Neutering is the surgical removal of the reproductive organs. Many male and female animals are neutered (castrated) as a best practice for health and handling. Neutering is often considered part of responsible pet ownership. This review article Evaluating the benefits and risks of neutering dogs and cats, provides some great insight on the risks and benefits pet owners should consider when deciding to neuter their pets.
What is involved in neutering a dog?
Neutering is the surgical removal of the testicles. Removing the testicles removes the primary source of testosterone in the body, resulting in changes in sex drive, hormone-related behaviors, and hormone-related health concerns. Removing the testicles can also protect against some later-life health concerns, such as testicular cancer and prostate enlargement, as well as hormone-related tumors of the perineum. Neutering may also be associated with an increased risk of some musculoskeletal disorders and cancers, when done before a given age. More specifically, dogs of both sexes are susceptible to infection with Brucella canis, a bacterium which can cause disease in dogs and humans. This bacterium can be transmitted during breeding or acquired from contact with aborted foetuses and other material from infected females. The incidence of this disease varies by country and region, from 1–18% in the USA to 25% and above in some countries. Clinical symptoms other than infertility are uncommon, though some dogs experience serious infections of the bone, eyes or nervous system.
When should my dog be neutered?
All dogs are not physiologically the same. Different breeds and sizes of dogs have different optimal ages for castration. According to a recent study, veterinarians and pet owners should work together to discuss the optimal age of neutering, instead of following a blanket age recommendation. Every dog owner should consult with their veterinarian about the health impacts of castration for their individual dog.
Historically, veterinarians have recommended neutering dogs before puberty. This not only minimizes the risk of unplanned litters, but also may offer behavioral benefits. Puberty and adolescence are the time when animals transition from youth to sexual maturity. The evidence is also mixed regarding the risks and benefits of neutering dogs before 5–6 months of age, and so no strong recommendation for or against the practice can be made. However, it is clear that spaying female dogs before their first heat is preferable to spaying them later. Hormone surges during puberty can and do influence the behavior of any individual. If you’re considering waiting until social or structural maturity before neutering, be sure to talk to your veterinarian in-depth about what to expect with respect to your dog’s needs for exercise, training, appropriate and safe confinement, and appropriate social environments.
What are the impacts of neutering on dog behavior?
The best predictors of a dog’s behavior are his genetic background combined with the social learning and training he receives. Reproductive status does play a role in behavior, but it is not the dominant influence over animal behavior.
Testosterone influences sex drive and sexual acts, searching for mates, territorial behavior such as urine marking, and aggression between males. Testosterone may also affect confidence and the role of the experience of fear in some dogs. Neutering will result in a reduction in sexual behaviors (breeding attempts and masturbation), seeking mating opportunities, and urine marking. Some of these sexual behaviors can be dangerous, resulting in fights between dogs, roaming and being injured by cars, fences and other threats, and neutering will decrease these risks.
There is conflicting evidence at this time, but it is possible that neutering males before puberty may correlate with increased aggression directed toward strangers and strange dogs. However, further research is needed before any firm conclusions can be drawn in this situation. Neutering was historically considered a crucial part of therapy for all dogs displaying unwanted aggression. A more careful examination of the aggression with a veterinarian experienced in treating behavior disorders is now recommended prior to neutering, as neutering may worsen fear-related behaviors in a small subset of dogs.
Is there an alternative to neutering my dog?
Dogs can also be sterilized using vasectomy. In dogs for which castration at any age may be associated with adverse health risks, vasectomy is an excellent alternative to prevent unplanned litters and continue to control the pet overpopulation epidemic.