The term "neutering" refers to both sexes. Males are castrated, females are spayed. There are several myths about neutering that must be dispelled. Males do not begin acting more like females, nor does their bark become higher. Males and females do not get fat and lazy after neutering. Weight gain comes from overfeeding and lack of exercise. Usually aggressive behavior toward people is not changed after neutering. Finally, there is no evidence that shows females to be better pets after having had a litter of pups. The age at which you neuter your dog is best determined by your veterinarian.

There are behavioral differences as a result of neutering, and they differ for males and females.

After castrating a male, you can expect to see a less aggressive position taken toward other male dogs. The male will be less inclined to exert his dominance over you and will be less predisposed to mount other dogs or people. Mounting is not just a sexual behavior but an assertion of dominance. After castration, the male will exhibit less urine marking in the house. He will be less inclined to roam for extended periods of time. It is estimated that these behavioral changes take place in about fifty percent of the dogs that are castrated. Do not expect castration to make your male dog calmer, less destructive, or better with children. Also, it does not seem to matter whether or not the dog is castrated in puberty or as an adult. For the sake of population control, I would urge you to castrate your male just as he is becoming fully sexually mature.

The main gain from spaying your female is that she will not contribute to the millions of unwanted puppies who are killed each year because of the lack of an adopter. As a warning, however, there is some research that indicates that early spaying, before six months, can result in submissive wetting and a degree of masculine aggressiveness in some dogs. This can be controlled with chemical hormone therapy. Also, there seems to be a five to ten percent weight gain associated with spayed females. This is due to their reduced caloric need and can be controlled by monitoring their diet.

There are some medical benefits as well. For example, you no longer need to be concerned about gondola and ovarian cancer in your companion. From a selfish standpoint, I think a neutered dog becomes a better pet in that he becomes more attentive to his human family