Not the Dog - Advantages of Neutering Tips on Dog Behavior Excerpt reproduced on the web from the book Get Rid of the Problem, Not the Dog , by Rod Cassidy. 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.