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When to spay or neuter

Refined recommendations change the timeline

Puppies and kittens are adorable! But spend a day in a shelter and you’ll likely be moved to tears by the number of unowned or abandoned pets in search of a forever home. The American Veterinary Medical Association has long supported the spaying and neutering of companion animals not intended for breeding, to reduce overpopulation and behaviors that may lead to relinquishment of pets to shelters.

While these goals have not changed, the recommended timing of the procedure has become more complicated. Recent research has shown that early removal of sex hormones may influence the incidence of a variety of disease processes and cancers in certain individuals. This has created a challenging environment for veterinarians and pet parents alike, who all want to make the best decision for their patients and pets.

For feline patients, we continue to recommend spaying or neutering prior to sexual maturity, which is by 5 to 6 months of age. For canine patients, there is no single timing recommendation that is appropriate for all dogs, and we encourage you to start this conversation with your veterinarian at your first puppy exam. For female and male dogs who are expected to be smaller than 45 pounds when full grown, surgery is recommended at 5 to 6 months of age. The goal is to spay female dogs prior to the first estrus to decrease the risk of mammary neoplasia.

Recommendations aren’t so clear for larger breed dogs. As a result of the possible orthopedic concerns, certain cancers in some breeds, males expected to be larger than 45 pounds should be sterilized when growth is complete, usually between 12 to 15 months. In female dogs expected to be larger than 45 pounds, veterinarians must weigh postponing the spay to potentially reduce risks of orthopedic disease, incontinence, and some cancers associated with early sterilization, against the risk of mammary neoplasia, unwanted litters, and possible other cancers if sterilized later.

Spaying and neutering remains an important tool against pet overpopulation, and we, as a profession, continue to support efforts to reduce the number of homeless pets. But as we continue to learn more about the complexities of the canine body and the influences of sex hormones on lifelong health, we encourage you to have early conversations with your veterinarian to make informed decisions on the timing of your pet’s spay or neuter.


Brought to you by:

Wilvet Salem (503) 741-8858

Emily Kalenius, DVM

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