What is Ovary-Sparing Spay (OSS)?

Parsemus Foundation is proposing that we all think more creatively about individualizing spay. In these situations, veterinarians should be prepared to remove the uterus and leave the ovaries, sometimes called "partial spay." This removes the nuisance of bleeding during heats, along with the risk of infection of the uterus (pyometra), as long as ALL of the uterus is removed. In traditional spay, there is no need to remove every bit of the uterus, since it will no longer be under stimulation by the ovaries. But in partial spay, the veterinarian must make a large enough incision to pull the uterus up to the service to see what he/she is doing and be able to tie off and cut precisely at the cervix rather than just anywhere on the uterus. Otherwise, it is still possible to develop an infection in the remaining uterine stump, "stump pyometra."

If the whole uterus is removed, very few long-term health issues remain. Ovarian cancer is rare enough that the ovaries should not be removed as a way to prevent it. That makes mammary tumors the remaining concern. Although a recent review article indicates that the limited research on the effect of neutering on mammary tumors is inconclusive. (Beauvais et al., 2012), decades of real-world experience indicate that mammary tumors occur more often in dogs with ovaries. Adopters of dogs who believe that their dog is likely to live longer or be healthier by keeping its ovaries can then be informed of the pros and cons and to keep alert to the possibility of mammary tumors as their dog ages. Owners with the economic means may even wish to have a mammary-gland ultrasound as part of their dog's annual exam once it reaches middle age; vets who are skilled with ultrasound should be pleased at the opportunity to offer this new service using existing equipment. Meanwhile, the shelters population goals are achieved too, because the dog will not be fertile without a uterus.