Early Neutering Important for Male Dogs and Cats
Michael W. Stephan, D.V.M.
Juno Beach Animal Hospital

Male dogs and cats usually attain sexual maturity slightly earlier than their female counterparts, most often between the ages of six and eight months. Males of both species will have increased tendencies towards aggression and territorial marking than males who are neutered. Male dogs who are left intact will be at higher risk of developing infections of the prostate gland, and show a higher incidence of prostate cancer.

Marking behavior consists of depositing small amounts of urine in areas where other males are likely to encounter the scent. This usually means trees, shrubs, and other vertical objects around the borders of their home or territory. If you routinely walk your dog or if your dog or cat is free roaming, his territorymay cover a mile or more. If he is confined to your house or yard, his marking behavior will be limited to objects around or in your house, including door frames, walls, and furniture. Males who are neutered after marking behavior starts will usually stop after the surgery, but the longer the behavior is allowed to go on, the greater the chance that it will continue in spite of neutering.

Aggression is also more common in males who are left intact than in males who are neutered. This aggression may be directed either at other animals, or at people, or both. Intact male cats, especially those who are kept indoors, are more inclined to stalk their owners as they would prey. This behavior often begins as play but usually escalate to the point of serious bites or scratches, especially if the owner has encouraged the aggressive behavior during the play stage. Intact male dogs often adopt the human family with whom they live as their pack. In the wild, all male dogs strive to be the leader of the pack, the alpha dog. If they adopt the human family as their pack, they will attempt to be the alpha male in the family. These dogs will usually show protective behavior towards the women and children in the family, and aggressive behavior towards the men. They will take a protective stance in front of the children and women during family arguments, and may even challenge a man who tries to enter his own house after dark, or who tries to come to bed after his wife has gotten into the bed. Although these dogs are protective towards women and children, the will growl or challenge them if they attempt to discipline him or if they approach his food or toys while he is eating or playing. These are very serious behaviors and should not be ignored or taken lightly! Once a dog begins to show these behaviors he should be neutered and started in obedience training immediately. The longer this behavior is allowed to develop, the stronger it will become and it may be difficult or impossible to reverse.

Intact male dogs are also more likely to develop prostate infections and prostate cancer as older dogs. Although neutering a male dog at any age greatly reduces his chances of developing prostate cancer, dogs who are neutered later in life at still at slightly higher risk than dogs who are neutered before sexual maturity.

While it is true that neutered males have a greater tendency towards weight gain than intact males, this is simply because they are not burning the calories required to maintain a territory. By encouraging regular exercise and play and by watching your dogs diet, you can easily avoid having an obese neutered male.

Neutering involves complete surgical castration. Performing a vasectomy on a male dog or cat will result in sterility, but will not alter the undesirable behaviors or reduce the health risks associated with remaining intact, and this procedure is rarely, if ever, performed.

As with spaying in female pets, the neutering of males is a safe and effective procedure and the benefits in terms of improved behavior and reduction of health risks make it well worth doing before the onset of sexual maturity. If you have any other questions about neutering, contact your veterinarian.