Estimating antimicrobial usage based on sales to beef and dairy farms from UK veterinary practices

Abstract

Background: Accurate estimation of antimicrobial use (AMU) is important in assessing reduction of agricultural AMU. This cross‐sectional study aimed to evaluate several approaches for estimating AMU at the herd level and to report on AMU for beef and dairy farms in Scotland. Methods: Pharmaceutical sales data for 75 cattle herds (2011‐2015) were screened for antimicrobial products and aggregated by herd and year. Several denominators for usage estimates were calculated and compared for their suitability at the herd level. Results: The median total mass of active ingredient sold per kg of bovine livestock was 9.5 mg/kg for beef herds and 14.3 mg/kg for dairy herds. The ‘highest priority critically important’ antimicrobials (HPCIA) were by total mass of active ingredient, 10.6% of all sales; by total defined daily dose veterinary (DDDVet), 29.8% and by DCDvet, 20.0%. These are the first estimates of AMU for beef cattle in the UK, and for cattle of any kind in Scotland. Estimates of herd‐level usage based on population correction unit (PCU) were sensitive to low values for PCU for specific herd‐years due to their demographic composition. Conclusion: Pharmaceutical sales data can provide useful estimates of AMU, but estimating usage per PCU is not appropriate for comparing groups of cattle with different demographic compositions or for setting herd‐level targets. Total mass of active ingredient per kilogram of livestock is more stable and hence suitable than PCU‐based methods for assessing AMU at the herd level.

Antimicrobial use and resistance in Scottish dairy herds: A survey of farmers’ knowledge, behaviours and attitudes

“…Farmers indicated mastitis as the main reason for AMU and penicillin as the most used antibiotic, as reported by previous studies in the UK and Scotland [12,35]. However, in the scenarios section, we found similar results to Jones and co-workers: antibiotics were most frequently chosen as a treatment option in calf pneumonia, followed by clinical mastitis [11].…”

Antimicrobial usage and resistance in scottish dairy herds: a survey of farmers’ knowledge, behaviours and attitudes

“…Farmers indicated mastitis as the main reason for AMU and penicillin as the most used antimicrobials, also reported by previous studies in the UK and Scotland [14,33]. Instead, in the scenarios section, we found that antimicrobials were most frequently chosen as a treatment option in calf pneumonia, followed by clinical mastitis.…”

Mastitis Control and Intramammary Antimicrobial Stewardship in Ireland: Challenges and Opportunities

“…In other words, an estimated 95% of Irish cows received DCT at drying off in 2019. In-lactation antimicrobial usage compares favorably with competitor countries, including the UK where reported usage is 0.59 DCDvet per cow per year ( 70 ). In contrast, reported national dry-cow antimicrobial usage in the UK, including 0.55 ( 70 ) and 0.68 DCDvet per cow per year ( 71 ), is considerably lower than in Ireland.…”

“…In-lactation antimicrobial usage compares favorably with competitor countries, including the UK where reported usage is 0.59 DCDvet per cow per year ( 70 ). In contrast, reported national dry-cow antimicrobial usage in the UK, including 0.55 ( 70 ) and 0.68 DCDvet per cow per year ( 71 ), is considerably lower than in Ireland. In Ireland, almost all in-lactation therapies and approximately 40% of dry-cow therapies contain critically important antimicrobials (CIAs) ( 19 ) and there has been an increase in usage of highest priority CIAs [HP-CIAs, essentially equivalent to EMA category B (“Restrict”) antimicrobials] in dry-cow therapies in recent years ( 66 ).…”