Table 3. Changes in wean-to-estrus interval in different groups based on average daily feed intake (ADFI) of sows

Item	Group according to ADFI (g/d)							SEM	p-value
	< 5,000	5,000–5,499	5,500–5,999	6,000–6,499	6,500–6,999	7,000–7,499	> 7,500		Linear	Quadratic
n	12	13	67	242	148	95	63
Parity	2.33	2.23	2.36	2.93	3.20	2.82	3.50
ADFI (g/d)	4,414	5,488	5,940	6,294	6,765	7,344	7,824
Lactation length (d)	20.2	19.7	20.4	21.5	22.3	21.5	21.4
Wean-to-estrus interval (d)	14.89	12.28	6.72	8.97	7.20	6.69	7.72	1.39	< 0.001	0.004