Reaching consensus amongst international experts on the use of high importance-rated antimicrobials in animals - a Delphi study.

In Australia, antimicrobials are given an importance rating by the Australian Strategic and Technical Advisory Group on antimicrobial resistance. High importance antimicrobials are those essential for the treatment or prevention of infections in humans, where there are few or no treatment alternatives. In this study we consulted with experts from across human and animal health using the Delphi consensus-building process to establish the circumstances under which antimicrobials with high importance to human health could be used in animals in Australia. We used three rounds of online surveys. Group responses were provided to participants in each subsequent round to facilitate convergence of opinion. Consensus was defined as 80 % or more of respondents selecting the same option for a question. By the end of the third round, consensus was achieved on eight items. This included the use of high importance antimicrobials being appropriate if culture and sensitivity testing indicated the organism was resistant to low- and medium-rated antimicrobials that could be used to treat the case. If any high-importance antimicrobials are prescribed for animals there was also agreement that a clear indication for this use and justification for antimicrobial choice must be recorded in the medical history, along with the dose rate, route of administration, the duration and the time point for review of the condition and associated antimicrobial therapy. Appropriateness of use of high importance antimicrobials in critically ill animals where culture and sensitivity results are not available is still undefined. Further work is also required to establish which particular organisation should be notified of the use of high importance antimicrobials not registered for use in animals. The Delphi process was valuable in facilitating consensus amongst international experts from a broad range of health backgrounds and experience.

Seeking simplicity, navigating complexity: How veterinarians select an antimicrobial drug, dose, and duration for companion animals.

BACKGROUND: Minimizing harm from antimicrobials requires use of the narrowest spectrum drug, at an effective dose for the minimum effective duration. Many prescribers are not currently following these guidelines. To address suboptimal antimicrobial use, the underlying reasons must be understood. OBJECTIVES: To identify factors influencing choices of antimicrobial drug, dose, and duration for companion animals. SUBJECTS: Twenty-two veterinarians treating companion animals in Australia. Diversity of participants was deliberately sought. METHODS: Semistructured interviews were conducted online. Two case studies were discussed, and then a range of broader questions was posed. Transcripts were analyzed thematically, using an inductive approach. RESULTS: Few participants chose guideline-concordant management for the case studies. Prescribing choices were influenced by a complex array of factors associated with the clinical case, pet owner, drug, veterinarian, veterinary colleagues, and external factors. Key factors driving broad-spectrum antimicrobial use included a sense of safety, habit, ease of administering the drug (especially in cats), pharmaceutical marketing, and the self-perpetuating dispensary cycle. Many participants were concerned about antimicrobial resistance, but insufficiently informed about how to minimize this risk. Several participants believed that longer duration of treatment and ensuring patients finish a predetermined course would decrease the risk of antimicrobial resistance and improve clinical outcomes. CONCLUSIONS AND CLINICAL IMPORTANCE: Veterinarians are engaged with the concept of antimicrobial stewardship, but face numerous practical barriers and require more information. In particular, improved education is needed on enhancing patient safety by minimizing both spectrum of activity and duration of treatment, and dispelling myths about "finishing the course."

Using natural language processing and patient journey clustering for temporal phenotyping of antimicrobial therapies for cat bite abscesses.

BACKGROUND: Temporal phenotyping of patient journeys, which capture the common sequence patterns of interventions in the treatment of a specific condition, is useful to support understanding of antimicrobial usage in veterinary patients. Identifying and describing these phenotypes can inform antimicrobial stewardship programs designed to fight antimicrobial resistance, a major health crisis affecting both humans and animals, in which veterinarians have an important role to play. OBJECTIVE: This research proposes a framework for extracting temporal phenotypes of patient journeys from clinical practice data through the application of natural language processing (NLP) and unsupervised machine learning (ML) techniques, using cat bite abscesses as a model condition. By constructing temporal phenotypes from key events, the relationship between antimicrobial administration and surgical interventions can be described, and similar treatment patterns can be grouped together to describe outcomes associated with specific antimicrobial selection. METHODS: Cases identified as having a cat bite abscess as a diagnosis were extracted from VetCompass Australia, a database of veterinary clinical records. A classifier was trained and used to label the most clinically relevant event features in each record as chosen by a group of veterinarians. The labeled records were processed into coded character strings, where each letter represents a summary of specific types of treatments performed at a given visit. The sequences of letters representing the cases were clustered based on weighted Levenshtein edit distances with KMeans+ + to identify the main variations of the patient treatment journeys, including the antimicrobials used and their duration of administration. RESULTS: A total of 13,744 records that met the selection criteria was extracted and grouped into 8436 cases. There were 9 clinically distinct event sequence patterns (temporal phenotypes) of patient journeys identified, representing the main sequences in which surgery and antimicrobial interventions are performed. Patients receiving amoxicillin and surgery had the shortest duration of antimicrobial administration (median of 3.4 days) and patients receiving cefovecin with no surgical intervention had the longest antimicrobial treatment duration (median of 27 days). CONCLUSION: Our study demonstrates methods to extract and provide an overview of temporal phenotypes of patient journeys, which can be applied to text-based clinical records for multiple species or clinical conditions. We demonstrate the effectiveness of this approach to derive real-world evidence of treatment impacts using cat bite abscesses as a model condition to describe patterns of antimicrobial therapy prescriptions and their outcomes.

