I am a proponent of spaying and neutering pets. Canine spay surgeries virtually eliminate the risk of breast cancer when performed before sexual maturity. Spays also dramatically reduce the rate of a potentially fatal infection called pyometra. Spayed dogs cannot develop ovarian cancer.

Spayed dogs do not go into heat. Their temperaments are more predictable. They are not injured during intercourse. They do not attempt to escape from the house in order to engage in trysts.

The most important thing is that spayed dogs do not get pregnant. Pregnancy is very metabolically demanding. Pregnancy and labor can lead to fatal complications. And pregnancy leads to puppies. Responsible people find homes for puppies (although each successfully housed puppy translates, roughly, into one shelter puppy being euthanized). Irresponsible people–I’m sure you realize there are plenty of irresponsible people in this world–dump the puppies at shelters, abandon them on roadsides, put them in gunny sacks to be thrown in rivers, or find other unsavory and unconscionable ways of dealing with an undesired litter.

There is no doubt that spaying is good for dogs as a species. But is it good for your dog?

Probably. But maybe not. From koamtv.com (article author: Jennifer Viegas).

Spaying is a procedure few of us question. This year alone, thousands of female dogs will undergo the hysterectomy operation, which removes the ovaries and uterus. Chances are your own pet has already undergone these removals.

A groundbreaking new study, however, may change the way we view this common surgery.

Longevity and Ovaries Linked

Women tend to live longer than men do, but did you know this life span edge holds true for female dogs too? “Like women, female dogs in our study had a distinct survival advantage over males,” according to project leader Dr. David Waters, Ph.D., a veterinarian, director of the Gerald P. Murphy Cancer Foundation and associate director of Purdue University’s Center on Aging and the Life Course.

Nevertheless, female dogs do not always reach the same age. That became obvious when Waters and his team studied information on the oldest living pet dogs in the United States. (Data on these canine seniors is tracked by the Center for Exceptional Longevity Studies.) Waters had a nagging suspicion: “We think that ovaries are part of a system that impacts longevity and perhaps the rate of aging.”

To test out the theory, Waters, who is also a professor in the department of veterinary clinical sciences at Purdue, and his team analyzed 119 rottweiler “centenarians,” which were elderly dogs that survived to 13 years. That’s 30 percent longer than the life span of most breed members. “We found that female rottweilers that kept their ovaries for at least six years were four times more likely to reach exceptional longevity compared to females who had the shortest lifetime ovary exposure.”

This study, in my opinion, does not prove that your dog will live longer if you don’t have her spayed until she is middle aged. And don’t forget that stunningly few people have the wherewithal to own an unspayed female dog for six puppy-free years.

I wish the study had shown that spayed dogs generally live longer than unspayed ones. But a conscientious clinician must accept facts rather than try to create them.

This subject demands more research. I will await the results with trepidation.