Table 4.
Risk factors associated with the herd-level presence of Mycoplasma bovis in univariable logistic regression models
| Variable | Category | Frequency | Frequency and prevalence (%) of case herds | OR | 90% confidence interval | P - value | |
|---|---|---|---|---|---|---|---|
| lower | upper | ||||||
| Brand of milking equipment* | Special brand Other brands | 14 21 | 12 (85.7) 6 (28.6) | 15.0 | 3.4 | 66.3 | 0.003 |
| Milk Production of herd (increase of 100 kg) | Continuous | Mean = 79.7, SD = 11.1 | 1.067 | 1.006 | 1.13 | 0.07 | |
| Presence of stress factors cows** | Yes No | 16 20 | 12 (75.0) 7 (35.0) | 5.6 | 1.6 | 18.9 | 0.02 |
| Presence of stress-factors calves*** | Yes No | 9 27 | 7 (77.8) 12 (44.4) | 4.4 | 1.01 | 18.9 | 0.1 |
| Animal movement (trade and exposition) | Yes No | 12 24 | 10 (83.3) 9 (37.5) | 8.3 | 2.0 | 35.5 | 0.02 |
| Fore-stripping | Yes No | 25 11 | 16 (64.0) 3 (27.3) | 4.7 | 1.3 | 17.5 | 0.05 |
| Additional stimulation until milk ejection | Yes No | 30 6 | 18 (60.0) 1 (16.7) | 7.5 | 1.1 | 50.3 | 0.08 |
Significance was set at P < 0.1.
*Information on brand of milking system is missing for one farm.
**Stress-factors cows include: overcrowding, moldy feed, high in-barn temperature, frequent transportation, concomitant disease.
***Stress-factors calves include: overcrowding, concomitant disease, high degree of calf traffic.