Three Things to Know
Since 2016, Greater Bangkok has been home to a major dog population management initiative using the Catch, Neuter, Vaccinate, Return (CNVR) method. To understand its effects, researchers explored residents’ views on the dog population and their care for both owned and free-roaming dogs.
The study revealed that the more CNVR rounds an area underwent (up to three), the more likely residents were to report a decline in dogs, puppies, and related nuisances over time. People in these CNVR-treated areas also expressed more positive or neutral feelings about the number of street dogs and reported being less bothered by their presence.
Additionally, the study found that 14.3% of respondents provided care for street dogs, primarily by offering food and water. Interestingly, dog owners were more inclined to tolerate and care for free-roaming dogs, favor sterilization as a management approach, and discourage sheltering.
For Dog Welfare Practitioners
This study, alongside another showing less roaming and increased sterilization in areas of Greater Bangkok with robust CNVR efforts, powerfully demonstrates the impact of sustained CNVR across a greater metropolitan area. We need more structured research to fully justify CNVR’s effectiveness, especially in how it shapes public perception of free-roaming dogs.
The Full Picture
Greater Bangkok has been the site of a significant dog population management initiative since 2016, employing the Catch, Neuter, Vaccinate, Return (CNVR) method. This large-scale effort aims to reduce free-roaming dog (FRD) populations and mitigate rabies risk. Over seven years, veterinarians treated more than 500,000 dogs across six provinces, with the CNVR intervention beginning in Bangkok and gradually expanding. As such, different areas received varying numbers of CNVR rounds based on local dog populations and logistical factors.
A study, ‘The Impact of Catch-Neuter-Vaccinate-Return (CNVR) on Greater Bangkok Residents’ Attitudes and Behaviours Towards Free-Roaming Dogs,’ delves into public perceptions and the care of free-roaming dogs, simultaneously assessing the impact of the CNVR program.
Study Methods
The researchers administered a 42-question survey, including 18 questions focused on FRDs and dog bites, designed to assess changes potentially linked to the CNVR program. Questions explored public experiences with FRDs, perceptions of roaming dog numbers, dog bite incidents, care provided to street dogs, and views on FRD management. Respondents also reflected on changes in FRD numbers over the past year and since 2014.
Study Results
The study engaged 3,203 respondents across Greater Bangkok, achieving a high response rate of 93%. Participants were an even split between men and women, representing a wide age range. In addition, researchers conducted interviews across areas that had experienced varying levels of CNVR (Catch, Neuter, Vaccinate, Return) intervention.
Dog Population
Respondents reported noticeable changes in street dog populations, particularly in areas where CNVR had been implemented. Over the past year, 34% of long-term residents observed fewer free-roaming dogs on their street (“soi”), a trend more pronounced in districts with two or three CNVR rounds (48% and 46%, respectively), while only 11% of residents in areas without CNVR reported a decline.
Over a nine-year timeframe, 35% of respondents noted that there used to be many more dogs on their soi, with those in high-CNVR areas significantly more likely to report such reductions.
The presence of puppies on the streets had diminished as well. Only 7% of respondents knew of a litter born on their street in the past year, with lower reports in high-CNVR areas. Most puppies were kept or given away, but some were abandoned, and none were reported as being euthanized or sent to shelters.
Trouble with Street Dogs
Feelings of being troubled by street dogs had improved over time, with 31% feeling less troubled now compared to nine years ago — particularly in areas with more CNVR coverage. Dog bite incidents were rare — only 1.5% of households reported a bite in the past year, with half involving owned dogs. Bites were less likely in areas with three CNVR rounds, although this result approached, but did not reach, statistical significance. Dog ownership did not affect bite risk.
Attitudes Towards Street Dogs
When asked about current attitudes toward street dogs, most respondents were neutral (58%) or positive (35%) about the number of dogs on their soi. Positive attitudes were more common in CNVR-treated areas and among dog owners, who were twice as likely as non-owners to express acceptance or happiness about street dog numbers. Only 13.5% of respondents reported being annoyed or troubled by street dogs in the past month, citing noise, waste, and garbage disturbances as the main issues. People in areas with one or two CNVR rounds experienced less trouble compared to those in untreated areas.
A total of 14.3% of respondents reported providing care to street dogs. They primarily fed and gave water to the dogs. Interestingly, fewer respondents in areas with two or three CNVR rounds reported providing care, which might reflect a reduced dog presence. However, dog owners were more likely to provide care than non-owners.
Dose-response Relationship
A clear dose–response relationship emerged: the more CNVR rounds an area received (up to three), the more likely residents were to report fewer dogs, fewer puppies, and fewer nuisances over time. People in CNVR-treated areas were also more likely to feel positively or neutrally about the number of dogs on their streets and less likely to report being troubled by them.
In terms of preferred dog population management strategies, sterilization was the most popular choice (55%), followed by sheltering (20%). Interestingly, the number of CNVR rounds in a given area influenced residents’ preferred approaches to dog population management:
- Two rounds of CNVR: Residents were significantly more likely (over six times higher odds) to prefer sterilization and less likely (50% lower odds) to prefer sheltering, suggesting a positive view of CNVR’s effectiveness.
- Three rounds of CNVR: Interestingly, residents in these areas, which likely saw the largest declines in free-roaming dog populations, were nearly twice as likely to prefer sheltering the remaining dogs and showed no significant difference in preferring sterilization. This suggests that with fewer dogs on the streets, sheltering became a more feasible option in residents’ minds, as opposed to areas with higher free-roaming dog populations where community members viewed sheltering of all dogs as impractical.
In addition, dog owners were more likely to prefer sterilization and less likely to support sheltering, suggesting that direct experience with dogs influences views on humane management.
While CNVR did not consistently reduce recent annoyance about FRDs, it did influence preferences for dog population management methods. Residents in areas with two CNVR rounds were much more likely to prefer sterilization over sheltering, showing support for the CNVR method. Those in areas with three rounds leaned more toward sheltering, potentially due to the reduced number of street dogs.
Impact of Dog Ownership
Dog ownership played a significant role in shaping perceptions and behaviors. Dog owners were more likely to tolerate and care for FRDs, prefer sterilization, and discourage sheltering. CNVR efforts also influenced owned dog care, with owners in CNVR areas more likely to sterilize and confine their dogs.
Owned dogs contribute substantially to the FRD population, often through abandonment or roaming. Thus, effective FRD control must also include policies focused on owned dogs—such as promoting responsible ownership, improving access to sterilization, and introducing identification and breeding controls.
Conclusion
Overall, the results suggest that CNVR efforts in Greater Bangkok have led to reduced street dog populations, improved public attitudes, fewer nuisances, and positive support for humane management approaches—especially sterilization. The program’s impact strengthens with increased implementation, providing compelling evidence for policymakers to invest in CNVR as a humane and effective dog population management strategy. To maximize success, cities should implement CNVR alongside interventions targeting owned dog populations.
Miscellaneous
Data From Study:
Street Dogs > Thailand > Community Perceptions
Year of Publication:
2025
External Link:
Hiby E, Rungpatana T, Izydorczyk A, Benka V, Rooney C. The Impact of Catch-Neuter-Vaccinate-Return (CNVR) on Greater Bangkok Residents’ Attitudes and Behaviours Towards Free-Roaming Dogs. Animals. 2025; 15(9):1274. https://doi.org/10.3390/ani15091274