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

摘要

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.