Table 3A.
The descriptive statistics of the farm structure variables of studied Dutch dairy herds (herd size, land use and farm intensity from dataset 1.1) and performance variables (gross margin and calving interval from dataset 1.1 and milk yield and SCC form dataset 2.1) as used to analyze the change in performance for herds that changed from “BVDV not free” to “BVDV free” (first analysisa).
| Variable | First analysis (case herds changed from “BVDV not free” to “BVDV free”) | |||||
|---|---|---|---|---|---|---|
| Case herds | Control herds | |||||
| Annual BVDV status | Years matched to case herds | |||||
| Year−1 (not free) | Year 0 (free) | Year 1 (free) | Year−1 (free) | Year 0 (free) | Year 1 (free) | |
| Herd size, n cows | 118 (43) | 117 (41) | 107 (37) | 120 (40) | 118 (41) | 116 (39) |
| Land use, ha | 55 (18) | 55 (17) | 55 (16) | 56 (19) | 56 (19) | 57 (18) |
| Farm intensity, n cows/ha/year | 2.18 (0.56) | 2.17 (0.47) | 1.90 (0.29) | 2.23 (0.58) | 2.14 (0.51) | 2.10 (0.49) |
| Calving interval, days | 406 (23) | 404 (18) | 413 (29) | 407 (22) | 406 (19) | 404 (17) |
| Gross margin, euro/kg milk | 0.238 (0.052) | 0.264 (0.056) | 0.276 (0.053) | 0.260 (0.055) | 0.289 (0.051) | 0.296 (0.044) |
| Milk yield, kg/cow/year | 8,270 (1,240) | 8,320 (1,240) | 8,230 (1,450) | 8,860 (830) | 8,990 (888) | 9,060 (885) |
| SCC, 1,000 cells/mL | 193 (80) | 170 (58) | 175 (61) | 171 (52) | 161 (47) | 156 (48) |