Evidence of a relationship between neutering and an increased risk of certain diseases has been mounting over the years, so although some of the details revealed in this study are new, the overall message is not. And before you ask, the message is not "do not neuter your dog," it is "like all medical procedures, neutering has risks and benefits that owners need to be aware of."
This current study is open access so you can look at it on your own for all the details, but to summarize:
Veterinary hospital records of 759 client-owned, intact and neutered female and male dogs, 1–8 years old, were examined for diagnoses of hip dysplasia (HD), cranial cruciate ligament tear (CCL), lymphosarcoma (LSA), hemangiosarcoma (HSA), and mast cell tumor (MCT). Patients were classified as intact, or neutered early (<12 br="" late="" mo="" or="">
Of early-neutered males, 10 percent were diagnosed with HD, double the occurrence in intact males. There were no cases of CCL diagnosed in intact males or females, but in early-neutered males and females the occurrences were 5 percent and 8 percent, respectively. Almost 10 percent of early-neutered males were diagnosed with LSA, 3 times more than intact males. The percentage of HSA cases in late-neutered females (about 8 percent) was 4 times more than intact and early-neutered females. There were no cases of MCT in intact females, but the occurrence was nearly 6 percent in late-neutered females.12>
The paper didn’t go into much detail about the potential benefits of spaying and neutering dogs other than to reference other research that "found the evidence that neutering reduces the risk of mammary neoplasia to be weak." I’ll have to look that one up; it doesn’t really jive with my clinical experience. Every case of mammary cancer I can think of from my career has been in an intact female.
Neutering has its benefits, such as:
- getting rid of heat cycles,
- preventing unwanted litters
- eliminating the dangers associated with whelping
- preventing potentially fatal uterine infections (pyometra)
- liminating the chance of ovarian or testicular cancer
- significantly reducing the risk of prostatic hyperplasia and infection
- lessening aggression and other unwanted behaviors like mounting, roaming, and marking
The authors of this paper cite the differences between policies in the U.S. that promote early age spay/neuter and other developed countries where intact pets are the norm, but fails to mention the much stricter regulations surrounding pet ownership and breeding that are in effect in many of those same countries.
So feel free to look at the paper to learn about some of the downsides of spaying and neutering dogs, but do not turn to it for a balanced argument for or against the procedure. Only you, in conversation with your veterinarian, can determine what is right for your pet.
Dr. Jennifer Coates