Evaluation of euthanasia and trap–neuter–return (TNR) programs in managing free-roaming cat populations
Paige M. Schmidt A D , Todd M. Swannack A , Roel R. Lopez A and Margaret R. Slater B CA Department of Wildlife and Fisheries Sciences, Texas A&M University, 2258 TAMU, College Station, TX 77843-2258, USA.
B College of Veterinary Medicine, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA.
C Present address: Animal Services Program Office, The American Society for the Prevention of Cruelty to Animals, 1717 South Philo Ave, Suite 36, Urbana, IL 61802, USA.
D Corresponding author. Email: pmhill@tamu.edu
Wildlife Research 36(2) 117-125 https://doi.org/10.1071/WR08018
Submitted: 3 February 2008 Accepted: 28 November 2008 Published: 20 February 2009
Abstract
Global estimates of the number of domestic cats (Felis catus) are >400 million. Issues associated with free-roaming cats are of global importance because of animal-welfare and public-health concerns and impacts on native wildlife through predation, competition and disease transmission. In the United States, proposed control solutions for managing urban free-roaming cat populations include euthanasia and trap–neuter–return (TNR) programs. We evaluated control methods using a demographic population model for a 25-year period, with parameters estimated from an unmanaged, free-roaming cat population in Texas. We modelled euthanasia and TNR at 25%, 50% and 75% implementation rates and a 50 : 50 combination of euthanasia and TNR at 25%, 50%, 75% and 100% implementation rates for 0%, 25% and 50% maximum immigration rates. We compared final population size, total number of cats treated and treatment effort relative to population reduction. Population decreases were comparable among euthanasia, TNR and a 50 : 50 combination for all treatment rates when the immigration rate was 0%; however, they were higher for euthanasia at 25% and 50% maximum immigration rates. Euthanasia required higher treatment effort than TNR. Our results indicate that immigration must be prevented and high (>50%) treatment rates implemented to reduce free-roaming cat populations.
Acknowledgements
Research was approved by the Clinical Research Review Committee at the College of Veterinary Medicine, Texas AandM University (CRRC 04-30, 04-31). We would like to thank W. Grant for assistance with this model and B. Collier and N. Silvy for helpful review of this manuscript. We are grateful to the City of Caldwell, Caldwell Veterinary Clinic, L. Anderson, and Dr N. L. Carter for assistance with this project and to the residents of Caldwell for permitting us to conduct our research and for enrolling their cats in our study. The National Council on Pet Population Study and Policy provided funding for this research.
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