Variable

n

Coefficient

Std. Error

t

P > |t|

95% CI

Age at conception

101

2.26

0.34

6.59

<0.0001

1.58

2.94

Enterprise type

Baseline

40

Holstein

Holstein-Friesian

29

57.44

43.14

1.10

0.274

−3.26

133.13

Holstein x

13

88.11

59.52

1.48

0.142

−30.12

206.34

Friesian x

4

−37.67

105.51

−0.36

0.722

−247.26

171.71

Other purebreds

9

84.23

71.73

1.17

0.243

−58.26

226.71

Jersey

6

−30.87

78.73

−0.39

0.696

−187.26

125.51

Calving pattern

Baseline

73

All year round

Autumn

14

−136.27

56.62

−2.41

0.018

−248.74

−23.81

Multi block

10

−39.30

61.76

−0.64

0.526

−161.98

83.37

Spring

5

−184.46

94.24

−1.96

0.053

−371.66

2.73