When’s the Best Time to Spay or Neuter Puppies and Kittens?


Spaying or neutering your new kitten or puppy is an important part of your pet’s veterinary care. Responsible pet owners should be aware of the pet overpopulation problem and do their part to reduce the number of homeless dogs and cats in shelters by fixing their own pets. Spaying and neutering is also good for your pet’s physical and behavioral health.

What is the best age to spay or neuter your pet? There is an ongoing debate about the pros and cons of early spay/neuter vs. waiting until your pet gets a little older. Dr. Heather Weir, a veterinarian at Colorado State University’s James L. Voss Veterinary Teaching Hospital, offers some practical advice for new pet owners.

Lifetime studies of pets have shown that early spay and neuter increases the amount of time it takes for bones to grow in kittens and puppies. Their limbs will grow longer and their joints may get misaligned. This could be especially significant in large dog breeds prone to orthopedic issues later in life. Waiting until your pet reaches skeletal maturity might be the best option for certain breeds.

There are some drawbacks to waiting until skeletal maturity. The risk of mammary cancer in female dogs increases with every estrus (or “heat”) cycle. Early spaying will decrease the risk of cancer, and also decrease the risk of unwanted litters of puppies. For male dogs and cats, waiting to neuter means that increased levels of testosterone could lead to aggression and other unwanted behaviors.


How do you decide when it’s time to fix your puppy or kitten? Dr. Weir recommends discussing the following issues with your veterinarian:

  • Is your pet at risk for orthopedic disease later in life?
  • Are you willing to put up with the inconveniences that go along with intact male and female pets if you wait to spay and neuter?
  • Is your pet vaccinated? Many vets prefer to wait until kittens and puppies are fully vaccinated.
  • Does your vet perform minimally invasive procedures to lower the risk of surgical complications?

Talk to your vet about the timing and importance of spay/neuter if your new kitten or puppy is not yet fixed. Click HERE for more information.