Castrating your dog, also commonly known as neutering, has several positive behavioral and physiological effects. Neutering eliminates or reduces the risk of certain conditions, like testicular cancer and prostate infections, and helps eliminate undesirable behaviors like urine-marking. While it isn't a cure for bad behavior, it can make training significantly easier and ultimately extend your pet's life.
Physical and Behavioral
Dogs who aren't castrated may be prone to both enlarged prostate and testicular cancer as they age. When you neuter your dog, you eliminate the risk of both. More readily noticeable, however, are the behavioral changes that follow castration. For example, neutered dogs are less interested in urine-marking their territory and freely roaming the neighborhood, as they no longer have the urge to mate. Castration reduces testosterone levels, which can make your dog less aggressive and can even reduce aggression from other dogs, who can detect high levels of testosterone in intact males, triggering aggressive behavior.