Thoracic Ultrasonography and Bronchoalveolar Lavage Fluid Analysis in Holstein Calves with Subclinical Lung Lesions.
BACKGROUND
Thoracic ultrasonography (US) and bronchoalveolar lavage fluid (BALF) analysis are antemortem methods used to identify the lung lesions associated with bovine respiratory disease (BRD). Accuracy of US and the cell distributions in BALF have not been characterized in calves with subclinical disease.


OBJECTIVE
To evaluate the accuracy of US and BALF and describe BALF characteristics in calves with subclinical lung lesions.


METHODS
Twenty-five Holstein calves, 1-12 weeks old.


METHODS
In this prospective study, calves with low respiratory scores underwent US, BALF and postmortem examination (normal US, n = 5; comet-tails, n = 5; consolidation, n = 15). Bronchoalveolar lavage fluid was collected and analyzed for total and differential cell counts. Lung lesions were assessed by gross and histopathologic examination. Data were analyzed using nonparametric methods and relative risk analysis. The accuracy of US and BALF were estimated relative to postmortem examination.


RESULTS
The sensitivity and specificity of US for detecting lung lesions was 94% (95% CI, 69-100%) and 100% (95% CI, 64-100%), respectively. A cut-point of ≥4% BALF neutrophils was associated with the highest BALF sensitivity and specificity, 81% (95% CI, 56-94%) and 75% (95% CI, 36-95%). The presence of consolidation on US increased the risk of having a BALF neutrophil proportion ≥4% (RR, 3.9; 95% CI, 1.13-13.45; P = .003).


CONCLUSIONS
Ultrasonography accurately detects lung lesions in calves with subclinical disease. Clinicians should use a cut-point of ≥4% BALF neutrophils to diagnose subclinical respiratory disease.
Department of Medical Sciences, UW-Madison School of Veterinary Medicine, Madison, WI.
T L
TL
Ollivett
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
J L
JL
Caswell
Department of Population Medicine and Diagnostic Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY.
D V
DV
Nydam
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
T
T
Duffield
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
K E
KE
Leslie
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
J
J
Hewson
Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
D
D
Kelton
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000662:veterinary*; D008297:Male; D012680:Sensitivity and Specificity; D014463:Ultrasonography
Bovine; Pneumonia; Respiratory; Validation