Most people vaguely know the benefits of spaying and neutering one’s pet. Here are the details.

Obviously, our society has millions of unwanted animals, and spaying and neutering prevents unintended pregnancies. For most responsible pet owners, that’s not the big issue, however, since their pets don’t have uncontrolled reproduction. The major benefits of spaying and neutering are medical and behavioral.

Medical Benefits of the Surgery
Female animals who are not spayed are at very high risk for malignant and non-malignant breast tumors – and the rate of tumor development is much higher than for humans. The preventative effect of the ovariohysterectomy surgery is strongest if it is done young, preferably before the first estrus cycle, which occurs on average at 7 to 9 months of age. There is no medical or behavioral benefit to waiting until after the first heat cycle.

Another major disease that unspayed female animals commonly develop is pyometra, or uterus abscessation. This severe infection comes on suddenly, and is fatal unless treated immediately, almost always with emergency surgery. Tumors of the ovary and uterus are also eliminated by spaying, and this is particularly an issue for rabbits, for whom uterine cancer will occur in 70 % of unspayed females.

Male dogs are exposed to different health risks if not neutered. They may develop prostate diseases such as prostate enlargement, which causes bleeding and urinary trouble, and prostatic infections. Testicular tumors are quite common in dogs, much more so than prostate cancer, which occurs only rarely. In addition, unneutered dogs can develop large hernias or tumors at the anus.

Behavioral Benefits of the Surgery
These benefits are strongest for cat owners since neutering a tom cat prevents the urine marking behavior and unbearable odors that usually develop in unneutered males. Aggressive or dominant male dogs are calmer and much less likely to fight other dogs and defy their owners if they are neutered.

Possible Disadvantages
There are some disadvantages. Some pets tend to gain weight after spay or neuter surgery. Weight gain can be controlled by monitoring diet and body appearance. The second disadvantage to spaying is that a very small percentage of female dogs develop urinary incontinence, which is easily treated with medication. And finally, a spayed or neutered animal is sterilized and no longer a breeding animal.