Table 4.
The estimated coefficients (β) and 95% confidence interval (CI) for associations between ln-transformed somatic cell count (lnSCC), sampling period, parity, milk yield and year. Based on 1901 samples from 384 Norwegian dairy goats in four herds, all of which were culture-negative at the time of sampling. Goat nested within herd was included as random effect
| Fixed effects | β | CI | p |
|---|---|---|---|
| (Intercept) | 5.74 | 5.51–5.98 | < 0.001 |
| Sampling perioda | |||
| Indoor spring/early lactation | Reference | ||
| Pasture/mid lactation | 0.85 | 0.65–1.05 | < 0.001 |
| Fall/late lactation | 0.97 | 0.76–1.19 | < 0.001 |
| Parity | |||
| First | Reference | ||
| Second | 0.66 | 0.43–0.89 | < 0.001 |
| Third | 1.23 | 0.93–1.53 | < 0.001 |
| ≥Fourth | 1.07 | 0.83–1.30 | < 0.001 |
| Milk yieldb | -0.38 | -0.46 – -0.31 | < 0.001 |
| Year | |||
| 2021 | Reference | ||
| 2022 | -0.43 | -0.52 – -0.34 | < 0.001 |
| Interaction terms | |||
| Period [Pasture] * Parity [Second] | 0.58 | 0.29–0.88 | < 0.001 |
| Period [Fall] * Parity [Second] | -0.03 | -0.34–0.28 | 0.839 |
| Period [Pasture] * Parity [Third] | 0.60 | 0.24–0.95 | 0.001 |
| Period [Fall] * Parity [Third] | 0.39 | 0.02–0.77 | 0.040 |
| Period [Pasture] * Parity [≥ Fourth] | 0.90 | 0.66–1.15 | < 0.001 |
| Period [Fall] * Parity [≥ Fourth] | 0.31 | 0.05–0.57 | 0.021 |
aEarly lactation: < 100 days in milk, mid lactation: 100–180 days in milk, late lactation: >180 days in milk
bKg milk at the day of recording