After examining 40,139 dog death records spanning a 20-year period, University of Georgia researchers have concluded that spayed or neutered dogs tend to live longer than intact dogs.

The study revealed that sterilized dogs had an average lifespan of 9.4 years, while intact dogs lived 7.9 years on average, according to ScienceDaily.

In addition to highlighting the differing mortality rates between intact and sterilized dogs, the study also showed that these groups of dogs often die from different causes. Sterilized dogs were more likely to die from cancer or autoimmune diseases, while intact dogs tended to die from infectious disease and trauma, researchers reported.

"At the level of the individual dog owner, our study tells pet owners that, overall, sterilized dogs will live longer, which is good to know," said Dr. Kate Creevy, assistant professor of internal medicine at the University of Georgia College of Veterinary Medicine. "Also, if you are going to sterilize your dog, you should be aware of possible risks of immune-mediated diseases and cancer; and if you are going to keep him or her intact, you need to keep your eye out for trauma and infection."

According to Daniel Promislow, Franklin College genetics professor and co-author of the paper, the study has provided insights that could benefit future research into how reproduction affects human mortality causes.

"When researchers have looked at the effect of survival rates in humans, the results have varied from one study to the next. Our findings suggest that we might get a clearer sense of potential costs of reproduction if we focus on how reproduction affects actual causes of mortality rather than its effect on life span," Promislow said.

Read the full study on PLOS One

Comments (6) -

Cherrie Metzner
Cherrie MetznerUnited States
4/18/2013 10:52:13 AM #

It is unfortunate that your proof reader did not catch the mistake - comparing sterilized dogs to sterilized dogs in paragraph 3, last line.  I was gong to share on our clinic facebook page but opted not to due to wording that will only confuse people.

EveUnited States
4/18/2013 11:06:07 AM #

going*  to Cherrie Metzner

Arnold L. Goldman DVM
Arnold L. Goldman DVMUnited States
4/18/2013 11:47:32 AM #

It is even more unfortunate that the study, as described, did not compare the sterilized and unsterilized dogs, with control for lifestyle. The title of the story as provided, and the details as given, imply that the presence or absence of testicles or ovaries are the cause of longevity or lack thereof. However, the fact that "trauma" and "infectious disease" are the stated more common causes of earlier deaths in unsterilized animals reveals that lifestyle at least partially underlies the differences in longevity between these two groups. Perhaps people who dont sterilize, also dont take steps to control exposure to risk factors for trauma or infectious disease.

In order to have trauma or contract disease, animals must be free to interact with the environment or with other animals in uncontrolled settings. In contrast, most cancers and most immune-mediated disease require no outside agents or actors. Therefore, the article and the study itself, as described in this article, are misleading and likely biased. Thus, no such conclusion as an increase in longevity in the sterilized animal may be concluded.

The correct conclusion from this study may be this: In order to maximize a dogs lifespan keep them controlled (leashed, indoors) to avoid trauma, and away from other un-vaccinated or ill animals, to avoid infectious disease.

Arnold L. Goldman DVM, MPH

clayton mackay
clayton mackayCanada
4/18/2013 3:07:08 PM #

Like Dr. Goldman, I am confused about what this study is telling us. There seems to be far too many variables involved to make specific comments about sterilized vs. non-sterilized animals alone. For instance, dogs living longer whether sterilized or not will most likely die more often from cancer, because aging is a risk factor for cancer. I would not want this study to be used to suggest that pet owners sterilize their animals because that will extend their life span, without all other environmental factors considered.

Sonnya Dennis
Sonnya DennisUnited States
6/18/2013 3:16:17 PM #

Great point, Dr. MacKay!  7.9 to 9.4 is roughly a 17% difference.  Is the cancer occurring during that last 17% of life when they are really old and more likely to get cancer?  Folks have to be careful to not confuse cause with correlation.  I just had a couple ask about waiting to sterilize their dog because of an article about the decreased risk of cancer for intact dogs.  There are so many variables.

ErikUnited States
5/24/2014 1:20:42 AM #

This is pure ignorance of the highest regard.  Spay/Neutering is a profit business.  America is hell bent on fixing dogs.  I agree that with strays and or dogs that live outdoor lives, it might be advisable to fix them. But claiming fixed dogs live longer than intact dogs is absolutely 100% false.  Case in point. European dogs live an avg of 1.5 years longer than American dogs. Why is this? Simple... because Europeans are not brainwashed into thinking you're an irresponsible pet owner if you dont fix your dog.  Testicles are meant to be on the male dog... My dog is 3 years old, and people ask constantly if hes still a puppy.  He also has puppy energy, which is great.  He's not a lump like, say, my sisters dog, who is 4 and acts 20. Lump on the ground. Men with Low T could relate to this. The irresponsibility lies with people who are unable to train their dogs.  My dog is WELL trained. Sure he focuses in on scent a bit more, and hes persistent. But he is the most gentle animal, ever. The fact he has his testicles, has ZERO impact on his gentle nature.  I would argue, why does a house dog, who spends every waking minute with his master need to be fixed. He's not going to breed unless I put him in the situation to breed. I have read MORE studies that intact dogs live longer lives than fixed dogs, due to injury healing, and a more efficient endocrine and immune system.  This opinion is wildly irresponsible. False False False.

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