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).
Researchers used 54 Holstein dairy calves in Al-Sharqiyah Province, Egypt in the study. They were divided into three groups. The first and 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 had 10 subclinical BRD-affected calves.
The research team conducted ultrasonographic examinations of the chest and thoracic ultrasound scoring once every two weeks for each calf. Blood samples were collected for serum separation to measure albumin (ALB), total protein (TP), globulin and haptoglobin (HP).
Results showed that 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.
In conclusion, the researchers found that thoracic ultrasound was 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 flip side, researchers found that regression models were very useful in assessing the prediction of biochemical blood parameters based on the ULS and CRS in diseased cases.
Ahmed E Mahmoud, et al. “Ultrasonographic diagnosis of clinical and subclinical bovine respiratory disease in Holstein calves.” Vet World. 2022 Aug;15(8):1932-1942. doi: 10.14202/vetworld.2022.1932-1942.
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