Like I said, that's what I had always gone by and that
was the recommended age some years back..but as does
happen, medical technology has advanced. That includes
Vets.  The anethesia is better, easier to control and administer.
The intruments are smaller, the science has advanced.
Especially for male cats who at that young age may not even
require stitches...doing it while they are younger can actually
be a benefit not only to the owner but to the cat.  I am sure not
everyone is going to agree with the new information, I didn't
expect that I would...but it's pretty interesting.

AG

few months ago myself.  I just recall how much trouble my 7 month
old male had versus how quickly the 10 week old male recovered.
Sher Khan walked funny for a week but Magellan acted like nothing
happened.  Still, I understand your concerns.  All we can do is keep
an open mind about things.

AG

I have mixed feelings myself. If I let males go until just before they
start behaving like males, they look more like tom cats.  If they are
completely mature functional males, they look like toms, and
unfortunately may continue to behave like them.  If they are fixed
early, they look more like females, but they recover faster and make
better pets.  Females heal faster, but there doesn't seem to be much
effect on their looks and less on their behavior, but still enough
effect to make them better pets if they are fixed early.  My vet is
one of those who prefers larger kittens around 6 months, so that's
when I try to have it done - not because of my preferences, but
because of his.

T.E.D. (tdavis@gearbox.maem.umr.edu - e-mail must contain "T.E.D." or my .sig in the body)

It is not ideal to wait this long.  Queens often times come in heat at
5 months, sometimes before.  There is much more fat and tissue which
needs to heal post-op, and the length of time under anestheisa is
longer.  Male cats may begin to spray by 5 months.  One study reports
a significant higher number of complications in animals spayed or
neutered after 24 weeks of age.

The research abstracts below should help to convince you (stolen from
another post).  There is simply *no* reason to wait as long as 6-8
months.   If the cat weights at least 2 lbs, it can be spayed or
neutered safely.

HTH,

-L.
_______________________

Clin Tech Small Anim Pract. 2002 Aug;17(3):124-8.  

Early spay-neuter: clinical considerations.

Kustritz MV.

Department of Small Animal Clinical Sciences, University of
Minnesota College of Veterinary Medicine, 1352 Boyd Avenue, St.
Paul, MN 55108, USA.

Early spay-neuter is ovariohysterectomy or castration of puppies or
kittens 6 to 14 weeks of age. Pediatric animals may have an
enhanced response to relatively low doses of anesthetic agents.
Animals should be fasted no more than 3 to 4 hours before surgery
to prevent hypoglycemia, and hypothermia should be avoided. Heart
and respiratory rates must be monitored carefully throughout
anesthesia. Pediatric gonadectomy surgeries are quick with minimal
bleeding. Anesthetic recovery is rapid. No significant short-term
or long-term effects have been reported. Prepuberal gonadectomy is
most useful for humane organizations and conscientious breeders
wishing to preclude reproduction of pet dogs and cats while placing
animals at a young enough age to optimize socialization and
training.

-----------------------
J Reprod Fertil Suppl. 2001;57:223-32.  

Early-age neutering of dogs and cats in the United States (a review).

Olson PN, Kustritz MV, Johnston SD.

Guide Dogs for the Blind, Inc, 350 Los Ranchitos Road, San Rafael,
CA 94903, USA.

Prepubertal gonadectomy, often referred to as early-age neutering,
has increased in popularity in the United States. The procedure is
often used at animal care and control facilities, where puppies and
kittens are neutered as early as 7 weeks of age or before adoption.
Although the anaesthetic and surgical procedures appear to be safe,
studies continue to evaluate the long-term effects on health and
behaviour. Early-age neutering is one technique that is used to
combat pet overpopulation, a problem whereby millions of unwanted
healthy dogs and cats are euthanased each year. Although neutering
animals is helpful in controlling pet overpopulation, other factors
must be considered. In addition, many animals are relinquished to
shelters when they show inappropriate behaviours, because owners
and veterinarians are unable to modify animal behaviour.  This
review discusses early-age neutering in the United States, and
includes the review of scientific studies that have evaluated this
procedure in puppies and kittens.  Early-age neutering does not
stunt growth in dogs or cats (a once-held belief), but may alter
metabolic rates in cats. The anaesthetic and surgical procedures
are apparently safe for young puppies and kittens; morbidity is
lower and recovery is faster than in adult animals. To date,
adverse side effects are apparently no greater in animals neutered
at early ages (7 weeks) than in those neutered at the conventional
age (7 months).

-----------------------
J Am Vet Med Assoc. 2000 Dec 1;217(11):1661-5.  

Long-term outcome of gonadectomy performed at an early age or
traditional age in cats.

Howe LM, Slater MR, Boothe HW, Hobson HP, Fossum TW, Spann AC, Wilkie
WS.

Department of Small Animal Medicine and Surgery, College of
Veterinary Medicine, Texas A&M University, College Station
77843-4474, USA.

OBJECTIVE: To determine long-term results and complications of
gonadectomy performed at an early age (prepubertal) or at the
traditional age in cats. DESIGN: Cohort study.  ANIMALS: 263 cats
from animal shelters. PROCEDURE: Cats that underwent gonadectomy
were allotted to 2 groups on the basis of estimated age at surgery
(traditional age, > or = 24 weeks old; prepubertal, < 24 weeks
old). Adoptive owner information was obtained from shelter records,
and telephone interviews were conducted with owners to determine
physical or behavioral problems observed in the cats after
adoption. Follow-up information was obtained from attending
veterinarians for cats with complex problems or when owners were
uncertain regarding the exact nature of their cat's problem.
RESULTS:  Compared with traditional-age gonadectomy, prepubertal
gonadectomy did not result in an increased incidence of infectious
disease, behavioral problems, or problems associated with any body
system during a median follow-up period of 37 months. Additionally,
the rate of retention in the original adoptive household was the
same for cats that underwent prepubertal gonadectomy as those that
underwent traditional-age gonadectomy.  CONCLUSIONS AND CLINICAL
RELEVANCE: Prepubertal gonadectomy may be performed safely in cats
without concern for increased incidence of physical or behavioral
problems for at least a 3-year period after gonadectomy.

-----------------------
Vet Clin North Am Small Anim Pract. 1999 Jul;29(4):935-43, vii.  

Early spay-neuter in the dog and cat.

Kustritz MV.

University of Minnesota College of Veterinary Medicine, St. Paul, USA.
rootk1@tc.umn.edu

Early spay-neuter refers to the surgical sterilization of 8- to
16-week-old animals.  Anesthetic and surgical techniques for the
dog and cat are described. Pros and cons of prepubertal gonadectomy
are discussed, and the veterinary literature is reviewed.

-----------------------
Vet Clin North Am Small Anim Pract. 1999 Jul;29(4):837-52, v.  

Pediatric health care and management.

Hoskins JD.

DocuTech Services, Baton Rouge, Louisiana, USA.

Pediatric health care is an integral part of providing for the
general health needs of puppies and kittens from birth to 6 months
of age. Successful rearing of puppies and kittens requires
providing them with a suitable environment; the correct quantities
and quality of nutrients for growth; a regular schedule of feeding,
sleeping, grooming, and exercise; and the stimulus that provokes
micturation and defecation. The intestinal parasites, such as
hookworms, roundworms, whipworms, tapeworms, Giardia, and
Cryptosporidium, occur commonly in puppies and kittens. The
advantages of early-age spay/neuter far outweight the risks.

-----------------------
J Am Vet Med Assoc. 1997 Jul 1;211(1):57-62.  

Short-term results and complications of prepubertal gonadectomy in
cats and dogs.

Howe LM.

Department of Small Animal Medicine and Surgery, College of
Veterinary Medicine, Texas A&M University, College Station
77843-4474, USA.

OBJECTIVE: To determine short-term results and complications of
prepubertal gonadectomy in cats and dogs. DESIGN: Prospective
randomized study. ANIMALS: 775 cats and 1,213 dogs. PROCEDURE:
Animals undergoing gonadectomy were allotted into 3 groups on the
basis of estimated age (group 1, < 12 weeks old; group 2, 12 to 23
weeks old; group 3, > or = 24 weeks old). Complications during
anesthesia, surgery, and the immediate postoperative period (7
days) were recorded. Complications were classified as major
(required treatment and resulted in an increase in morbidity or
mortality) or minor (required little or no treatment and caused a
minimal increase in morbidity). An ANOVA was used to detect
differences among groups in age, weight, body temperature, and
duration of surgery. To detect differences in complication rates
among groups, chi 2 analysis was used. RESULTS: Group 1 consisted
of 723 animals, group 2 consisted of 532, and group 3 consisted of
733. Group-3 animals had a significantly higher overall
complication rate (10.8%) than group-1 animals (6.5%), but did not
differ from group-2 animals (8.8%). Differences were not detected
among the 3 groups regarding major complications (2.9, 3.2, and
3.0% for groups 1, 2, and 3, respectively), but group-3 animals had
significantly more minor complications (7.8%) than group-1 animals
(3.6%), but not group-2 animals (5.6%). CLINICAL IMPLICATIONS: In
this study, prepubertal gonadectomy did not increase morbidity or
mortality on a short-term basis, compared with gonadectomy
performed on animals at the traditional age. These procedures may
be performed safely in prepubertal animals, provided that
appropriate attention is given to anesthetic and surgical
techniques.

-----------------------
J Am Vet Med Assoc. 1996 Dec 1;209(11):1864-71.  

Effects of prepubertal gonadectomy on physical and behavioral
development in cats.

Stubbs WP, Bloomberg MS, Scruggs SL, Shille VM, Lane TJ.

Department of Small Animal Clinical Sciences, College of Veterinary
Medicine,
University of Florida, Gainesville 32610-0125, USA.

OBJECTIVE: To determine the effect of prepubertal gonadectomy on
physical and behavioral development in cats. DESIGN: Prospective
controlled study of kittens randomly assigned to 3 treatment
groups: group 1, neutered at 7 weeks of age; group 2, neutered at 7
months of age; and group 3, sexually intact controls. ANIMALS: 31
clinically normal male and female kittens. PROCEDURE: Age at distal
radial physeal closure and mature radius length were determined
radiographically. Six behavioral characteristics were recorded
monthly. At 1 year of age, body weight was recorded and thickness
of the falciform ligament was measured from a lateral abdominal
radiographic view. Secondary sex characteristics were also examined
at 1 year of age. RESULTS: There were no differences between
group-1 and group-2 cats for any of the study variables.  Sexually
intact cats (group 3) weighted significantly less than group-2 cats
and had less falciform fat and earlier distal radial physeal
closure than cats of both neutered groups. Group-3 cats manifested
greater intraspecies aggression, less affection, and greater
development of secondary sex characteristics than neutered cats.
CLINICAL IMPLICATIONS: Neutering cats at 7 weeks of age had similar
effects on physical and behavioral development, compared with
neutering at the more traditional age of 7 months. These data lend
support to the concept of prepubertal gonadectomy, already
performed by many animal shelters/humane organizations, as a method
of enhancing the effectiveness of pet population control programs.

-----------------------
Am J Vet Res. 1996 Mar;57(3):371-4.  

Effect of prepuberal and postpuberal gonadectomy on heat production
measured by indirect calorimetry in male and female domestic cats.

Root MV, Johnston SD, Olson PN.

Department of Small Animal Clinical Sciences, College of Veterinary
Medicine, University of Minnesota, St Paul 55108, USA.

OBJECTIVE--To use indirect calorimetry to compare heat production
between gonadectomized and sexually intact male and female cats.
DESIGN--Male (n = 6) and female (n = 6) kittens were gonadectomized
at 7 weeks or 7 months of age, or left sexually intact. Body heat
production was measured by indirect calorimetry in all cats at 12,
18, and 24 months of age. ANIMALS--18 male and 18 female clinically
normal domestic shorthair cats. PROCEDURE--Heat production was
measured, using an open-circuit, respiratory, indirect calorimeter.
All cats underwent calorimetry at 12, 18, and 24 months of age. The
heat coefficient, a measure of resting metabolic rate, was
calculated for each cat at each test; heat coefficient is defined
as logarithm of heat (kcal/h) divided by logarithm of body weight
(kg). RESULTS--Heat production did not vary with age in male or
female cats. Heat coefficient was higher in sexually intact male
and female cats than in gonadectomized male and female cats at 12,
18, and 24 months of age (12 months, females, P < 0.01, males, P =
0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months,
females and males, P < 0.01).  CONCLUSIONS--These data suggest that
resting metabolic rate in cats decreases after gonadectomy.
CLINICAL RELEVANCE--A decrease in metabolic rate is synonymous with
a decrease in caloric requirements. Gonadectomized animals fed in a
manner similar to sexually intact animals may be predisposed to
obesity and its sequelae.

-----------------------
Semin Vet Med Surg (Small Anim). 1995 Feb;10(1):8-12.  

Implications of early neutering in the dog and cat.

Stubbs WP, Bloomberg MS.

Department of Small Animal Clinical Sciences, University of
Florida, Gainesville 32610-0126.

Early age neutering of dogs and cats is a safe and effective means
of pet population control. The surgical techniques are similar to
those already familiar to the veterinary practitioner and pose
minimal risk to the animal patient. Advantages include a shorter
operative time, better intra-abdominal visualization, and rapid
animal patient recovery. Prepubertal gonadectomy does not seem to
adversely affect skeletal, physical, or behavioral development in
the dog and cat.

