Quantitative analysis of antibiotic usage in British sheep flocks

Area of Science:

• Veterinary Medicine
• Antimicrobial Stewardship
• Sheep Production

Background:

• Antibiotic usage in commercial sheep flocks is a key concern for antimicrobial stewardship.
• Understanding variation in prescribing practices is crucial for effective antimicrobial reduction strategies.
• Previous research has highlighted the need to analyze sheep-specific antibiotic consumption patterns.

Purpose of the Study:

• To investigate the variability of antibiotic use across 207 commercial sheep flocks.
• To identify key drivers of antibiotic consumption at flock and veterinary practice levels.
• To compare sheep flock antibiotic usage with established UK livestock sector targets.

Main Methods:

• Analysis of veterinary practice prescribing records from 207 commercial sheep flocks.
• Calculation of antibiotic usage metrics: mass per population corrected unit (mg/PCU) and animal defined daily dose (ADDD).
• Variance partitioning to determine the contribution of farm and veterinary practice to overall antibiotic usage.

Main Results:

• Mean antibiotic usage (11.38 mg/PCU) was significantly below the UK target of 50 mg/PCU.
• Parenteral oxytetracycline for lameness constituted the majority (82%) of prescribed antibiotic mass.
• Farm-level factors accounted for 79% of variation in antibiotic usage, while veterinary practices accounted for 21%.

Conclusions:

• While overall sheep antibiotic use is low, significant variation exists between flocks.
• Targeted interventions focusing on high-usage farms and veterinary prescribing behaviors are needed.
• Reducing antibiotic use in the sheep sector is feasible through a better understanding of usage drivers.