Brookhaven Animal Rescue Alliance Ltd
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When is a Puppy or Kitten Old Enough to Neuter?
Dr. Lila Miller, D.V.M., ASPCA Sr. Director Animal Sciences and Vet Advisor
Spaying and castration have enough documented medical and behavioral benefits that
veterinarians routinely include them in their overall health care recommendations
to pet owners. Today, however, the question is not just whether to perform the surgery,
For years it was believed that the best age at which to neuter animals was six months.
In the late 1970s, however, as animal shelters began to seek new ways to combat pet
overpopulation, this belief was challenged. Shelter professionals realized that
conventional neutering contracts didnít work, and one obvious remedy was to neuter
all animals before they were adopted. The controversy arose because many of these
animals were considered to be too young to undergo surgery.
No conclusive, controlled studies have ever been done to determine the best age to
neuter dogs and cats. On the other hand, current research does show that spaying
before the first heat prevents the development of mammary gland tumors. Since females
can go into heat as young as four months of age, they should be spayed before then to
receive that protection. Early-age, or pediatric neutering is currently performed on
animals who are six to eight weeks of age and who weigh at least two pounds.
From the outset, veterinarians expressed concern about the long- and short-term safety
of operating on such young animals. Short-term safety was documented in 1993 when
doctors at Angell Memorial Hospital in Boston published protocols for safe surgery
and anesthesia in the Journal of the American Veterinary Medical Association. Other
studies have since confirmed their conclusions, and in December 2000, JAVMA reported
that researchers at Texas A&M University found no increase in physical or behavioral
problems in cats for at least three years postoperatively. Veterinarians have been safely
performing the surgeries for shelters since the 1980s, adding to the growing body of
supportive anecdotal information.
The lack of controlled studies on the long-term effects of pediatric neutering is still
cited as grounds for concern, despite the fact that studies have never been conducted
about the long-term effects of neutering at six months of age either. Concerns about
obesity, stunted growth, underdevelopment of secondary sex characteristics, behavioral
problems and increased incidence of both lower urinary tract disease and urinary
incontinence have been addressed in the veterinary literature and found to be unwarranted.
Any differences that have been found appear to have no clinical significance, or occur
regardless of the age at neutering.
The American Veterinary Medical Association and the American Animal Hospital Association
are just two professional organizations that support pediatric neutering. For a few
years now, veterinarians at the ASPCA have been neutering all shelter animals who
weigh at least two pounds before adoption. Yet despite the research, testimonials,
anecdotal information and endorsements, the controversy continues.
Ironically, veterinarians who perform pediatric surgery insist that it is faster and
less stressful to the animal than surgery at the conventional age. There is less body
fat to contend with, bleeding is minimal and the patients are awake much sooner after
surgery. They can be fed a small meal and sent home the same day. No special surgical
equipment is needed. If the procedure is performed when the last vaccination is given
at three to four months of age, owner compliance is increased. Most veterinarians who
at first were reluctant to try pediatric neutering now find that they prefer itóthe
hardest part was deciding to try something different. The best part is that everyone
Dr. Miller is ASPCA veterinary advisor and senior director of Animal Sciences