How to Decide Whether to Neuter Your Dog

The only way to be sure your dog doesn’t produce a litter of puppies is to get your female dog spayed or your male dog castrated.

Spaying involves the removal of both the uterus and the ovaries. Castration refers to the removal of a male dog’s testicles. The term neutering is a general term to describe either spaying or castration (but you may hear the terms neutering and castrating used to mean the same thing).

In addition to preventing unwanted puppies, neutering your dog has many benefits:

Female dogs who are spayed prior to their first heat cycle (which usually occurs between six and nine months of age) have a significantly reduced chance of developing mammary (breast) cancer compared to dogs who have had even one heat cycle.
Spayed females can’t develop pyometra, an infection of the uterus that can be quite severe and can even result in death.
Spayed females tend to have more even temperaments and do not go through the hormone-induced mood swings that unsprayed dogs sometimes have.
Neutered male dogs often are better behaved than their intact counterparts. Not only are they less likely to roam (visiting neighborhood females is a major reason for roaming), they are also less likely to mark their territory by urinating in the house (testosterone is one of the major drives for this dominance-related activity).

Neutered male dogs are much less likely to be aggressive toward other male dogs. These behavior benefits are particularly true if you castrate your dog between the ages of 9 and 12 months, before he becomes sexually mature and develops bad habits.
Neutering males prevents the development of prostate problems often seen in older dogs.
A neutered male won’t develop testicular cancer, a common cancer of older, intact male dogs.

Many people think their dogs will get fat if they are spayed or castrated, but this isn’t the case. Neutered dogs often don’t need as much food as their intact compatriots, so there is a simple solution: Don’t feed them as much.