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Early Sterilization Program
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By Dr.
Dick Rosebrock
Early spaying and
neutering, pre-puberal spaying and neutering, pediatric spaying and
neutering are all talking about the same thing … the neutering of
our dogs and cats earlier than the commonly recommended and accepted
ages. Veterinarians decided years ago that the time to spay a female
dog or cat was after she had a litter. Motherhood appeared to mature
the female. The male did not have babies so they were not figured
into the formula and consequently ignored. Quite possibly a man
thing. J Later we found that if the female dog was spayed
before she had a litter, the incidence of mammary tumors
was reduced to zero and the recommendation was modified to, "spay
her just before her first heat". The client then asked, "When does
she come into heat the first time?" And so, the time to spay her
became, on the average, "about six months". Again male dogs did not
have babies and many male owners anthropomorphised and were
reluctant to have the males neutered. "Gee Doc, ain’t you gonna let
em have some fun?" This type of comment is still heard today. I
usually ask if they have seen the dogs mating act. It is very
uncomfortable and doesn’t look to be much fun to me. Most male dogs
were neutered to minimize or stop aggression; their part in the
reproductive process was not a viewed as a problem … if the
neighbor’s bitch was in heat … keep her locked up.
Well, times and attitudes
changed. Unwanted puppies and kittens were inundating the planet and
something had to be done. The hue and cry became, "spay and neuter"
your dogs and cats. But S & N alone have not been able to quell the
tide of pet overpopulation. The animal shelters are overcrowded …
animals were adopted and even though they were required to leave a
neuter deposit … fifty to sixty percent of these animals were not
spayed or neutered and became contributors to the overpopulation
problem.
Quietly over the past
twenty-five to thirty years a few progressive animal shelters began
various early sterilization programs with uniformly consistent
success stories. If they are spayed or neutered before
they leave the shelter … they cannot become contributors.
Puppies and kittens are being neutered as young as six to eight
weeks. The development of new anesthetics and surgical procedures
has made these procedures as safe or safer than the commonly
accepted time of six months. The younger patients recover faster and
have fewer surgical and post-surgical complications than their older
counterparts. There is very little to no body fat to contend with,
the incision is smaller, surgery time is reduced and recovery time
is very short.
The research available on
the physical, behavioral, short and long-term effects of
prepubescent neutering in dogs and cats shows no adverse results.
Based on this information, the American Humane Association supports
this practice as a feasible solution to decreasing pet
overpopulation and the tragedy of resulting deaths. Early
sterilization practices are also endorsed by the American Veterinary
Medical Association, the American Animal Hospital Association and
the California Veterinary Medical Association.
On a personal note, I
heartily endorse this program also. I have been actively
participating in ESP since 1984 and have performed ESP on
approximately 1000 animals. We have not noted any negative results,
in fact, clients typically report these puppies and kittens are the
"best we have ever had". We have not lost a single animal because of
this procedure! Seven of sixteen Irish Wolfhound puppies from our
last litter and two of nine from the litter prior to that were
neutered prior to placement in their new homes at ten weeks of age.
The first litter is now twenty-eight months, the last litter is now
eighteen months old, and no negative results have been reported.
People worry that this
early procedure might stunt growth. In fact, research shows that the
dogs will actually get a little larger. The reason for this is that
the long bones tend to grow for a slightly longer period. Since this
extra growth is not caused by more rapid growth, but instead by
prolonged growth, the implication is that this might be a good thing
in our giant breed. It is known that when growth proceeds slowly
over a longer period, the bone density (strength) increases.
Conscientious breeders
have, for years, sold companion quality puppies without registration
papers and/or with a non-breeding or spay/neuter contract to try and
prevent undesirable reproduction. In fact, these methods were not
always effective. Dogs, which shouldn’t have been bred, still were.
Pediatric spay/neuter is foolproof!
