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

Model feed α-tocopherol^a (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

 TMR^b

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 herd^b

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

 Breed^b

SR

Baseline

–

–

–

SH/MB

0.45

0.12

0.001

0.21–0.69

 Fat^c (%)

0.20

0.023

< 0.001

0.15–0.25

 Herd size

0.0014

0.00046

0.006

0.00047–0.0024

 Type of herd^b

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

 Breed^b

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 herd^b

LM

Baseline

–

–

–

HM

− 0.099

0.15

0.53

− 0.42 to 0.23

Model calf serum α-tocopherol^a (µg/mL) (n = 187)

 Constant

0.026

0.11

0.82

− 0.20 to 0.25

 Breed^b

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 herd^b

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