When I graduated vet school nearly 25 years ago, we were taught all dogs and cats should be spayed and neutered around 6 months of age. New research proves that early spay or neuter may not be ideal for all dogs, especially German Shepherds. What do these findings mean for pet parents, and why do recommendations differ?
The U.S. has historically struggled with dog and cat overpopulation. To combat this problem, we formed the recommendation to sterilize dogs and cats before they could reproduce. There was also some preliminary evidence that early spay and neuter may provide some protection from certain cancers, especially breast cancer, and could potentially lessen marking behaviors (urinating on things to “claim” them).
The dilemma veterinarians currently face is the responsible pet parent who has a sexually-intact puppy or kitten. When is the optimal time to spay or neuter their pet? Before sexual maturity at 4 to 6 months old, or later? If later, how much older? If you wait, what are the advantages and risks?
Veterinary scientists from the University of California Davis have been investigating this issue for many years. In 2014, they discovered that Golden Retrievers spayed or neutered earlier than 1 year of age had four times the number of joint disorders than those who had the surgery later. They also found Labrador Retrievers had twice the number of joint problems when sterilized before 1 year.
In their latest study, they evaluated nearly 1,200 German Shepherds over a 14.5 year period. They wanted to determine if those spayed and neutered early had more or less joint disease and cancer. The results were surprising.
- Dogs spayed or neutered before 1 year of age had three times the number of joint disorders.
- Breast cancer was diagnosed in 4% of intact females, compared with less than 1% in females neutered before 1 year of age.
- Instances of other cancers were not higher in the spayed and neutered dogs than in intact dogs.
- Urinary incontinence, not diagnosed in later spayed or intact females, was observed in 7% of females neutered before 1 year of age.
The trend of several studies is becoming clearer: Early spay and neuter may increase the risk of joint disease. Other studies have shown early sterilization may also increase pet obesity and subsequent joint disease and other problems.
The time has come for serious individualized spay and neuter conversations. My advice for the past 15 years has been pretty straightforward:
- If you can prevent unwanted pregnancy, wait as long as possible before sterilization. For most of my patients, this means around 10 to 14 months of age.
- If you can’t guarantee no unwanted litters, spay and neuter around 6 months.
- For shelter and rescue environments, sterilize prior to adoption; we simply can’t take the risk of producing additional puppies and kittens without loving homes.
And also be sure to consider other factors like the breed of the pet.
Veterinary medicine shouldn’t be reduced to cookie cutter, one-size-fits-all recommendations. With advances in our scientific understanding and abilities, I believe we must have individualized advice and care based on personalized needs, not a simplified set of rules. If you have a puppy or kitten and are a responsible pet owner, it’s time to talk to your veterinarian about the optimal age to spay or neuter your pet.