The choice to spay or neuter your pet may be one of the most important decisions you make impacting their long-term health—and your wallet!

Your pet's health and longevity

The average lifespan of spayed and neutered cats and dogs is demonstrably longer than the lifespan of those not. A University of Georgia study, based on the medical records of more than 70,000 animal patients, found that the life expectancy of neutered male dogs was 13.8% longer and that of spayed female dogs was 26.3% longer. The average age of death of intact dogs was 7.9 years versus a significantly older 9.4 years for altered dogs.

Another study, conducted by Banfield Pet Hospitals on a database of 2.2 million dogs and 460,000 cats reflected similar findings, concluding that neutered male dogs lived 18% longer and spayed female dogs lived 23% longer. Spayed female cats in the study lived 39% longer and neutered male cats lived 62% longer.

The reduced lifespan of unaltered pets can, in part, be attributed to an increased urge to roam (exposing them to fights with other animals resulting in injuries and infections), to trauma from vehicle strikes and to other accidental mishaps.

A contributor to the increased longevity of altered pets is their reduced risk of certain types of cancers. Intact female cats and dogs have a greater chance of developing pyometra (a potentially fatal uterine infection) and uterine, mammary gland and other cancers of the reproductive system. Neutering male pets eliminates their risk of testicular cancer and results in lower rates of prostate cancer.

A handful of studies conducted at UC Davis may appear to challenge the health benefits of widespread spaying/neutering of companion pets, by raising concerns that these surgeries may predispose some altered dogs to certain orthopedic conditions and cancers. As a result, they have caused some pet owners to question altering their pets at an early age or altering them at all. However, on closer examination, the results of these studies pertain specifically to male dogs of certain large breeds and their conclusions should not be generalized to other breeds of dogs, or other species, including cats.

These are the best general recommendations that can be drawn from a thorough analysis of research currently available: