Cats - Concept of Early Spaying




Spaying/neutering before the animal is sexually mature is not a

new concept. At the beginnning of 1900 the early neutering was a

normal procedure and not much later already questions were raised

about the negative side effects. Experts acknowledge that there has

not been enough information available about the most appropriate

age to neuter a pet. There was no research data that supported or

disproved the idea neutering cats before they reach the age of five

to eight months. Well, a little scientific basis for selecting this

age group as the most appropriate time for neutering is available. So

one investigator pointed out that various vets practiced early neutering

over years since there is an incredible range of ages for cats about

reaching the secual maturity. There were many documented reasons to

spay and castrate cats. Females that are getting spayed are protected

against mammary cancer and uterine infections. If you castrate a male,

it reduces the risk of testicular cancer and enlargement of the prostate

and related infections. The most important side efffect for pet lovers

is that their beloved animal is less aggressive and more affectionate than

their unaltered counterparts because they don't feel the urge to reproduce.


A few university based studies in this area have been made, e.g. M.A. Herron

of Texas A&M reported in 1972 that neutering before sexual maturity had

relatively little effect on the diameter of the urethra in male cats.


At Angell Memorial Hospital in Boston, the College of Veterinary Medicine at

the University of Minnesota, and the Department of Small Animal Clinical

Sciences at the University of Florida started a project in 1991 that was

completed in 1992 and funded by the Winn Feline Foundation in conjunction

with the American Veterinary Medical Association (AVMA). In this study a

serious attempt was made to limit background influences and genetic variation.

They bred kittens especially for this project. Litter mates were divided among

3 groups. The females were bred and housed in quarantined facilities since both

pre- and post-natal nutrition and other factors can contribute to the ultimate

size, weight, and overall health of the kittens. Dr. Mark Bloomberg indicates

that even without long-term follow-up results, the initial results are

extremely positive. During the study a total of 31 domestic shorthair kittens

from 7 litters were born on the Gainesville campus.


They divided the kittens into three groups:


Group 1: In total 11 kittens were neutered or spayed at the age of 7 weeks.

Group 2: In total 11 kittens were neutered or spayed at the age of 7 months.

Group 3: The control group with a total of 9 kittens that were not neutered

until maturity and after the completion of the first phase of the study at

12 months.


It was reported that the surgical procedures for the kittens of Group 1

were straight forward and uncomplicated. The kittens recovered more rapidly

than the kittens of Group 2 and the cats of Group 3.


Dr. Bloomberg notes that although there is very little material on paediatric

anaesthesia in animals, the paediatric patient in human medicine is generally

considered to be a very good surgical candidate and there is no reason why

this should not also be true for dogs and cats.


The major concerns in paediatric surgery are: preventing hypothermia

(maintaining body heat); utilizing proper doses of aesthetic agents (since the

respiratory centers are not as well developed in the paediatric patient); and

maintaining proper blood glucose. The investigators did not fast the paediatric

patients as long as adult patients and administered small amounts of Karo

syrup prior to induction of anaesthesia as a precaution. It should be noted

that due to the rapid recovery of the paediatric patient, then common practice

of reducing anaesthesia during final stages of the surgery was modified.


Critics have claimed several possible detrimental side effects from early

neutering. It is commonly believed that neutered animals are less active and

more prone to obesity than unaltered animals. It was also suggested that

neutering at an early age would stunt normal growth. In male cats in particular,

it was feared that early castration would affect the development of the urinary

tract and lead to an increased incidence of cystitis or urinary obstruction.

Concerns have also been raised as to the effect of early neutering on beaviour,

food consumption and dietary requirements, etc.


The investigators attempted to answer most of these questions by evaluating

several parameters in the three groups of kittens. In particular, they looked

at weight and body composition (i.e., percent of body fat); bone length and

the age of physeal closure (the age when long bone growth stops); behaviour;

food consumption; development of the urinary tract; and the development of

secondary sexual characteristics and degree of sexual maturity.


The results of the comparisons of weight showed some differences between

the three groups. Males weighed consistently more than females, but this was

uniform in all groups. The studies of body composition and body fat indicated

that Group 1 (neutered at 7 weeks) and Group 2 (neutered at 7 months) were

identical nd were generally fatter than Group 3 (neutered at 12 months, after

they were sexually mature). Investigators point out that by 12 months, the

male cats in Group 3 were already exhibiting the normal adult male characteristics

of decreased weight and the development of jowls, which accounts for some of the

differences. It has also been noted that in the course of follow-up, the differences

between the weight in cats from Group 1 and 2 and Group 3 are becoming less

apparent. All these cats have been placed in selectedand supervised pet homes

and are more active than they were in the University facilities. A three-year

follow-up exam was to be conducted in May of 1994.




