Precision and accuracy of clinical illness scores, compared with pulmonary consolidation scores, in Holstein calves with experimentally induced Mycoplasma bovis pneumonia.
OBJECTIVE
To determine the precision of a clinical illness score (CIS) system for identification of clinical signs in calves with experimentally induced Mycoplasma bovis pneumonia and to evaluate the accuracy of CISs in relation to pulmonary consolidation scores assigned at necropsy.


METHODS
178 Holstein bull calves that were 52 to 91 days of age at the time of pneumonia induction.


METHODS
5 trials involved calves challenged with M bovis and scheduled for euthanasia and necropsy 12 to 24 days afterward. Nine veterinarian observers with various degrees of experience simultaneously assigned CISs to calves within 48 hours before necropsy. The precision of the CIS system among observers was evaluated via the Cohen κ statistic. The accuracy of each observer's CISs relative to 6 cutoffs (≥ 5%, ≥ 10%, ≥ 15%, ≥ 20%, ≥ 25%, and ≥ 30%) of percentage pulmonary consolidation was determined by comparing prenecropsy CISs with the gross pulmonary consolidation scores assigned at necropsy. Estimates for sensitivity and specificity were calculated relative to the 6 pulmonary consolidation cutoffs.


RESULTS
A slight level of agreement was evident among observers (κ range, 0.10 to 0.21 for the individual trials) and overall (κ = 0.16; 95% confidence interval, 0.10 to 0.24). Median sensitivity and specificity changed with pulmonary consolidation score cutoff. Median sensitivity for all observers ranged from 81.7% to 98.9%, and median specificity ranged from 80.8% to 94.9% over all cutoff values.


CONCLUSIONS
Agreement among observers assigning CISs to calves was low; the accuracy of the CIS system in relation to that of pulmonary consolidation scoring varied with the severity of consolidation considered to represent bovine respiratory disease.
Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
David E
DE
Amrine
Brad J
BJ
White
Robert
R
Larson
David E
DE
Anderson
Derek A
DA
Mosier
Natalia
N
Cernicchiaro
D000818:Animals; D001344:Autopsy / Q000662:veterinary; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000382:microbiology; D008297:Male; D045682:Mycoplasma bovis / Q000502:physiology; D015588:Observer Variation; D011019:Pneumonia, Mycoplasma / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index