Table 4.
Multivariate Cox proportional hazards model for pregnancy rate using detection of lameness before and after ESD as time dependent variables. Farm is included as a cluster effect in the analysis. There were no significant interactions in the model
| Variable | N | Coefficient (SE) | P-value | Hazard ratio (95 % CI) |
|---|---|---|---|---|
| Lameness detection group | ||||
| NN | 612 | 1.00 | ||
| YN | 47 | −0.13 (0.17) | >0.05 | 0.88 (0.62 – 1.29) |
| NY | 69 | −0.42 (0.15) | <0.01 | 0.65 (0.52 – 0.81) |
| YY | 43 | −0.46 (0.19) | <0.05 | 0.62 (0.42 – 0.93) |
| BCS at Calving | ||||
| ≤2.75 | 162 | 1.00 | ||
| 3.0 | 314 | 0.25 (0.13) | <0.05 | 1.28 (1.01 – 1.64) |
| 3.25 | 243 | 0.44 (0.15) | <0.01 | 1.55 (1.15 – 2.07) |
| ≥3.5 | 52 | 0.41 (0.23) | >0.05 | 1.51 (0.96 – 2.36) |
| Max BCS loss after Calving | ||||
| 0 | 143 | 1.00 | ||
| 0.25 | 315 | −0.41 (0.12) | <0.01 | 0.66 (0.52 – 0.85) |
| 0.5 | 252 | −0.53 (0.14) | <0.01 | 0.59 (0.44 – 0.78) |
| >0.5 | 61 | −1.0 (0.23) | <0.01 | 0.37 (0.23 – 0.57) |
| Month of Calving | ||||
| Jan/Feb | 457 | 1.00 | ||
| March | 206 | −0.33 (0.10) | <0.01 | 0.72 (0.60 – 0.86) |
| Apr/May | 108 | −0.69 (0.15) | <0.01 | 0.50 (0.37 – 0.68) |
| EBI overall (€) | 771 | 0.01 (0.001) | <0.01 | 1.00 (1.00 – 1.01) |