Table 3.
Final hierarchical multivariable linear-regression analysis of variables significantly ( P <0.05) associated with somatic cell count (SCC; transformed using the BoxCox power transformation) at monthly milk recordings during a follow-up period of 120 days after a veterinary treated clinical mastitis
| Variable 1 | β | S.E. ( β ) | P -value | LSM 2 | 95% CI (LSM) |
|---|---|---|---|---|---|
| Intercept | 3.996 | 0.17 | - | - | - |
| Bacterial finding | |||||
| S. dysgalactiae | Ref.3 | - | - | 86.6 | 70.1, 107.5 |
| S. uberis | 0.260 | 0.093 | 0.005 | 138.6 | 106.3, 182.6 |
| Other factors | |||||
| Parity | |||||
| First | Ref. | - | - | 75.9 | 59.8, 97.1 |
| Second | 0.219 | 0.113 | 0.051 | 112.0 | 82.8, 153.4 |
| Third | 0.169 | 0.137 | 0.218 | 102.3 | 68.7, 155.6 |
| Fourth or higher | 0.433 | 0.136 | 0.001 | 260.5 | 109.1, 260.5 |
| Milk yield | −0.002 | 0.0005 | 0.000 | - | - |
| At Q1: 23.8 kg | - | - | - | 132.8 | 108.1,164.2 |
| At Q2: 28.7 kg | - | - | - | 109.8 | 92.0, 131.4 |
| At Q3: 33.4 kg | - | - | - | 91.8 | 76.3, 111.0 |
| Days in milk | −0.001 | 0.0004 | 0.001 | - | - |
| At Q1: 67 days | - | - | - | 129.4 | 105.0, 160.5 |
| At Q2: 115 days | - | - | - | 115.6 | 96.4, 139.3 |
| At Q3: 188 days | - | - | - | 97.8 | 81.5, 117.7 |
1Q1, Q2, and Q3 = first quartile, second quartile/median, and third quartile, respectively.
2Least square means (LSM) of Box-Cox transformed SCC back-transformed to original scale (×1 000/ml) presented by variable.
3Ref. = Reference category.