Ovary-Sparing Spay Surgery (OSS)

Photo Credit: Flicker CC, Smerikal, BeautifulMy last blog focused on the boys, specifically canine vasectomy, a surgical technique for sterilizing male dogs without removal of their reproductive organs (testicles). Now, it’s time to talk about the girls! The corollary surgery in female dogs is called ovary-sparing spay (OSS).

What exactly is ovary-sparing spay surgery?

The canine spay surgery traditionally performed in the United States is called ovariohysterectomy in which both ovaries (ovario) and the uterus (hyster) are removed. OSS surgery is simply a hysterectomy- only the uterus is removed and, as the name implies, the ovaries are spared. The hysterectomized dog is sterile, but her ability to produce reproductive hormones remains intact.

Why consider OSS?

There are a few different reasons why people might opt for OSS surgery:

  • They want a sterilized dog, but believe in the importance of maintaining normal reproductive hormones status. Over the past decade or so, we’ve learned considerably more about some deleterious effects of traditional spay surgery particularly when performed before one year of age. The studies to date have mostly been breed-specific (Rottweilers, Labrador Retrievers, Golden Retrievers, Vizslas, and German Shepherds). In these studies, removal of the reproductive organs increased the risk for development of behavioral problems, orthopedic diseases, urinary incontinence, and various types of cancers. At this point, we really don’t know if this information can be extrapolated to other breeds.
  • They want their sterilized dog to achieve “normal” or “breed typical” stature and conformation. Conventional spaying, particularly at a young age, tends to create a somewhat different physical appearance.
  • They want to eliminate the risk of pyometra (see below), but don’t want the loss of normal reproductive hormone production.

Not for everyone or every dog

While OSS makes perfect sense for some people and some dogs, there are a number of important factors to consider:

  • A dog who has had OSS surgery will continue to have heat cycles complete with a swollen vulva, behavioral changes, and an invitation to all the unneutered male dogs in the neighborhood. The good news is that the amount of vulvar discharge associated with the heat cycle should be significantly diminished.
  • Dogs who have had OSS surgery will be subject to developing mammary (breast) cancer, one of the most common malignancies in female dogs. Removal of the ovaries, particularly before the first heat cycle occurs, protects against this disease.
  • When the ovaries are spared, it’s super important that the uterus, including the cervix, is removed in its entirety. Most veterinarians do not have experience removing the uterus this “aggressively”. Leaving even a remnant behind can result in pyometra (pus within the uterus). This “stump pyometra” can make for a very sick dog, and treatment typically requires surgery. Correctly performed, OSS surgery prevents pyometra from ever occurring. If you opt for OSS surgery, pick your surgeon wisely. Consider working with a veterinarian who specializes in surgery.
  • Although she will be receptive to male dogs when she’s in heat, the female who has had OSS surgery should not be bred. Given that her cervix will have been removed, from an anatomical point of view she may not be able to accommodate the male dog.
  • Just like dogs who have not been spayed, dogs who have undergone OSS surgery may exhibit symptoms of pseudopregnacy, also known as false pregnancy. This is a truly interesting phenomenon in which reproductive hormones trick the dog into thinking she’s pregnant even though she’s not. So, at right around 60 days following her heat cycle, the pseudopregnant dog begins behaving just as she might if she were getting ready to give birth. She might exhibit behaviors such as nesting, aggression, panting, pacing, whining, and not eating. She may even begin producing milk. While none of these are symptoms that typically need to be treated, they can create a nuisance that lasts for quite awhile.

Would you ever consider OSS surgery for your dog?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook

Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at http://www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.


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5 Comments on “Ovary-Sparing Spay Surgery (OSS)

  1. I had a purebred miniature schnauzer. She was spayed by the conventional method before she had a heat cycle. When she was about 10, she became blind, which was followed by jaundice. Her veterinarian did not know what was causing her blindness and jaundice, so she had me take my dog to the University of Illinois, Veterinarian School. The Vetrenarian who examined her, had a student with him, they both looked at her eyes through the same instrument. The Veterinarian explained that my dog had SARDs (Sudden Acquired Retinal Degeneration), which is usually seen in middle age sprays. He told me that if I got another female, I should let her have one season before having her spayed. He did not mention that SARDs was breed specific. Please consider this when you consider having your female spayed, whatever method you choose.

  2. In the 60’s, some of us requested ovary-sparing spays of our vets, who referred to the procedure as a “hippy spay.” (I worked for the vets as a tech at the time and took it with good humor…) My dog was about 4 years old at the time of her OSS surgery…she later (age 7-8?) developed mammary tumors which were removed but not otherwise treated. She died at 11 of a brain tumor, which I’ve long suspected had metastasized from the mammary tumors, but who knows. Would I do it again? Probably not, without a very good reason. (I don’t neuter my male dogs and, with good training, have no problems there.)

  3. Dr. Kay, thank you so much for another excellent article about alternatives to conventional sterilization which preserve normal hormonal function. Two of my bitches have had OSS procedures. Bernese Mountain Dogs have a high incidence of cancer and joint problems, two of the diseases at higher incidence in neutered animals. Elderly bitches have a high incidence of pyo, so OSS was the logical alternative. Both of my bitches cycle regularly, but they have virtually no discharge, which makes them less attractive to males.
    it is heartening to see more vets interested in the benefits of vasectomy and OSS, and I hope that your discussion encourages more surgical specialists to offer these procedures.

  4. I have been considering OSS for my 13 month old Australian Shepherd. I found one vet, around an hour away, who does it but it is very expensive. The holistic veterinary practice in town will not do it and does not believe in it. They will do the opposite, leaving the uterus and removing the ovaries.
    My dog has been through one heat cycle and it wasn’t that fun to deal with , but I may just keep her intact. I think in this country, we just don’t know how to deal with intact dogs any more and equate it with accidental pregnancy. In other countries like Sweden and Norway, they never spay or neuter unless there is a health issue, and they do not have a stray dog problem. No overpopulation either and few to no dogs in animal shelters.

  5. My Great Dane was spayed at 18 months by laparoscopic surgery to remove just her ovaries. She still has her uterus. She is now 7, and in good health.

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