Antimicrobial use on Australian dairy cattle farms - A survey of veterinarians

Abstract

Aims: The aims of this study were to determine antimicrobial prescription patterns and the factors affecting antimicrobial selection amongst Australian dairy veterinarians.

Methods: A structured questionnaire was administered to Australian dairy cattle veterinarians using the Qualtrics online survey platform. Questions focused on their (1) demographics; (2) opinions surrounding antimicrobial use, resistance, and stewardship; (3) decision-making drivers of both prescription and selection of commonly prescribed antimicrobials; (4) awareness on the guidelines for antimicrobial usage and sources of information concerning antimicrobials.

Key results: A total of 135 responses (14.1% response rate) from all eight dairying regions in Australia were received. The attitudes, perceptions, and concerns of dairy veterinarians towards antimicrobials indicated a high agreement regarding label indications (96%), consequences of off-label prescription (95%), and the presence of an antimicrobial resistance (AMR) risk (73%), when prescribing antibiotics. A four-dimensional categorical principal components analysis (CATPCA) model indicated most of the variation in opinion was due to AMR risk, trade-offs, prescription concerns and active substance concerns. The first active substance most dairy veterinarians chose for a scenario involving mastitis and dry cow therapy (DCT) treatment was cloxacillin. Decision-making drivers for antimicrobial choice when providing advice regarding the supply of antimicrobials for mastitis and DCT treatment were predominately clinical factors; however, diagnostics were rarely used in determining antimicrobial choice due to cost of implementation, diagnostic accuracy (sensitivity, specificity), and benefit issues. Non-clinical decision-making drivers included the perception of practicality for Australian Veterinary Association (AVA) prescription guidelines, opinions surrounding AMR risk and prescription concerns, consideration of Expert Advisory Group on Antimicrobial Resistance (EAGAR) scores, number of years worked with dairy farms, and the number of dairy farms they regularly consult for. When available at the practice, prescription policies were considered to impact on animal welfare outcomes and on the probability of AMR emergence. The major information sources influencing decision making on antimicrobial prescription for the Australian dairy veterinarians were clinical experience (93%) and product labels (81%).

Conclusions: Australian dairy veterinarians are generally aware of the risk of resistance to antimicrobials and the need for stewardship, with clinical factors having the most impact on antimicrobial prescription. However, non-clinical factors incorporating awareness of guidelines and their attitudes on antimicrobial resistance risk and prescription concerns impact on the choice and prescription of antimicrobials.

Implications: The development of prescription policy and guidelines, alongside effective communicative extension programs to increase veterinarian uptake, provides an avenue to mitigate AMR risk in Australian dairy cattle.

Keywords: Antimicrobial use; Awareness; Dairy cattle; Opinions; Prescription behavior.