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Table 5 Contribution of the second eigenvalue of the genetic covariance matrix, correlation between the two genetic effects (± SE) and goodness-of-fit (BIC was set to 0 for the model without climatic variable) for reaction norm models including a constant and a regression on one climatic variable at a time, in the case of milk yield and age at first calving traits

From: Two approaches to account for genotype-by-environment interactions for production traits and age at first calving in South African Holstein cattle

Climatic variable

Milk yield

Age at first calving

Eigenvalues (%)

Correlation (SE)

BIC

Eigenvalues (%)

Correlation (SE)

BIC

C1: Average rainfall

9.93

− 0.637 ± 0.016

− 28.1

8.97

0.236 ± 0.035

202.6

C2: Max temperature

2.64

0.599 ± 0.041

726.9

7.30

− 0.366 ± 0.040

241.5

C3: Min temperature

0.37

− 0.499 ± 0.107

1199.6

3.07

− 0.692 ± 0.037

66.9

C4: Max relative humidity

1.78

− 0.837 ± 0.029

188.3

18.82

0.439 ± 0.023

52.0

C5: Min relative humidity

1.01

− 0.880 ± 0.025

204.0

23.25

− 0.061 ± 0.027

106.2

C6: Solar radiation (SR)

1.13

0.797 ± 0.032

748.5

10.26

0.115 ± 0.039

234.5

C7: Evapotranspiration

1.07

0.867 ± 0.026

315.7

12.14

− 0.119 ± 0.038

206.3

C8: Max temperature in summer

0.99

0.895 ± 0.029

400.9

26.11

0.895 ± 0.029

− 26.3

C9: Max relative humidity in summer

1.06

− 0.911 ± 0.022

65.5

16.09

− 0.346 ± 0.025

− 100.7

C10: Max solar radiation in summer

1.35

0.692 ± 0.048

876.8

16.43

0.692 ± 0.048

110.5

  1. RH relative humidity; SR solar radiation; T temperature