We offer this procedure
at no extra charge to all our puppy purchasers who are not
interested in showing their puppy. So far, in our last two litters,
100% of the buyers to whom we offered this procedure were thrilled
to accept. It saved them money and the emotional trauma of having
their pet undergo an elective procedure AFTER they had become
attached to it. We strongly recommend that breeders consider this
option and discuss it with your own veterinarian.
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EARLY
NEUTERING OF THE DOG
AND CAT
W PRESTON STUBBS,
Gainesville, Florida
KATHARINE R. SALMERI,
Red Bank, New Jersey
and MARK S. BLOOMBERG
Gainesville, Florida
Early neutering of the dog and cat by Stubbs, Salmeri and Bloomberg.
1995.In: Bonagura (ed), Kirk's Current Veterinary Therapy, XII, WB
Saunders & Co., Phila., pp.1037-1040.
Pet overpopulation continues to be a leading cause of death in dogs
and cats in the United States, with millions of animals being
euthanatized each year despite current population control programs.
Surgical sterilization is the most common and reliable means of pet
population control, leading most animal shelter/ control facilities
to employ mandatory neuter policies. However, because surgery is
usually delayed until dogs and cats are at least 6 months of age
(Stone, Cantrell, and Sharp, 1993), many animals adopted from
shelters remain sexually intact and are never neutered. Prepubertal
gonadectomy or early age neutering (6 to 14 weeks) is being
advocated by animal shelter and humane organizations as a means of
enhancing the efficacy of sterilization programs. As the terminology
suggests, surgical sterilization is performed prior to the onset of
sexual maturity, and hence reproductive capability, which may occur
as early as 6 months of age in dogs and 4 months of age in cats.
Although it is one of the oldest surgical procedures performed on
domestic animals, few objective scientific data exist to suggest an
optimal age for elective gonadectomy in the dog and cat (Salmeri,
Olson, and Bloomberg, 1991). In the United States, dogs and cats are
routinely neutered between 5 and 8 months of age. Most veterinarians
are comfortable performing elective gonadectomy on animals of this
age group because untoward effects are minimal. A more rational
basis for this policy is lacking, however.
The safety of early neutering has been questioned by veterinarians
because of their unfamiliarity with surgery and anesthesia on
pediatric patients. Other concerns about prepubertal neutering of
dogs and cats include stunted growth, obesity, perivulvar dermatitis,
vaginitis, behavioral changes, urinary incontinence, increased
morbidity/mortality during surgery and anesthesia, and impaired
immunocompetence (Salmeri, Olson, and Bloomberg, 1991). In the cat,
urethral obstruction (males) and defective formation of the
preputial cavity (Herron, 1971) have been cited as potential
problems. Mounting clinical and research data, however, would
suggest that most concerns regarding prepubertal gonadectomy are
unfounded (Aronsohn and Faggella, 1993; Theran, 1993; Salmeri et
al., 1991). In fact, several studies have found that early neutering
affects skeletal and physical development, behavior, and urethral
function in much the same manner as more traditionally timed
gonadectomy.
CLINICAL AND RESEARCH DATA
The aforementioned concerns were addressed in two separate but
parallel studies conducted at the University of Florida. The effects
of prepubertal gonadectomy on skeletal growth, weight gain, food
intake, body fat, secondary sex characteristics, urethral function,
and behavioral development were investigated in both dogs (Salmeri
et al., 1991) and cats. Both studies divided animals into three
treatment groups: animals neutered at 7 weeks of age (I), 7 months
of age (II), and those which remained sexually intact as a control
population (III).
Gonadectomy (groups I and II) delayed closure of the distal radial
growth plate in both dogs and cats as compared with sexually intact
controls. This allowed for an extended period of growth and greater
radial/ulnar length in all neutered male dogs and group I bitches.
Although delayed physeal closure was observed in neutered cats,
there was no significant difference in mature radius/ulna length
amongst the three treatment groups. Thus, rather than causing
stunted growth, prepubertal gonadectomy may actually result in
normal or greater stature. This delay in physeal closure probably
occurs because gonadal hormones facilitate physeal cartilage
maturation; in their absence the growth plate remains open for a
longer period of time. Some investigators have suggested that this
may increase the risk of physeal fractures (Houlton and McGlennon,
1992).
