Table 2. Responses of pigs to calcium and phosphorus ratio to variations in ADG, ATTD of Ca, ATTD of P, and CP in different body weight categories

Weight (kg)	Independent variable	With phytase					Without phytase
		Obs	Estimates	SE	t-value	p-value	Obs	Estimates	SE	t-value	p-value
6–11	Intercept	62	–1,034.10	281.20	–3.68	< 0.001	75	–2.19	197.40	–0.01	0.991
	ADG		1,964.20	443.60	4.43	< 0.001		382.40	303.40	1.26	0.216
	ADG2		–717.50	172.50	–4.16	0.001		–135.40	115.10	–1.18	0.243
	Intercept	25	–13.06	122.80	–0.11	0.916	23	–76.59	104.60	–0.73	0.472
	ATTD Ca		124.01	197.60	0.63	0.536		208.81	162.40	1.29	0.213
	ATTD Ca2		–50.30	78.50	–0.64	0.527		–79.53	61.87	–1.29	0.213
	Intercept	25	25.27	119.00	0.21	0.833	23	–46.58	100.60	–0.46	0.648
	ATTD P		43.45	191.4	0.23	0.822		151.84	156.10	0.97	0.342
	ATTD P2		–15.14	76.03	–0.20	0.843		–57.73	59.49	–0.97	0.343
	Intercept	48	83.55	11.94	6.99	< 0.001	63	71.27	19.37	3.68	< 0.001
	CP		–4.13	19.05	–0.22	0.829		4.90	29.83	0.16	0.869
	CP2		0.58	7.49	0.08	0.938		–1.72	11.30	–0.15	0.879
11–25	Intercept	103	–272.40	219.30	–1.24	0.217	72	19.90	445.50	0.04	0.964
	ADG		965.40	334.60	2.86	0.005		540.80	704.50	0.77	0.445
	ADG2		–338.27	125.50	–2.69	0.008		–198.10	274.40	–0.72	0.472
	Intercept	114	58.70	22.60	2.60	0.010	76	22.14	31.14	0.71	0.479
	ATTD Ca		26.10	34.90	0.75	0.456		63.74	46.17	1.38	0.171
	ATTD Ca2		–13.00	13.10	–0.99	0.323		–27.76	16.65	–1.67	0.099
	Intercept	117	66.28	26.98	2.46	0.015	78	35.27	31.43	1.12	0.265
	ATTD P		–2.22	41.45	–0.05	0.957		33.48	46.65	0.72	0.475
	ATTD P2		–0.34	15.52	–0.02	0.982		–18.54	16.83	–1.1	0.274
	Intercept	109	80.05	3.04	26.28	< 0.001	99	55.98	8.22	6.81	< 0.001
	CP		–1.37	4.67	–0.29	0.769		25.77	12.40	2.06	0.042
	CP2		0.52	1.75	0.30	0.767		–9.01	4.61	–1.95	0.053
25–50	Intercept	53	–288.20	460.10	–0.63	0.533	53	–443.20	590.40	–0.75	0.456
	ADG		1,413.20	685.70	2.06	0.044		1,721.30	903.80	1.9	0.063
	ADG2		–482.10	252.90	–1.91	0.062		–642.00	340.90	–1.88	0.065
	Intercept	49	–41.50	95.10	–0.44	0.665	56	–117.40	59.10	–1.99	0.052
	ATTD Ca		161.00	147.50	1.09	0.28		262.80	91.50	2.87	0.066
	ATTD Ca2		–58.80	56.50	–1.04	0.303		–99.10	34.90	–2.84	0.006
	Intercept	49	–8.29	67.82	–0.12	0.903	56	–52.66	64.31	–0.82	0.416
	ATTD P		102.74	105.10	0.98	0.333		154.10	99.40	1.55	0.127
	ATTD P2		–37.30	40.28	–0.93	0.359		–58.84	37.95	–1.55	0.127
	Intercept	51	24.99	18.89	1.32	0.192	62	42.04	13.910	3.02	0.004
	CP		84.44	28.20	2.99	0.004		48.21	21.20	2.28	0.026
