In fact, we encourage people to wait until at least a year to 18 months for all dogs and up to 2 years for large and giant breed dogs.
Because we believe the reproductive hormones are necessary for correct growth. While we are not veterinarians, and most vets will disagree with us, we have read the research on the orthopedic ramifications of early spay/neuter.
Just as with humans, the sex hormones are responsible for a lot more than reproduction and associated behaviors. One major responsibility is regulating growth. When you surgically alter a dog and remove those hormones, you affect their growth. Bones continue to grow longer than they should. Because different bones in the body stop growing at different times, some bones would wind up longer than they should be. And that causes problems.
Effects Of Neutering A Dog Too Early
Let’s look at what this research shows are the three most important reasons you should reconsider neutering your dog.
Early NeuterIng And Joint Disease
We’ll get to the Vizsla study later. They didn’t investigate the link between neuter and joint disease … but they didn’t really need to. There was already plenty of research showing the link.
Hip Dysplasia
A 2013 study on Golden Retrievers found that male dogs who were neutered before 12 months of age had double the risk of hip dysplasia than their intact counterparts (2). Other research shows that dogs sterilized before the age of six months have a 70% increased risk of developing hip dysplasia. The authors of this study propose that …
“…it is possible that the increase in bone length that results from early-age gonadectomy results in changes in joint conformation, which could lead to a diagnosis of hip dysplasia.“
There’s even more evidence that neutering can increase the risk of hip dysplasia.
Cruciate Ligament Tears
Cranial cruciate ligament (CCL) tears have also been linked to neutering in numerous studies. The Golden Retriever study found that although there were no cases of cruciate tear in the intact dogs, 5% of males neutered before 12 months (and 8% of females) did suffer tears.
Whitehair et al (JAVMA Oct 1993), found that spayed and neutered dogs of any age were twice as likely to suffer cranial cruciate ligament rupture (4). In 2004, Slauterbeck et al also found an increased risk of cruciate tears (5).
Chris Zinc DVM PhD DACVP explains (6) …
Additionally, sterilization can cause obesity and a loss of bone mass (7). Both of these factors could lead to an increased risk of cranial cruciate ligament tear and hip dysplasia. And a 2005 Austrian study showed that spayed/neutered dogs are over three times more likely to suffer from patellar luxation (8).
There are many things you can do to help your dog’s joints. Unfortunately … there are even more sinister issues with early neutering in dogs.
Contrary to popular belief, we can’t neuter cancer. In fact, this surgery mostly increases the risk of many common canine cancers.
The Golden Retriever study found that the incidence of lymphosarcoma was three times higher in males neutered before 12 months of age. These results are similar to other studies. They also found that spayed/neutered dogs were 3.5% more likely to suffer mast cell cancer and 4.3 times more likely to suffer lymphoma.
2002 research on Rottweilers at Purdue University found that male and female dogs neutered or spayed before 1 year of age had an approximate one in four lifetime risk for bone sarcoma … and they were significantly more likely to develop bone sarcoma than dogs that were sexually intact (9).
A 2002 study at Utrecht University found that prostate cancer occurs in neutered males about four times as frequently as in intact males (10) … despite the popular belief that neutering prevents prostate cancer.
Neutering had been previously linked to cognitive impairment and even a three-fold risk of hypothyroidism (which often creates behavior changes). But the Viszla study yielded some particularly interesting insight into this link. They found that neutered dogs were also more likely to develop behavior disorders than intact dogs. The problems included:
Another study in 2010 (10) found neutered dogs were more:
This is contrary to the popular belief that neutering reduces aggression and other behavior problems.
These findings also present a conundrum for shelters and rescues who advocate early neutering in dogs.
What happens if you neuter a dog too early?
Nikki is the marketing manager for IPH and has been writing for Intermountain Pet Hospital since 2014.