Risk factor | Herds (n) | OR | p | 95% CI |
---|---|---|---|---|
BRSV prevalence in heifersa | Â | Â | Â | Â |
0 | 46 | 1 | - | - |
1-49% | 40 | 6.2 | 0.010 | 1.6; 25.0 |
≥50% | 14 | 1.3 | 0.769 | 0.2; 8.2 |
Herd sizeb | Â | Â | Â | Â |
20-99 cows | 40 | 1 | - | - |
100-199 cows | 19 | 1.3 | 0.81 | 0.2; 8.2 |
200-399 cows | 23 | 2.8 | 0.160 | 0.7; 11.8 |
> 400 cows | 18 | 4.7 | 0.052 | 1.0; 22.8 |