Dogs May Live Longer If They Are “Fixed”

A new study shows spayed dogs live a year and a half longer, on average, than their fertile counterparts

Perrin Doniger

Responsible pet owners spay and neuter their dogs in order to reduce the number of unwanted animals that end up in shelters, or worse, but it turns out there’s another upside to “fixing” furry friends. On average, dogs that are spayed or neutered live longer than those whose goods remain intact, new research finds.

Scientists from the University of Georgia analyzed more than 40,000 dog death records from 1984 to 2004 contained in a national veterinary database. The average age of death for dogs that had not been fixed was 7.9 years, they found, whereas those that had been spayed or neutered lived to 9.4 years.

The researchers saw that spayed and neutered dogs were more likely to die from cancer or autoimmune diseases than their gonad-carrying counterparts. The latter group typically died from trauma or an infectious disease. (One caveat: this group of dogs represented a population of sick animals that had come to the vet, so the average lifespan in this study is likely lower than that of dogs in general.)

Dogs, of course, share their lives with humans, meaning many of the factors that impact our health can also affect them. Our two species have the same reproductive hormones in common, too, including progesterone and testosterone, which can both suppress the immune system and perhaps make a dog or person more susceptible to disease.

On the human side of the equation, some studies on castrated men have shown that they, too, tended to outlive men who had not been castrated, and also tended to get fewer infections, raising questions about how our sex organs may be impacting our lifespans and overall health.

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