There was generally no difference in food consumption between the three

groups other than the differences between males and females, which were

consistent in all groups. There was no difference observed in the growth

rates in all three groups, although the males grew faster in all groups.

Increased long bone length was observed in both males and females in Groups

1 and 2. This appeared to be due to the fact that physeal closing (closure

of the bone growth plate) was delayed in Groups 1 & 2. This explains why

cats neutered and spayed as kittens are frequently larger (longer and taller)

than unaltered cats or cats altered later in life. This seems to be

particularly true for males. In terms of behaviour, after 7 months, the cats

in Group 3 were noticeably less affectionate and more aggressive prior to

altering than the cats in Groups 1 and 2. Contrary to popular opinion, neutered

animals were as active as their unaltered age mates.


Observations of urinary tract development showed no differences between

the three groups other than the differences related to sex and these were

consistent accross all roups. The investigators measured the diameter of the

urethra in the male kittens only and found no differences between the groups.

Concerns have been raised that early neutering would result in smaller

diameters in the urinary tract, resulting in an increased incidence of

cystitis and related problems. This does not appear to be the case. The

main differences observed between the groups occurred in the comparison of

secondary sex characteristics. Males were examined for differences in the

development of the penis and prepuce (skin covering the penis), as well as

for the development of penile spines. The penile spines were absent in

Group 1, smaller than normal in Group 2, and normally developed in Group 3.

In the examination of the female kittens, investigators found that the

vulvas were more infantile in Groups 1 and 2 and normal in Group 3. None

of these differences had any impact on the ability to catheterize the kittens.

Concerns that development of the urinary tract might be arrested or impaired

by early spaying and neutering proved unsupported. The results of this study

so far indicate that the differences between cats neutered at 7 weeks and 7

months are insignificant. The differences observed between animals in Groups

1 and 2 and the animals in Group 3, while in some cases statistically

significant, are not differences which appear to affect the health of the

animal in a negative way. While the final results will depend on the

analysis of long-term follow-up, the indications are that early neutering

is not detrimental to the overall health of the animal. From the erspective

of shelters and particularly in respect to the problem of surplus puppies

and kittens these results are encouraging. If all the animals adopted from

shelters, including puppies and kittens, are neutered prior to adoption,

there should be a corresponding decrease in the numbers of animals euthanized

each year in this country. Preliminary results from Alachua County, near

the University of Florida at Gainesville, would seem to support this theory.


Alachua County Animal Control has been working with the investigators

at the University and have had an early neuter policy in place since 1990.

No animal leaves the shelter without being neutered. In 1987 the county

euthanized 1,250 cats and dogs per month. Since implementing the early

neuter policies they have seen the numbers drop to 940 per month in 1992

and there has been no increase in morbidity or mortality associated with

the program.


In the last year, recognition of the safety and efficacy of early spay/neuter

has grown rapidly. The American Humane Association has endorsed neutering

prior to adoption as a feasible solution to decreasing pet overpopulation

and the tragedy of resulting deaths. In July 1993, delegates to the American

Veterinary Medical Association Annual Meeting voted to give AVMAs support to

the concept of early neutering. Work done by veterinarians at Angell Memorial

Hospital for the Massachusetts Society for the Prevention of Cruelty to

Animals supports Dr. Bloomberg's observations. Other organiz. involved in

early neuter programs include the Denver Dumb Friends League in Colorado,

the Miami Humane Society and Alachua County Animal Control in Florida.

The Humane Society of Austin and Travis County in Texas, the Chicago Animal

Control in Illinois, the King County Animal Control in Washington state,

the Vancouver SPCA in British Columbia and the Southern Oregon Humane

Society in Oregon. The Dekalb Humane Society in Decatur, Collie Rescue

of Metro Atlanta, the Georgia Alliance of Purebred Canine Rescuers, The

Haven (dog rescue) and Dog River Sanctuary in Douglasville are among the

Georgia organizations working with early neuter in dogs and cats, as well

as exotic species. The Cat Fanciers' Association (CFA) has changed its

show rules to permit altered kittens to compete. Many breeders of pedigreed

cats are working with their veterinarians to neuter pet quality kittens

prior to placement in new homes. Those breeders who have adopted this

policy report that they are very happy with the practice. New pet owners

acquiring an already neutered animal relieves them of the worry and expense

indicate that of scheduling the surgery at a later date, enablingthem to

relax and enjoy their new companion. As is the case for shelter managers,

breeders can relax in the knowledge that the kitten they place today is not

going to contribute to the surplus pet population tomorrow.


A progress report on a study funded by The Winn Feline Foundation


Summary prepared by Diana Cruden, Ph.D








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