My 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?