TABLE 3:
Baseline characteristics of the control (n=11) and intervention (n=13) flocks as recorded at visit 1
| Control (n=11 flocks) |
Intervention (n=13 flocks) |
||||||
|---|---|---|---|---|---|---|---|
| Variable | Flock-adjusted prevalence (%) | 95% CI* | Flock-adjusted prevalence (%) | 95% CI* | P value† | ||
| Foot lesions | |||||||
| CODD active | 2.86 | 1.99 to 4.09 | 2.11 | 1.42 to 3.13 | 0.3 | ||
| CODD healed | 5.78 | 4.31 to 7.72 | 4.61 | 2.91 to 7.24 | 0.4 | ||
| Footrot | 12.14 | 8.60 to 16.87 | 30.24 | 19.17 to 44.20 | 0.002 | ||
| Scald | 12.34 | 6.55 to 22.05 | 10.46 | 4.83 to 21.19 | 0.7 | ||
| Granuloma | 0.52 | 0.37 to 0.74 | 0.19 | 4.9e−4 to 0.76 | 0.1 | ||
| White-line disease | 22.95 | 15.45 to 32.67 | 32.50 | 21.55 to 45.77 | 0.2 | ||
| Foot abscess | 0.20 | 0.10 to 0.41 | 0.19 | 0.10 to 0.36 | 0.9 | ||
| Interdigital hyperplasia | 0.81 | 0.31 to 2.09 | 0.38 | 0.17 to 0.85 | 0.2 | ||
| Overgrown | 2.20 | 1.18 to 4.04 | 1.11 | 0.53 to 2.30 | 0.1 | ||
| Lame | 9.19 | 4.91 to 16.57 | 13.32 | 8.20 to 20.91 | 0.3 | ||
| Flock variables | n flocks | % flocks | 95% CI | n flocks | % flocks | 95% CI | P value‡ |
| Farm size (ha) | |||||||
| Small (28.3–52.6) | 5 | 45.45 | 16.83 to 77.42 | 5 | 38.46 | 14.64 to 69.48 | 0.7 |
| Medium (60.7–78.9) | 2 | 18.18 | 3.45 to 58.00 | 4 | 30.77 | 10.21 to 63.45 | 0.5 |
| Large (80.9–131.5) | 4 | 36.36 | 11.67 to 71.20 | 4 | 30.77 | 10.21 to 63.45 | 0.8 |
| Land type | |||||||
| Hill | 0 | 0 | – | 2 | 15.38 | 0.00 to 35.00 | 0.2 |
| Upland | 4 | 36.36 | 7.93 to 64.79 | 5 | 38.46 | 12.01 to 64.91 | 0.9 |
| Lowland | 7 | 63.64 | 35.21 to 92.07 | 6 | 46.15 | 19.05 to 73.25 | 0.4 |
| Cattle | 10 | 90.91 | 73.92 to 100 | 10 | 76.92 | 54.02 to 99.82 | 0.4 |
| Breed | |||||||
| Upland | 8 | 72.73 | 46.41 to 99.05 | 10 | 76.92 | 54.02 to 99.82 | 0.8 |
| Lowland | 11 | 100 | – | 12 | 92.31 | 77.83 to 100 | 0.4 |
| Flock-adjusted proportion (%) | 95% CI* | Flock-adjusted proportion (%) | 95% CI* | P value† | |||
| Age | |||||||
| Lamb | 7.39 | 2.87 to 17.76 | 17.97 | 8.45 to 34.21 | 0.2 | ||
| 1 year | 14.46 | 9.54 to 21.33 | 15.32 | 11.45 to 20.20 | 0.2 | ||
| Adult | 78.14 | 67.76 to 85.88 | 66.72 | 50.71 to 79.61 | 0.2 | ||
For the foot lesions and for age, the flock-level prevalence/proportion (%) has been adjusted to account for the clustering at flock level for each group—control and intervention. For the other flock variables, the percentage of the control flocks and intervention flocks for each variable is calculated directly
*These 95% CIs are calculated using robust standard errors
†P value from a test of independence comparing the farm-adjusted mean farm prevalence for the control farms with that for the intervention farms for each variable using the Pearson χ2 statistic with the Rao and Scott (1981, 1984) second-order correction
‡P value from a two-sample test of proportions of flocks comparing the proportion of control flocks with the proportion of intervention flocks for each variable
CODD, contagious ovine digital dermatitis