In dogs, gonadectomy did not affect growth rate, food intake, weight
gain, or back-fat depth (body fat). Body weight and body fat were
similar among neutered (group I and II) cats; however, sexually
intact cats weighed less and had less body fat than their neutered
counterparts. Prepubertal gonadectomy had no adverse effect on
urethral function in the dog or cat as deter
mined by urethral pressure profilometry. Male cats of all three
groups had similar urethras diameters.
The external genitalia of prepubertally neutered animals of both
sexes and species remained infantile in appearance. Male cats
neutered at 7 weeks of age had a virtual absence of penile spines,
but the penis could be fully exteriorized, indicating separation of
the balanopreputial fold. This is contrary to results describing
persistent preputial adhesions in four of ten male cats neutered at
5 months of age (Herron, 1971). The penis, prepuce, and os penis of
group I dogs were infantile, as were the vulvas of early neutered
bitches and queens. No problems with vaginitis or perivulvar
dermatitis were noted, however. Behavioral characteristics were
similar amongst all groups with the exception of greater
intraspecies aggression and fewer demonstrations of affection in
sexually intact cats. Neutering did not result in lethargy or
inactivity in either dogs or cats.
The safety of early neutering in a clinical setting has been well
established (Aronsohn and Faggella, 1993; Theran, 1993). In the
Massachusetts SPCA study (Theran, 1993), gonadectomies were
performed on over 350 6- to 14-week-old dogs and eats without
serious complications or mortality. The authors have had similar
experience with a smaller group of research animals.
SURGICAL TECHNIQUES
Ovariohysterectotny
Methods for prepubertal ovariohysterectomy are similar to those
routinely used in more mature animals and have been described in
detail (Salmeri et al., 1991; Aronsohn and Faggella, 1993; Theran.
1993). Because of the small amount of abdominal fat present in young
animals, visualization of the ovarian pedicle is excellent. This,
coupled with the small vessel size, allows for precise hemostasis
and shortens operative time. Fine (3-0 or 4-0) absorbable suture
material such as chromic gut (chromic gut, Ethicon), polyglyconate (Maxon,
Davis and Geck) or stainless steel hemostatic clips may be used for
ligation of the ovarian pedicles and uterine body. The linea alba
can be closed using either fine (3-0 or 4-0) absorbable or
nonabsorbable suture material in an interrupted or continuous
pattern. Closure of the subcutaneous layer is optional if skin
sutures are to be used. The use of subcuticular sutures without skin
sutures has been suggested (Aronsohn and Faggella, 1993) to decrease
the patient's interest in the incision.
Orchidectomy
In dogs and cats, the testicles are usually descended at birth and
are easily palpable in the immature scrotum by 6 to 8 weeks of age.
Orchidectomy in the kitten is similar to the procedure performed in
adult cats. The spermatic cord may be ligated in a closed or open
fashion with fine absorbable suture material, stainless steel
hemostatic clips, or by tying the cord upon itself using a hemostat.
The scrotal incisions are left to heal by second intention. A
scrotal (rather than prescrotal) approach to the testicles is also
used in 6- to 8-week old puppies. The procedure can be performed in
an open or closed fashion, using absorbable suture material or
hemostatic clips for ligatures. Fine subcuticular sutures can be
used to close the scrotal incisions or they can be left to heal by
second intention.
Pediatric Considerations
The potential for hypothermia and hypoglycemia, a relatively small
blood volume, and delicate tissues are factors that must be
considered when performing surgery on pediatric patients.
Hypothermia can be minimized by placing patients on recirculating
warm water blankets during surgery and by administering warm
balanced electrolyte solutions intravenously (ovariohystereetomy).
