| Important
Facts on Sterilisation
extracted from Chicago
House Rabbit Society website
Terminology
The word "neuter" refers to the removal of
the reproductive organs of either a male or a female
of a species, although people frequently refer to the
surgery in a female as a "spay". The 'scientific'
terminology for neutering in the male is castration
and in the female is ovariohysterectomy . Let's now
take a look at the whys and wherefores of this important
issue.
Reasons
for neutering rabbits
- Prevention of Pregnancy - This is the most
common reason that rabbits are neutered, particularly
if there are both male and female rabbits living together
in a household. There are certainly enough rabbits
in the world and too many are neglected or abandoned.
One should not consider breeding these pets just for
"fun" or "education".
- Prevention of Uterine Cancer - This is the
most compelling medical reason to neuter female rabbits.
In some rabbit populations the rate of malignant uterine
cancer (specifically called uterine adenocarcinoma)
can approach 80% of all the females. It is believed
that the incidence may be related to the genetic makeup
of the rabbit. Since we usually don't know the genetic
background of most of our rabbits, it is best to have
the surgery done as a preventative for this cancer.
Uterine adenocarcinoma can spread rapidly to other
organs of the body such as the liver, lungs and even
the skin and it is not treatable once it reaches this
point. We see many cases of this disease each year
and sadly these rabbits could have avoided this problem.
Rabbits under two years of age rarely develop this
disease so it is best to get your little one spayed
before this age.
- Prevention of Other Uterine Disease - Although
cancer is the most common disease of the rabbit uterus
we see many cases a year of other uterine disease
such as pyometra (infected uterus full of pus), uterine
aneurism (uterus full of blood) and endometritis (inflamed
uterine lining. Like uterine cancer, these conditions
are all more common in female rabbits over two years
of age.
- Prevention of False Pregnancies - Female
rabbits can go into a hormonal state triggered by
their ovaries where they think they are pregnant but
they are not. Although this is not medically harmful,
it can be very stressful for the rabbit who goes through
all the motions of being pregnant including nest building,
milk production and aggressive protection of its territory.
This aggression can be taken out on the caretakers
and cagemates and can make the pet very difficult
to handle during this period. Some rabbits experiencing
false pregnancy will develop a decreased appetite
and have gastrointestinal disturbances as well.
- Prevention of Mammary Gland (Breast) Disease
- Breast cancer is not common in female rabbits, but
when it occurs it can spread rapidly and be very difficult
to treat. It is preventable if the pet is neutered
before two years of age. It is interesting to note
that the most common type of mammary cancer is a malignant
form called mammary carcinoma and it is almost always
associated with uterine cancer. The other common mammary
gland disease is mammary dysplasia or cystic mammary
glands. This is a benign condition, where the mammary
glands fill with a cystic material. It can be uncomfortable
to the pet. Neutering a female rabbit before two years
of age will prevent both of these diseases.
- Prevention of Aggressive Behavior - Both
male and female rabbits can display aggressive behavior
when they reach sexual maturity. Many rabbits are
sweet and easy to handle as little babies, but when
the teenage years hit...watch out! They can turn (it
seems like overnight) into little Frankensteins! They
don't want to be touched or picked up and they act
like they want to destroy everything in site. This
is their way of learning to protect themselves, their
territory and potential future families and make a
"niche" for themselves in the big wide rabbit
world. However, they can often take out their aggression
on YOU or their cagemates. There may be more biting,
striking, lunging and chasing. It is best to neuter
just before or shortly after sexual maturity to keep
this behavior to a minimum.
- Prevention of Urine Spraying - Both male
and female rabbits can spray urine on vertical surfaces
to mark their territory. Intact mature males do this
at least 10 times more frequently than females. In
addition, sexually mature male rabbit urine can develop
a very strong odor which is unpleasant to many humans.
If this behavior is allowed to continue for months
or certainly years, it may be impossible to retrain
the pet, if it is neutered at a later date, to learn
to use the litter box again. Therefore, it is best
to "nip it in the bud" and get the little
guys neutered just prior to shortly after sexual maturity.
- Prevention of Testicular Disease - Disease
of the testicle is rare in the male rabbit, but it
can occur. Most commonly we see abscesses (often from
bite wounds from other rabbits), hematomas (blood
filled areas) and cancers.
