**Table 2 : 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 hot and humid season (June to September).**

Hot and humid s.eason |
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 | -0.4213 (0.0392) | <0.01 | 0.5121 (0.0125) | <0.01 |

Maximum temperature (HT) | 0.0014 (0.0041) | 0.73 | 0.0050 (0.0011) | <0.01 |

Relative humidity (RH) | 0.0024 (0.0011) | 0.02 | 0.0011 (0.0005) | 0.03 |

Parity groups (Parity) |
||||

Parities 3 to 5 | 0.3334 (0.0199) | <0.01 | 0.0672 (0.0087) | <0.01 |

Parity 6 or higher | 0.9063 (0.0283) | <0.01 | 0.2385 (0.0103) | <0.01 |

HT x Parity |
||||

HT x Parities 3 to 5 | 0.0152 (0.0043) | <0.01 | -- | -- |

HT x Parity 6 or higher | 0.0217 (0.0061) | <0.01 | -- | -- |

Total number of pigs born (TPB) | 0.2317 (0.0054) | <0.01 | 0.0549 (0.0023) | <0.01 |

TPB-squared | 0.0092 (0.0011) | <0.01 | 0.0033 (0.0002) | <0.01 |

TPB-cubed | -0.0003 (0.0001) | <0.01 | -- | -- |

RH x TPB | 0.0006 (0.0003) | 0.03 | 0.0003 (0.0001) | 0.04 |

Parity x TPB |
||||

Parities 3 to 5 x TPB | 0.0172 (0.0062) | <0.01 | 0.0106 (0.0030) | <0.01 |

Parity 6 or higher x TPB | 0.0452 (0.0086) | <0.01 | 0.0208 (0.0034) | <0.01 |

Parity x TPB-squared |
||||

Parities 3 to 5 x TPB-squared | -0.0038 (0.0013) | <0.01 | -- | -- |

Parity 6 or higher x TPB-squared | -0.0069 (0.0018) | <0.01 | -- | -- |

Intercept variance at herd level | 0.1157 (0.0180) | -- | 0.0070 (0.0013) | -- |

Intercept variance at sow level | 0.1156 (0.0188) | -- | -- | -- |

Intraclass correlation coefficient (ICC; records within the same herd), % |
3.3 | -- | 1.2 | -- |

ICC (records within the same sow), % | 6.6 | -- | -- | -- |

^{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