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Estimating the Maximum Total Population of Pedigreed

May 13, 2008 | By Jill R. | Category: General

BY:
John J. McGonagle
April 30, 2008 (working draft)
Comments
There is no firm data on the total population of pedigreed cats in US households or even
the number of cats of specific breeds that live in US households, including both cherished
cats in registered catteries as well as those in homes as beloved pets. What follows is
based on the application of actuarial principles to the data that exists. As readers will
note, in almost every case, my assumptions or estimates will have the effect of increasing
the number of pedigreed cats. It is for that reason I refer to the “maximum” number.
This is a work in progress. The author encourages those who read this to forward their
comments to him at info@breedingpedigreedcats.com. Any suggestions for improving
the approach, refining the data, etc. will be considered and incorporated, with credit, into
later version of this working document.
When 2007 data comes available, this article will be updated. That will probably occur in
the Summer of 2008.
Executive Summary
The limited data available, when analyzed according to established actuarial principles,
indicates that the percentage of pedigreed cats in all US households, including breeders,
has fallen from 4.2% in 1994 to a maximum of 3.4% in 2006. While the total population
of cats living in US households is estimated to have remained relatively constant
(growing only from 2.5 million to slightly under 3.0 million in 12 years), the total number
of all cats, pedigreed and non-pedigreed living in US households has grown from 59 to
88 million, an overall growth of almost 50%.
The pedigreed cat population living in US households will soon reach the point of
negative population growth. Anecdotal data indicates that some specific breeds of
pedigreed cats may already be at that point.
The methodology developed in this article can also be used to estimate the total
population of any specific breed in US households as well.
What is a Pedigreed Cat?
It should first be noted that the term pedigreed cat refers to a cat that has been registered
with one or more cat registries so that its heritage is known, documented, and registered.
By registry, I mean a major, recognized registry that tracks the history of the cats as well
as sanctioning shows, such as CFA, TICA and ACFA in the United States.
Unless a cat is registered, and therefore is actually pedigreed, what a person has is a cat
which “looks like” a particular breed, or which the person that sold it “said” was a
Siamese. “To put it bluntly, you cannot be sure you have a purebred cat unless you have a
pedigreed cat.” [Vella and McGonagle, 2006]
Realistically, many kittens are registered with the various registries in litter registrations,
but, when sold as pets, are not finally registered as cats. They still can be registered at any
point by their new owners. So, for the purposes of calculating total cat populations, we
will count them as pedigreed.
One object of this paper is to come up with a methodology for estimating both the
number of pedigreed cats currently in US households as well as for determining the
number of pedigreed cats of any particular breed in US households.
Estimates of Cat Population
Estimates of the total population of cats living in US households, as distinguished from
free-roaming or non-owned cats, have been produced since the 1980s by the American
Pet Products Manufacturers Association and its predecessors, as follows:
APPMA National
Pet Survey –
Number of Cats
(millions)
1988 52.6
1990 60.8
1992 62.6
1994 59.4
1996 66.2
1998 64.2
2000 72.8
2002 77.6
2004 90.5
2006 88.3
Sources: [APPMA 2007]
Data on Births of Pedigreed Cats
(See Sheet 2)
Data on the birth of pedigreed cats is confused because, in the US, there are three major
registries of pedigreed cats and several smaller ones. The major ones are, in order, the Cat
Fanciers’ Association, The International Cat Association, and the American Cat Fanciers
Association.
While I know from personal experience that many breeders will register cats and kittens
in more than one registry, I am assuming that the total number of registered cats is
relatively unduplicated. The effect of this assumption is to slightly overstate the total
number of pedigreed cats registered.
APPMA National
Pet Survey –
Number of Cats
(thousands)
Total Number of
Pedigreed Cats
Registered with
CFA, TICA and
ACFA
(thousands)
1988 52, 600.00
1990 60, 800.00
1992 62, 600.00
1994 59,400.00 85.78
1996 66,200.00 85.74
1998 64,200.00 80.05
2000 72,800.00 66.87
2002 77,600.00 64.93
2004 90,500.00 62.46
2006 88,300.00 59.14
Registration Data: [Shelton 2007]
This data is cats registered, not kittens born. However, the figure I need is an estimate of
the number of live births underlying these numbers, for not all kittens that are sold as pets
are registered as adult cats, and not all kittens born live will survive long enough to be
registered as adults.
