TABLE 1.
Initial, peak, and final counts of indicators and pathogens in cow pats placed on pasture in each season
| Measurement | Concn (CFU/g [dry wt] of feces)a
|
||||
|---|---|---|---|---|---|
| E. coli | Fecal streptococci | Enterococci | C. jejuni | S. enterica | |
| Winter | |||||
| Initial | 2.2 × 106 | 6.9 × 105 | 3.2 × 102 | 6.7 × 106 | 1.1 × 107 |
| Peak | 1.0 × 106 (21) | 1.3 × 103 (21) | 2.4 × 107 (7) | ||
| Final | 91 (149) | 1.3 × 103 (149) | 4.7 × 102 (149) | 3.1 × 102 (76)b | 5.0 × 102 (140) |
| Spring | |||||
| Initial | 3.3 × 105 | 7.2 × 106 | 1.3 × 105 | 6.3 × 106 | 1.7 × 107 |
| Peak | 5.0 × 105 (7) | 3.4 × 107 (7) | 3.5 × 106 (7) | ||
| Final | 1.4 × 103 (148) | 1.4 × 103 (148) | 71 (148) | 46 (16)b | 40 (153) |
| Summer | |||||
| Initial | 3.0 × 106 | 1.4 × 106 | 2.8 × 104 | 2.7 × 107 | 1.7 × 107 |
| Peak | 4.8 × 107 (7) | 5.0 × 107 (7) | 1.3 × 105 (7) | ||
| Final | 2.9 × 104 (141) | 1.3 × 104 (141) | 1.5 × 103 (141) | 4 (10)b | 1.5 × 104 (146) |
| Autumn | |||||
| Initial | 2.2 × 105 | 4.0 × 106 | 99 | 6.1 × 106 | 3.2 × 107 |
| Peak | 1.9 × 106 (14) | 9.6 × 102 (7) | 6.5 × 107 (5) | ||
| Final | 1.7 × 103 (155) | 1.6 × 102 (155) | 1 (155) | 54 (27)b | 1.6 × 103 (153) |
a
Each count is the mean for four samples (one sample from each cow pat). Peak counts are given only where they were greater than the initial count. The number in parentheses is the day on which the count was recorded.
b
Last day on which C. jejuni was detected.