When Should I Neuter My Dog

Loving pet parents always want to do what’s best for their four-legged friends. In the United States, it is routine for pet owners to have their furry friends neutered or spayed.

Neutering a male dog involves castration, while spaying in female dogs means the removal of ovaries and the uterus, something called an ovariohysterectomy. According to the American Kennel Club, some 78% of dog owners have their dogs spayed or neutered.

Spaying/neutering your pet avoids unwanted litters and pet overpopulation, which result in an estimated 1.5 million each year, being euthanized. There are some important considerations related to when you should have that done. Read on for some of the most important things to think about.

What are the Advantages of Neutering or Spaying Your Dog?

Research shows that the sterilization of your dog has some important advantages. Because the procedure involves removing the reproductive organs, there is a significant decrease in diseases that affect the reproductive tract.

For female dogs, there is a decrease in pyometra, a uterine infection that can be lethal. There is a decreased chance of mammary cancer, also known as breast cancer. It also eliminates the risk of ovarian cancer.

Of course, there is also a decrease in common problems related to pregnancy and giving birth. This includes infections of the mammary glands and hormone-related problems like vaginal prolapse.

For male dogs, neutering, which involves removing the testicles, eliminates the risk of testicular cancer. It also decreases the instances of undesirable sexual behavioral problems. These behaviors include aggression toward other animals and the desire to roam when females are in heat. Additionally, the tendency for male dogs to engage in humping behaviors may be reduced.

These are significant advantages, and they argue for spaying/neutering your pet at an early age. But are there some disadvantages that might cause you to think twice before neutering your pet?

What are the Disadvantages of Spaying or Neutering Your Dog?

Because of the advantages of neutering, it has become very common to have the procedure done in the first year of life. Some recent research, however, suggests that there may be some associated risks with doing so. Let’s take a look at some of the possible disadvantages.

Undesirable Behaviors

While neutering your dog may reduce certain behaviors mediated by sex hormones, it may not actually reduce aggressive behaviors. Castration often reduces intermale aggression, but it may not affect other forms of aggression at all.

In one study of older dogs, the researcher found that the presence of circulating testosterone in intact dogs may prevent or slow the progress of cognitive impairment. However, another study found that intact older dogs had more DNA damage to the brain than castrated animals.

Prostate Cancer

Researchers note that several studies report an increase in the incidence of prostate cancer in castrated male dogs. They have found the increased risk to be from 2.4 to 4.3 times that of intact dogs.

Still, this type of cancer is extremely uncommon in dogs. This may mean that the benefits of neutering outweigh this particular drawback.

Musculoskeletal Disease

Among the musculoskeletal problems associated with early neutering are growth plate closure problems, hip dysplasia, and ligament issues. Specifically, delayed growth plate closure in both dogs and cats neutered before the onset of puberty. This may indicate it’s better to neuter your dog after they go through puberty.

One study found that hip dysplasia and other related joint disorders like arthritis, increased in male and female dogs neutered at an early age.

Hip dysplasia does have a strong genetic component in certain large breed dogs. This includes the Chesapeake Bay Retriever, English Setter, German Shepherd, Golden Retriever, Labrador Retriever, Samoyed, and St. Bernard.

Still, researchers found that the benefits of neutering male dogs at six to eight months of age outweighed this risk. For female dogs, however, they found that spaying should be delayed until at least three months of age to avoid urinary incontinence associated with early spaying.

Another musculoskeletal risk that increased in neutered dogs was the rupture of the anterior or cranial cruciate ligament (CCL). This is a ligament in the knee joint. The injury is common in certain breeds, including:

• Akita
• American Staffordshire Terrier
• Chesapeake Bay Retriever
• German Shepherd
• Golden Retriever
• Labrador Retriever
• Mastiff
• Neopolitan Mastiff
• Newfoundland
• Poodle
• Rottweiler
• St. Bernard.

It is also associated with an increased risk of obesity and decrease in energy seen in neutered dogs. Additionally, problems with growth plate closure could change the angle of this joint and make a rupture of the ACL more likely.

So, When Should You Neuter Your Dog?

Based on all of the aforementioned factors, you may be confused about when to neuter or spay your dog. You may even be unsure if you should do it at all. It’s clear these procedures are readily available at a low cost to owners, but there may be some associated risks.

As one study notes, those increased risks include certain cancers such as:

• hemangiosarcoma (cancer of the blood)
• osteosarcoma (bone cancer)
• mast cell tumors
• lymphoma

Still, most of those risks were in animals neutered before six months of age.

The risks were higher in certain breeds of dogs, most notably small breeds. Boston Terriers and Shih Tzus in particular showed a significant increased risk of cancer with neutering.

The study concluded, however, that in most cases pet parents can choose any age of neutering without significantly increasing the risk of either joint disorders or cancer.

They suggest that it’s important for professionals in veterinary medicine to assist pet owners in making these decisions about the best age to neuter. Researchers advocate for a guideline for a breed-by-breed and sex basis on deciding the best age to neuter your dog.

What’s the Bottom Line on Spaying or Neutering Your Pet?

The American Veterinary Medical Association (AVMA) advocates for the use of professional judgment. Taking into account all risks and benefits of spaying/neutering pets will help clients decide on sterilization. Many vets now no longer recommend a standard six months of age for the procedure.

Instead, they choose to tailor the best age to spay or neuter a pet to each individual case. For purebred dogs, pet parents should speak with their breeder, who might also be able to provide some valuable insight.

For some dogs, six to nine months of age may be best. As for others, like larger breeds or giant breeds, it may be better to wait until they are over a year old to decrease the risks of certain joint problems. This is particularly true for dog breeds with a genetic predisposition to those problems.

For female dogs, it’s a good idea to wait until after three months of age to avoid the increased risk of urinary incontinence. Additionally, when a female dog is in her heat cycle, she should not be spayed as that can cause excessive bleeding.

The greatest risk of spaying/neutering your four-legged friend still appears to be that associated with anesthesia. It certainly helps decrease the number of euthanized pets.

Still, the timing is likely the most important consideration to avoid some of the increased risks associated with sterilization.

The bottom, bottom line? Talk to your vet and have them help you make the best decision on when to spay/neuter your individual pet.

This content is for informational use only and does not replace professional nutrition and/or medical advice, diagnosis, or treatment. It is not a substitute for and should not be relied upon for specific nutrition and/or medical recommendations. Please talk with your veterinarian about any questions or concerns.

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‌Waters. 2014. “Life Expectancy, Antagonistic Pleiotropy, and the Testis of Dogs and Men.” The Prostate 43 (4). https://doi.org/10.1002/1097-0045(20000601)43:4%3C272::aid-pros6%3E3.0.co;2-d.

‌Spain, C. Victor, Janet M. Scarlett, and Katherine A. Houpt. 2004. “Long-Term Risks and Benefits of Early-Age Gonadectomy in Dogs.” Journal of the American Veterinary Medical Association 224 (3): 380–87. https://doi.org/10.2460/javma.2004.224.380.

‌American Veterinary Medical Association. n.d. “Spaying and Neutering.” American Veterinary Medical Association. https://www.avma.org/resources-tools/pet-owners/petcare/spaying-and-neutering.

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