Answers to questions concerning responsible pet ownership
Q: Why should I spay/neuter? Is it worth the expense?
Some health benefits of spaying/neutering:
- Prevention of mammary adenocarcinomas (malignant tumors of the
mammary gland) or testicular tumors.
- Prevention of pyometra (septic uterine infection) or other
uterine problems in older females.
- Prevention of ovarian tumors, cysts, or other
- Prevention of prostatic hyperplasia (enlarged prostate) and
reduction of the likelihood of prostatic infection/abscess or
neoplasia (tumor and/or cancer).
- Prevention of unwanted/unexpected pregnancy (ultimately
contributes exponentially to the pet overpopulation problem).
- Prevention of injury/infection risks of whelping, especially in
a difficult pregnancy (if the pups are too big, etc.).
- Prevention of tendency to fight, or other aggressive behavior,
in males. Bite and scratch wounds from fighting can cause permanent
injury, abscess, or infection in cats and dogs.
- Prevention of roaming/escaping/running away in search of a
mate. This roaming often results in the animal being involved in
car accidents, becoming lost/stray, caught by animal control,
- Prevention of acquiring diseases from infected animals
(especially cats) via bite wounds or mating. Sexually transmitted
diseases such as feline leukemia (FeLV) or feline immunodeficiency
virus (FIV) are fatal.
- Prevention of unwanted territorial marking behavior (both in
dogs and cats).
- Prevention of estrus in females that may result in blood
staining in the house (dogs) or unwanted estrus behavior in
A: Spaying/neutering has many benefits, including
prevention of disease and unwanted behavior. The cost of any one of
these occurrences far outweights the cost of spay/neuter
Debra L. Zoran, DVM, PhD
Diplomate, American College of Veterinary Internal Medicine
Q: If I spay/neuter my pet, will it become lazy?
Historically, pets have been spay/neutered around the time of
puberty (5-8 months of age). Changes in the pet's behavior often
occur around this time, but are due to many factors. Many animals,
particularly cats, become less playful during this time. Although
alterations in metabolism occur due to changes in hormone levels,
these have only a small effect on the animal's overall activity
level. Many pets seem to become less active after neutering, but
the bulk of this effect has more to do with the age of the
Because spay/neutering only affects sexually dimorphic
behaviors, and does not affect learning, it will not impair an
animal's ability to do work, hunt, guard, etc. Animals actually may
be better able to focus on their task, since they will be less
distracted by other dogs and cats. In addition, they will not be
subject to the "emotional" effects of hormonal fluctuations.
Spay/neutered animals are three times less likely to develop
behavior problems as intact animals. (Beaver, Canine Behavior: A
Guide for Veterinarians. WB Saunders. 1999 p208).
A: A: Spaying/neutering will not detract from
performance, and may actually enhance it.
Lore I. Haug, DVM
Friskies PetCare Resident in Companion Animal Behavior
Candidate, American College of Veterinary Behavior
Q: If I spay/neuter my pet, won't it get fat?
If you do not decrease your pet's food by 20-25%, it will get
fat. Respiratory calorimetry measurements in kittens, a definitive
measure of calorie requirements, have shown that energy
requirements decrease about 20-25% after the kitten is
spay/neutered. It does not matter whether it is a female or a male,
the energy decrease is the same, nor does it matter whether you
neuter them early or late (Root et al. Am J Vet Res 57:371-374,
1996). What is different between females and males is the effect of
estrogen on food intake. Estrogen is appetite suppressing, so loss
of estrogen from spaying a female will cause them to eat more if
allowed food free-choice (Flynn et al. J AM Vet Med Assoc
174:1083-1085, 1979). This is one reason spayed females tend to be
4 times as likely to be overweight than intact females, and
castrated males may be only twice as likely as intact males.
We have no calorimetry data from puppies like we have from
kittens as of yet. However, the same anecdotal observations apply
for both dogs and cats about spayed/neutered animals getting/being
fatter. The epidemiological data from dogs is consistent with the
cat-calorie findings. In my experience, dogs maintain their weight
on 75% of what was prior fed to being spay/neutered. The estrogen
effects are from both cats (Flynn) and dogs (Houpt).
A: If you adjust your pet's diet appropriately, it will
not get fat.
William J. Burkholder, DVM, PhD
Diplomate, American College of Veterinary Nutrition
Other false impressions about spaying/neutering
Can early spay/neuter stunt my pet's growth?
No. Your puppy/kitten will develop normally. In fact, young
animals tend to recover from surgery more rapidly than older
animals. Dogs and female cats don't generally have secondary sexual
characteristics, and male cats neutered at a young age will avoid
"tomcat jowls" and the undesirable behaviors associated with intact
Is it true that a dog/cat should be allowed to go through one
No. In general, the risk of an unwanted pregnancy is too great.
In some cases, a female dog with a history of vaginal infection may
be allowed to go through estrus once with the hope of reducing
these problems. The result is a hotly debated subject, and should
be discussed with your veterinarian.
Additionally, spaying a female dog before her first heat will
decrease the incidence of mammary tumors later in life.
One litter won't hurt anybody, will it?
Pet overpopulation affects everybody. Every litter born
contributes exponentially to the problem. Did you know that two
uncontrolled breeding cats and their offspring could produce a
population of 80 million cats within 10 years?
In 1996, the Brazos Animal Shelter received 8,655 animals, while
only 3,048 were claimed or adopted. You do the math . . .
But my animal is purebred with papers. I could make some
Many purebred animals are surrendered at the shelter. Breeders
spent hundreds of years developing individuals breeds - and all of
this hard work can be undone in just one mating. A dog should be
proven in field trials or kennel club shows. It should be certified
by veterinarians as free from genetic defects, such as hip
dysplasia, heart conditions, and other undesirable traits.
Everyone thinks their dog or cat is the best in the world.
That's great! But please visit your local shelter before you make
the decision to breed. Don't be a part of the problem when you can
be part of the solution!
Lisa M. Howe, DVM, PhD
Diplomate, American College of Veterinary Surgery