Variable

d. f.

Parameter estimate

SE

Hazard ratio

p-value

Stillbirth vs. live calf

1

−27

0.06

0.74

<0.001

Male vs. female calf

1

−0.07

0.04

0.93

0.003

Multiparous vs. primiparous

1

−0.11

0.04

0.89

<0.01

Assisted vs. unassisted

1

−0.18

0.06

0.84

0.004