Neutering or spaying a dog at 6 months old can be dangerous to their health

Superfact 21: Neutering or spaying a dog at 6 months old can be dangerous to their health depending on breed. It is often recommended that you should neuter or spay your dog by the age of 6 months even as early as 8 weeks. This may be OK for some smaller breeds but is dangerous to the health and longevity of many larger breeds.

Many dog welfare organizations, SPCA, ASCA, etc., recommend that dogs are neutered or spayed by the age of 6 months, or even as early as 8 weeks. It is also a common advice in dog books.

In addition, some veterinarians still hold onto this belief. It is easy to understand why. Dogs running loose and causing unwanted pregnancies resulting in puppies having to be euthanized is a sad problem we don’t want. 

Unfortunately, research has shown that neutering or spaying a dog at 6 months old can be dangerous to their health depending on the breed. You may need to wait 18 months or two years, and some breeds should not be neutered at all. In addition to the scientists in the relevant fields, professional and certified breeders, AKC and dog breed clubs and veterinarians who kept themselves informed on this issue are all aware of this.

In other words, we know this to be true, it is an important fact since so many of us own a dog, roughly half of all US households do, and yet this information is highly surprising to many. This is why I consider it a super fact.

This is our Labrador Baylor and German Shepherd Baby. Too early neutering and spaying can severely harm their health.

This less than a year-old article from the AKC states that “an age of six to nine months of age may be appropriate for neutering or spaying a toy breed puppy or small breed puppy but a larger or giant breed may need to wait until they are near or over 12-18 months of age.” The article also provides the following interesting information.

Research conducted by the University of California – Davis reveals that for some dog breeds, neutering and spaying may be associated with the increased risks of certain health conditions such as joint disorders including hip or elbow dysplasia, cranial cruciate rupture or tear, and some cancers, such as lymphoma, mast cell tumor, hemangiosarcoma, and osteosarcoma.

The research conclusions are not surprising. Sex hormones are important in the development of any animal.  We know they affect psychological development as well as the musculoskeletal, cardiovascular, and the immune system.

I believe this is the University of California – Davis article in question. It is from 2020. Notice that the suggested guidelines for age of neutering is beyond 23 months for several of the giant breeds in the table featuring 35 breeds.

Our three months old Leonberger Bronco. The Leonberger is a giant breed you can neuter when they are older than two years old.

Recommended Ages for Neutering and Spaying

Below is a list of recommended ages for neutering and spaying for selected dog breeds.

  • Australian Shepherd, for neutering and spaying it is your choice.
  • Bernese Mountain Dog, you should neuter beyond the age of 23 months, but for spaying you have a free choice.
  • Boxer, neuter and spay beyond the age of 23 months.
  • Boston Terrier, neuter beyond 11 months, but for spaying you have a free choice.
  • Doberman Pincher, never neuter, and you need to spay beyond the age of 23 months.
  • German Shepherd, neuter and spay beyond the age of 23 months.
  • Labrador Retriever, neuter beyond 6 months and spay beyond 11 months.
  • Corgi, neuter beyond 6 months, but for spaying you have a free choice.
  • Great Dane, despite being a very large dog you have a free choice for both neutering and spaying.
  • Rottweiler, neuter beyond 11 months, but for spaying beyond 6 months.
Our mini-Australian Shepherd puppy Rollo. You can neuter this breed at an earlier age.

We used to own a male Leonberger dog, which is a giant breed. Our breeder told us to wait beyond two years before neutering him, for health reasons. This article from Hillhaven Leonbergers states the following “We recommend not neutering until at least 2 years of age…Some Vets would recommend from 6 months but this is NOT a good idea.” To read more about the neutering and spaying of Leonberger dogs click here.

Our Leonberger dog Bronco is giving me a hug. He was about one year old in the picture. That is still too early to neuter him.

This article from the Saint Bernard Club of America states that “above all, no giant breed puppy should be altered before the growth plates in the bones have matured and closed, usually between 15 and 24 months of age.” This Newfoundland dog magazine states : Currently, the recommended age that a Newfoundland dog should be neutered is 18 to 24 months due to the possible health problems that can arise from altering before that age.

According to the article above you should wait to neuter Saint Bernard Dogs until they are close to two years old. Saint Bernard Stock Photo ID: 1713912484 by fred12.
According to the article above you should wait to neuter Newfoundland Dogs until they are between 18 to 24 months old. Newfoundland dog Stock Photo ID: 1925281937 by Marsan.

Even though the expert advice regarding the best age for neutering and spaying varies, it is clear that doing it at six months old is too early for many breeds and can harm their health.


To see the other Super Facts click here