In 2005, CFA reported that its data showed 92,496 live births of pedigreed cats. [CFA
2006]. That produced 39,971 registered cats [Shelton, 2007], or 2.3 live pedigreed kittens
born for every cat finally registered. The percent of cats registered from litter
registrations has probably grown slightly over the past decade, due to marketing efforts
by the registries, but I will use this adjustment. Its effect is to slightly underestimate the
number of kittens born several years ago.
Cat Ages and Human Equivalents
To this data, I then apply the estimates of cat longevity and equivalence to human ages
developed by the Waltham pet food company [Waltham, n.d.] Translating that into
tabular form produces the following:
Cat's Age: ...............Equivalent Human's Age:
6 months.................10 years
8 months.................13 years
10 months................14 years
1 year......................15 years
18 months...............20 years
2 years....................24 years
4 years....................32 years
6 years....................40 years
8 years....................48 years
10 years...................56 years
12 years...................64 years
14 years...................72 years
16 years...................80 years
18 years...................88 years
20 years...................96 years
21 years...................100 years
I applied this chart to the current US mortality statistics. {Centers for Disease Control
2007], producing Sheet 1, even though kitten mortality is almost certainly much higher
than human baby mortality. For example, the mortality rate for free-roaming domestic
kittens is estimated at 75% during the first 9 months. [Nutter, et al., 2004] The only
adjustment I made was to increase the effective mortality of live birth pedigreed kittens
by 2.1% starting in the first (cat) year. Human figures put that at less than 1% in the first
year. The effect of this is to zero out cats of any age beyond 21.
(See Sheets 1 and 3)
Number of Pedigreed Cats Living in US Households
There are no data on the relative longevity of pedigreed cats versus that of all other cats.
Anecdotal evidence indicates that while some pedigreed cats have extremely long lifespans,
the overall average must also reflect factors such as genetically-transmitted
diseases or conditions that contribute to shorter life spans. Absent data to the contrary, I
have assumed that pedigreed cats have the same mortality statistics as non-pedigreed cats
do.
Thus, to determine the number of pedigreed cats in US households, you then use the 2.3
factor to convert cats registered into kittens born, and then apply the table to take the total
number of kittens born each year and estimate the number still alive in the last year, in
this case, 2006. In addition, I have to insert estimates for the odd years to provide a foot
total. To do so, I am taking the average between the two data points.
The results are as follows:
Total new pedigreed kittens added to total household population from 1994 through 2006
– 1,987.06 thousands (net). Add to that the number of pedigreed cats alive in 1994 and
still alive in 2006, which is 999.98 thousands (see below). That produces a total
pedigreed cats in 2006 of 2,987.04 thousands of 88,300.00 thousand cats, or 3.4%
maximum of the total cat population in US homes. As noted below, this is a decline from
an estimated 4.2% in 1994.
While the total number of pedigreed cats living in US households has increased slightly
since 1994, the demographic trend shown on Sheet 2 clearly indicates that within a few
years, the number of new pedigreed kittens born in a given year will not replace those
born in previous years that are dying. To put it another way, the pedigreed cat population
living in US households will soon reach the point of negative population growth.
Anecdotal data indicates that some specific breeds may already be at that point.
Please see my companion paper, posted at www.breedingpedigreedcats.com for a current
analysis detailing several breeds which are already “endangered”.
Technical Appendix:
To estimate the total population of pedigreed cats or pedigreed cats
of a specific breed in 1994
First, take the number of kittens born in 1994 to that breed. Unless you have other data,
you will have to assume that the same number of kittens were born for each of the
previous 21 years. While numbers of kittens born may have been higher for the early
1990s than for 1996, almost certainly they were lower in the 1980s than in 1996. The net
effect should balance out, or, at worst, slightly overstate the annual new births.
To estimate the number of pedigreed cats of any breed alive in 1994, means
P1994 (population of pedigreed cats in 1994) = K1994 (kittens born in 1994) + .9692K1993 +
…0.0002 K1973.
But I have assumed K1994 through K1973 are each equal to K1994. That transforms the
equation into
P1994=15.4541K1994
When I tested this with the number of pedigreed kittens born in 1994, 161.29 thousand, it
produces an estimate of 2,492.59 thousand pedigreed cats in US households in 1994, or
4.2% of the total APPMA estimate for that year.
