what is the best age to spay or neuter your dog?

White dog on grass | When to neuter your dog | The best age to spay a female dog | Petplan
Posted by Dr. Kim Smyth on Oct 12 2015

Updated September 24, 2019

I’m often asked what the best age is to spay and neuter a dog – and the real answer is, it depends! Let’s take a look at the benefits and risks of these surgeries and what, if any, is the best time to schedule the snip.

What are the benefits to spaying and neutering dogs?

Removing your pet’s ability to reproduce benefits all furry friends, and it goes beyond just helping the pet overpopulation issue. Here are a few of the ways:

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By reducing the pet population, you make it easier for shelter pets to find a loving home. A staggering 10 million pets are surrendered to shelters each year, and of those, three to four million are humanely euthanized just because they have no home. As it turns out, being homeless is the #1 killer of companion animals. Don’t add to that problem!

Spaying your female dog before she has her first heat cycle reduces her chances of developing mammary cancer to almost zero. If she is allowed to go through one heat cycle, her odds of developing mammary cancer shoot up to about 8%, and if she goes through two cycles, it increases to 25%.

Spaying females also eliminates heat cycles, which can be messy at best and downright annoying at worst.

For males, removing the testicles removes the risk of testicular cancer and benign prostatic hyperplasia. It also decreases the likelihood that unwanted behaviors like humping and roaming will persist into adulthood.

Intact (or unspayed/unneutered) animals have shorter lifespans than fixed animals. There is a lot of conflicting evidence regarding the diseases that cats and dogs get later in life when intact versus spayed/neutered, but the take home story is that fixed animals live longer lives.

Now that you know the benefits of spaying and neutering, I’m sure you’re clamoring to the phone to schedule Fluffy’s appointment, right?

What’s the best age to spay or neuter your dog?

Typically, we’d like to see female pets spayed before their first heat cycle, so in the past, we’ve recommended that pets get spayed and neutered around 6 months of age. But, as we advance veterinary medicine, we are realizing that this blanket approach is not always best for every pet. Here are some other factors to consider:

Large and giant breed dogs cycle much later than their smaller counterparts. Some of these giant dogs don’t have their first heat cycle until they are a year old or later.

Large and giant breed dogs are prone to developmental bone diseases. It makes sense to wait until a dog, and her skeleton, is a little more mature before considering surgery. There are fewer orthopedic problems down the line if these big dogs (or high-performance sporting dogs) are allowed to grow before they are spayed. Studies have even shown that German Shepherds have increased health risks if spayed or neutered too early

Consider how you want your male dog to appear when he’s fully grown. If you have a Rottweiler, and you want him to look like a typical strong, muscled Rottie with a large head, you’ll want to delay his neuter a bit. Without a good dose of testosterone, he just won’t look the same. If his appearance doesn't matter to you, this is not an issue.

One more reason to wait: puppy vaginitis. If you have a puppy who has had issues with puppy vaginitis, it’s best to delay until after her first heat. You’ll definitely want to get her taken care of before her second heat, though, to avoid the increased risk of mammary cancer.

Is there a wrong age to spay or neuter dogs?

Again, this is a highly individualistic issue. Shelters generally have a rule to wait until an animal is 2 months old and a weight of 2 lbs. This is a very young, very small animal, but shelters just can’t hold pets until they are 6 months old to spay. There’s simply not room. In very young pets, we worry about keeping them safe and healthy under anesthesia during surgery.

The same goes for older pets, too. Surgery always carries a risk, and for older dogs whose health may be compromised, the risk is slightly greater. That said, I’d still rather spay an old dog who is relatively healthy than to have to deal with an old dog who has to be spayed on an emergency basis because she has developed a uterine infection (which is very common, by the way).

Are there any risks to spaying or neutering?

Like I said earlier, any surgery carries risks, even a spay or neuter, but the chances of complications are very small in healthy animals. While pet insurance does not cover spaying or neutering itself, since it is seen as a preventive measure, if there are health complications that arise as a result of the procedure, they may be eligible for coverage. 

One last note about spayed dogs: they are more likely to develop urinary incontinence later in life. This has nothing to do with the age at which they were spayed, as previously thought, but the chances of hormone responsive incontinence are higher in spayed females than in intact females. Generally, the condition responds very well to medication, and does not pose a serious health threat.

To make a very long story short, having your pet spayed or neutered should be a question of WHEN, not IF. The best age to have your pet spayed or neutered depends heavily on your pet’s size, breed and lifestyle. Talk to your veterinarian to determine the best time for your family, and then follow through. Your pet, and future generations of shelter dogs, will thank you!

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