Health and behavioral concerns areoften given as reasons for spaying
and castrating dogs, but are we hearingthe whole story?
We are mostly aware that spaying abitch before her first season halves
her risk of mammary cancer, and obviously castration frees you
from concerns about testicular cancer,which is particularly worrisome in
boys with retained testicles, but whatabout other cancers? Here are some
figures that may surprise you. Spayed bitches had four times the
incidence of cardiac hemangiosarcomas comp a r e d to i n t a c t
bitches. Neutered males have a significantly greater risk for these tumors
compared to their intact brethren.Prostate cancer is four times more
common in castrated dogs compared to intact ones.
Neutered and spayed dogs have up to 3 times the likelihood of developing
bladder cancer compared to intact ones, and are twice as likely to
develop osteosarcoma (bone cancer).Males are four times more likely
to die within 2 years of diagnosis when compared with females. Dogs
neutered or spayed before they were a year old had a one in four lifetime
risk of getting osteosarcoma.Ultimately, with the unfolding of the
canine genome, we may know which cancers our dogs are most likely to
get, and be able to say whether an individual is better intact or neutered,
in the meantime, as with most questions,the answer to whether spaying
or neutering is better from a health point of view is "it depends."
At the AKC's Canine Health Foundation Conference in St. Louis in October,
Dr. James Serpell of U.Penn presented data from a survey study

(Canine Behavior and Response Questionnaire C-BARQ www.vet.upenn.edu/cbarq )
distributed by regular vet practices,
breed clubs and Veterinary Behavior
Clinics - preliminary report at:
http://www2.vet.upenn.edu/
research/centers/cias/pdf/
HsuSerpellJAVMA2003.pdf.

The interesting additional information he gave at the meeting was that neutering
seemed to worsen most problem behaviors. Even if you removed
dogs neutered for aggression, castrated dogs tended to be more aggressive,
more fearful, and in some breeds less trainable. They also
have increased body sensitivity and excitability. Similarly for the girls,
spayed bitches are more aggressivewith strangers, and showed a tendency
to worse general behavior.Neutering does not appear to
diminish aggression in aggressive dogs. A smaller survey of Springer
Spaniels by 3 veterinary behavior clinics recently reported in the Journal
of the AVMA also found increased aggression in neutered dogs, even
when dogs neutered for aggressive behavior were removed from the
data.It could be argued that those keeping
intact animals may be more involved in dog related activities and
spend more time training and working with their dogs - this study was in North America, where most vets can't see a set of testicles without wanting
them off - but I do think they help dispel the myth that intact dogs are testosterone
driven airheads. Society is a long way from accepting this. Pet
overpopulation is a very serious concern,and it does not serve the best
interests of the shelter and veterinary personnel, nor of the overproduced
dogs themselves to advertise the facts too loudly. The biggest reason
for spaying and neutering should be the only proven one - they cannot
reproduce, and we put far too many unwanted dogs to sleep. Dogs with
retained testicles do run a much greater risk of testicular cancer, but
that doesn't mean it's not OK to wait for them to grow up - 18 -24 months -
before castrating them. For dogs living with responsible owners who
are dedicated to their care, and who won’t put them in jeopardy of producing
unwanted puppies, delaying spaying and neutering may be advisable.