BRD Detection Rate Study: Ear Temperature vs. Visual Observation

Bovine respiratory disease is responsible for an estimated 70–80% of feedlot morbidity and 40–50% of feedlot mortality. Despite its prevalence, the industry has long lacked a reliable, scalable method for identifying affected animals before clinical signs become apparent. This study was designed to quantify that gap under commercial feeding conditions.

Study Design

The trial was conducted across two pens of 500 crossbred steers each, matched by origin, weight, and vaccination status. Pen A was monitored using continuous ear-temperature sensing with alerts triggered at ≥104°F (40.0°C). Pen B was managed using standard daily visual observation by experienced pen riders. Both pens were managed identically in all other respects.

Primary Outcome Measures

Detection time was defined as the interval between first recorded temperature elevation (≥104°F / 40.0°C) and treatment. In Pen A, this was measured from first alert. In Pen B, it was measured from pen rider pull, with temperature confirmed at treatment.

Key Findings

Animals in the continuously monitored pen (Pen A) were treated a mean of 18.4 hours earlier than animals in the visually observed pen (Pen B) at equivalent temperature thresholds. Pen A showed a 23% reduction in second treatments and a 31% reduction in chronic cases.

Responder Rates

First-treatment success rates differed meaningfully between groups. In Pen A, 84% of animals required only one treatment course. In Pen B, that figure was 67%. The difference is consistent with the clinical literature showing that BRD treated early responds better to standard antibiotic protocols.

Limitations

This study was conducted at a single location over a single feeding period. Environmental conditions, cattle origin, and pen management practices can all influence detection rates, and results should not be assumed to generalize universally. Broader multi-site trials are ongoing.

Conclusion

Continuous temperature monitoring identified BRD cases significantly earlier than visual observation under commercial conditions. The magnitude of the detection gap — nearly 18 hours on average — is large enough to have material effects on treatment outcomes, chronic case rates, and death loss. These results support the value of continuous monitoring as a complement to, not a replacement for, experienced pen management.