TABLE 4.

Differences between daily average counts of E. coli O157:H7 and statistical significance^a

Day and overall avg	Comparison between groups				Comparison between P1 and P3
	P1		P3		Group 2		Group 1
	Diff.	P value	Diff.	P value	Diff.	P value	Diff.	P value
Day
1	0.7	0.27	−0.1	0.94	0.4	0.54	0.2	0.66
3	0.4	0.53	−0.4	0.54	−0.5	0.47	0.5	0.34
6	0.6	0.34	0.2	0.67	−0.5	0.49	1.3	0.01
9	0.4	0.42	0.4	0.50	−0.6	0.44	1.4	0.006
12	0.1	0.87	0.8	0.23	−0.5	0.44	1.4	0.008
15	0.8	0.18	0.8	0.22	0.7	0.29	0.9	0.08
18	1.2	0.06	0.8	0.18	0.4	0.54	1.6	0.002
21	1.5	0.02	0.9	0.15	0.6	0.37	1.8	0.001
24	0.2	0.80	0.5	0.40	−0.5	0.42	1.2	0.02
Overall	0.7	0.12	0.4	0.30	−0.05	0.93	1.1	0.001

^aShown are differences (diff.) between groups for P1 and P3 and between P1 and P3 of the same group. Differences are expressed as log₁₀ CFU/g. Diets of group 2 calves were supplemented with 10⁷ CFU of the colicinogenic E. coli strains per g in P1, and diets of group 1 calves were supplemented with 10⁸ CFU of the eight colicinogenic E. coli strains per g in P3.