Bovine Respiratory Diseases (BRD) are one of the most common and important disease problem affecting newborn calves. The aim of this study was to use clinical respiratory score and thoracic ultrasonography as a screening method for diagnosis BRD in newborn calves. This study was carried out on 59 newborn calves in Al-salhia farm for investment in Alsharqia Governorate, Egypt. These calves were divided into two groups. The first group (G1) including 16 healthy control calves and the second group (G2) including 43 newborn calves suffered from respiratory disorders. The most prominent clinical finding in BRD affected calves were fever, nasal and ocular discharge, coughing with abnormal tracheal and lung sounds. According to ultrasonographic examination of lung, the lower respiratory tract disorders classified lesion into lobar pneumonia 12 calves (35.3%), lobular pneumonia 16 calves (47.1%), mixed pneumonia 3 calves (8.82%) in addition to lung abscess 3 calves (8.82%). Clinical respiratory score and thoracic ultrasound score showed a highly significant increase in BRD affected calves, meanwhile CRS showed a nonsignificant change in calves suffered from upper and lower respiratory tract disorders. TUS revealed a non-significant change in calves with lobar and mixed pneumonia and in lung abscess, in addition to a significant increase in calves with lobar pneumonia when compared with lobular pneumonia. BRD affected calves had CRS ≥ five meanwhile calves with TUS ≥ two were considered sick.

Background and Aim: Bovine respiratory disease (BRD) is the main cause of death in calves, and early BRD diagnosis saves lives. This study aimed to diagnose clinical and subclinical BRD in calves by assessing some biochemical alterations and ultrasonography (USG). Materials and Methods: Fifty-four Holstein dairy calves in Al-Sharqiyah Province, Egypt, were used in the study. They were divided into three groups. The first control group consisted of 10 clinically healthy calves. The second group consisted of 34 calves suffering from clinical lower respiratory tract disorders. The third group consisted of 10 subclinical BRD-affected calves. Ultrasonographic examinations of chest and thoracic ultrasound scoring were performed once per 2 weeks for each calf. Blood samples were collected for serum separation to measure albumin (ALB), total protein (TP), ALB, globulin, and haptoglobin (HP). Results: The USG revealed small consolidation areas within an aerated lung lobe, a hypoechoic parenchyma of the entire distal lung lobe, and a hypoechoic-circumscribed structure surrounded by an echogenic wall appeared within the lung tissue in calves that suffered from lobular pneumonia, lobar pneumonia, and lung abscess, respectively. However, subclinical cases showed a small consolidation area in the cranial aspects of the right cranial lung lobe. The ultrasound lung score (ULS) was greater in clinical than in subclinical cases. The BRD-affected calves recorded significant increases in serum TP, globulin, and HP. Meanwhile, serum ALB decreased significantly. Conclusion: Thoracic ultrasound had a reliable tool in the BRD diagnosis, especially in the early prediction of subclinical cases in newborn calves. In addition, the ULS appeared to be a better classifier than the clinical respiratory score (CRS) for BRD diagnosis. On the other side, it was found that regression models were very useful in assessing the prediction of biochemical blood parameters based on the ULS and CRS in diseased cases.