Influence of stakeholders on the implementation of regulations The Sub-DAHLP appeared to be the link between the central level and local stakeholders. They had field expertise and were consulted by the upper level, while they transmitted information on ABR, ABU, and regulations to the lower level. They were in contact with drug sellers, veterinarians, and farmers (though they were unable to inspect all farms), as well as researchers. However, respondents reported differences between provinces on regulatory implementation, which might impact the benefits of the regulatory changes. National private stakeholders were consulted on the design of the new legislation, and we saw better understanding, compliance, and adaptability amongthesestakeholders. They were also better controlled by the competent authorities. They were motivated to reduce their ABU to access the international market and export their products. However, our study was unable to determinetheexact influence of private companiesonthedesignofthelaw.Localstakeholders were not involved in the process and showed a lower level of understanding and compliance. Nevertheless, they were identified as key stakeholders in achieving objectives due to their position in the chain as end-users and must be more involved. International partners perceived themselves as having a moderate influence on the legislative process. However, in Vietnam, ABU and ABR monitoring remained dependent on research projects, and legislation was partly developed based on the recommendations of international researchers. The NAP was adopted in response to a call from international organizations (OMS 2015) and influenced by international stakeholders, even though the final decision rests with the government. Regulations were sometimes elaborated too far away from Vietnamese reality. Consequently, these regulations developed by national authorities under the influence of international factors may favor production intensification in Vietnam. As explained by one participant, the policy to intensify the farms was done without the farmers' involvement. To be effective, regulations need to be adapted to the context rather than simply copied from another country's regulations (Kirchhelle et al. 2020). For example, there were still a large number of small retailers who lacked the legally required practice certificates or qualifications, and they were the only source of antibiotics in remote areas. In this case, strict regulation could limit small-scale farmers' access to antibiotics. Difficulties to implement the regulations Our study showed that the new regulations would be difficult to implement in Vietnam in the short term, and that local compliance could take longer than anticipated. Indeed, respondents stressed that the use of antibiotics for preventive purposes, by mixing antibiotics themselves with feed, is deeply rooted in the practices of farmers and drug sellers. In addition, these practices are difficult to control due to the large number of small-scale farmers in the country. This finding is consistent with several studies that have shown that the regulatory enforcement of antibiotic usage is low or absent in low- and middle-income countries (LMICs), particularly in Vietnam (Nguyen et al. 2013). The new NAP issued in 2021 also highlighted the need for better regulatory enforcement to fight against ABR (MARD 2021), and an analysis of NAP in Southeast Asia reached the same conclusion (Chua et al. 2021). Not all local stakeholders who will be affected by mandatory prescriptions in a few years' time were aware of the regulatory changes, and most of the respondents at different levels did not believe that they would be implemented soon. In veterinary medicine in Vietnam, buying