Despite recent research, spaying and neutering early still a good option
CLAYTON, CA (Feb. 3, 2025) — For decades, veterinarians for decades have been taught and have counseled clients that early spaying and neutering are extremely important for the health of dogs and cats and to minimize pet overpopulation.
In the past few years, however, there have been some indicators of possible benefits of waiting to spay or neuter until a later age in some breeds of dogs. This can be accomplished in a conscientious home with good control of the pet’s activities.
Having said that, if we look at the overall life expectancies of intact vs. neutered/spayed dogs and cats, the overwhelming evidence still supports spaying and neutering. A large U.S. study of client-owned pets looking at more than 2 million dogs and 460,000 cats showed that neutered male dogs live on average 18% longer than intact males, and spayed female dogs 23% longer than intact females. In cats, the difference was 62% longer for neutered male cats and 39% longer for spayed female cats.
This difference at least in part is due to preventing roaming and fighting, keeping the animals safer in the confines of their homes and environments. Other studies have also shown that spays and neuters lead to significantly longer lifespans as compared to unneutered/unspayed dogs and cats.
I would like to highlight the tremendous success accomplished by shelters and rescue groups by implementing spays and neuters before placement of animals in new homes, including via “early spay and neuter” process.
Early spays and neuters – before an animal leaves the shelter and often at a young age – prevent millions of dogs and cats from being euthanized simply because they are “surplus” and cannot find a loving home to care for them. It also prevents the “oops” factor of forgetting to get your puppy or kitten spayed or neutered before they are sexually mature, which can occur as early as 4-5 months of age. It can also alleviate concerns about demeanor in more aggressive male dogs.
Spaying and neutering prevent some major health issues. Early spays, before a first heat cycle, almost completely resolve the risk of mammary (breast) tumors in dogs and cats. Since 50% of canine mammary tumors are malignant and almost 100% of feline mammary tumors are malignant, it is clearly beneficial to avoid this scenario.
Spaying avoids heat cycles: Picture trying to keep your menstruating female dog away from potential breeding males for weeks to avoid unintended pregnancies. Spaying also prevents pyometra, a potentially life-threatening uterine infection, as well as uterine and ovarian cancers. For males, neutering eliminates the concern for testicular tumors and significantly lowers the risk of prostate infections to nil if performed prior to development of prostatitis, an older male dog disease.
In cats, spraying and “tomcat” odor are typically eliminated. Female cats will go in and out of heat until they are bred and can make quite a ruckus when they are willing to breed. Female dogs come into season typically every 7 months, but when in season, they will need to avoid a male for 3-4 weeks at a time, which can be difficult.
Next month, I will look at the ins and outs of choosing when and if to neuter. I would still call this a “when” and not an “if” in most circumstances. I will walk through this to help you make an informed decision.
Send questions and comments by email to Micki McCabe Walls at drmccabevet@gmail.com.
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Micki McCabe
Micki McCabe Walls, DVM, DACVIM, FAAVA, is a long-time Clayton resident. The recently retired local veterinarian has an interest in internal and integrative medicine.