TABLE 3.
Logistic mixed effects regression modelj of factors associated with prevalence of any “Top 7” STEC
| Factor evaluated | ORa | 95% CI | P value |
|---|---|---|---|
| Humidityb | 1.09 | 1.02–1.16 | 0.006g |
| Regionc | 0.001i | ||
| Waikato | 0.09 | 0.03–0.29 | <0.001g |
| Taranaki | 0.11 | 0.03–0.39 | <0.001g |
| Manawatu-Wellington | 0.23 | 0.06–0.87 | 0.030g |
| Canterbury | 0.19 | 0.05–0.72 | 0.014g |
| Southland | 0.30 | 0.08–1.13 | 0.076 |
| No. of calves in calf pend | 1.04 | 1.01–1.07 | 0.003g |
| Temperaturee | 1.20 | 0.96–1.49 | 0.114h |
| Agef | 0.43 | 0.27–0.68 | <0.001g |
a
OR, odds ratio.
b
Difference between inside pen versus outside the calf housing area (increase in 1% relative humidity).
c
Compared to Northland.
d
Increase of one calf.
e
Difference between inside pen versus outside the calf housing area (increase of 1°C).
f
Young calves (2 to 9 days of age) versus older calves (10 to 21 days of age).
g
Significant variable (P < 0.05).
h
Confounding factor for calf pen humidity, left in model.
i
Likelihood ratio test of factor.
j
Variance of random effects: calf pen within farm (variance, 1.09); farm (variance, 1.34).