Table 3.
Proportional hazard model for mortality in 3519 white veal calves, housed in 10 commercial veal herds in Belgium with the studied diseases added as fixed factors
| Variable | Level | Calves (n) | ß | SD | HR | HR (95% CI) | P-value |
|---|---|---|---|---|---|---|---|
| Calf gender |
Male (ref) |
3202 |
0 |
- |
|
|
|
| Female |
317 |
−0.8 |
0.4 |
0.4 |
0.2-0.9 |
0.04 |
|
| Breed |
|
|
|
|
|
|
0.04 |
| |
Black HF (ref.) |
1296 |
0 |
- |
|
|
|
| Red HF |
124 |
0.7 |
0.3 |
2.1 |
1.1-5.5 |
0.03 |
|
| Crossbreds |
884 |
−0.2 |
0.3 |
0.8 |
0.5-1.4 |
0.44 |
|
| BB |
1215 |
−0.3 |
0.3 |
0.7 |
0.4-1.4 |
0.33 |
|
| Number of BRD episodes |
|
|
|
|
|
|
<0.001 |
| None (ref.) |
2997 |
0 |
- |
|
|
|
|
| 1 |
451 |
1.0 |
0.2 |
2.6 |
1.9-3.6 |
<0.001 |
|
| 2 |
59 |
1.4 |
0.3 |
4.1 |
2.2-7.8 |
<0.001 |
|
| ≥ 3 |
12 |
1.9 |
0.5 |
6.5 |
2.5-16.5 |
<0.001 |
|
| Diarrhea |
No (ref.) |
3333 |
0 |
- |
|
|
|
| Yes |
186 |
1.0 |
0.2 |
2.8 |
1.9-4.2 |
<0.001 |
|
| Arthritis |
No (ref.) |
3467 |
0 |
- |
|
|
|
| Yes |
52 |
1.1 |
0.3 |
2.9 |
1.6-5.3 |
<0.001 |
|
| Herd effect a | 0.3 | 0.2 | <0.001 |
SD = standard deviation; HR = hazard ratio; BRD = bovine respiratory disease; HF = Holstein Friesian; BB = Belgian Blue; ref. = referent category; afrailty term.