-----------------------
J Am Vet Med Assoc. 1994 Jul 15;205(2):308-14.  

Evaluation of anesthetic protocols for neutering 6- to 14-week-old
pups.

Faggella AM, Aronsohn MG.

Massachusetts Society for the Prevention of Cruelty to Animals,
Angell Memorial Animal Hospital, Boston 02130.

Ninety-nine 6- to 14-week-old pups were given anesthetic agents
according to 10 anesthetic protocols. Mean quality rating scores
were determined to compare anesthetic protocols. In male pups, IV
administration of propofol (6.5 mg/kg of body weight) 15 minutes
after IM administration of atropine (0.04 mg/kg) and oxymorphone
(0.22 mg/kg)  provided the best quality anesthesia. Intramuscular
administration of midazolam (0.22 mg/kg) and butorphanol (0.44
mg/kg) instead of oxymorphone provided little sedation, but induced
good analgesia. Atropine/oxymorphone/midazolam/xylazine,
atropine/butorphanol/midazolam/xylazine, and tiletamine/zolazepam
were unsatisfactory combinations for use in castration of 6- to
14-week-old male pups. In female pups, IV administration of
propofol (3.4 mg/kg) 15 minutes after IM administration of atropine
(0.04 mg/kg) and oxymorphone (0.11 mg/kg) was the most effective
anesthetic protocol.  Administration of the drugs according to this
protocol enabled a pup to be intubated.  Anesthesia was maintained
with isoflurane in oxygen. If inhalational induction was preferred,
IM administration of 13.2 mg of tiletamine/zolazepam/kg, 0.04 mg of
atropine/kg and 0.11 mg of oxymorphone/kg, or 0.22 mg of
midazolam/kg and 0.44 mg of butorphanol/kg may be used prior to
mask delivery of inhalational anesthetics. In female pups, it was
not advantageous to combine midazolam with oxymorphone, and use of
high dosages of oxymorphone (0.22 mg/kg) or midazolam/butorphanol
provided little sedation. Time of recovery after use of
tiletamine/zolazepam was the longest for the combinations used, but
did not adversely affect pups. Male pups were castrated via scrotal
incisions, using hemostatic clips. Ovariohysterectomies were
performed via a ventral abdominal midline approach, using
hemostatic clips for ligation, five females developed signs of
inflammation at the surgical site within 1 to 2 weeks after
surgical, and were treated conservatively with warm compresses.

-----------------------
J Am Vet Med Assoc. 1991 Apr 1;198(7):1193-203.  

Gonadectomy in immature dogs: effects on skeletal, physical, and
behavioral development.

Salmeri KR, Bloomberg MS, Scruggs SL, Shille V.

Department of Small Animal Clinical Sciences, University of
Florida, Gainesville 32610-0126.

In a 15-month study, the effects of prepubertal gonadectomy on
skeletal growth, weight gain, food intake, body fat, secondary sex
characteristics, and behavioral development were investigated in 32
mixed-breed dogs. Male and female pups from 5 litters were randomly
allotted to 3 groups: group I, neuter at 7 weeks (n = 14); group
II, neuter at 7 months (n = 8); and group III, sexually intact dogs
(n = 10). Growth plate closure was delayed (group I vs group III; P
less than 0.000001; group II vs group III, P less than 0.000001) in
all neutered dogs, as compared with sexually intact dogs. Growth
plate closure was delayed longer (group I vs group II, P less than
0.000045) in dogs neutered at 7 weeks old, compared with dogs
neutered at 7 months old. The rate of growth was unaffected by
gonadectomy, but the extended growth period resulted in greater
final radial/ulnar length in all male dogs and bitches neutered at
7 weeks.  Gonadectomy did not influence food intake, weight gain,
or back-fat depth. Penile development was immature in the adult
group-I males (mean +/- SEM diameter of pars glandis = 11.1 +/- 1.0
mm), compared with adult group-II (16.3 +/- 0.5 mm) and group-III
(21.0 +/- 2.2 mm) males. Subjectively, the prepuce and os penis of
the group-I males were immature, compared with those of group-II
and group-III males.  Vulvar development in group-I and group-II
bitches was less mature than vulvar development in the sexually
intact bitches. Of 7 behavioral characteristics assessed, only
general activity and excitability rated differently among treatment
groups. All neutered dogs were judged to be more active (group I, P
less than 0.004) than sexually intact dogs. Group-I males were
judged to be more excitable (P less than 0.02) than group-III
males. It was concluded that with respect to skeletal, physical,
and behavioral development, the effect of neutering pups at 7 weeks
old was similar to that of neutering pups at 7 months old.