Neutering Dogs

Most male animals (stallions, bulls, boars, rams, and tomcats) that are kept for companionship, work, or food production are neutered (castrated) unless they are intended to be used as breeding stock. This is a common practice to prevent unacceptable sexual behavior, reduce aggressiveness, and prevent accidental or indiscriminate breeding. However, many dog owners choose not to neuter their male dogs, despite the benefits.

How does neutering affect behavior?
The only behaviors that will be affected by castration are those that are under the influence of male hormones (See below). A dog’s temperament, training, personality and ability to do “work” are a result of genetics and upbringing, not its male hormones. Castration does not “calm” an excitable dog, and unless a castrated male dog is overfed or under-exercised, there is no reason for it to become fat and lazy.

What is castration?
Castration or neutering of male dogs is surgical removal of the testicles (orchidectomy). The procedure involves general anesthesia. An incision is made just in front of the scrotal sac and both testicles, leaving the sac intact. Vasectomies are not performed since it is both sterilization and removal of the male hormones that provide the behavioral and medical benefits. A chemical castration agent has been recently introduced for puppies but, although these products do sterilize dogs to prevent reproduction, they may not prevent or reduce the behavioral signs that can be achieved by castration since hormone levels are still present.

Which of my dogs’ behavior problems can be expected to improve following castration?
As mentioned, only those behaviors that are “driven” by male hormones can be reduced or eliminated by castration. Although the hormones are gone from the system almost immediately following castration, male behaviors may diminish quickly over a few days or gradually over a few months.

Undesirable sexual behavior: Attraction to female dogs, roaming, mounting, and masturbation can be reduced or eliminated by castration.

(a) Case studies show that for roaming there was moderate improvement in 70% of dogs with marked improvement in 40%. For mounting there was moderate improvement in 70% of dogs with marked improvement in 25%.

(b) In one study, castration led to reduced aggression toward other dogs in the house in 1/3 of cases, towards people in the family in 30% of cases, towards unfamiliar dogs in 20% of cases and towards unfamiliar people in 10% of cases.

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