Cross-sectional evaluation of a large-scale antimicrobial stewardship trial in Australian companion animal practices.

BACKGROUND: Antimicrobial stewardship programmes (ASPs) are critically important for improving the appropriate use of antimicrobial agents in veterinary practice. METHODS: One of three ASPs was implemented in 135 Australian general veterinary practices in 2018-2020. The ASP interventions and the perceived impact they had on antimicrobial prescribing were assessed by the veterinarians working in these veterinary practices. An online survey was distributed to all 520 veterinarians working in the trial practices and 267 responses were analysed. RESULTS: Most veterinarians (174/267, 65%) thought they had an ASP at their clinic and most respondents who said that they were aware that they had an ASP at their clinic indicated that they had changed the way they prescribed antimicrobials because of the trial (125/170, 74%). Antimicrobial prescribing guidelines, the traffic light system for indicating antimicrobial importance, delayed prescribing and antimicrobial stewardship champions were reported to have had the biggest impact. LIMITATIONS: All practices in the trial belong to a single corporate group, which may impact the external validity of these results when applied to general small animal practice. CONCLUSION: Antimicrobial stewardship has a positive impact on antimicrobial prescribing in veterinary medicine and future interventions should focus on the implementation of the effective interventions identified in this study.

'Brave Enough': A Qualitative Study of Veterinary Decisions to Withhold or Delay Antimicrobial Treatment in Pets.

Veterinarians sometimes prescribe antimicrobials even when they know or suspect that they are unnecessary. The drivers of this behaviour must be understood to design effective antimicrobial stewardship interventions. Semi-structured interviews were conducted with 22 veterinarians who treated companion animals in Australia. The Theory of Planned Behaviour was used to organise interview themes, focusing on a decision to withhold antimicrobial therapy in the absence of a clear indication. Many background factors influenced antimicrobial-withholding decisions, including the veterinarian's communication skills, general attitudes towards antimicrobial resistance (AMR), habits and energy levels. Client awareness of AMR and the veterinarian-client relationship were also important. Beliefs about the consequences of withholding antimicrobials (behavioural beliefs) were dominated by fears of the animal's condition deteriorating and of failing to meet client expectations. These fears, weighed against the seemingly distant consequences of AMR, were major barriers to withholding antimicrobials. Normative beliefs were primarily focused on the expected approval (or disapproval) of the client and of other veterinarians. Control beliefs about the difficulty of withholding antimicrobials centred around client factors, most importantly, their capacity to adequately monitor their animal, to pay for further investigations, or to undertake non-antimicrobial management, such as wound care, at home. The use of antimicrobials by companion animal veterinarians in the absence of a clear indication is often powerfully driven by behavioural beliefs, chiefly, fears of clinical deterioration and of failing to meet client expectations.

Attitudes towards Use of High-Importance Antimicrobials-A Cross-Sectional Study of Australian Veterinarians.

The timely implementation of antimicrobial stewardship interventions could delay or prevent the development of higher levels of antimicrobial resistance in the future. In food-producing animals in Australia, high-importance antimicrobials, as rated by the Australian Strategic and Technical Advisory Group (ASTAG), include virginiamycin and third-generation cephalosporins (in individual pigs or cattle). The use of high-importance antimicrobials in companion animals is more widespread and less regulated. There is no national antimicrobial use surveillance system for animals in Australia. Consequently, there is a gap in the knowledge about reasonable use across all sectors of veterinary practice. This study explored attitudes towards the use in veterinary medicine of antimicrobials with high importance to human health, and determined levels of agreement about the introduction of restrictions or other conditions on this use. An online survey was distributed via social media and email from June to December 2020 to veterinarians working in Australia. Of the 278 respondents working in clinical practice, 49% had heard of the ASTAG rating system, and 22% used a traffic light system for antimicrobial importance in their practice. Overall, 61% of participants disagreed that veterinarians should be able to prescribe high-importance antimicrobials without restrictions. If there were to be restrictions, there was most agreement amongst all respondents for only restricting high-importance antimicrobials (73%). There is a need for education, guidance, and practical support for veterinarians for prescribing high-importance antimicrobials alongside any restrictions.