Estimating the Number of Cats Alive in 1994 Still Alive in 2006
How many of the total number of cats alive in 1994 would survive to 2006? Here I used
the mortality tables. Thus, for example, taking Kittens born in 1990, K1990, to determine
how many are alive in 1994 produces K1990=.9545K1994, and only 81.75% of the kittens
born in 1990 would be alive in 2006, or .8175K1990.
Pedigreed cats that were alive in 1994 and that are still alive in 2006 =
(0.8567)K1994 + (0.8175)K1993 +(0.7660)K1992 + (0.6988)K1991 + (0.6126)K1990 +
(0.5064)K1989 + (0.3818)K1988 + (0.2501)K1987 + (0.1319)K1986 + (0.0463)K1985 +
(0.0200)K1984
For simplicity, I have also assumed that only kittens born after 1983, that is in 1984 or
later, may still be alive in 2006.
Where I lack actual data for the kittens going this far back, I will have to use the kittens
born in 1994 and work back as above. This assumption and complete substitution
produces a formula as follows:
(0.8567)K1994 + (0.8175)K1994 +(0.7660)K1994 + (0.6988)K1994 + (0.6126)K1994 +
(0.5064)K1994 + (0.3818)K1994 + (0.2501)K1994 + (0.1319)K1994 + (0.0463)K1994 +
(0.0200)K1994
This, in turn, reduces to the number of pedigreed cats alive in 1994 and still alive in 2006
equals 5.06861994, where K1994= 197.29 thousand kittens, or 999.98 thousands.
When dealing with specific breeds, where cumulative data across all three major US
registries is not available, I would use CFA data, assuming that CFA represents at least
60% of the total. Again, this estimate probably overstates the total number of kittens for
some breeds that are registered in multiple registries.
--------------------
Key Resources
American Pet Products Manufacturers Association, Inc., “New National Pet Owners
Survey Details Two Decades of Evolving American Pet Ownership”, June 18, 2007,
accessed June 25, 2007 at www.appma.org/press_releasedetail.asp?id=109.
American Pet Products Manufacturers Association, Inc., “National Pet Survey”, 2007.
Felicia B. Nutter, DVM, et al., “Reproductive capacity of free-roaming domestic cats and
kitten survival rate”, Journal of the American Veterinary Medical Association, November
1, 2004, Vol. 225, No. 9, Pages 1399-1402.
Cat Fanciers Association, Inc., Birth Statistics by Breed – Derived from the Number of
Living Births Reported on Litter Applications, 2006.
Centers for Disease Control, National Vital Statistics Reports, Vol. 54:14, revised as of
March 28, 2007.
Joan Miller, Pedigreed Cats In Peril, Cat Fancy, June 2008, 44-45.
Lorraine Shelton, RegistryStats06, 2007, based on data from the Cat Fanciers
Association, The International Cat Association, and the American Cat Fanciers
Association [cats registered].
Carolyn M. Vella and John J. McGonagle, Breeding Pedigreed Cats (2nd ed. 2006,
Pegasus Productions).
Waltham Veterinary Diets Pet Information Poster, cited by Blackness Veterinary
Surgery, accessed June 23, 2007, www.blackness2000.fsnet.co.uk/whatage.htm
Thanks to the following for assistance in locating much of this hard to locate data:
Carolyn M. Vella
Lorraine Shelton
Joan Miller
Fran Shaw
Nancy Peterson (and her actuary friend)
Thanks to the following for their useful comments :
Mary Kolencik
Author
John J. McGonagle is a former breeder of pedigreed cats and an award-winning
professional member of the Cat Writers’ Association. His academic background includes
a BA in economics (intensive) with a minor in mathematics from Yale University and a
M.A. in Business and Applied Economics from The Wharton School, the University of
Pennsylvania. His work experience includes working as an insurance actuarial intern.
Rights
This article and its tables are copyrighted by the author. Permission is granted to those
who wish to reprint the entire article and its tables only under the following conditions
(1) no additions or deletions, (2) send a copy of that reprint to the author, and (3) include
this consent with that reprint. Duplication of any part of the article or the tables other than
as set forth above without the specific written permission of the author is forbidden.
