AI-powered acoustic surveillance for early detection of calf respiratory disease.

Effective management of Bovine Respiratory Disease Complex (BRDC) requires timely, non-invasive diagnostic tools to protect calf health and welfare. Among early clinical signs, coughing stands out as both frequent and informative. To explore its potential for early BRDC detection, we deployed an artificial intelligence (AI)-driven acoustic monitoring system that recorded over 2 730 h of audio during a 30-day period. Four experimental pens, each housing seven calves and stratified by infection status and antibiotic treatment, were equipped with a dedicated microphone to enable targeted acoustic surveillance. This configuration enabled pen-specific detection of cough events, which were subsequently classified using an AI lightweight Hidden-Unit BERT (HuBERT)-based model trained on 1 045 labelled clips. The classifier achieved 92% accuracy. Temporal patterns in cough frequency aligned with infection dynamics, treatment responses, and circadian patterns. Notably, AI-detected coughs consistently preceded clinical scores by 1-2 days, confirming the system's sensitivity to early respiratory disorders. These findings support the use of acoustic surveillance as a valid, scalable, and autonomous tool for continuous monitoring and early warning of respiratory diseases in calves.