Modeling Interventions in the Owned Cat Population in Knox County, TN

The rapid growth of cat populations in many communities across the United States has resulted in overpopulation and an increase in euthanasia procedures. To combat these challenges, communities have instituted spay/neuter programs as a preventative strategy. In particular, Knox County, Tennessee, has developed and implemented a program, called the Spay Shuttle, which offers free spays and neuters for owned cats throughout the county.

We develop a discrete time, age-structured model of owned female cats in Knox County to investigate the effects of implementing extra spaying intervention strategies to the population over the course of 5 years. We determine that a 50% increase in spay surgeries per two month time step for each age class capable of reproducing will result in a 33% decrease in the population. Also, the number of surgeries performed during those five years will also drop. Analysis of the cumulative number of surgeries performed reveals a sharp increase in surgeries during the first two years, followed by a decrease in surgeries in the following years. We also examine other scenarios, by which we target different age groups for extra spay interventions. We determine that the most impact is seen when extra spaying of cats ages 4-6 months is included in the intervention.