Table 1.
Summary dairy characteristics.
| Dairy characteristic | Mean | SE | N | 95% Confidence limits | |
|---|---|---|---|---|---|
| Lower | Upper | ||||
| Herd size | |||||
| Preweaned calves | 246 | 43.02 | 67 | 160 | 331.78 |
| Milking cows | 1,507 | 105.12 | 144 | 1,299 | 1,715 |
| Rolling herd average milk production (kg) | 11,118 | 187.07 | 139 | 10,748.86 | 11,488.67 |
| Bulk tank somatic cell count (cells/mL) | 245,863 | 6,703 | 139 | 232,608 | 259,118 |
| Predominant breed (%) | |||||
| Holstein | 79.21 | 3.03 | 142 | 73.22 | 85.19 |
| Jersey | 11.82 | 2.27 | 142 | 7.34 | 16.3 |
| Crossbred | 7.58 | 1.87 | 142 | 3.88 | 11.28 |
| Other | 0.99 | 0.35 | 142 | 0.05 | 1.43 |
The values indicate mean properties of the herds based on the participant responses to the 2017 mail and online survey of California Grade A dairy milk producers on antimicrobial drug use in preweaned dairy calves.