Antimicrobial consumption: Comparison of three different data collection methods.

The increasing incidence of antimicrobial resistance represents a global threat. As a result, surveillance programmes monitoring antimicrobial consumption and resistance in animals have been implemented in several countries throughout the world. However, such programmes depend on the accurate and detailed collection of data on antimicrobial consumption. For this reason, the aim of this longitudinal study was to compare the consistency of data on antimicrobial consumption between three different data collection methods. Antimicrobial consumption data associated to udder health were collected from 20 veterinary practices and 92 dairy farms for 18 months. The compared data sources were: 1) data extracted from veterinary practice software 2) farm treatment journals and 3) on-farm discarded drug packages (garbage). Two different procedures were chosen to analyse the data issued from treatment journals: 1) only complete entries were analysed 2) entries with missing dosage were supplemented with the information provided by the Swiss Compendium of Veterinary Medicinal Products. The antimicrobial data were divided into intramammary preparations used during lactation (IMM), intramammary preparations used for dry off (DRY) and systemic treatments (SYS). We compared the quantities of injectors (IMM and DRY), the quantities of active substances (SYS) and the treatment incidences (TI) for the defined daily dose (DDD) per 1000 cow-days (IMM and SYS) and the defined course dose (DCD) per 1000 cow-days (DRY). Additionally, the variety of antimicrobial products among the different data sources was compared. The highest quantity of antimicrobials for IMM, DRY and SYS could be collected with the software data. The lowest quantity was collected by using the data of the treatment journal with only complete entries. For IMM and DRY, software and garbage performed similar, with agreement on the number of injectors used in 56.1% of the analysed cases. The widest variety of intramammary antimicrobial preparations was found in the garbage whilst most systemic preparations were collected using software data. The results of the study show a lack of data consistency between the three different data sources. None of the methods was able to collect the integral antimicrobial consumption in the participating farms. Finally, the results emphasise the need to implement a standardised system to quantify and assess the antimicrobial consumption at veterinary practice and farm level.