Myocardial Stress Biomarkers and Inflammatory Indices in Cattle With Bovine Respiratory Disease Complex.

BACKGROUND

Bovine respiratory disease complex (BRDC) is primarily considered a pulmonary disorder; however, hypoxia and systemic inflammation associated with this condition may also impose cardiovascular stress.

OBJECTIVES

This exploratory study investigated myocardial stress biomarkers in cattle with BRDC and evaluated their relationships with haematological inflammatory indices and ratio-derived enzyme patterns reflecting tissue injury dynamics.

METHODS

Twenty-four Simmental crossbred cattle aged 6-10 months were included, comprising 16 BRDC-affected animals and 8 clinically healthy controls. Myocardial stress biomarkers, including heart-type fatty acid-binding protein (H-FABP), creatine kinase-MB (CK-MB), creatine kinase (CK), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH), were measured. Haematological indices and ratio-derived parameters, including the lymphocyte-to-monocyte ratio (LMR), AST/CK and CK-MB/H-FABP, were calculated. Group comparisons, correlation analyses, receiver operating characteristic analysis and multivariable linear regression were performed.

RESULTS

Compared with controls, BRDC cattle showed significantly higher WBC, LYM, LMR, H-FABP, CK-MB, CK, AST, LDH, AST/CK, CK-MB/H-FABP, heart rate, respiratory rate and rectal temperature, whereas MCH and MCHC were lower (p < 0.05). For example, H-FABP concentrations were higher in BRDC cattle (0.65 ± 0.09 vs. 0.34 ± 0.07 ng/mL), and heart rate was markedly increased (146 [106-184] vs. 79 [60-88] beats/min). H-FABP correlated positively with inflammatory and physiological parameters and strongly with heart rate. Multivariable linear regression identified RBC as an independent factor associated with H-FABP concentrations (p < 0.001), whereas LMR was not independently associated with H-FABP after adjustment (p = 0.087; adjusted R2 = 0.837). ROC analysis indicated preliminary discriminatory capacity for several biomarkers, although these findings should be interpreted cautiously given the limited sample size and potential overfitting.

CONCLUSIONS

BRDC may be accompanied by elevations in myocardial stress biomarkers that parallel systemic inflammatory activation and physiological stress. Integrated evaluation of myocardial stress biomarkers and inflammatory indices may offer a potentially useful exploratory framework for characterizing cardiopulmonary stress responses in BRDC; however, further validation in larger cohorts is required.