Optimizing antimicrobial use by improving medication adherence among pig producers.

In Japan, many pig producers buy antimicrobials using veterinarians' prescriptions. Even if veterinarians prescribe antimicrobials for treatments and metaphylaxis, producers may be using them for prophylaxis on farms with a high incidence of chronic diseases. To reduce the frequency of antimicrobial use, we applied the concept of medication adherence and launched an intervention in eight farrow-to-finish farms. For the intervention farms, we attempted to implement measures for preventing the repeated onset of chronic infections that interfered with adherence, confirmed the need to continue medications, and discontinued medications if possible. For each farm, these interventions began at different time points after 2017 and continued until 2020. We evaluated the effectiveness of this intervention based on the amount of active ingredients/population correction unit and the total number of defined daily doses for the weight group/slaughter pig. The ratio of antimicrobial use for both indicators in the year 2020 compared with the start of the intervention decreased on all farms. Among the eight non-intervention farms, six showed an increase in both indicators. These results suggest that interventions for chronic diseases administered by producers and veterinarians lead to high adherence to prescriptions and responsible and prudent use of antimicrobials on pig farms.