Objective—To evaluate the efficacy of trap-neuterreturn
and trap-euthanatize management strategies
for controlling urban free-roaming cat populations by
use of matrix population models.
Sample Population—Estimates of free-roaming cat
populations in urban environments.
Procedure—Data from the literature describing the
biology of free-roaming cat populations in urban environments
were gathered. A matrix population model
was developed with a range of high and low survival
and fecundity values and all combinations of those
values. The response of population growth rate to a
range of management actions was assessed with an
Results—All possible combinations of survival and
fecundity values of free-roaming cats led to predictions
of rapid, exponential population growth. The
model predicted effective cat population control by
use of annual euthanasia of ≥ 50% of the population
or by annual neutering of > 75% of the fertile population.
Elasticity analyses revealed that the modeled
population was most susceptible to control through
Conclusions and Clinical Relevance—Free-roaming
cat populations have a high intrinsic growth rate, and
euthanasia is estimated to be more effective at reducing
cat populations than trap-neuter-return programs.
(J Am Vet Med Assoc 2004;225:1871–1876)