Age to
neuter
The best age to neuter is shortly after sexual maturity.
Depending on the breed, this could range from 4 to 6
months and with giant breeds up to possibly 9 months.
If the rabbit is neutered much younger than 4 months
of age, not only is the surgery more difficult due to
the immature condition of the reproductive organs (in
males the testicles might not even be descended into
the scrotal sacs prior to three months) but we do not
know what the long term effect is on the endocrine system
of the body. The reproductive organs are part of an
interconnecting system of hormone producing organs including
the thyroid, pituitary, pancreas and adrenal. If we
remove a large "chunk" of the endocrine system
before it is done developing, we suspect there could
be long term effects on the health of the rabbit. This
has been studied in mice and rats where ill effects
have been found with early neutering, but as yet has
not been researched in rabbits. For the pet rabbit,
there is really no good reason to neuter your rabbit
before it is mature.
You should have your rabbit examined by an veterinarian
who has experience with rabbits to make sure your pet
is in good condition and ready for neutering. Sexual
maturity can be gauged a number of ways including the
presence of the testicles in the scrotal sacs, a well
developed and possibly swollen vulva (this has to be
checked by "pushing" the vulvar tissue out
by pressure placed above it), a mature body condition
and by behavioral changes such as urine spraying and
increased aggression. Your veterinarian may recommend
some simple tests prior to surgery, particularly if
your pet is older or has had other medical problems.
I do not recommend performing routine neutering procedures
on obese animals or those with other disease. The weight
should be reduced and other disease managed prior to
having a major surgical procedure performed.
What
happens at neutering
When a male rabbit is castrated, the testicles are completely
removed. There may either be one incision made in front
of the testicles, in the area of the lower abdomen through
which they are both removed, or there may be one incision
made over each scrotal sac. The incisions may be left
open (perfectly acceptable if scrotal incisions are
made) or closed with suture or surgical glue. The scrotal
sacs may swell after surgery within 24 to 48 hours and
by 7 to 10 days the swelling should be gone. The scrotal
sacs will eventually shrink to be barely noticeable
over time. It is important to note that neutered males
should not be put with intact females for at least 3
weeks after neutering. Male rabbits can still have living
sperm in the portion of the spermatic cord (vas deferens)
which is still in place after surgery. These sperm can
live for a couple of weeks. Testosterone blood levels
drop slowly after neutering and male rabbits will still
try to mate with female rabbits for weeks after the
testicles are removed. After three weeks the sperm are
dead and since no new sperm are being produced it is
safe to put a male and female rabbit back together again.
When a female rabbit is neutered the ovaries, the oviducts,
the uterus and often both cervices are removed. Rabbits
have a uterus that is made up of two long tubes with
an ovary at one end and a cervix at the other. They
have two cervices unlike cats, dogs, humans and many
other species. An incision is made approximately midabdomen
and the uterus and associated structures are gently
pulled out from the abdomen through this incision. The
blood vessels supplying the uterus and ovaries are tied
off with suture material and reproductive organs are
removed. The incision is sutured with two to three layers
of suture material. Since rabbits have incisors that
are excellent at cutting through many materials we find
it beneficial to bury final row of sutures under the
skin so they are not accessible. In this way the rabbit
has nothing to chew on or pull out. These sutures dissolve
eventually over several weeks and there are no external
sutures to remove. Some veterinarians use skin staples
as the final closure which also work nicely in rabbits,
particularly the larger breeds. Skin staples can't be
chewed through like nylon suture or other more flexible
materials.
It is important with any surgeries to check the surgical
site at least one, and even better twice a day for any
signs of unusual swelling, discharges or gapping of
the wound. Many rabbits will be off feed for a day after
surgery, but this should gradually return to normal
over the next two to three days. In addition, some rabbits
will have unusual stools for a day or two including
soft stools, clumped stools, irregular shaped or small
stools. If your rabbit is acting very uncomfortable,
is not eating at all or is unwilling to move, you need
to contact your veterinarian right away. Your veterinarian
may prescribe a pain medication for your pet postsurgically,
particularly for females that may have had any complications
at surgery or for those that are older. After doing
literally hundreds of these procedures over the years
I find that the great majority of rabbits return to
normal within 2 to 5 days and are none the worse for
wear. The long term benefits of neutering far outweigh
the temporary discomfort that might be felt. 
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