Table 5. The result of univariable logistic regression analysis of contributing risk factors for the occurrence and contamination of the milk with S. aureus in the study area.
| Variable | Category | Tested | Positive (%) | Odds Ratio | 95% CI | P value |
|---|---|---|---|---|---|---|
| Town | Gedo | 54 | 8 (14.8) | 1 | - | - |
| Ginchi | 67 | 11 (16.4) | 1.13 | 0.42–3.02 | 0.810 | |
| Ejere | 91 | 16 (17.6) | 1.23 | 0.49–3.09 | 0.665 | |
| Age | Adult | 93 | 10 (10.75) | 1 | - | - |
| Young | 69 | 9 (13.04) | 1.25 | 0.48–3.25 | 0.655 | |
| Old | 50 | 16 (32.00) | 3.91 | 1.61–9.47 | 0.003 | |
| Parity | Few | 104 | 10 (9.6) | 1 | - | - |
| Moderate | 86 | 16 (18.6) | 2.15 | 0.92–5.02 | 0.077 | |
| Many | 22 | 9 (40.9) | 6.51 | 2.23–19.00 | 0.001 | |
| Lactation stage | Mid | 136 | 15 (11.02) | 1 | - | - |
| Early | 37 | 9 (24.3) | 2.59 | 1.03–6.53 | 0.043 | |
| Late | 39 | 11 (28.2) | 3.17 | 1.31–7.64 | 0.010 | |
| Hand washing before milking | Yes | 105 | 27 (7.62) | 1 | - | - |
| No | 107 | 8 (25.23) | 4.09 | 1.76–9.50 | 0.001 | |
| Hand washing b/n each milking | Yes | 79 | 5 (6.33) | 1 | - | - |
| No | 133 | 30 (22.56) | 4.31 | 1.60–11.63 | 0.004 | |
| Udder of the cow cleaning | Only before milking | 37 | 4 (10.81) | 1 | - | - |
| Before and after milking | 56 | 9 (16.07) | 1.60 | 0.45–5.56 | 0.477 | |
| No cleaning | 119 | 22 (18.49) | 3.87 | 0.60–5.83 | 0.280 | |
| Management | Intensive | 113 | 14 (12.39) | 1 | - | - |
| Semi-intensive | 99 | 21 (21.21) | 1.90 | 0.91–3.98 | 0.087 | |
| Dairy house cleaning interval | Per day | 99 | 7 (7.07) | 1 | - | - |
| >twice /week | 39 | 5 (12.82) | 1.93 | 0.57–6.50 | 0.287 | |
| twice/week | 74 | 23 (31.08) | 5.93 | 2.38–14.76 | 0.001 | |
| Presence of a drainage system | Yes | 137 | 16 (11.68) | 1 | - | - |
| No | 75 | 19 (25.33) | 2.57 | 0.19–0.81 | 0.012 |