Table 2 Multivariable logistic regression analysis of subclinical mastitis and bacteriology with various risk factors
Risk factors | Number of cows examined | CMT | Bacteriology | ||||
|---|---|---|---|---|---|---|---|
Number of positive | Crude odds ratio (95% CI) | Adjusted odd ratio (95% CI) | Number of positive | Crude odds ratio (95% CI) | Adjusted odd ratio (95% CI) | ||
Body condition score | |||||||
Poor | 7 | 3 | 1 | 1 | 3 | 1 | 1 |
Medium | 198 | 77 | 0.86 (0.18–3.97) | 0.74 (0.13–4.03) | 74 | 0.79 (0.17–3.65) | 0.70 (0.13–3.77) |
Good | 57 | 25 | 0.96 (0.19–4.73) | 0.73 (0.12–4.37) | 24 | 0.96 (0.19–4.73) | 0.72 (0.12–4.26) |
Milk yield (litres) | |||||||
≥ 15 | 106 | 39 | 1 | 1 | 36 | 1 | 1 |
< 15 | 156 | 66 | 1.25 (0.75–2.09) | 2.06 (0.95–4.44) | 65 | 1.38 (0.83–2.31) | 2.32 (1.05–5.08)a |
Age (years) | |||||||
[2–6) | 163 | 51 | 1 | 1 | 49 | 1 | 1 |
[6–9) | 81 | 41 | 2.25 (1.30–3.89)a | 1.63 (0.76–3.53) | 39 | 2.16 (1.24–3.74)a | 1.48 (0.67–3.23) |
≥ 9 | 18 | 13 | 5.70 (1.93–16.86)a | 1.86 (0.39–8.73) | 13 | 6.04 (2.04–17.8)a | 1.79 (0.37–8.46) |
Parity | |||||||
1–3 | 204 | 68 | 1 | 1 | 65 | 1 | 1 |
4–6 | 53 | 32 | 3.04 (1.63–5.68)a | 2.34 (0.91–5.97) | 31 | 3.01 (1.61–5.60) | 2.39 (0.93–6.18) |
≥ 7 | 5 | 5 | – | – | 5 | – | – |