many thanks again Andrew!

    1. Hi Carly. Thanks for the feedback. Re your mastiff, 18 months should be quite sufficient but I’ll also repeat that behaviour comes first. If you notice any aggression (unlikely in the English), that takes priority. As for a British Bulldog, their joint issues seem unrelated to desexing (they have unusual stifle joints) so desexing time isn’t likely to matter much. I’d go with 6-9 months.

  9. “In large studies, the lifespan of neutered or spayed female dogs is 0.8 to 1 year greater than entire females. It is unproven and unlikely that this benefit will persist by just removing the uterus.”

    You should learn to properly cite your sources good Dr. The ‘research’ that supports complete desexing in dogs and cats is replete with misinformation, scare tactics and twisted ‘partial’ facts (carefully phrased for effect) in the USA, where veterinary medicine is still in the ‘dark’ ages. Come to Europe and we can show you many OLD dogs who are intact. These same dogs also did not have aggression issues, mammary or testicular tumors, skin allergies, cancers of the spleen, … and a host of other issues ALL related to your sick desire to remove the sex organs of an animal. Those are the FACTS.

    1. Trust me- no one would be happier not to be speying dogs, but these are the facts as they stand. I would be delighted to be shown evidence to the contrary but the studies so far are clear. One such peer-reviewed scientific paper is:
      Michell, A. R. Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease. The Veterinary Record 145.22 (1999): 625-629.
      Others can be found in my page on desexing male dogs.

  10. DearAndrew
    I am SO glad you mentioned late desexing. I totally agree.I have just done medical science and my mother had a friend that was hysterectomised at 20. At 80 her spine crumbled so that her ribs touched her hips. I was always suspicious of removing vital hormones too early. Otherwise why would evolution have them at all?

  11. Hello Sir..My dog is 9 years old..Last year her uterus was removed but not her overies..She is now having Pseudopregnancy..Is there any sort of danger???

    1. Hi. Pseudopregnancy is not normally a health risk to a dog but it can be very distressing for them, and sometimes also quite prolonged. In some countries there is a product called Galastop that can help, but the condition should pass with time. This is certainly one of the disadvantages of ovary sparing spay

  12. What do you think about just taking ovaries, and leaving uterus ? Less avasive surgery, and does away with heat cycle.. been told no risk of pyametry without ovaries? What do you think?

    1. Good question Sue. I think that ovariectomy alone is a good option. I have only done it rarely but you are right that pyometra is a minimal risk without ovarian stimulation. The reason we rarely leave the uterus is simply that it is quite easy to remove, and prior to the first heat, it’s not very traumatic surgery. Lararoscopic spey could be an example of when ovariectomy alone would make sense.

  13. My 8 month cherry spayed before 4 month but before 4 days she came in heat and mating too..i was so angry on dr and called him ,he says during surgery one ovary was left due to some complications and now we wont able to remove the left ovary because it get deep inside.
    So my cherry will come in heat but no puppies,actually i dont want her to come in heat.please advise

    1. Hi Smita. Why don’t you ask a second vet if they can go back to remove the ovary? It should be quite possible to do this and a second opinion won’t hurt. Otherwise, yes, your dog will continue to have heats. If that’s the case it’s essential that the vets removed the entire uterus down to the cervix.

  14. So what about the transitional cell carcinoma risk related to traditional spayerd

    1. Thanks Mary. TCC is not a common cancer but I’m also not aware of studies that report an increased incidence. If you know of any, please post the info & I will look it look into it for you.

  15. Thanks for your response Andrew. I must say, no one seems to offer this procedure in Sydney and nobody seems to have heard of it being done in pets. They do offer the partial desex with scope where only the ovaries are removed. I am very surprised at how rare. Well done for offering your unique skills to your local community. Their good fortune indeed.

  16. Good morning

    Thank you for your article on desexing options. I am in Sydney north. Do you have an colleagues who perform tubal litigation on dogs in my city?

    Many thanks

    1. Hi Tania- I’m not aware of which vets offer the procedure but it’s not difficult for any experienced vet to perform. You should be able to find someone by ringing around.

      1. Hi Andrew!
        Thank you for educating owners on spay and neuter options available in the US. I have two female Westies (10 month old & 3.5 month old) and am considering either OSS or the surgery that only removes the ovariectomy. Is the percentage of urinary incontinence lower with an ovariectomy as well? My vet mentioned that about 10-20% of the hormones remain with the cervix still in place. I would like to give my girls a long life without any health issues and am trying to decide which procedure is beat. Thank you!

      2. Hi Ania. It’s likely that ovariectomy will have similar rates of urinary incontinence to a full spay procedure. However, it hasn’t been studied specifically to my knowledge and I suspect that your vet may be correct in saying there will be a slight reduction in risk.

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