Respiratory diseases of cattle represented the most important health and economic problems of cattle rearing. It was possible to diagnose ultrasonographically bronchopneumonia, consolidation, pulmonary emphysema, pleural effusion and pleuritis. The study aimed to correlate between the changes in clinical findings and laboratory assays mainly haematological pictures and serum acute phase proteins (APPs) i.e. haptoglobin, and the characteristic ultrasonographic findings in bovine respiratory diseases and their importance in differentiation between upper respiratory diseases and lower respiratory diseases in cattle. A total number of 84 cattle were included in the study and divided into 3 groups: healthy control group (n=15), upper respiratory diseased group [URG] (n=29) and lower respiratory diseased group [LRG] (n=40). The animals were admitted to the Veterinary Teaching Hospital at Assiut University-Egypt with a history of anorexia, respiratory distress, nasal discharge, cough and/or abnormal lung sounds. These animals were undergoing clinical and ultrasonographic examinations as well as laboratory analyses. Regarding to the ultrasonographic findings, the diseased cases were classified into URG and LRG. Ultrasonography differentiated many of the affections such as bronchopneumonia (n=16), Lung consolidation (n=12), pulmonary emphysema (n=8), and pleuritis and pleural effusion (n=4). Neutrophilic leukocytosis was reported in URG and LRG. The biochemical assays revealed significant elevation in serum levels of haptoglobin, fibrinogen, total cholesterol, triglyceride, high density lipoprotein cholesterol and very low-density lipoprotein in URG and LRG. Serum albumins were remarkably (P<0.05) decreased in URG. The study concluded that thoracic ultrasonography considered a diagnostic tool in cows with respiratory diseases because it determined the location and extent of the lung lesions as well as the severity of the affection. APPs and lipid profile used as biomarkers for the diagnosis of bovine respiratory diseases.