Introduction: Overpopulation of free-roaming cats is a controversial issue in local communities worldwide. While free-roaming cats are often fed by some people, free-roaming cats are viewed as a public nuisance by others. Trap-neuter-return (TNR) has been promoted as a humane alternative to euthanasia for free-roaming cats, but its effectiveness is hard to evaluate. The aim of this study was to evaluate the impact and effectiveness of a cat TNR subsidy project by Osaka City, Japan focusing on reductions in cat impoundment, cat-related complaints and improvement of cat welfare.
Methodology: Data for the 24 wards of Osaka City in 2015 were collected from Osaka City officers and websites. In multi-regression analyses, the data of cats impounded to the city, cat-related complaints, and injured cats were entered as response variables with the total number of TNR cats and one of the three socio-economic factors (income, education, or elderly population rates) as explanatory variables in total of nine models. Additionally, a route census of free-roaming cats was carried out in two wards: one as a high TNR ward and the other as a low TNR ward, to compare effect of TNR on cat welfare. All cats encountered in two selected one-kilometer routes in each ward were identified, and their body conditions were recorded.
Main results: There was no significant effect of TNR on impoundment (p = 0.65~0.73), complaints (p = 0.49~0.97), or welfare (p = 0.85~0.86). Instead, the effects of the socio-economic variables were statistically significant for increased impoundment (p = 0.00) and complaints (p = 0.00~0.01) suggesting poverty, educational level, and age of the human population had more effect on free-roaming cats than the TNR project. Moreover, the ‘level’ of TNR of the route did not affect the body condition of cats on the route census.
Principal conclusions and implications for field: More research would determine the effect of non-government TNR programmes, as these may have had an unknown impact on our data. However, our findings suggest that TNR alone may not solve the free-roaming cat problems. Furthermore, in line with the concept of One Welfare, improving human welfare may lead to improvements of free-roaming cat welfare.