**Table 3 : Estimates of climatic factors, other fixed effects and random effect variance included in the final models ^{1} for the probability of a sow having stillborn piglets and for the number of stillborn piglets^{2} during the cold season (December to March).**

Cold season |
Probability of a sow having stillborn piglets |
Number of stillborn piglets |
||

Fixed effects (factors)^{3} and variance |
Estimate (+SE) |
P-value |
Estimate (+SE) |
P-value |

Intercept | -0.3920 (0.0414) | <0.01 | 0.5329 (0.0135) | <0.01 |

Minimum temperature (LT)^{4} |
-0.0198 (0.0039) | <0.01 | -0.0052 (0.0013) | <0.01 |

Parity groups (Parity) |
||||

Parities 3 to 5 | 0.2663 (0.0171) | <0.01 | 0.0351 (0.0088) | <0.01 |

Parity 6 or higher | 0.8290 (0.0246) | <0.01 | 0.1908 (0.0105) | <0.01 |

LT x Parity |
||||

LT x Parities 3 to 5 | 0.0120 (0.0048) | 0.01 | -- | -- |

LT x Parity 6 or higher | 0.0076 (0.0063) | 0.23 | -- | -- |

Total pigs born (TPB) | 0.2193 (0.0044) | <0.01 | 0.0574 (0.0023) | <0.01 |

TPB-squared | 0.0059 (0.0006) | <0.01 | 0.0032 (0.0002) | <0.01 |

LT x TPB | -0.0032 (0.0008) | <0.01 | -0.0010 (0.0003) | <0.01 |

Parity x TPB |
||||

Parities 3 to 5 x TPB | 0.0196 (0.0058) | <0.01 | 0.0045 (0.0029) | 0.12 |

Parity 6 or higher x TPB | 0.0445 (0.0081) | <0.01 | 0.0200 (0.0034) | <0.01 |

Intercept variance at herd level | 0.1354 (0.0208) | -- | 0.0093 (0.0017) | -- |

Intercept variance at sow level | 0.1194 (0.0190) | -- | -- | -- |

Intraclass correlation coefficient (ICC; records within the same herd), % |
3.8 | -- | 1.7 | -- |

ICC (records within the same sow), % | 7.2 | -- | -- | -- |

^{1}Logistic regression and Poisson regression models were used respectively for the probability of a sow having stillborn

piglets and for the number of stillborn piglets.^{2}Omitted data were records of sows with no stillborn piglets.^{3}Reference category was the parities 1 and 2 sow group.

Koketsu et al.*Veterinary Medicine and Animal Sciences* 2016** 4**:3DOI : 10.7243/2054-3425-4-3