The impacts of dog sterilization campaigns in Thailand: understanding changes in dog population dynamics

Abstract

Introduction Of the estimated near 10 million dogs in Thailand, most are free roaming, raising concerns about nuisance behaviors, dog welfare, and the transmission of diseases such as rabies. Minimal research examines dog population management in Thailand, particularly beyond the Bangkok area. Methods We examine the impact of dog population management (DPM), particularly sterilization campaigns in the form of Catch-Neuter-Vaccinate-Return (CNVR), by the non-governmental organization Jai Dog Rescue in the Thai province of Nakhon Nayok. Using transect data collected by the organization and generalized linear mixed models we investigated whether sterilization effort was associated with changes in (1) free-roaming dogs observed per km; and the presence of (2) sterilized dogs; (3) lactating females and puppies; and (4) welfare-related indicators. We triangulated these results with data from a Knowledge, Attitudes, and Practices (KAP) survey in two districts within Nakhon Nayok. Results Jai Dog's DPM effort was associated with changes in the dog population through dog counts and people's perceptions. Dogs observed per km and the presence of puppies decreased significantly ( p < 0.05) in association with sterilization effort. The KAP survey suggests that, when compared with a control district where Jai Dog had not worked, respondents in the intervention district were more likely to report decreased number of dogs on their street ( p < 0.001), positive perceptions of dog numbers ( p = 0.01), and less complaints regarding dogs and nuisance behaviors such as dog bites. Our findings show sustained sterilization coverage up to 3 years following peak sterilization effort. The number of sterilizations conducted each year had a compounding effect on this sterilization coverage, but the number of sterilizations 1 year ago showed the strongest association. Furthermore, KAP survey respondents in the intervention district reported higher numbers of sterilizations among their owned dogs ( p < 0.001) and greater preference for humane dog management strategies ( p < 0.001). Discussion DPM effort was associated with meaningful reductions in free-roaming dogs in Nakhon Nayok province. Jai Dog's monitoring approach using transect counts of directly observed free-roaming dogs is operationally useful, providing a quantitative longitudinal measure of their programme impacts. These results suggest that transects are feasible and valuable for other organizations conducting dog population management.

The authors' abstract, as published at the source. Frontiers in Veterinary Science, 2026 · DOI ↗