Evaluating the dose, indication and agreement with guidelines of antimicrobial use in companion animal practice with natural language processing.

BACKGROUND: As antimicrobial prescribers, veterinarians contribute to the emergence of MDR pathogens. Antimicrobial stewardship programmes are an effective means of reducing the rate of development of antimicrobial resistance. A key component of antimicrobial stewardship programmes is selecting an appropriate antimicrobial agent for the presenting complaint and using an appropriate dose rate for an appropriate duration. OBJECTIVES: To describe antimicrobial usage, including dose, for common indications for antimicrobial use in companion animal practice. METHODS: Natural language processing (NLP) techniques were applied to extract and analyse clinical records. RESULTS: A total of 343 668 records for dogs and 109 719 records for cats administered systemic antimicrobials from 1 January 2013 to 31 December 2017 were extracted from the database. The NLP algorithms extracted dose, duration of therapy and diagnosis completely for 133 046 (39%) of the records for dogs and 40 841 records for cats (37%). The remaining records were missing one or more of these elements in the clinical data. The most common reason for antimicrobial administration was skin disorders (n = 66 198, 25%) and traumatic injuries (n = 15 932, 19%) in dogs and cats, respectively. Dose was consistent with guideline recommendations in 73% of cases where complete clinical data were available. CONCLUSIONS: Automated extraction using NLP methods is a powerful tool to evaluate large datasets and to enable veterinarians to describe the reasons that antimicrobials are administered. However, this can only be determined when the data presented in the clinical record are complete, which was not the case in most instances in this dataset. Most importantly, the dose administered varied and was often not consistent with guideline recommendations.

Governance Processes and Challenges for Reservation of Antimicrobials Exclusively for Human Use and Restriction of Antimicrobial Use in Animals.

The majority of antimicrobials that are produced are administered to animals, particularly food animals. While the overall impact of antimicrobial use in animals on antimicrobial resistance in humans and the environment is unclear, it undeniably has a role. Yet, some degree of antimicrobial use in animals is necessary for animal health and welfare purposes. Balancing the benefits and risks of antimicrobial use in animals is challenging because of the complexity of the problem and limitations in available data. However, a range of measures can be implemented to reduce, refine and optimize antimicrobial use in animals, with a goal of minimizing the impact on human and environmental health while maintaining necessary therapeutic use in animals. A pandemic instrument can provide the necessary foundation for the whole-of-society and whole-of government One Health approach that is required to strengthen surveillance, communication, collaboration, and action.

Pet Owners and Antibiotics: Knowledge, Opinions, Expectations, and Communication Preferences.

Despite the important role of antimicrobial use in companion animals in the global challenge presented by antimicrobial resistance (AMR), very few studies have quantified pet owner factors that can contribute to suboptimal veterinary antimicrobial use. We conducted an online survey of pet owners, asking about their experiences with veterinarians, their opinions on antibiotic use and knowledge of antibiotics, and their communication preferences regarding judicious prescribing. Just over half (54%) of the 558 pet owners had received antibiotics for their pet at their last non-routine veterinary consultation and most owners were happy (83%) with the antibiotic prescribing decision of their veterinarian. A quarter (25%) indicated that they had been surprised, disappointed or frustrated when a veterinarian had not given their pet antibiotics; 15% had explicitly requested them. Owners placed a higher priority on their pet receiving the most effective treatment than on treatment being cheap or convenient. Most respondents recognized the limitations of antibiotic therapy and the risks associated with antibiotic use, but 50% believed the risks were confined to the treated animal; only a minority was aware of inter-species transfer of bacteria. Pet owners indicated that they would find judicious prescribing messages focused on the direct risks of antibiotics to their pet more compelling than those about public health. Our findings suggest that veterinary communications about responsible antibiotic use should focus on pet owners' priorities and address or bypass their gaps in understanding regarding antibiotic resistance.

