Catherine de la Cruz

According to a recent article in the Cornell Animal Health Newsletter, much misunderstanding still exists regarding neutering dogs and cats. Even the experts admit to not having all the answers when it comes to the best age for neutering. However, there is little scientific basis for selecting the conventional age of five to eight months as the best time to neuter. As more studies are done in this area, it is hoped that both pet owners and veterinarians will soon feel more confident about early neutering.

Some Positive Effects of Neutering

There is solid medical evidence regarding the benefits of neutering for both males and females. For the bitch, the most important effect of spaying is protection against mammary cancer, the most common tumor in sexually intact female dogs. The risk to intact bitches of developing this kind of cancer is three to seven times greater than that of neutered bitches. The risk of mammary tumor is lowest for bitches spayed prior to the first heat - a mere 0.5% ; spayed after the first or second season, the risk of mammarycancer rises as high as 26%.

A more obvious benefit of spaying is the prevention of Pyometra, a severe infection of the uterus. Also, risks due to unwanted matings and to pregnancy and whelping are removed.

Benefits of neutering male dogs

Since testicular cancer is second only to skin cancer as the most common cancer in dogs, castration of the male obviously removes this risk as well as risks associated with testicular torsion and infections. As with human males, non-cancerous enlargement of the prostate is a major problem, involving more than 60 percent of the sexually intact male more than five years of age.

How will neutering change my pet?

Many owners believe that neutering a dog or bitch causes it to gain weight. However, if feed is restricted to only that which a dog needs, and a program of activity (such as daily walks) is undertaken, the neutered can remain as trim and fit as it should be. This is probably as true of the intact pet as it is of the neutered one.

Studies show that as many as 60% of the castrated males show a decline in unprovoked aggression toward other dogs. In addition, one study showed a decrease of 90% in the tendency of neutered dogs to roam. Animal behavior expert Benjamin L. Hart, DVM, PhD, sums up the effects of neutering on pet personality by noting that the procedure causes no basic personality changes except in the cases of roaming and aggression. Activities such as playfulness, activity level, watchful barking and affection-seeking are, in Dr. Hart's opinion, not changed at all by the neutering.

Early vs. Late Neutering

At Minnesota, Dr. Katherine Salmeri and associates conducted an extensive study of the effects of early neutering on dogs. There were no problems in neutering seven-week old puppies; anesthesia was simple and recovery uncomplicated. Surgical time in bitches was considerably reduced due to the lack of abdominal fat. Pups were returned to their litters and were eating within an hour.

Castration before puberty did not adversely affect growth; in fact, there was some evidence that early castration increased long-bone length. The neutered dogs were not less active as they went into adulthood, there were no changes in social behavior and the effect of neutering at seven weeks was, in all respects, similar to that of neutering at seven months.

See also Early Sterilization ProgramReturn to Library