Blood gases, acid‐base, and metabolic alterations in calves with bronchopneumonia diagnosed via clinical signs and thoracic ultrasonography: A cross‐sectional study.

Background: Bronchopneumonia (BP) in calves potentially causes systemic changes. Objectives: To describe metabolic, arterial blood gas, and acid‐base disorders in calves with BP diagnosed by thoracic ultrasound (TUS), Wisconsin score (WISC), and combinations of WISC and TUS. Animals: Two hundred thirty‐one dairy preweaned dairy calves from 13 dairy farms. Methods: Cross‐sectional study. Each calf sequentially underwent arterial blood gas evaluation, WISC score, venous sampling, and TUS. Calves were grouped based on a single diagnostic method and combination of WISC and 2 TUS cutoffs (≥1 cm; ≥3 cm) as healthy, upper respiratory tract infection, subclinical BP, and clinical BP. Results: Oxygenation and acid‐base variables were unaffected. Glucose concentration in TUS‐affected calves was significantly lower (P <.001) than in healthy calves (median ≥TUS1cm = 5.2 mmol/L 25%‐75% interquartile range [IQR] 4.5‐6.1, <TUS1cm = 5.9 mmol/L IQR 5.5‐6.6; ≥TUS3cm = 5.1 mmol/L IQR 4.4‐6.2, <TUS3cm = 5.8 mmol/L IQR 5.3‐6.4). Paraoxonase‐1 was significantly lower (P <.001) in TUS‐affected calves (≥TUS1cm = 64.1 U/mL IQR 40.8‐78, <TUS1cm = 77.3 U/mL IQR 61.9‐96.5; ≥TUS3cm = 59.2 U/mL IQR 37.7‐72.4, <TUS3cm = 72.9 U/mL IQR 53.4‐95.5). None of the variables highlighted clear distinctions in WISC‐detected clinical and subclinical BP calves based on the combination of WISC and TUS. Conclusions and Clinical Importance: Clinical signs indicate minor systemic disorders compared to TUS. The abnormalities detected by ultrasonographic examination were moderate and did not deviate from normal reference ranges. [ABSTRACT FROM AUTHOR]