History of the 70% solution

[Guest guest]

Pet Overpopulation and the 70% Rule

W. Marvin Mackie, D.V.M.

March 2003

 

In a front-page article of Animal People, October 2002, editor Merritt

Clifton mentioned the Fibonacci 70% rule. His writing piqued my interest to

the point that I asked him for further clarification, and then conducted

some research of my own. This concept is amazingly insightful into success

or failure as it relates to ultimate pet overpopulation and deserves to be

understood by all who are decision makers in the effort to bring it under

control. Leonardo Fibonacci, a preeminent mathematician of his time,

created a formula (model) in the early 1200’s relating to agricultural

productivity. Six centuries later, Louis Pasteur, while working on an early

vaccine for disease prevention, used the model to predict that 70% of a

susceptible population would have to be vaccinated in order to prevent an

epidemic of almost any contagious disease. Fibonacci’s 70% model is still

recognized as valid by leading public health authorities such as the World

Health Organization and the Center for Disease Control.

 

It is not a great leap to advance to the notion that pet sterilization is in

effect “vaccinating” against the disease of overpopulation. Using this

premise, we can say that 70% of the susceptible population (animals with

outside privileges) in a defined demographic area must be sterile in order

to affect the decrease in over-birthing that will result in a population

decrease within that area. The outcome at this 70% sterilization level is

that the transmission odds (successful breeding encounters) of the remaining

30% are reduced to the point that births then occur at a rate only great

enough to replace normal attrition.

 

Mr. Clifton cites data from two separate street dog sterilization programs

in India. One program saw a drop in animal population at 64% sterilized and

the second at 68%. In November 1998, I took part in a massive sterilization

effort on the Native American land called the Flathead Nation in western

Montana. It was a weeklong three-town effort in which we volunteer

veterinarians sterilized 1336 dogs and cats in six days. Actual census

numbers are probably unknown but the following years’ drop in shelter

turn-ins was profound. Clifton also reported that in the U.S., animal

control agencies reported a marked drop in the number of dog euthanasias in

the late 1980s, soon after the sterilization percentage of owned pet dogs

reached 67%. A rapid drop in cat euthanasias was noted when sterilization

of owned pet cats reached 85%. The “X” factor with cats lies in the number

of local ferals (street cats). Feral dogs are not nearly as plentiful and

therefore do not significantly impact the statistics.

 

If we follow the logical conclusions of the 70% rule, which is broadly

accepted by those who work in epidemiology, we arrive at some interesting

answers. For instance, those working so diligently to control pet

overpopulation in the greater Los Angeles and Orange county areas are

confounded by the fact that, in spite of their tireless efforts, they have

not seen the hoped for reduction in euthanasias. Unfortunately, the fertile

pet population was so large at the onset and the densely populated

two-county area was so great that they were unable to sterilize the numbers

required to reach the 70% mark. Mr. Clifton states emphatically that you

must reach 70% or FLUNK – there is no progress made with a “B” or “C” grade.

Quoting Mr. Clifton, “Fall short of 70%… and a sterilization…project will

get a big “F” for fecund animals, fearful people fleeing dog packs, feline

feces in gardens and children’s sandboxes and frothing-at-the-mouth critics

flinging allegations of fraud.”

 

Clearly, the 70% rule applies to any circumscribed area. It can be an

isolated town or community (e.g. the Native American communities of the

Flathead Nation) or the mere acreage of a feral cat colony. Generally, more

affluent areas can and do reach 70% (or better) pet sterilization and the

over-birthing problem ends in those areas. The more impoverished areas don’

t come close to 70% and the shelters serving those communities are the

recipients of the hapless victims of too many births and too few homes.

This plight is the major theme of Bob Christianson’s book, Save Our Strays,

CLC Publishing, 1996.

 

All too often, enthusiastic humane activists campaigning for pet control

projects inadvertently over-promise results to those who are providing

funding. When the government sources that provide “start up” funds as a

result of these promises, cannot be shown any statistical improvement, they

therefore conclude that their funding is not producing the desired results.