Antimicrobial stewardship in Australia: the role of qualitative research in programme development.

Antimicrobial stewardship (AMS) in Australia is supported by a number of factors, including enabling national policies, sectoral clinical governance frameworks and surveillance programmes, clinician-led educational initiatives and health services research. A One Health research programme undertaken by the National Centre for Antimicrobial Stewardship (NCAS) in Australia has combined antimicrobial prescribing surveillance with qualitative research focused on developing antimicrobial use-related situational analyses and scoping AMS implementation options across healthcare settings, including metropolitan hospitals, regional and rural hospitals, aged care homes, general practice clinics and companion animal and agricultural veterinary practices. Qualitative research involving clinicians across these diverse settings in Australia has contributed to improved understanding of contextual factors that influence antimicrobial prescribing, and barriers and facilitators of AMS implementation. This body of research has been underpinned by a commitment to supplementing 'big data' on antimicrobial prescribing practices, where available, with knowledge of the sociocultural, technical, environmental and other factors that shape prescribing behaviours. NCAS provided a unique opportunity for exchange and cross-pollination across the human and animal health programme domains. It has facilitated synergistic approaches to AMS research and education, and implementation of resources and stewardship activities. The NCAS programme aimed to synergistically combine quantitative and qualitative approaches to AMS research. In this article, we describe the qualitative findings of the first 5 years.

Faecal microbiota and antimicrobial resistance gene profiles of healthy foals.

BACKGROUND: The human and domestic animal faecal microbiota can carry various antimicrobial resistance genes (ARGs), especially if they have been exposed to antimicrobials. However, little is known about the ARG profile of the faecal microbiota of healthy foals. A high-throughput qPCR array was used to detect ARGs in the faecal microbiota of healthy foals. OBJECTIVES: To characterise the faecal microbiota and ARG profiles in healthy Australian foals aged less than 1 month. STUDY DESIGN: Observational study. METHODS: The faecal microbiota and ARG profiles of 37 Thoroughbred foals with no known gastrointestinal disease or antimicrobial treatment were determined using 16S rRNA gene sequencing and a high-throughput ARG qPCR array. Each foal was sampled on one occasion. RESULTS: Firmicutes and Bacteroidetes were dominant in the faecal microbiota. Foals aged 1-2 weeks had significantly lower microbiota richness than older foals. Tetracycline resistance genes were the most common ARGs in the majority of foals, regardless of age. ARGs of high clinical concern were rarely detected in the faeces. The presence of ARGs was associated with the presence of class I integron genes. MAIN LIMITATIONS: Samples were collected for a case-control study so foals were not sampled longitudinally, and thus the development of the microbiota as individual foals aged could not be proven. The history of antimicrobial treatment of the dams was not collected and may have affected the microbiota of the foals. CONCLUSION: The ARGs in foal faeces varied concomitantly with age-related microbiota shifts. The high abundance of tetracycline resistance genes was likely due to the dominance of Bacteroides spp.

Use of Local Antibiogram Data and Antimicrobial Importance Ratings to Select Optimal Empirical Therapies for Urinary Tract Infections in Dogs and Cats.

International and Australian veterinary antimicrobial use guidelines recommend amoxicillin or trimethoprim-sulfonamide (TMS) for the empirical treatment of sporadic urinary tract infections (UTIs) in dogs and cats. However, in practice, these antibiotics are rarely used, and no large-scale analyses have examined the antibiograms of bacteria isolated from UTIs to validate these recommendations in Australia. We analyzed five years of urine culture and antimicrobial susceptibility data from an Australian veterinary laboratory. The analysis included 6196 urinary isolates from dogs and cats, 78% of which were from samples submitted by first-opinion veterinary clinics. Escherichia coli, Enterococcus faecalis, Staphylococcus pseudintermedius and Proteus spp. were the most prevalent organisms. More than 80% of all isolated cocci were susceptible to amoxicillin, and more than 80% of bacilli were susceptible to TMS. A total of 94% of isolates were susceptible to at least one antimicrobial drug categorized as low-importance in Australia. The prevalence of multi-drug resistance (MDR) was highest in E. coli, at 9.7%; 84% of these MDR isolates were susceptible to amoxicillin-clavulanate. We performed population-level antimicrobial treatment simulations and proposed a novel method for integrating antimicrobial importance ratings with antibiogram data to optimize the selection of empirical therapy. Our findings support current guideline recommendations to use amoxicillin or TMS. We also found that bacterial morphology assisted with selection; amoxicillin was a better choice for cocci and TMS for bacilli.

