Factors associated with lung cytology as obtained by non-endoscopic broncho-alveolar lavage in group-housed calves.
Authors: van Leenen Katharina, Van Driessche Laura, De Cremer Lieze, Gille Linde, Masmeijer Christien, Boyen Filip, Deprez Piet, Pardon Bart
Journal: BMC veterinary research
Summary
# Editorial Summary Respiratory tract infections represent the largest driver of antimicrobial prescribing in young calves, yet our ability to diagnose lower airway inflammation before clinical disease becomes advanced remains limited in practical settings. This cross-sectional investigation of 352 calves aged 1–6 months across 62 commercial herds examined whether non-endoscopic broncho-alveolar lavage (nBAL) cytology findings correlated with clinical respiratory signs, thoracic ultrasound consolidation patterns, and BALf bacteriology—key diagnostic markers currently used to guide treatment decisions. The researchers performed clinical examinations, lung ultrasound imaging, and cytological and bacteriological analysis on nBAL samples collected using a technique that could realistically be deployed in field conditions rather than requiring endoscopic equipment. Results demonstrated that lung cytology obtained via nBAL provided measurable data on airway inflammation that did not always align with clinical observations or ultrasonographic findings, suggesting that subclinical lower airway inflammation may be more prevalent than visible disease suggests and that cytology adds diagnostic value beyond conventional assessment. For practitioners, this indicates that nBAL sampling—being non-invasive and compatible with on-farm use—may help identify calves with evolving lower airway pathology before overt pneumonia develops, potentially enabling earlier targeted intervention and more judicious antimicrobial stewardship in young stock.
Read the full abstract on PubMed
Practical Takeaways
- •Lung cytology via non-endoscopic BAL offers a practical tool to assess deep airway inflammation in calves without requiring endoscopy, potentially improving respiratory disease diagnosis on farm
- •Correlating cytology findings with clinical signs and ultrasound consolidation may help target antimicrobial treatment more precisely and reduce unnecessary antibiotic use in respiratory disease
- •Consider implementing lung sampling protocols in group-housed calves with respiratory signs to better understand subclinical inflammation patterns before disease progresses
Key Findings
- •Lung cytology obtained via non-endoscopic broncho-alveolar lavage was performed in 352 group-housed calves aged 1-6 months across 62 commercial herds
- •Study examined associations between lung cytology findings, clinical signs, lung consolidation on ultrasound, and broncho-alveolar lavage fluid characteristics including bacteriology
- •Non-endoscopic broncho-alveolar lavage is a feasible technique for sampling deep airways in calves to assess respiratory inflammation