TABLE 1.
Fecal shedding of E. coli O157:H7 by calves during period 1 of the experimenta
| Group and calf no. |
E. coli O157:H7 count (log10 CFU/g) at dayb:
|
||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | 3 | 6 | 9 | 12 | 15 | 18 | 21 | 24 | |
| Group 1 | |||||||||
| 72 | 6.0 | 4.1 | 5.5 | ND | ND | ND | ND | ND | ND |
| 74 | 7.6 | 4.8 | 4.4 | 3.2 | 2.3 | 1.3 | 2.1 | 3.0 | 1.0 |
| 76 | 7.0 | 5.1 | 5.1 | 4.1 | 3.1 | 2.8 | 2.9 | 3.4 | 2.0 |
| 78 | 7.0 | 5.9 | 4.5 | 3.3 | 2.7 | 2.7 | 2.7 | 2.4 | 4.4 |
| 79 | 5.7 | 4.6 | 4.1 | 4.3 | 3.5 | 5.4 | 4.7 | 5.0 | 2.0 |
| 80 | 7.0 | 5.4 | 5.2 | 3.3 | 3.9 | 3.0 | 2.9 | 3.4 | 3.7 |
| 83 | 6.0 | 3.8 | 4.2 | 4.9 | 3.6 | 2.6 | 2.0 | 2.4 | 3.6 |
| 87 | 4.0 | 4.6 | 3.3 | ND | ND | ND | ND | ND | ND |
| Avg | 6.7c | 5.0c | 4.6c | 3.8 | 3.2 | 3.0 | 2.9 | 3.3 | 2.8 |
| SD | 0.7 | 0.7 | 0.5 | 0.7 | 0.6 | 1.4 | 1.0 | 0.9 | 1.3 |
| Group 2 | |||||||||
| 73 | 7.0 | 4.6 | 4.6 | 4.3 | 3.4 | 3.8 | 3.9 | 4.6 | 6.3 |
| 75 | 5.2 | 4.8 | 5.1 | 4.8 | 3.1 | 1.0 | 2.2 | 2.7 | 2.7 |
| 77 | 7.1 | 3.7 | 3.5 | 1.5 | 2.2 | + | + | + | + |
| 81 | 6.3 | 5.5 | 4.5 | 3.2 | 3.6 | 2.7 | 2.0 | 2.3 | 2.1 |
| 82 | 6.3 | 5.4 | 4.6 | 3.3 | 3.1 | 1.5 | 2.1 | − | 1.0 |
| 84 | 5.7 | 4.6 | 4.1 | 4.3 | 2.5 | 2.3 | 3.0 | 3.1 | 4.8 |
| 85 | 6.1 | 4.8 | 4.3 | 3.4 | 4.3 | 3.7 | + | 1.7 | 1.6 |
| 86 | 4.6 | 3.1 | 1.3 | 2.1 | 2.4 | 2.0 | − | − | 2.3 |
| Avg | 6.0 | 4.6 | 4.0 | 3.4 | 3.1 | 2.2 | 1.7 | 1.8 | 2.6 |
| SD | 0.9 | 0.8 | 1.2 | 1.1 | 0.7 | 1.2 | 1.4 | 1.7 | 2.0 |
a
The diets of group 2 calves were supplemented with 107 CFU of E. coli (the colicinogenic E. coli strains) per g.
b
+, detected only by enrichment and assigned an arbitrary value of 0.3 log10 CFU/g for calculation of averages; −, assigned a value of 0 log10 CFU/g for calculation of averages; ND, not detected due to death of calf.
c
Due to the deaths of two calves in the control group, their data were not used to calculate these averages.