Table 7.
Results from linear models investigating the association of O. ostertagi, F. hepatica and D. viviparus BTM ELISA results and average milk protein content (%) in three regions of Germany. Full models were significantly different from null models containing only an intercept term (North: Df = 12, F = 2.3, p = 0.009; East: Df = 14, F = 2.7, p = 0.001; South: Df = 15, F = 6.0, p < 0.001). Significant p-values are printed in bold. Seropositivity categories are defined as follows: O. ostertagi: +: ODR ≥ 0.5, ++: ODR ≥ 0.8; F. hepatica: +: 30% < S/P ≤ 80%, ++: 80% < S/P < 150%, +++: S/P ≥ 150%; D. viviparus: +: ODR ≥ 0.41.
| North (N = 192) | East (N = 195) a | South (N = 208) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Variable | Est. | SE | t | p | Est. | SE | t | p | Est. | SE | t | p |
| Intercept | 3.58 | 0.15 | 24.03 | <0.001 | 3.78 | 0.22 | 17.11 | <0.001 | 4.08 | 0.25 | 16.58 | <0.001 |
| O. ostertagi + | −0.01 | 0.01 | −0.87 | 0.388 | 0.01 | 0.02 | 0.43 | 0.666 | 4.36 × 10−3 | 0.02 | 0.21 | 0.831 |
| O. ostertagi ++ | 2.81 × 10−3 | 0.02 | 0.12 | 0.902 | 0.01 | 0.03 | 0.22 | 0.823 | 0.01 | 0.04 | 0.18 | 0.861 |
| F. hepatica + | 0.02 | 0.03 | 0.56 | 0.575 | −0.01 | 0.09 | −0.10 | 0.921 | 0.01 | 0.03 | 0.29 | 0.774 |
| F. hepatica ++ | 0.10 | 0.03 | 3.17 | 0.002 | - | - | - | - | −0.05 | 0.03 | −1.71 | 0.089 |
| F. hepatica +++ | 2.79 × 10−3 | 0.03 | 0.10 | 0.921 | 0.01 | 0.07 | 0.19 | 0.854 | −0.05 | 0.04 | −1.30 | 0.196 |
| D. viviparus + | −2.29 × 10−3 | 0.03 | −0.07 | 0.943 | 0.06 | 0.04 | 1.29 | 0.199 | - | - | - | - |
| Breed type (DP vs. HD) | 0.02 | 0.06 | 0.36 | 0.718 | 3.98 | 1.57 | 2.54 | 0.012 | −0.66 | 0.17 | −3.91 | <0.001 |
| Breed type (Mix vs. HD) | −0.11 | 0.06 | −1.78 | 0.077 | −0.26 | 0.13 | −2.00 | 0.047 | −0.66 | 0.20 | −3.25 | 0.001 |
| Lactation no. | −0.12 | 0.10 | −1.24 | 0.217 | −0.21 | 0.16 | −1.28 | 0.202 | −0.11 | 0.11 | −1.02 | 0.308 |
| Lactation no. (squared) | 0.02 | 0.02 | 1.08 | 0.281 | 0.04 | 0.03 | 1.22 | 0.223 | 0.01 | 0.02 | 0.73 | 0.464 |
| SCC (×1000/mL) | 1.30 × 10−4 | 7.96 × 10−5 | 1.63 | 0.105 | 6.55 × 10−5 | 7.78 × 10−5 | 0.84 | 0.401 | 3.91 × 10−4 | 9.78 × 10−5 | 3.99 | <0.001 |
| Farm type (ORG vs. CON) | −0.10 | 0.04 | −2.45 | 0.015 | −0.10 | 0.03 | −3.15 | 0.002 | −0.10 | 0.03 | −2.99 | 0.003 |
| Farm type (TRA vs. CON) | - | - | - | - | - | - | - | - | −0.08 | 0.04 | −1.75 | 0.082 |
| Milk yield (kg) | - | - | - | - | −1.00 × 10−5 | 6.12 × 10−6 | −1.64 | 0.104 | 4.40 × 10−5 | 1.92 × 10−5 | −2.30 | 0.023 |
| Breed type (DP)/Milk yield | - | - | - | - | −4.52 × 10−4 | 1.86 × 10−4 | −2.43 | 0.016 | 7.52 × 10−5 | 2.02 × 10−5 | 3.72 | <0.001 |
| Breed type (Mix)/Milk yield | - | - | - | - | 3.04 × 10−5 | 1.69 × 10−5 | 1.80 | 0.074 | 7.05 × 10−5 | 2.59 × 10−5 | 2.72 | 0.007 |
a One outlier was excluded. Abbreviations: CON, conventional; Est., estimate; DP, dual-purpose; HD, high-performance dairy; ORG, organic; SCC, somatic cell count; SE, standard error; TRA, in transition from conventional to organic.