Study links dog longevity to ovaries

A recent study suggests that female dogs that keep their ovaries through their whole lives are more likely to live to an extreme old age than those that don’t.

The study, “Exploring mechanisms of sex differences in longevity: lifetime ovary exposure and exceptional longevity in dogs,” says that female dogs, like women, are generally more likely to achieve “exceptional longevity” than their male counterparts.

The researchers collected information on Rottweilers that lived to be 13 or older, which is more than 30 percent above the average life expectancy for that breed. Female dogs in general lived longer, but the researchers found that removal of the ovaries in the first four years of life “erased the female survival advantage.”

Robert Hutchison, DVM, is a canine reproduction expert and owner of Animal Clinic Northview in Ohio. Hutchison said that while the study shows that the oldest Rottweilers in the study had their ovaries intact, it is not an argument against spaying. Hutchison compared the study to someone saying if they drive 100 miles an hour to Columbus, they will get there faster. True, but there are also risks to consider.

“There are health advantages to spaying a bitch,” he said. “People are assuming that if you don’t spay bitches they all live longer, but I don’t believe that is what he is saying.”

Jeanette O’Quin, DVM, president of the Association of Shelter Veterinarians, warned against misinterpreting the study’s results.

“This study neither proves nor disproves that dogs may live longer if they retain their ovaries,” O’Quin said. “Rottweiler dogs that died at ages less than 8 years of age or between 10.8 and 13.3 years were not included in the study, so we do not know what effect spaying had on those groups or on the population as a whole.”

Although the oldest Rottweilers in the study had their ovaries, dogs that keep their ovaries can develop other problems related to the reproductive system, such as mammary tumors and pyometritis from continued heat cycles.

“There are things that can shorten a bitch’s life by leaving the ovaries in there,” Hutchison said.

Hutchison, who sometimes consults for the Veterinary Information Network (VIN), said he has been asked by some veterinarians about the study.

“Veterinarians are geared up for doing the best thing for their clients,” he said. “When we suddenly get that curve ball thrown at us by the national news, that just makes a blanket statement saying ‘your dog will live longer if it has its ovaries,’ it undermines some of the things they are telling their clients.”

If clients ask about the study, Hutchison recommended telling them about the other health issues related to keeping the ovaries. He also said to remind clients that the research is preliminary, and not a definitive work, as it may appear to be in the media.

O’Quin said the study is not likely to change any minds about the benefits of spaying, but could spur some healthy debate.

“I think the study will initiate a lot of discussion and possibly encourage additional research in this area,” she said. “There are many studies documenting the benefits of spaying and neutering, so I do not expect a change in veterinary recommendations or current practices in response to a single study.”

The study is available to read free online in the journal Aging Cell.

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