Table 7.

The effect of dietary ME level on the weaning-to-estrus interval of sows¹ (Exp. 1)

Item	Parity	No.	ME level, Mcal/kg								P-value
			3.06	3.16	3.20	3.25	3.30	3.40	Mean3	SEM	Treat	Linear	Quadratic
Weaning to estrus interval, d	1	26	6.50	6.50	6.00	6.25	6.20	5.60	6.16x	0.54	0.87	0.23	0.72
	2	25	6.25	6.00	5.50	5.50	5.60	5.75	5.77xy	0.45	0.86	0.35	0.35
	3+	79	5.69	5.62	5.15	5.14	5.15	5.31	5.34y	0.32	0.72	0.25	0.35
	Overall2	130	5.93	5.82	5.35	5.39	5.42	5.40	5.55	0.25	0.38	0.09	0.34

¹Data on 130 sows. Sows which did not exhibit estrus within 20 days were excluded (not induced by the treatment effect). The sows were washed out largely caused by other factors (such as leg problems, mastitis)

²Parity effect was included in the model

³Parity effect and treatment effect was included in the model

^{x, y}Within a column, values with no common superscript differ significantly (P < 0.05)