The animal should also be kept from getting excessively wet during
preparation of the surgical site. Neonates are also more susceptible
to hypoglycemia than adults; therefore, food should be withheld no
longer than 8 hr prior to surgery, with 3 to 4 hr being optimal in
the youngest patients. If necessary, oral or intravenous 50%
dextrose or oral corn syrup can be administered perioperatively and
animals should he fed within a few hours of recovery. If not yet
weaned, neonates should be returned to their dam and littermates as
soon as they have recovered sufficiently from anesthesia. Handling
of the animals should be minimized and they should be housed in a
quiet environment preoperatively and postoperativeiy. Friable
pediatric tissues necessitate gentle handling, with special
attention given to careful hemostasis in light of the relatively
small blood volume of these patients.
ANESTHETIC TECHNIQUES
Although concerns are often expressed regarding the risks and
feasibility of pediatric anesthesia, it can be performed safely
using a number of different techniques. Special considerations in
the pediatric patient include differences in drug uptake,
distribution, and action as compared to adults as well as immature
hepatorenal, respiratory, and cardiovascular system function (Grandy
and Dunlop, 1991; Theran, 1993).
Neonates have a larger percentage of total body water, lower albumin
concentration and body fat levels, and relatively high cardiac
output to vessel-rich organs. All of these factors affect drug
pharmacoldnetics. A heightened sensitivity to protein-bound drugs
may be seen and, in general, dosages of parenterally administered
anesthetic agents should be reduced (Grandy and Dunlop, 1991).
Pediatric patients have immature hepatic enzyme systems responsible
for drug metabolism; therefore, anesthetics metabolized in this
manner may have a longer duration of action. Glomerular filtration
and tubular function are also incompletely developed, delaying renal
excretion of certain drugs.
The high rate of oxygen consumption in neonates necessitates a
greater respiratory rate; therefore, anesthetic-induced respiratory
depression and subsequent hypoventilation should-be avoided by
careful monitoring. Because of differences in respiratory dynamics,
atelectasis is also of concern (Grandy and Dunlop, 1991). Cardiac
output in young animals is mainly rate dependent and baroresponses
are immature; therefore, bradycardia and hypotension should be
avoided.
Various anesthetic combinations have been used successfully in
pediatric patients. The preanesthetic administration of
anticholinergics (atropine or glycopyrrolate) has been advocated by
some authors to stabilize heart rate and thus cardiac output, and to
decrease respiratory secretions (Grandy and Dunlop, 1991). We have
not found this to be necessary however.
General
anesthesia can be rapidly induced and maintained with isoflurane (AErrane,
Anaquest) or halothane (Halocarbon Labs) administered by mask or
tank infusion. Most young animals (6 to 14 weeks) will tolerate the
required restraint with minimal excitement or struggling, A
tight-fitting mask will serve well through out the short duration of
an orchidectomv procedure. Endotracheal intubatian should be
performed in animals undergoing ovariohysterectomy. A 2.0- to 3.5-mm
Cole or Magill endotracheat tube is recommended in kittens (Aronsohn
and Faggella, 1993). Intubation should be gentle to avoid airway
trauma and edema and the tube should be suctioned at 30-min
intervals to prevent obstruction by respiratory secretions, a
potential problem with tubes o£ such small diameter (Grandy
and Dunlop,
1991). It is also vitally important to select a tube of proper
length to minimize dead space and
avoid
endobronchial intubation. Isoflurane is probably the preferred
inhalant agent in young animals due to its rapid induction and
recovery characteristics (low solubility), decreased need for
metabolism, and diminished cardiovascular depression as compared
with halothane (Grandy and Dunlop, 1991). A nonrebreathing
anesthetic circuit should be used for neonatal patients weighing
less than 5 kg (Ayres T -piece, Bain circuit,
Norman elbow).
Fresh gas flow rates x£200 ml/kg/minare recommended.