SHEET 1
Cat Age
(x)
Human
Age
Number
Surviving to
age x [CDC]
% of births
survivng
to age x
Adjusted by
increase in
2.1% for 1st
year
mortality
0.00 0 100,000 100.00% 100.00%
1.00 15 99,022 99.02% 96.92%
2.00 24 98,315 98.32% 96.22%
3.00 28 97,940 97.94% 95.84%
4.00 32 97,551 97.55% 95.45%
5.00 36 97,080 97.08% 94.98%
6.00 40 96,442 96.44% 94.34%
7.00 44 95,555 95.55% 93.45%
8.00 48 94,338 94.34% 92.24%
9.00 52 92,719 92.72% 90.62%
10.00 56 90,595 90.59% 88.49%
11.00 60 87,774 87.77% 85.67%
12.00 64 83,854 83.85% 81.75%
13.00 68 78,705 78.70% 76.60%
14.00 72 71,982 71.98% 69.88%
15.00 76 63,362 63.36% 61.26%
16.00 80 52,743 52.74% 50.64%
17.00 84 40,283 40.28% 38.18%
18.00 88 27,113 27.11% 25.01%
19.00 92 15,289 15.29% 13.19%
20.00 96 6,734 6.73% 4.63%
21.00 100 2,118 2.12% 0.02%
1545.41%
Copyright 2007 by John J, McGonagle.
. Permission is granted to those who wish to reprint the entire article and its tables only
under the following conditions
(1) no additions or deletions,
(2) send a copy of that reprint to the author, and
(3) include this consent with that reprint.
Duplication of any part of the article or the tables other than as set forth above .
without the specific written permission of the author is forbidden
SHEET 2
American Pet
Products
Manufacturers
Associations
National Pet
Survey –
Number of
Cats
(thousands)
Total Number
of Pedigreed
Cats
Registered
with CFA,
TICA and
ACFA
(thousands)
Estimated
Number of
Pedigreed
Kittens born
(thousands)
Percent of
births
surviving
to 2006
Estimated
Number of
Pedigreed
Kittens
born this
year and
alive in
2006
1994 59,400.00 85.78 197.29 81.75% 161.29
62,800.00 85.76 197.25 85.67% 168.98
1996 66,200.00 85.74 197.20 88.49% 174.50
65,200.00 82.90 190.66 90.62% 172.77
1998 64,200.00 80.05 184.12 92.24% 169.83
68,500.00 73.46 168.96 93.45% 157.89
2000 72,800.00 66.87 153.80 94.34% 145.10
75,200.00 65.90 151.57 94.98% 143.96
2002 77,600.00 64.93 149.34 95.45% 142.54
84,050.00 63.70 146.50 95.84% 140.40
2004 90,500.00 62.46 143.66 96.22% 138.23
89,400.00 60.80 139.84 96.92% 135.53
2006 88,300.00 59.14 136.02 100.00% 136.02
TOTAL 1987.06
Copyright 2007 by John J, McGonagle.
. Permission is granted to those who wish to reprint the entire article and its tables only
under the following conditions
(1) no additions or deletions,
(2) send a copy of that reprint to the author, and
(3) include this consent with that reprint.
Duplication of any part of the article or the tables other than as set forth above .
without the specific written permission of the author is forbidden
SHEET 3
Cat Age
(x)
Number
Surviving to
age x [CDC]
Adjusted
by
increase
in 2.1% for
1st year
mortality
In
percentages
0.00 100,000 100,000 100.00%
1.00 99,022 96,922 96.92%
2.00 98,315 96,215 96.22%
3.00 97,940 95,840 95.84%
4.00 97,551 95,451 95.45%
5.00 97,080 94,980 94.98%
6.00 96,442 94,342 94.34%
7.00 95,555 93,455 93.45%
8.00 94,338 92,238 92.24%
9.00 92,719 90,619 90.62%
10.00 90,595 88,495 88.49%
11.00 87,774 85,674 85.67%
12.00 83,854 81,754 81.75%
13.00 78,705 76,605 76.60%
14.00 71,982 69,882 69.88%
15.00 63,362 61,262 61.26%
16.00 52,743 50,643 50.64%
17.00 40,283 38,183 38.18%
18.00 27,113 25,013 25.01%
19.00 15,289 13,189 13.19%
20.00 6,734 4,634 4.63%
21.00 2,118 18 0.02%
Copyright 2007 by John J, McGonagle.
. Permission is granted to those who wish to reprint the entire article and its tables only
under the following conditions
(1) no additions or deletions,
(2) send a copy of that reprint to the author, and
(3) include this consent with that reprint.
Duplication of any part of the article or the tables other than as set forth above .
without the specific written permission of the author is forbidden
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