When to Spay and Neuter: One Vet’s Opinion

First it was easy, then it was more complicated, and now it’s more complicated still. What am I talking about? Giving advice from a veterinary perspective on exactly when to spay or neuter dogs and cats.

What do I say when I’m asked these days? I honestly don’t have a “stock” answer anymore. I lay out the pros and cons based on current best practice and cutting-edge research and tailor the advice to the breed or mix and household situation — in short, I use all my professional skills to provide pet owners with the tools to make an educated, informed decision based on what’s best for an individual pet in a specific family.

How did things get so complicated? It comes down to following the current research and looking out for the greater good.

Neuter Now? Or Never?

I still believe that for the overwhelming majority of family pets, altering is the best bet; the real issue is timing, not neutering.

For the most part, altered pets are healthier and easier to live with — that’s especially true of cats of both genders and female dogs. The issue is not quite so clear-cut for male dogs, with some studies showing some protective health benefits to maintaining some level of testosterone.

But even for male dogs, blocking reproductive ability is generally a good thing, as are what most believe to be the behavioral benefits of castration: no intense desire to escape in pursuit of a female in season and a reduced inclination toward some types of aggressive behavior. Yes, it’s true that solid fences, strong leashes and good training can reduce or eliminate the problems linked to being an intact male dog, but it’s also true that most pet owners don’t want to deal with troublesome pet behaviors that can be eliminated with a knife or a needle. And, honestly, who can blame them?

Of course, we can’t ever forget the bigger issue: Wide-scale spay-neuter has been a critical part of successful efforts to reduce the number of pets born without homes every year. The number of pets euthanized for lack of a home every year has fallen dramatically in the past few decades, but 3 million to 5 million pets still need to find forever homes every year. To keep the numbers low enough to give these animals the best chance, we need to keep spaying and neutering.

Few things in medicine are clear-cut, and it’s a good thing that the pros and cons and timing of spay-neuter continue to be researched and debated. But I’m still coming down firmly on the side of spay-neuter, and most of my colleagues are, too.

The Question Remains: When?

What I’m not so bullish about now is spay-neuter of young kittens and puppies, even though I understand why shelters are so keen on it. Like the majority of veterinarians, I have seen many an accidental litter of puppies or kittens born to the pet of a well-meaning person who overlooked spay-neuter until a young pet was already pregnant. Being able to prevent that unintended litter by altering a pet before placement makes good sense on a large scale.

But the evidence now suggests there may be benefits to letting animals mature, especially with regard to the health of their bones. Early spaying and neutering may result in extended bone growth and potentially increase the likelihood of certain types of cancers and orthopedic problems such as ruptures of the ligaments around the knee. Letting these animals mature before spay-neuter may reduce some of that risk. When you add that spay-neuter can also reduce the risk of reproductive-related cancers, the case is still strong for the procedure.

If you’re thinking of adopting from a shelter that insists on altering kittens or puppies before they leave, it’s worth trying to negotiate for time. But if the policy is set in stone, I still say you should adopt anyway. Remember that health is a matter of addressing wellness overall and working with your veterinarian to achieve it. Simply put: Delaying a pet’s neutering but allowing him to become overweight or obese or letting his teeth and gums rot isn’t a good wellness plan. I'd rather see a pet neutered early and aggressively managed for weight and overall wellness.

What if you have the option of picking when and how to alter your pet — what should you do?

I recommend talking to your pet’s veterinarian. In the same way that vaccines are no longer “one size fits all” for dogs and cats, the decision of when and how to alter a pet can also be made to fit an individual animal’s best medical interests. When I started practicing medicine more than three decades ago, most veterinarians said “alter at 6 months.” Then many of us went to “the earlier the better.” By the same token, there are more options for the type of procedure your pet has; injectable zinc neutering with Zeuterin, a nonsurgical procedure that allows male dogs to keep about half of their testosterone, may be available as an option, and there are two kinds of spay surgeries to choose from now.

These days, when people ask me about when and how to alter their pets, I have no blanket answer. I give my best advice based on the most current research and on what I believe is best for each individual animal. And maybe that was the right answer all along.