Evaluation of cardiac troponin I as a predictor of clinical outcomes in cattle treated for bovine respiratory disease (BRD) in commercial feedyards

Bovine respiratory disease (BRD) is a major cause of morbid­ity and mortality in feedlot cattle and prognostic tools would be valuable for managing individual cases. Cardiac tro­ponin I (cTnI) is a protein released into the circulatory sys­tem after myocardial damage that may serve as a prognostic biomarker. The study objective was to determine potential associations between cTnI serum concentration of cattle at initial BRD treatment with the risk of retreatment or mortal­ity within 60 days. In this observational study, serum was collected from cattle in 2 central high plains feedyards at initial BRD treatment. Indi­vidual animal treatment outcomes were determined (treatment success, retreated, died, or culled due to BRD) at 60 days post-enrollment. Troponin concentrations were determined using a commercially available Bovine Cardiac Troponin ELISA assay and categorized as LOW (< 0.156 ng/mL) or HIGH (≥ 0.156 ng/mL). Of 318 serum samples, troponin concentrations were LOW for 310 and HIGH for 8 samples. Cattle with HIGH cTnI concentrations had a significantly (P < 0.05) greater probabil­ity of not finishing the 60-day post enrollment period (0.56 +/- 0.22 SE) compared to cattle with LOW cTnI (0.11 +/- 0.03 SE). Cattle with high cardiac troponin concentrations at initial BRD treatment were more likely to have negative clinical out­comes. However, a low number of cases were identified as having high cTnI. High troponin concentrations may be valuable to improve management decisions; however, further research is neces­sary to optimize cut-off values predictive of clinical outcome and evaluate prognostic value in subpopulations of feedlot cattle.