Animal People Reports That 70% of Population Must Be Fixed to Make a Difference
Any data on how many animals must get FIXED per thousand per year to
have that nice 10% per year decrease New Hampshire saw? We increased
our s/n numbers from 100 to 400 last year, and I'm can almost taste
the decrease in euthanasia...but am I being overly optimistic?
You cannot determine the number of animals whom you need to fix on a
per-1,000 basis without knowing how many have already been fixed.
What you need to do is get to 70% sterilized, minimum, to see any
significant results at all. You will not see anything happen until
you get to 70%, but will see your shelter intake and killing rates
fall like a rock from 70% on.
I cannot overstate the importance of 70%.
Sterilizing and vaccinating 70% of the street dog or feral cat
population in any given locale is the minimum standard for success,
but there is no "gentleman's C" in grading this kind of test.
Reach 70% and the effort earns an A for All's well, because then the
odds that animals will meet who are capable of infecting or
reproducing with each other drop to the vanishing point.
Fall short of 70%, however, and a sterilization and vaccination
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.
Impatient politicians will reinstitute the high-volume killing
campaigns that have failed to lastingly reduce street dog and feral
cat populations despite more than 1,000 years of effort in some parts
of the world. Years may pass before sterilization and vaccination
get another chance--which will not be a fair chance until and unless
the resources needed to reach 70% are available.
To avoid becoming entangled in unfair tests, advocates of sterilizing
and vaccinating street dogs and feral cats need to learn to promise
only what they can deliver. For example, sterilizing a lesser
percentage of the animals at risk somewhere will not bring any
visible reduction in numbers. Instead, the dogs or cats who have not
been sterilized will have less competition for food and cover, and
will be able to raise larger litters.
If the carrying capacity of the habitat has already been reached,
the larger litters may experience higher mortality, through
predation, starvation, or disease, and sterilizing only 10% or 20% of
the street dogs or feral cats per year might over time produce the
sum of 70% sterilized. But humans typically consider street dogs and
feral cats intolerably abundant long before their populations ever
approach carrying capacity.
Animal aid societies often introduce sterilization and vaccination
programs on a limited scale, of economic necessity. Yet acceding to
economic reality must not be confused with economic prudence,
because sterilizing and vaccinating 70% can be done most economically
by getting to 70% within a single breeding cycle.
Further, the most effective demonstration a small and poor group can
make of the value of sterilization and vaccination is to concentrate
the effort on a particular building, block, or neighborhood, within
which 70% can be realized. Scattering efforts beyond that range
usually will have little or no demonstrative value, because the
results will be almost invisible.
Where did the figure 70% come from?
The late Paradise Animal Welfare Society cofounder Bob Plumb, a
retired physics professor, initially derived the 70% figure from the
math models for animal population growth or reduction developed by
Leonardo Fibonacci of Pisa, 1170-1240. Fibonacci was studying
agricultural productivity, but more than six centuries later his work
also furnished the 70% vaccination target recognized by Louis Pasteur
(and most subsequent public health authorities) as the minimum
necessary to prevent an epidemic of almost any contagious disease.
Sterilization is in effect surgically "vaccinating" animals against
reproduction. The goal is to reduce the vulnerability of the
potential host population to the condition, by reducing the
possibility of transmission to odds so slim that the condition cannot
replicate itself more rapidly than it dies out.
Christine and Jeremy Townend in 1999 collected data from the Help In
Suffering street dog sterilization program in Jaipur, India, showing
sterilization of 64% of the local street dogs as the actual point at
which the population began to drop. Recent data from the Animal Birth
Control program in Hyderabad, India,indicated that the street dog
population there began to drop when 68% were sterilized.
In the U.S., the numbers of dogs killed by animal shelters began
falling fast after the percentage of owned pet dogs who were
sterilized reached 67%, in the late 1980s.
The numbers of cats killed by U.S. animal shelters began a rapid drop
after 1991, when the percentage of owned cats who were sterilized
reached about 85%, as indicated by studies done by Andrew Rowan of
Tufts University, Carter Luke of the Massachusetts SPCA, and Karen
Johnson of the National Pet Alliance. At that time, 85% of the pet
cat population equaled about 60% of the estimated total U.S. cat
population, including ferals.
Since then, the advent of neuter/return to control feral cat numbers
and increasing human acceptance of responsibility for outdoor cats
has blurred the statistical distinction between pets and ferals. Of
the estimated 73 million "pet" cats in the U.S. now, 10 to 15 million
may in truth be fed ferals, who a decade ago would not have been
considered "owned."
The rapidly falling shelter intake of cats and the fast-rising volume
of cats being sterilized--twice the rate of pet cat population growth
during the past 10 years--indicate, however, that the feral cat
population today is probably no more than half what it was in 1991.
An easy demonstration of the need to vaccinate and sterilize 70% of a
street dog and/or feral cat population can be done with dice.
Throwing a pair of dice gives you 19 possible number combinations
adding up to 11 possible totals. Designate the combinations adding up
to 2-7 and 12 as "immune" or "sterile" (68%) and the rest as
"vulnerable" to either disease or pregnancy.
Explain to your audience that you are now going to show them how far
rabies can spread and how large the street dog and/or feral cat
population can grow if 70% of the dogs are vaccinated. Ask for 10
volunteers to pretend to be 10 of the community's dogs and/or cats,
to act out the demonstration as a skit.
Throw the dice 10 times, once for each person, to represent any
random group of 10 dogs or cats who may be attacked by a rabid animal
or may become pregnant.
If the dice show 2, 3, 4, 5, 6, 7, or 12, the "dog" or "cat" is
sterilized and vaccinated. She will neither get rabies nor become
pregnant. Have those volunteers step back.
If the dice show 8, 9, 10, or 11, the "dog" or "cat" has a litter,
gets rabies, and can spread it.
Each time you get 8, 9, 10, or 11, ask for another volunteer to step
forward from the audience, to represent the surviving offspring from
the litter who may also breed and/or get rabies, and throw the dice
again. Continue until all of your volunteers have stepped back.
Results will vary, but almost always you will end "dog" and "cat"
reproduction and halt the "rabies outbreak" within fewer than 10
throws after your initial 10 - which at the normal rate of street dog
or feral cat mortality would be the replacement population level.
To check the results, you can decrease the numbers of "immune"
combinations.
The importance of reaching 70% should soon manifest itself.
Dice. Don't leave home on a humane education mission without them.
--
Merritt Clifton
Editor, ANIMAL PEOPLE
P.O. Box 960
Clinton, WA 98236
Telephone: 360-579-2505
Fax: 360-579-2575
E-mail: anmlpepl@whidbey.com
Web: http://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-
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Posted on SHARE Yahoo group May 9, 2004