Table 4.

Dietary Ca and P intake, fecal Ca and P output, and apparent total tract digestibility (ATTD) of Ca and P in Exp. 2

	Limestone			Dicalcium phosphate			Mixed diets				P-value
Item	0.4	0.5	0.6	0.4	0.5	0.6	0.4	0.5	0.6	SD	Source	Linear effect1	Source × level
No. of observations	8	8	8	8	8	7	8	8	8
DMI, g/d	505	506	476	511	486	521	500	511	489	29.0	0.34	0.20	0.25
Ca digestibility
Ca intake, g/d	2.55	3.11	3.44	2.34	2.52	3.40	2.58	3.19	3.58	0.20	0.20	<0.001	0.59
Fecal Ca output, g/d	0.86	1.05	1.13	0.69	0.77	0.98	0.82	0.97	1.06	0.11	0.33	<0.001	0.84
Digested Ca, g/d	1.69	2.06	2.32	1.65	1.75	2.41	1.76	2.22	2.52	0.18	0.52	<0.001	0.55
ATTD of Ca, %	66.0	66.1	67.3	70.5	69.4	71.1	67.9	69.7	70.3	3.37	0.50	0.17	0.68
P digestibility
P intake, g/d	2.20	2.84	3.22	2.40	2.69	3.39	2.33	2.82	3.32	0.17	0.84	<0.001	0.95
Fecal P output, g/d	0.56	0.66	0.66	0.78	0.80	0.93	0.69	0.68	0.76	0.09	0.64	<0.001	0.43
Digested P, g/d	1.64	2.18	2.56	1.62	1.89	2.46	1.64	2.14	2.56	0.16	0.92	<0.001	0.65
ATTD of P, %	74.3	76.7	79.6	67.6	70.2	72.5	70.2	75.7	77.1	3.24	0.45	<0.001	0.65

¹Linear effect of dietary Ca concentration