Use of cefovecin in dogs and cats attending first-opinion veterinary practices in Australia.

BACKGROUND: Cefovecin is a long-acting third-generation cephalosporin commonly used in veterinary medicine. Third-generation cephalosporins are critically important antimicrobials that should only be used after culture and susceptibility testing. The authors describe the common indications for cefovecin use in dogs and cats, and the frequency of culture and susceptibility testing. MATERIALS AND METHODS: A cross-sectional study was performed using clinical records extracted from VetCompass Australia. A previously described method was used to identify records containing cefovecin. The reason for cefovecin use was annotated in situ in each consultation text. RESULTS: Over a six-month period (February and September 2018), 5180 (0.4 per cent) consultations involved cefovecin administration, of which 151 were excluded. Cats were administered cefovecin more frequently than dogs (1.9 per cent of cat consultations and 0.1 per cent of dog consultations). The most common reasons for cefovecin administration to cats were cat fight injuries and abscesses (28 per cent) and dermatitis (13 per cent). For dogs, the most common reasons for cefovecin administration were surgical prophylaxis (24 per cent) and dermatitis (19 per cent). Culture and susceptibility testing were reported in 16 cases (0.3 per cent). CONCLUSION: Cefovecin is used in many scenarios in dogs and cats where antimicrobials may be either not indicated or where an antimicrobial of lower importance to human health is recommended.

Describing the antimicrobial usage patterns of companion animal veterinary practices; free text analysis of more than 4.4 million consultation records.

Antimicrobial Resistance is a global crisis that veterinarians contribute to through their use of antimicrobials in animals. Antimicrobial stewardship has been shown to be an effective means to reduce antimicrobial resistance in hospital environments. Effective monitoring of antimicrobial usage patterns is an essential part of antimicrobial stewardship and is critical in reducing the development of antimicrobial resistance. The aim of this study is to describe how frequently antimicrobials were used in veterinary consultations and identify the most frequently used antimicrobials. Using VetCompass Australia, Natural Language Processing techniques, and the Australian Strategic Technical Advisory Group's (ASTAG) Rating system to classify the importance of antimicrobials, descriptive analysis was performed on the antimicrobials prescribed in consultations from 137 companion animal veterinary clinics in Australia between 2013 and 2017 (inclusive). Of the 4,400,519 consultations downloaded there were 595,089 consultations where antimicrobials were prescribed to dogs or cats. Antimicrobials were dispensed in 145 of every 1000 canine consultations; and 38 per 1000 consultations involved high importance rated antimicrobials. Similarly with cats, 108 per 1000 consultations had antimicrobials dispensed, and in 47 per 1000 consultations an antimicrobial of high importance rating was administered. The most common antimicrobials given to cats and dogs were cefovecin and amoxycillin clavulanate, respectively. The most common topical antimicrobial and high-rated topical antimicrobial given to dogs and cats was polymyxin B. This study provides a descriptive analysis of the antimicrobial usage patterns in Australia using methods that can be automated to inform antimicrobial use surveillance programs and promote antimicrobial stewardship.

Population wide assessment of antimicrobial use in dogs and cats using a novel data source - A cohort study using pet insurance data.

Antimicrobial use in veterinary practice is under increasing scrutiny as a contributor to the rising risk of multidrug resistant bacterial pathogens. Surveillance of antimicrobial use in food animals is extensive globally, but population level data is lacking for companion animals. Lack of census data means cohorts are usually restricted to those attending veterinary practices, which precludes aggregating data from large cohorts of animals, independent of their need for veterinary intervention. The objective of this study was to investigate the exposure of dogs and cats to antimicrobials at a population level. A retrospective cohort study was performed using a novel data source; a pet insurance database. The rate of antimicrobial prescribing, and the rate of prescribing of critically important antimicrobials, was measured in a large population of dogs (813,172 dog-years) and cats (129,232 cat-years) from 2013 - 2017. The incidence rate of antimicrobial prescribing was 5.8 prescriptions per 10 dog years (95% CI 5.8-5.9 per 10 dog years) and 3.1 prescriptions per 10 cat years (95% CI 3.1-3.2 per 10 cat years). Critically important antimicrobials accounted for 8% of all the antimicrobials prescribed over the 4-year study. Cats were 4.8-fold more likely than dogs to be prescribed 3rd-generation cephalosporins. The level of antimicrobial exposure in dogs and cats was less than half that for the coincident human community. Data such as this provides a unique opportunity to monitor antimicrobial prescribing in veterinary medicine, which is a critical component of optimal antimicrobial stewardship.

