Culling in served females and farrowed sows at consecutive parities in Spanish pig herds

Table 5 Model selection for two-level mixed-effects log-binomial regression models for farrowed sows

	Model specification							pseudo-AIC
Model for culling risk of farrowed sows
	Fixed effect^a,b						Random effect	Consecutive parities
Model No.	HG	PBA	SB	Interaction	Interaction	Interaction	Herds	1	2	3	4	5	6
Model No.	HG	PBA	SB	HG × PBA	HG × SB	PBA × SB	Herds	1	2	3	4	5	6
1	✓						✓	34,280	24,293	26,657	28,691	32,820	39,007
2		✓					✓	34,062	23,631	25,841	27,850	31,659	NC
3			✓				✓	34,136	24,145	26,505	28,510	32,542	38,858
4	✓	✓	✓	✓	✓	✓	✓	33,970	23,516	25,717	27,716	31,472	37,658
5	✓	✓	✓	✓	✓		✓	33,976	23,511	25714^c	27,713	31,488	37,672
6	✓	✓	✓		✓	✓	✓	33,967	23,534	25,729	27,727	31,484	NC
7	✓	✓	✓	✓		✓	✓	33,968	23,512	25,718	27,713	31469^c	37655^c
8	✓	✓	✓	✓			✓	33,974	23508^c	25,715	27710^c	31,486	37,670
9	✓	✓	✓		✓		✓	33,973	23,530	25,727	27,723	31,498	NC
10	✓	✓	✓			✓	✓	33,965	23,532	25,733	27,723	31,481	NC
11	✓	✓		✓			✓	34,067	23,611	25,818	27,835	31,646	NC
12		✓	✓			✓	✓	33964^c	23,537	25,745	27,731	31,486	37,668
13	✓		✓		✓		✓	34,140	24,146	26,494	28,507	32,545	38,857
14	✓	✓	✓				✓	33,971	23,528	25,730	27,719	31,498	NC
COVTEST for Model								<0.01	<0.01	<0.01	<0.01	<0.01	<0.01

HG herd groups, PBA pigs born alive, SB stillborn piglets
^aEntry years were included into all models
^bThe univariate models were not shown because the AIC were higher than those shown in Models 1–3
^cFinal model is selected by the lowest pseudo-AIC
NC means the models did not converge

ISSN: 2055-5660