The emergence and spread of antimicrobial resistance is a major concern for human and animal health worldwide. Consequently, there is increasing pressure to reduce antibiotic use in food-producing animals.
Recently, the World Health Organization recommended producers, veterinarians and other professionals involved in livestock production reduce the use of antibiotics to prevent or delay emergence of antimicrobial resistance.
Despite a lack of data to definitively link increased antimicrobial resistance in bacteria isolated from humans to increased antibiotic use in dairy cows, the dairy sector should decrease the use of antibiotics to retain its “social license.”
Surveillance of antibiotic use is important to indicate that dairy producers are practicing “good stewardship.” Therefore, dairy producers are encouraged to monitor antibiotic use.
In the future, the data may be crucial to support future quotas or perhaps a ban on the use of antibiotics and specific therapies (i.e., selective versus blanket dry cow therapy), and also to serve as a basis to improve the rational use of antibiotics.
The method used to assess antibiotic use should be based on time and resources, as well as accuracy. The most obvious choice of determining total antibiotic use is on-farm treatment records.
We recently compared this method with another: tracking the inventory of empty drug containers. This method has been considered a very accurate way for recording total antibiotic use.
Both methods were implemented in 51 Canadian dairy herds. For every treatment record entry, on average, 2.2 times more treatments were detected using the inventory of empty drug containers. However, both methods had a high correlation.
Therefore, herds recording more treatments using one method also recorded more treatments using the other (see Figure 1).
Based on these results, we recommend the use of treatment records, as they measure what they should. However, our study showed they generally underestimate total antibiotic use by a considerable amount.
The underestimation associated with treatment records is due to incomplete and unverifiable records. However, in our study, there was considerable variability among herds.
Some herds, however, had a 1-to-1 association between methods (their treatment records were essentially perfect).
In addition, we found herds with poor treatment records also had higher bulk tank somatic cell counts. Not surprisingly, accurately recording antibiotic use using treatment records was more likely in well-managed herds.
To be effective, treatment records require a minimum number of fields: cow identification, reason for treatment, date, product and treatment duration. Additional fields may also be considered such as dose or volume.
Templates are available online, although digital forms or user-friendly software is ideal. Most dairy management computer programs include cow health records, where each treatment can be easily recorded and herd-level antibiotic use summarized.
Other options to monitor total antibiotic use in herds include inventory of antibiotics acquired, questionnaires, inventory of empty drug containers, copies of prescription forms and data from veterinarians.
However, the data from veterinarians only provide an accurate picture in countries where over-the-counter acquisition of antibiotics is not allowed.
To accurately monitor antibiotic use, recording methods should be validated. Depending on the current management of a farm, implementation of these alternative methods may be challenging. Every method has advantages and limitations, and different methods may be suitable for different herds.
In any successful antimicrobial resistance control program, organization, effort and attention to detail are all required. In our experience, dairy producers are willing to initiate protocols to record diseases and treatments, and we fully expect that other dairy producers will also be willing to participate.
