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Table 3 Descriptive statistics and unconditional associations of continuous variables selected as candidates for multivariable model for within-herd cow mortality rate in years 2017–2018 in 212 Estonian dairy herds estimated in linear regression analysis

From: Herd-level risk factors for cow and calf on-farm mortality in Estonian dairy herds

Variable

Median (Q1; Q3)

n

p-valuea

Herd size (number of cows)

129.7 (53.7; 459.7)

212

 < 0.001

Herd average milk yield per cow per year (kg)

8787 (6950; 9758)

212

0.002

Herd average milk fat/protein ratio

1.2 (1.2; 1.3)

212

0.001

Herd average age at first calving (days)

813.0 (764.3; 888.7)

212

0.024

Herd average interval from calving to insemination (days)

92.3 (79.6; 111.7)

204

0.061

Herd average number of inseminations per conception

1.9 (1.7; 2.2)

204

0.004

Herd average first insemination conception rate (%)

53.9 (47.2; 60.6)

204

0.003

Herd proportion of stillbirths (%)

7.5 (5.6; 9.5)

212

0.008

Herd proportion of abortions (%)

0.8 (0; 1.6)

212

0.022

Herd average number of lactations

2.4 (2.2; 2.7)

212

 < 0.001

Herd average age at first insemination (days)

498.7 (457.3; 585.7)

187

0.123

  1. aEstimated in bivariable linear regression models including herd number of cows to that category