Several injectable anesthetics ale suitable for premedication or
anesthetic induction for longer procedures (ovariohysterectamy) or
as sole agents for a shorter procedure (orchidectomy). In kittens,
benzodiazepine/dissociative combinations such as tiletamine/
zoIazepam (Telazol, AH Robins) and midazolam (Versed,
Hoffman-LaRoche)! ketamine (Ketaset, Fort Dodge Laboratories) are
very safe and effective. Tiletamine/zolazepam at 11 mg/kg IM (2 to 4
mg/kg IV) has been recommended for orchidectomy in young kittens (Faggella
and Aronsohn, 1993, Theran, 1993). If necessary, supplemental
inhalational anesthetic can be provided by mask. This combination
can also be used in puppies.
Midazolam (0.22 mg/kg IM)/ketamine (11 mg/kg IM) followed by
intubation and administration of an
inhalant agent is recommended for feline ovariohystereetomy (Faggella
and Aronsohn, 1993; Theran, 1993). The authors have successfully
used an intravenous combination o£ 0.2 mg/kg diazepam (Valium,
HoffmanLaRoche) and 5 to 7 mg/kg ketamine for anesthetic induction.
Xylazine (Rompun, Miles) and phenothiazine tranquilizers (such as
acepromazine) should be avoided in animals less than 3 months old
because of their potential to cause bradycardia (decreased cardiac
output) and hypotension, respectively. The use of barbiturates in
animals less than 3 months of age is also discouraged.
Ogioitis provide analgesia and sedation as premedicants but should
be administered with anticholinergics to prevent bradycardia. An
advantage to their use is the potential for reversal with
antagonists or agonist/antagonist agents.
Another option for intravenous anesthetic induction is propofol (Dipnvan,
Stuart Pharmaceuticals). This drug produces a rapid, smooth
induction and recovery. It is given at a dose of 4 to 6 mg/kg
following premedications and 8 to 12 mg/kg as a sale agent. It has
been used successfully for early neutering in pups (Theran, 1993).
Monitoring during anesthesia is similar to that performed in adults,
with care being taken to prevent bradycardia, hypotension, and
hypothermia. A Doppler ultrasound device (Ultrasonic Doppler Flow
Detector Model 811-AL, Parks Medical Electronics) is useful to
monitor blood pressure.
SUMMARY
Early neutering in dogs and cats is a safe and effective means of
pet population control. The risks associated with surgery and
anesthesia of pediatric patients are minimal, with the advantages
being a shorter operative time, better visualization, rapid recovery,
and decreased morbidity. The effects of prepubertal gonadectomy on
skeletal, physical, and behavioral development are similar to those
seen in animals that are neutered at a more traditional age.
Additional links below supplied by J.P. Yousha (Chromadane)
Here are links
to some articles about early spay/neuter. They are from the SPDR
e-mail list (Seattle Purebred Dog Rescue):
http://www.columbusdogconnection.com/PedSpayNeuter.htm
Gives references to more articles and approving organizations,
including the American Veterinary Medical Association.
http://infoweb.magi.com/~cfhs/fact.htm
http://www.pacificpets.ca/spay&neuter.htm
This one written by a veterinary reproductive specialist!
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/reprod/petpop/early.html
From CSU.
http://www.petloverspublications.com/oc/EarlySpayNeuter.htm
http://www.petorphans.com/earlyneut/earlyneut.html
http://www.warrickhumane.com/juvenile.html
And here are some more articles and
some fact sheets about early spay and neuter:
http://infoweb.magi.com/~cfhs/fact.htm
http://www.rallyobedience.com/early.htm
http://www.cvm.uiuc.edu/ceps/ivb/spay-neu.htm
Note here the AVMA comes out in support of *very* early "spay/neuter."
http://www.petorphans.com/earlyneut/earlyneut.html
http://www.exoticbengals.com/spay.htm
More also if you
do a search on "Early Spay & Neuter," you'll find. It seems
scientific studies are OVERWHELMINGLY positive with quite an
impressive body of literature. Naturally it doesn't suit all animals
in all places, but certainly food for thought & not to be dismissed
lightly as a valid approach to both pet population control & pet H&W
issues? Anyway, certainly "required reading" for the inquisitive DOL
lot.
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