Table 3.
Bovine respiratory disease predictive values for measured parameters
| Parameter | COVa | PPVb | NPVc | Efficiencyd | Sensitivitye | Specificityf |
|---|---|---|---|---|---|---|
| Clinical scores | 3 | 94.5 | 98.0 | 96 | 98.6 | 92.5 |
| Core temperature (°C) | 39.8 | 100 | 79.3 | 91 | 80.3 | 100 |
| White blood cells (×103 μL−1) | 10.5 | 85.6 | 48.8 | 70 | 25.4 | 94.3 |
| Neutrophil/lymphocyte ratio | 0.51 | 78.9 | 51.3 | 67 | 38.0 | 86.5 |
| Salivary cortisol | 3.44 | 66.4 | 57.1 | 62 | 70 | 52.9 |
| IRT absoluteg | 38.1 | 87.2 | 66.9 | 79 | 67.6 | 86.8 |
| IRT mean ratioh | 1.0 | 81.8 | 63.0 | 73 | 64.0 | 81.1 |
Data used is for the day clinical illness was observed or was true positive for the true positive calves in the population.
a
COV = most efficient cut off value determined by response operant characteristic (ROC) analysis.
b
Positive predictive value.
c
Negative predictive value.
d
Efficiency determined as per the methods of Humblet et al. (2004).
e
Sensitivity.
f
Specificity determined by MedCalc (2006) software.
g,h
The absolute IRT or infrared thermography value is equal to the orbital (eye) maximum value in °C, the mean ratio value is the mean infrared maximum temperature for the individual animal divided by the mean infrared maximum temperature value for the contemporary group of calves.