What can truly make an impact on reduced birthing is to target a reasonable

area and within a short period of time massively sterilize within it to

achieve the 70% goal. If the sterilization is accomplished within one

breeding cycle, the result will be immediate measurable results. The money

saved in reduced animal control and shelter overhead could easily support

the major funding needed for the initial sterilization effort. When the

70% sterilization goal is attained, both the funding and effort could be

reduced to a maintenance-only level. A mobile spay/neuter unit visiting

multiple sites one day each month is good for public relations, raises

awareness in the community and is certainly 100% helpful to the individual

family and their pet, but it cannot achieve the number of sterilizations

required in any one area to significantly reduce over-birthing.

 

The standard mantra, or battle cry, in the fight to curb overpopulation has

been “Spay or neuter your pet and save the lives of hundreds of innocent

animals.” Perhaps a more acceptable and understandable approach would be

to educate the pet owner to the fact that in addition to the health and

behavioral benefits, sterilization for their pet is quite analogous to a

vaccination for the unwanted pregnancies that contribute to over production

and unintended deaths by euthanasia. Spay/neuter saves lives by

eliminating killing.

 

I have presented this article on the Fibonacci 70% rule in order to broaden

your understanding of the task we face and to present a tangible way to

evaluate our efforts toward our goal. Because there are so many variables

in getting an accurate census of a given area, it may seem that 70% is

difficult to determine. For additional reading, I suggest the Animal People

News website, www.animalpeoplenews.org, where you can benefit from Merritt

Clifton’s excellent editorials, and the Best Friends Question and Answer

forum, http://www.bestfriends.org/nmhp/forumarchive/qa20to24mc.html, where

Mr. Clifton succinctly and completely covers the issue in an answer to

another interested reader.

 

Reprint from The Pet Press, Los Angeles, CA., Vol. 4, Issue 6, Mar-April,

2003.

Also National Animal Control Association News, May/June 2004.

 

Dr. Mackie, the owner/director of two Animal Birth Control clinics in Los

Angeles, has been a spay/neuter specialist since 1976 and is nationally

recognized for his work in early age sterilization. He offers an extensive

surgical training program and a widely distributed video on his procedure.

E-mail: Spaydvm.

 

 

--

Merritt Clifton

Editor, ANIMAL PEOPLE

P.O. Box 960

Clinton, WA 98236

 

Telephone: 360-579-2505

Fax: 360-579-2575

E-mail: anmlpepl

Web: www.animalpeoplenews.org

 

[ANIMAL PEOPLE is the leading independent

newspaper providing original investigative

coverage of animal protection worldwide, founded

in 1992. Our readership of 30,000-plus includes

the decision-makers at more than 9,900 animal

protection organizations. We have no alignment

or affiliation with any other entity.]

--

Merritt Clifton

Editor, ANIMAL PEOPLE

P.O. Box 960

Clinton, WA 98236

 

Telephone: 360-579-2505

Fax: 360-579-2575

E-mail: anmlpepl

Web: www.animalpeoplenews.org

 

[ANIMAL PEOPLE is the leading independent

newspaper providing original investigative

coverage of animal protection worldwide, founded

in 1992. Our readership of 30,000-plus includes

the decision-makers at more than 10,000 animal

protection organizations. We have no alignment

or affiliation with any other entity. $24/year;

for free sample, send address.]

--

Merritt Clifton

Editor, ANIMAL PEOPLE

P.O. Box 960

Clinton, WA 98236

 

Telephone: 360-579-2505

Fax: 360-579-2575

E-mail: anmlpepl

Web: www.animalpeoplenews.org

 

[ANIMAL PEOPLE is the leading independent

newspaper providing original investigative

coverage of animal protection worldwide, founded

in 1992. Our readership of 30,000-plus includes

the decision-makers at more than 10,000 animal

protection organizations. We have no alignment

or affiliation with any other entity. $24/year;

for free sample, send address.]