Updated Spay and Neuter Recommendations

By Dr. Kim Hsu, Bothell Pet Hospital

It has been said that practicing medicine is an art. Doctors continuously make recommendations that affect the health and well-being of their patients both short and long-term. The latest technology, new research findings, and owners’ resources all factor in to our diagnostic and treatment plans. These can be constantly changing.

For example, we recently reevaluated our recommendations on when to spay or neuter your pet. While the debate on whether or not to spay/neuter remains unchanged at this time, recent studies have created controversy within the industry over the best time to spay or neuter, specifically dogs.

The Right Age to Spay / Neuter

Chances are that if you adopted your pet from a shelter or rescue group, your pet was already spayed or neutered. These organizations are up against the challenge of over-pet population and providing the healthiest animals for potential adoption. It makes sense to spay or neuter these animals beforehand, even if done at an earlier than typical age.

Veterinarians have historically recommended spaying dogs at about 6 months of age, before the first heat cycle, but when they are bigger to tolerate anesthesia better.

Studies show that estrous (heat) cycles increase the risk of mammary cancer in dogs. If spayed before the first heat, there is almost a zero percent chance of mammary cancer.

After the first heat, various studies estimate the risk goes up to 12-16% (some studies say up to about 25%). After the second heat cycle, spaying seems to have minimal, if any, impact on preventing mammary tumors.

New Studies Suggest a Benefit to Delayed Spay / Neuter

Recently, there have been a number of studies suggesting a benefit to waiting to spay or neuter. Estrogen could have a protective effect against certain cancers and oxidative stress. Dogs spayed later lived longer. Another study correlated later spay and neuter with lower incidences of certain types of cancers and joint disorders.

It is important to note that these studies were done in larger breed dogs, for example, Golden Retrievers, Labrador Retrievers, German Shepherds, and Rottweilers.

So what about mammary cancer? Well, it turns out that mammary cancer in intact females in larger breeds is relatively low. There are huge breed differences, and more studies need to be done.

Bothell Pet Hospitals’ Recommendation

As mentioned before, there is still controversy and conflicting information on when to spay or neuter your dog. However, the doctors at Bothell Pet Hospital have concluded that there is enough evidence to support later spay/neuter in larger and giant breed dogs to minimize the risk of joint disease and certain cancers.

We are still recommending spay/neuter in smaller breeds at about 6 months of age, before the first heat cycle, to avoid mammary cancer.

In addition, cats should also be spayed or neutered at about 6 months of age.

There are clearly breed differences, specific individual circumstances, and other factors that influence the decision on when to spay/neuter. The point is, talk to your doctor about what is best for you and your four-legged family member. Like you, we want the longest, healthiest life possible for them.