Table 3 Odds ratios, coefficients, and p-values of the association between epidemiological factors and herd-level Johne’s disease status, based on ELISA assays performed on individual milk samples in 600 herds in Minnesota

Herd size

< 0.001

< 0.001

 1 to ≤195

Ref

–

–

–

–

–

 196 to ≤553

1.67(1.39–2.02)

< 0.001

1.58

0.43

4.84(2.20–12.27)

< 0.001

 554 to 1929

13.74(2.86–246.87)

0.011

1.54

1.08

4.67(0.83–88.29)

0.153

Testing frequency

< 0.001

< 0.001

 1

Ref

–

–

–

–

–

 > 1 to ≤5

3.04(2.03–4.57)

< 0.001

1.03

0.21

2.81(1.86–4.29)

< 0.001

 6 to ≤20

13.15(6.16–32.64)

< 0.001

2.48

0.43

11.85(5.44–29.82)

< 0.001

 21 to 30

64.30(19.64–396.39)

< 0.001

3.77

0.73

43.34(13.00–269.33)

< 0.001

Soil type (texture)

< 0.001

0.017

 Sand

Ref

–

–

–

–

–

 Silt

2.87(1.69–5.01)

< 0.001

0.63

0.32

1.88(1.01–3.54)

0.047

 Loam

1.79(1.21–2.63)

0.003

0.63

0.22

1.88(1.21–2.93)

0.005

 Clay

3.59(0.56–69.51)

0.25

1.62

1.15

5.04(0.68–102.54)

0.162

Herd turnover rate

0.164

 18 to 37

Ref

 38 to 50

1.02(0.93–1.11)

0.698

 51 to 78

0.79(0.66–0.95)

0.014

Soil pH

0.004

 < 6.0

Ref

–

 6.0 to 7.0

2.15(1.14–4.03)

0.02

 > 7.0

2.21(1.05–4.70)

0.037

Hydrologic soil type

0.87

 A

Ref

 B

1.23(0.64–2.29)

0.527

 C

0.95(0.47–1.85)

0.874

 D

0.95(0.49–1.76)

0.872

0.84

 Non-participants

Ref

–

 Participants

1.09(0.46–2.87)

0.84

Agroecological zone

0.57

 Crop/Grassland

Ref

–

 Non-vegetated land

0.85(0.76–0.96)

0.76

 Shrubland

0.94(0.82–1.07)

0.50

 Deciduous Forest

1.08(0.95–1.22)

0.50

 1 km

 5 km

0.962

 10 km

0.171

 15 km

0.256

 20 km

0.157

 109.7 km

0.352