Table 4.
Adjusted odds ratios (OR) and 95% confidence intervals from five risk factor groups
| Model & variables | Level | Odds ratio | 95% CI | p-value |
|---|---|---|---|---|
|
Herd management |
|
|
|
|
| Exclusive piglet producer without any fattening pigs |
Yes |
0.90 |
0.39-2.10 |
0.81 |
| No |
1.00 |
|
|
|
| Between 250 and 500 sows per herd |
Yes |
1.88 |
0.81-4.33 |
0.14 |
| No |
1.00 |
|
|
|
| More than 500 sows per herd |
Yes |
1.61 |
0.40-6.59 |
0.50 |
| No |
1.00 |
|
|
|
|
No batch farrowing or farrowing rhythm not in accordance with the sows’ natural oestrus cycle |
Yes |
2.67 |
1.24-5.73 |
0.01 |
| No |
1.00 |
|
|
|
|
Farrowing |
|
|
|
|
| Maximum number of farrowing pens per compartment: 8-16 |
Yes |
1.81 |
0.74-4.42 |
0.19 |
| No |
1.00 |
|
|
|
|
Maximum number of farrowing pens per compartment: > 16 |
Yes |
3.31 |
1.69-9.37 |
0.02 |
| No |
1.00 |
|
|
|
| Air inlet in the farrowing unit not solely comprised by door inlet |
Yes |
1.57 |
0.68-3.63 |
0.59 |
| No |
1.00 |
|
|
|
| Air outlet in the farrowing unit not solely comprised by door outlet |
Yes |
1.79 |
0.65-4.94 |
0.26 |
| No |
1.00 |
|
|
|
| Age of piglets when ear tagging takes place: > 3 and < 7 days |
Yes |
2.50 |
0.56-11.27 |
0.23 |
| No |
1.00 |
|
|
|
| Age of piglets when ear tagging takes place: > 7 days |
Yes |
3.74 |
0.68-16.23 |
0.08 |
| No |
1.00 |
|
|
|
|
Vaccination of suckling pigs |
|
|
|
|
|
one-shot-vaccine against M. hyopneumoniae |
Yes |
5.50 |
1.62-18.65 |
0.01 |
| No |
1.00 |
|
|
|
|
two-shot-vaccine against M. hyopneumoniae |
Yes |
4.69 |
1.31-16.80 |
0.02 |
| No |
1.00 |
|
|
|
|
Vaccine against PRRSV |
Yes |
4.39 |
1.66-11.61 |
<0.01 |
| No |
1.00 |
|
|
|
|
Replacement policy |
|
|
|
|
| 4 - 7 purchases of gilts per year |
Yes |
1.40 |
0.49-3.99 |
0.53 |
| No |
1.00 |
|
|
|
| > 8 purchases of gilts per year |
Yes |
4.28 |
0.75-24.45 |
0.10 |
| No |
1.00 |
|
|
|
| Total number of gilts purchased per year: 80 -119 |
Yes |
1.09 |
0.38-3.14 |
0.88 |
| No |
1.00 |
|
|
|
|
Total number of gilts purchased per year: > 120 |
Yes |
5.80 |
1.68-20.03 |
0.01 |
| No |
1.00 |
|
|
|
| Age of gilts, when delivered < 180 days |
Yes |
1.00 |
0.99 |
1.01 |
| No |
1.00 |
|
|
|
|
Vaccination of replacements |
|
|
|
|
|
Vaccination of gilts against PCV2 |
Yes |
3.55 |
1.31-9.63 |
0.01 |
| No |
1.00 |
|
|
|
| Vaccination of replacement boars against M. hyopneumoniae |
Yes |
1.71 |
0.48-6.13 |
0.41 |
| No |
1.00 |
|
|
|
| Vaccination of replacement boars against PCV2 |
Yes |
2.38 |
0.62-9.06 |
0.20 |
| No | 1.00 |
Results were obtained from independent multivariable logistic regression models.