Veterinary Students' Knowledge and Perceptions About Antimicrobial Stewardship and Biosecurity-A National Survey.

A better understanding of veterinary students’ perceptions, attitudes, and knowledge about antimicrobial stewardship and biosecurity could facilitate more effective education of future veterinarians about these important issues. A multicenter cross-sectional study was performed by administering a questionnaire to veterinary students expected to graduate in 2017 or 2018 in all Australian veterinary schools. Four hundred and seventy-six of 1246 students (38%) completed the survey. Many students were unaware of the high importance of some veterinary drugs to human medicine, specifically enrofloxacin and cefovecin (59% and 47% of responses, respectively). Fewer than 10% of students would use appropriate personal protective equipment in scenarios suggestive of Q fever or psittacosis. Students expected to graduate in 2018 were more likely to select culture and susceptibility testing in companion animal cases (OR 1.89, 95% CI 1.33–2.69, p < 0.001), and were more likely to appropriately avoid antimicrobials in large animal cases (OR 1.75, 95% CI 1.26–2.44, p = 0.001) than those expected to graduate in 2017. However, 2018 graduates were less likely to correctly identify the importance rating of veterinary antimicrobials for human health (OR 0.48, 95% CI 0.34–0.67, p < 0.001) than 2017 graduates. Students reported having a good knowledge of antimicrobial resistance, and combating resistance, but only 34% thought pharmacology teaching was adequate and only 20% said that teaching in lectures matched clinical teaching. Efforts need to be made to harmonize preclinical and clinical teaching, and greater emphasis is needed on appropriate biosecurity and antimicrobial stewardship.

Barriers to and enablers of implementing antimicrobial stewardship programs in veterinary practices.

BACKGROUND: Antimicrobial stewardship (AMS) programs are yet to be widely implemented in veterinary practice and medical programs are unlikely to be directly applicable to veterinary settings. OBJECTIVE: To gain an in-depth understanding of the factors that influence effective AMS in veterinary practices in Australia. METHODS: A concurrent explanatory mixed methods design was used. The quantitative phase of the study consisted of an online questionnaire to assess veterinarians' attitudes to antimicrobial resistance (AMR) and antimicrobial use in animals, and the extent to which AMS currently is implemented (knowingly or unknowingly). The qualitative phase used semi-structured interviews to gain an understanding of the barriers to and enablers of AMS in veterinary practices. Data were collected and entered into NVivo v.11, openly coded and analyzed according to mixed methods data analysis principles. RESULTS: Companion animal, equine, and bovine veterinarians participated in the study. Veterinary practices rarely had antimicrobial prescribing policies. The key barriers were a lack of AMS governance structures, client expectations and competition between practices, cost of microbiological testing, and lack of access to education, training and AMS resources. The enablers were concern for the role of veterinary antimicrobial use in development of AMR in humans, a sense of pride in the service provided, and preparedness to change prescribing practices. CONCLUSION AND CLINICAL IMPORTANCE: Our study can guide development and establishment of AMS programs in veterinary practices by defining the major issues that influence the prescribing behavior of veterinarians.

Cross-sectional study of antimicrobials used for surgical prophylaxis by bovine veterinary practitioners in Australia.

Antimicrobials are widely used in veterinary practices, but there has been no investigation of antimicrobial classes used or the appropriateness of their use in bovine practice. This study investigated antimicrobial use for surgical prophylaxis in bovine practice in Australia. A cross-sectional study of veterinarian antimicrobial usage patterns was conducted using an online questionnaire. Information solicited included respondent's details, the frequency with which antimicrobials were used for specific surgical conditions (including the dose, timing and duration of therapy) and details of practice antimicrobial use policies and sources of information about antimicrobials. In total, 212 members of the Australian veterinary profession working in bovine practice completed the survey. Antimicrobials were always or frequently used by more than 75 per cent of respondents in all scenarios. Generally, antimicrobial drug choice was appropriate for the reported surgical conditions. Procaine penicillin and oxytetracycline accounted for 93 per cent of use. However, there was a wide range of doses used, with underdosing and inappropriate timing of administration being common reasons for inappropriate prophylactic treatment. There was very low use of critically important antimicrobials (3.3 per cent of antimicrobials reported). Antimicrobial use guidelines need to be developed and promoted to improve the responsible use of antimicrobials in bovine practice.