Table 3 : Estimates of climatic factors, other fixed effects and random effect variance included in the final models1
for the probability of a sow having stillborn piglets and for the number of stillborn piglets2 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 -- -- --

1Logistic regression and Poisson regression models were used respectively for the probability of a sow having stillborn
piglets and for the number of stillborn piglets.
2Omitted data were records of sows with no stillborn piglets.
3Reference 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