Table 2. Effects of feeding type and dietary energy level on backfat thickness change, feed intake and weaning to estrus interval in sows during summer season

Item1)	Feeding type		Energy level (ME, kcal/kg)		SEM	p-value
	CF	FF	3,300	3,400		F	E	F × E
Parity	3.61	3.52	3.59	3.51	0.37	0.701	0.998	0.848
Sow body weight (kg)
Gestation (d 109)	233.53	231.08	233.92	230.68	6.51	0.517	0.834	0.660
Weaning	214.92	215.37	215.55	214.74	6.00	0.828	0.875	0.724
Change (–)	18.61	15.71	18.37	15.94	1.34	0.031	0.084	0.579
Sow backfat thickness (mm)
Gestation (d 109)	20.92	20.99	21.23	20.68	0.69	0.934	0.538	0.750
Weanling	16.67	17.36	16.92	17.11	0.44	0.182	0.537	0.298
Change (–)	4.26	3.62	4.31	3.57	0.37	0.089	0.070	0.517
Daily feed intake (kg/d)	4.52	5.13	4.93	4.73	0.11	0.001	0.124	0.401
Weaning to estrus interval (d)	5.25	4.71	5.14	4.82	0.38	0.169	0.407	0.926

Data are means of seven replicates.
SEM, Standard error of means; CF, conventional feeding; FF, free feeding; F, feeding type, E, dietary energy level, F × E, feeding type × dietary energy level.