Other than population control, there
are lots of very, very good reasons to castrate (remove
the testicles from) male dogs. They basically fall into
one of two categories – they are either behavioral
or medical. Regardless of which category we are talking
about, most of the unwanted characteristics or conditions
are caused by the male hormone testosterone, which is
produced within the testicle. That is the major reason
vasectomies have never been that popular in veterinary
medicine. A vasectomy eliminates successful breeding,
but it does not reduce any of the undesirable problems
of the intact male, since it does affect testosterone
production or its distribution throughout the rest of
the dog's body.
advantages of neutering
One of the most important behavioral advantages of castration
is that as adults, these dogs will tend to be less aggressive
both toward other male dogs and also people. The androgen
(male) hormones, of which testosterone is the most important,
are responsible for the development of many behavioral
patterns. When young puppies are sexually mounting their
7 and 8-week old litter mates this is because of androgen
surges in their bodies. The same is true with aggressive
behavior. Some medications that have androgenic hormonal
activity often cause increased aggression (an example
would be the birth control medication, Cheque Drops,
which contains one of these androgen-type chemicals).
The degree castration has on suppressing aggression
varies between animals and the age at which it is done.
Its effect is greatest if it is done before one year
A second behavioral advantage of neutering is that these
dogs will not 'roam' when they sense a female in heat.
Male dogs can sense females in heat through pheromones.
These are airborne chemical attractants that are liberated
from the female when she is cycling. They travel through
the air for great distances. We grew up on a farm where
the next closest house was over a mile away, but when
one of our female dogs was in heat, the males would
come for miles from upwind, downwind, and crosswind.
Pheromones are, to say the least, very effective stimuli.
In the seventies, it was briefly popular to do vasectomies
on dogs thinking that we would not be taking the 'joy
of sex' away from our canine counterparts. The problem
with this reasoning was that many of us keep our dogs
restricted in our homes, a kennel, or on a chain. Now
think of the psychological stress the vasectomized male
is under when he is locked up, but yet smells that female
in heat four blocks away. There is no joy of sex, as
he is trapped on your property unable to go and mate
with her. He is, in effect, teased continuously for
three to fourteen days while the female is in estrus
and he is unable to mate with her. If dogs are neutered
at an early age, they will not sense or respond to pheromones,
and would certainly be less stressed and tend to stay
A third behavioral advantage occurs when you are training
or working your dog, or using him for field work. If
neutered, he will be a much better student with a much
longer attention span when there are females nearby
that are in heat. This is because he will not be constantly
distracted by pheromonal stimuli.
are numerous behavioral and medical benefits to neutering your dog.
The medical advantages are numerous
and even more significant. Again, all are caused by
the effects of testosterone on the body or are physical
problems that arise within the testicles themselves.
Here again, a vasectomy would not serve any real or
There are several different tumor types, both benign
and malignant, that arise within the testicles. As
with most cancers, these usually are not noted until
the animal reaches 5 or more years of age. Therefore,
these would not be a problem in those individuals
castrated at the recommended age.
Genetics: We all agree that a male
carrying a harmful genetic trait like hip dysplasia
or epilepsy should be neutered. We must do all that
is possible to prevent the spread or continuation
of these conditions and others like them.
A hernia is a protrusion of an organ or parts of an
organ or other structure through the wall of a cavity
that normally contains it. Perianal hernias occur
when the colon, urinary bladder, prostate, or fat
protrude from the abdominal cavity, through the muscular
wall by the anus and then lie just under the skin.
This type of hernia is far more common in older, unneutered
male dogs. The levels of testosterone and other hormones
appear to relax or weaken the group of muscles near
the anus. When the animal then strains to defecate
or urinate, the weakened muscles break down and the
abdominal organs and fat bulge out under the skin.
In shorthaired breeds, this large bulge is noted by
the owner almost immediately, but in the longhaired
dogs, the problem may go on for months before anyone
realizes there is an abnormality. Left untreated,
these organs may become damaged, unable to function
or even die from loss of blood supply. Additionally,
because of the displacement of organs into this area,
the animal may not be able to defecate or urinate
correctly or completely and may become constipated
or have urinary incontinence (dribble urine). The
surgery to repair this condition is not simple and
today can easily cost $700 to $1500 or more, depending
on the severity.
There are tumors whose growth is stimulated by testosterone.
These occur near the anus and are called perianal
adenomas (benign) or perianal adenocarcinomas (malignant).
As with the hernias, these usually do not occur until
the dog is at least 7-years old. They require surgical
treatment and should be caught early in their development
to prevent recurrence. These tumors and the above
hernia are very, very rare in those individuals castrated
at 7 to 8-months of age.
The most common medical problems eliminated in dogs
neutered at an early age are those involving the prostate.
Over 80% of all unneutered male dogs develop prostate
disease. Prostate conditions such as benign enlargement,
cysts, and infection are all related to the presence
In the United States, most dogs
are neutered between 5 and 8 months of age. Many humane
shelters and veterinarians are starting to neuter
male animals at a younger age, even 6-14 weeks of
age. This early neutering does not affect the growth
rate, and there are no appreciable differences in
skeletal, physical, or behavioral development between
those animals neutered early than those neutered at
a more traditional age. It must be remembered that
younger animals may need different anesthetics and
are more prone to hypothermia (lower than normal body
temperature) during surgery. As long as procedures
are modified to account for these differences, early
neutering is very safe. In fact, animals neutered
at a younger age often have faster recoveries than
those neutered when they are older.
None of the behavioral or medical
problems caused by testosterone are rare. Veterinarians
deal with them on a daily basis. To say it in a way
that may not sound very nice but is certainly true
– veterinarians would make a lot less money
if everyone neutered their male dogs before they were
a year of age.
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