Bovine Respiratory Disease (BRD) remains a persistent challenge in feedlot systems because early detection and objective assessment of recovery remain difficult. Visual appraisal and clinical scoring are valuable tools, yet they can be inconsistent across observers and environments.
A recent collaborative study between researchers at the USDA-ARS US Meat Animal Research Center and the College of Veterinary Medicine at Kansas State University explores whether inflammatory biomarkers track BRD in ways that could meaningfully support veterinary decision making.
To accomplish this, researchers followed the inflammatory response of BRD cattle over time. Blood samples were collected from feedlot cattle on the day of purchase, the time of diagnosis, and five days after treatment. Several clear patterns emerged that are relevant to clinical practice.
What the Data Showed: Key Inflammatory Patterns in BRD
Haptoglobin tracked both disease onset and recovery
Haptoglobin, a glycoprotein that plays a critical role in tissue protection and prevention of oxidative damage, showed the most consistent and biologically meaningful response to BRD. Concentrations rose significantly from arrival to the time of clinical diagnosis, then declined within five days following treatment.
- Haptoglobin levels increased markedly at BRD diagnosis compared with baseline
- Levels declined after treatment, indicating resolution of inflammation
- The rise and fall pattern closely mirrored disease presence and early recovery
This response supports haptoglobin’s role as a true acute-phase protein in BRD, rather than a nonspecific indicator of arrival stress alone. Importantly, the post-treatment decline suggests haptoglobin reflects treatment response, not just disease detection.
IL-6 Mirrored Acute-Phase Activation
Interleukin-6 (IL-6) followed a similar temporal pattern, increasing at diagnosis and decreasing after treatment.
- IL-6 concentrations rose significantly with active BRD
- Levels declined post-treatment as inflammation resolved
- The response aligned with IL-6’s known role in driving acute-phase protein production
While IL-6 is not likely to be a practical field biomarker due to its short, variable half-life and higher sensitivity to non-disease stressors, its behavior reinforces the biological relevance of haptoglobin as a downstream indicator of inflammatory activity.
Other Cytokines Showed Limited or Inconsistent Shifts
Not all inflammatory markers changed meaningfully across disease stages.
- TNF-∝ differed between baseline and disease time points but showed less consistent normalization after treatment
- IL-1β and IFN-γ did not change significantly through BRD
- These cytokines could reflect background immune signaling rather than actionable disease markers
Correlations were observed among some of these cytokines, particularly IL-1β and TNF-∝, reflecting interconnected inflammatory pathways. However, these were not necessarily helpful for monitoring the course of BRD.
Haptoglobin remained the clearest marker tied to both disease and recovery.
What This Means for BRD Diagnosis
The pattern of haptoglobin observed in BRD cattle in this study indicates systemic inflammation is measurably active through the disease course and that haptoglobin tracks early resolution of that response during therapy.
While field-ready diagnostic tools continue to advance, understanding which biomarkers reflect BRD becomes increasingly important. This work helps narrow that field and provides biological justification for further exploration of acute-phase proteins, particularly haptoglobin, as decision support tools.
In BRD management, these inflammatory signals could help veterinarians assess disease and recovery before performance data catches up.
