Factor | Category | IRR (95% CI) | P-value |
---|---|---|---|
Milk yield | High (> 6,122 kg) | 1.25 (1.03-1.52) | 0.01 |
Low (≤ 6,122 kg) | 1.0 | - | |
Somatic cell count controls | At longer intervals | 1.44 (1.13-1.84) | 0.003 |
≤2 times/month | 1.0 | - | |
Bacteriological test carried out for clinical mastitis | Never | 0.61 (0.42-0.88) | 0.01 |
Always/occasionally | 1.0 | - | |
Dry cow udder controls during the dry period | Yes | 0.67 (0.54-0.83) | <0.001 |
No | 1.0 | - | |
Teat cleaning material | Washable towel | 1.53 (1.04-2.25) | 0.02 |
Other†| 1.0 | - | |
Body condition scoring | No | 0.74 (0.62-0.90) | 0.002 |
Yes | 1.0 | - | |
Important characteristic when selecting a bull for artificial insemination | Total merit values | 1.57 (1.17-2.11) | 0.002 |
Other‡ | 1.0 | - | |
Clean bedding material at calving | Yes | 1.72 (1.24-2.38) | 0.001 |
No | 1.0 | - | |
Hands and arms are cleaned if intervention is required at calving | Yes | 0.75 (0.61-0.93) | 0.009 |
No | 1.0 | - | |
Ropes or chains available at calving if required | Yes | 1.37 (1.08-1.75) | 0.009 |
No | 1.0 | - |