Antibiotics confound breath-based respiratory disease detection in calves

Area of Science:

• Veterinary Medicine
• Analytical Chemistry
• Biomarkers

Background:

• Breath analysis using volatile organic compounds (VOCs) shows potential for non-invasive livestock disease detection.
• Antibiotic use in veterinary medicine may interfere with VOC-based diagnostics, particularly for bovine respiratory disease (BRD).

Purpose of the Study:

• To evaluate VOCs as biomarkers for BRD in calves.
• To investigate the confounding effect of antibiotics on BRD breath diagnostics.
• To explore breath analysis for monitoring antimicrobial treatment.

Main Methods:

• Analysis of breath samples from 65 calves to identify BRD-associated VOCs.
• A secondary trial involving antibiotic treatment of healthy calves to assess VOC profile changes.
• Gas chromatography-mass spectrometry (GC-MS) or similar techniques to detect and quantify VOCs.

Main Results:

• Candidate VOCs like formaldehyde and acetone/propanal showed modest BRD detection capability (AUC 0.53-0.77).
• Antibiotic administration significantly altered breath VOC profiles, with rapid increases in specific compounds like dimethyl sulphide.
• Antibiotic-induced VOC changes could mimic or mask disease signals, impacting diagnostic accuracy.

Conclusions:

• Breath VOC profiles are influenced by antibiotic treatment in calves, necessitating consideration of treatment history for accurate BRD diagnosis.
• Breath analysis shows promise for monitoring antimicrobial exposure and optimizing livestock drug dosages.
• Further research is needed to refine VOC-based diagnostics and therapeutic monitoring in livestock.