Making Sense of All the Studies on Early Spay/Neuter
The recent Golden Retriever study from UC Davis has been getting lots of publicity, and being used to raise concerns about early spay/neuter. But what does it really say, and is it fair to extrapolate this to all early spay/neuter? Not in my opinion.
This study is specific to Golden Retrievers and some issues to which the breed is prone. The number of affected patients is small and the authors themselves warn the information cannot be extrapolated to other breeds. The database used was from the University of California's small animal hospital, a hospital staffed mostly by board certified veterinary specialists. There may be socioeconomic variables here that can skew the findings. For example, the majority of dogs will never see the inside of a specialty referral center, either because their owners can't afford the service or it is impractical for them to make the travel, or maybe the dogs were just plain healthy and didn't need specialty services.
When the data is carefully reviewed, there are several categories where spayed or neutered dogs actually scored better than intact Goldens. The authors made this generalization from their study: “For all five diseases analyzed in the present study, the disease rates in males and/or females were significantly increased when neutering was performed early and or late.” This generalization is much too broad and conflicts with the data reported. It just doesn't hold water.
Keep in mind that this is a very narrow study that does not look at the big picture. The study was limited to a small data set made up on only one breed. Every breed is predisposed to its own unique list of medical conditions, so studies within a single breed cannot be extrapolated to other breeds. And then there is the question for mixed breeds, "Where and how do they fit in?" The number of dogs affected in each category was fewer than 20, with some in single digits. Compare this to the millions of companion animals at risk of euthanasia in shelters, or those impacted by mammary cancers, pyometra (infection of the uterus), or puppies, and sometimes mothers, lost to difficult deliveries.
It’s also one study. There are other recent studies that show the benefits of early spay/neuter that cover a much larger sampling.
For example, a more recent study from the University of Georgia shows that neutered and spayed dogs live 14% and 23% longer, respectively, than intact dogs. The Georgia study looked at more than 70,000 dogs and 185 different breeds, thereby lending it more validity. Those results were backed up by an even more recent study from Banfield that shows neutered dogs live 18% longer and spayed females live 23% longer.
According to the Georgia study, spayed and neutered dogs are dramatically less likely to die from infectious disease, trauma, vascular disease, and degenerative disease than intact dogs. The UC Davis study fails to mention or compare the protective effect preventing mammary cancer by spaying dogs before their first heat. Mammary cancer is the most common cancer in intact dogs they are nearly 20 times more likely to be affected by this cancer than any of the cancers reviewed in the UC Davis study.
When I look at the big picture, the scales tip heavily in favor of spaying and neutering by 4 months. I will trade an increased risk of less common maladies for an increased life expectancy of 20-25% longer. I choose to have my furry family members with me for as long as possible.