Should I Spay or Neuter My Pet? If So, When?

By July 6, 2016 Uncategorized

By Dr. Perry Stanfied, DVM

Every responsible cat and dog owner needs to answer these questions. Information is available from various resources:  who we affectionately refer to as Dr. Google, as well as other pet owners, breeders, trainers, and so on.  Veterinarians are in a unique position to provide guidance: while we have the social responsibility to help to minimize the country’s horrid cat and dog overpopulation problem, we also can provide advice based on what we call evidence based medicine.  In short, we make recommendations based on data, not anecdotes.

In general,  if you have a male or female cat, or a male or female dog that is a small or medium sized breed, then sterilization is a very good idea at 5-6 months of age, before puberty.  If you have a large breed dog- over 60 pounds mature weight- and you want to keep life simple, and you wish to sterilize your pet at 5-6 months, DO NOT let anyone tell you that you are making a mistake.  It is a very informed opinion that can be well defended.  You really need not read any further!  For those that want to learn more, consider the following.

There are many arguments that you will read about that support delaying spaying or neutering.  The following are some very BAD reasons we still hear for delaying spaying or neutering (or not doing it at all):

  • Your dog will get fat and/or lazy
  • You’ve heard it’s a good idea to let them have a heat first
  • You want your children to go through the experience of a litter of puppies
  •  You desire a pet, but she is so,  so sweet, you think she should have a litter before spaying her
  • You are thinking about breeding, and want to keep your options open
  • You have some friends that want to breed your boy to their female dog when he is old enough


The list of respectable reasons for delaying sterilization is much shorter:

  • You are an ethical breeder, who desires to improve your dog breed.    You plan to do the recommended health clearances that are recommended by your breed club prior to breeding your dog.    When you have retired your dog from breeding, you will spay her.
  • You are aware that there may be certain health risks associated with early sterilization of large breed dogs, and wish to delay sterilization until after they mature.


Most, but not all studies have linked large dog  sterilization to certain low incidence conditions: prostate neoplasia, bladder cancer, bone cancer, diabetes, and hypothyroidism.    In some large breeds there appears to be a higher incidence of cranial cruciate injuries and certain dysplasias. The rub is, all of these are very LOW INCIDENCE conditions- most of them less than 2% of the population.  So yes, you can probably delay sterilization and reduce your risk by 50%- but what is the downside to delaying sterilization to enjoy a risk reduction from 2% down to 1%?

For males, you risk more behavioral problems;benign prostatic hyperplasia and you are potentially contributing to an animal population problem.  For females, you are risking mammary tumors (3.4% incidence by allowing just one heat cycle),  unplanned pregnancy and uterine infections.

The bottom line is that sterilized pets across the board live longer than their intact counterparts. It is impossible to eliminate all health risks with pets, regardless of when you sterilize yours.  Utilize your veterinarian to help you sort through the complexities of your specific situation to make the choice that is right for you.


  • You stated that if you have a male or female cat, or a male or female dog that is a small or medium sized breed, then sterilization is a very good idea at 5-6 months of age, before puberty. When I got home from work today my wife had bought our kids a new puppy. Does it ever depend on the breed of the dog as well as the age? Finding a reputable animal hospital might be our best option.

    • kulshanvh says:

      Thank you for your question and congratulations on the new addition! In large breed dogs there are theories about how the timing of sterilization can effect different aspects of the dogs joint and bone health in the future. We recommended having an exam done on all new puppies and kittens. This visit would be a great time to discuss this further with your veterinarian and how it pertains specifically to your new puppy! Feel free to contact our clinic any time with questions.

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