	CP2		–32.06	10.44	–3.07	0.003		–18.25	7.92.00	–2.30	0.024
50–75	Intercept	61	–83.50	455.60	–0.18	0.855	59	–176.80	444.90	–0.40	0.692
	ADG		1,592.90	700.00	2.28	0.056		1,823.90	717.30	2.54	0.014
	ADG2		–608.20	265.20	–2.29	0.025		–761.00	286.90	–2.65	0.011
	Intercept	52	–16.72	36.70	–0.46	0.65	42	2.33	24.00	0.10	0.923
	ATTD Ca		131.20	55.70	2.36	0.022		88.50	32.70	2.70	0.010
	ATTD Ca2		–50.91	20.80	–2.45	0.047		–31.50	10.70	–2.93	0.006
	Intercept	52	6.75	39.86	0.17	0.866	42	–13.84	29.90	–0.46	0.646
	ATTD P		85.17	60.46	1.41	0.165		93.44	40.78	2.29	0.057
	ATTD P2		–34.76	22.58	–1.54	0.13		–32.76	13.33	–2.46	0.018
50–75	Intercept	60	48.74	15.20	3.20	0.002	47	–3.51	19.95	–0.18	0.861
	CP		44.30	23.37	1.90	0.063		108.80	27.18	4.00	< 0.001
	CP2		–16.11	8.85	–1.82	0.074		–34.65	8.88	–3.90	< 0.001
75–100	Intercept	59	1,460.80	1,371.00	1.07	0.291	64	83.80	426.10	0.20	0.844
	ADG		–680.20	2,046.00	–0.33	0.74		1,299.40	651.40	1.99	0.056
	ADG2		244.80	760.10	0.32	0.748		–490.50	245.20	–2.00	0.050
	Intercept	56	–66.60	62.90	–1.06	0.294	60	6.52	21.70	0.30	0.765
	ATTD Ca		193.70	93.80	2.06	0.043		75.20	33.20	2.26	0.027
	ATTD Ca2		–67.50	34.80	–1.94	0.048		–24.40	12.50	–1.95	0.036
	Intercept	56	–117.27	70.72	–1.66	0.103	60	–14.94	31.50	–0.47	0.637
	ATTD P		260.55	105.50	2.47	0.017		108.04	48.28	2.24	0.029
	ATTD P2		–95.05	39.19	–2.43	0.019		–42.45	18.22	–2.33	0.023
	Intercept	59	–17.04	82.14	–0.21	0.836	67	57.08	8.40	6.79	< 0.001
	CP		143.14	122.50	1.17	0.247		24.49	11.59	2.11	0.038
	CP2		–52.99	45.52	–1.16	0.249		–8.47	3.84	–2.20	0.031
Overall	Intercept	338	–2,141.40	581.60	–3.68	< 0.001	323	–76.60	765.50	–0.10	0.920
	ADG		41,110.10	887.70	4.63	< 0.001		1,188.80	1,187.00	1.00	0.317
	ADG2		–1,493.70	335.00	–4.46	< 0.001		–503.60	454.80	–1.11	0.269
	Intercept	296	48.60	16.50	2.94	0.004	257	12.23	14.83	0.82	0.410
	ATTD Ca		33.40	25.29	1.32	0.187		71.70	21.58	3.32	0.001
	ATTD Ca2		–13.65	9.57	–1.43	0.154		–27.20	7.69	–3.54	< 0.001
	Intercept	299	66.32	17.04	3.89	< 0.001	259	14.85	15.19	0.98	0.329
	ATTD P		–8.47	26.02	–0.33	0.745		58.12	22.12	2.63	0.009
	ATTD P2		3.05	9.81	0.31	0.755		–23.90	7.88	–3.03	0.003
	Intercept	327	71.90	4.59	15.64	< 0.001	338	52.79	5.03	10.50	< 0.001
	CP		11.19	7.01	1.60	0.112		30.61	7.25	4.22	< 0.001
	CP2		–4.26	2.64	–1.61	0.108		–10.45	2.56	–4.09	< 0.001

ADG, average daily gain; ATTD, apparent total digestibility, Ca, calcium; P, phosphorus; CP, crude protein; Obs, number of observations.