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Table 5 Results from multivariable linear regression models of the associations between predictors and concentration of α-tocopherol

From: α-Tocopherol and β-carotene concentrations in feed, colostrum, cow and calf serum in Swedish dairy herds with high or low calf mortality

Model/variable Class α-Tocopherol concentration
Estimate Robust std. err. P value 95% CI
Model feed α-tocopherola (mg/kg DM; n = 57)
 Constant   3.59 0.14 < 0.001 3.29–3.90
 Herd size   0.0023 0.00053 < 0.001 0.0012–0.034
 Region Halland/Skåne Baseline
Skaraborg 0.28 0.14 0.065 − 0.19 to 0.58
 Third harvest in feed sample No Baseline
Yes − 0.36 0.12 0.006 − 0.60 to − 0.12
 TMRb No Baseline
Yes − 0.80 0.12 < 0.001 − 1.07 to − 0.54
 Interaction: TMR × region     0.006  
TMR: no × Halland/Skåne Baseline
TMR: yes × Halland/Skåne − 0.80 0.13 < 0.001 − 1.07 to − 0.53
TMR: no × Skaraborg 0.28 0.14 0.065 − 0.19 to 0.58
TMR: yes × Skaraborg 0.08 0.11 0.48 − 0.15 to 0.32
 Type of herdb LM Baseline
HM 0.054 0.11 0.615 − 0.17 to 0.28
 % Grass silage of total diet   0.86 0.28 0.008 0.26–1.45
Model colostrum α-tocopherol (µg/mL)a (n = 162)
 Constant   − 1.68 0.32 < 0.001 − 2.34 to − 1.02
 Breedb SR Baseline
SH/MB 0.45 0.12 0.001 0.21–0.69
 Fatc (%)   0.20 0.023 < 0.001 0.15–0.25
 Herd size   0.0014 0.00046 0.006 0.00047–0.0024
 Type of herdb LM Baseline
HM − 0.11 0.11 0.34 − 0.35 to 0.13
 Total solids (Brix%)   0.042 0.013 0.005 0.015–0.069
Model cow α-tocopherol (µg/mL) (n = 189)
 Constant   2.77 0.18 < 0.001 2.40–3.14
 Breedb     0.10  
  SR Baseline
SH − 0.33 0.14 0.027 − 0.62 to − 0.04
MB − 0.30 0.19 0.13 − 0.70 to 0.10
 Parity     0.0053  
  1 Baseline
2 0.26 0.15 0.10 − 0.057 to 0.57
3–8 − 0.32 0.13 0.028 − 0.60 to − 0.040
 Type of herdb LM Baseline
HM − 0.099 0.15 0.53 − 0.42 to 0.23
Model calf serum α-tocopherola (µg/mL) (n = 187)     
 Constant   0.026 0.11 0.82 − 0.20 to 0.25
 Breedb SR Baseline
SH/MB 0.24 0.11 0.043 − 0.0081 to 0.48
 Days transition milk is fed (days) ≥ 3 Baseline
< 3 − 0.21 0.076 0.013 − 0.37 to − 0.052
 Total protein (g/L) ≥ 55 Baseline
< 55 − 0.16 0.11 0.16 − 0.40 to 0.073
 Type of herdb LM Baseline
HM − 0.17 0.14 0.219 − 0.47 to 0.12
 Interaction: type of herd × total protein (g/L)     0.036  
  LM × total protein ≥ 55 Baseline
  LM × total protein < 55 − 0.16 0.11 0.16 − 0.40 to 0.072
  HM × total protein ≥ 55 − 0.17 0.14 0.22 − 0.47 to 0.11
  HM × total protein < 55 − 0.68 0.14 < 0.001 − 0.97 to − 0.40
  1. SR Swedish Red, SH Swedish Holstein, MB mixed breed
  2. aOutcome transformed with a natural logarithm (ln) to approximate normal distribution
  3. bForced into model
  4. cFive missing values