Table 2 Staphylococcus aureus prevalence in udder quarter secretions of heifers and cows by parity status
Herd | Total N of quarters heifers/cows | STA Heifers N (%) | STA Cows N (%) | Prevalence ratio | 95% Confidence interval | |||
|---|---|---|---|---|---|---|---|---|
First lactation | Second lactation | Second lactation plus | All lactation cows | |||||
A | 1246/1882 | 6 (0.48) | 5 (0.41) | 1 (0.33) | 3 (0.83) | 9 (0.48) | 1.01 | (0.36, 2.82) |
B | 1404/4008 | 10 (0.71) | 12 (1.18) | 12 (1.6) | 33 (1.47) | 57 (1.42) | 0.50 | (0.26, 0.98) |
C | 804/2548 | 0 (0) | 9 (1.29) | 9 (1.7) | 14 (1.06) | 32 (1.26) | 0.00 | (0, 0.8) |
D | 1756/3243 | 37 (2.11) | 28 (2.63) | 23 (1.85) | 32 (3.42) | 83 (2.56) | 0.82 | (0.56, 1.21) |
E | 640/2320 | 14 (2.19) | 1 (0.3) | 4 (1.1) | 11 (0.68) | 16 (0.69) | 3.17 | (1.52, 6.32) |
F | 1123/2716 | 4 (0.36) | 6 (0.9) | 5 (0.87) | 18 (1.22) | 29 (1.07) | 0.33 | (0.12, 0.95) |
G | 932/2659 | 6 (0.64) | 10 (1.1) | 6 (1.04) | 11 (0.94) | 27 (1.02) | 0.63 | (0.26, 1.53) |
H | 352/2071 | 1 (0.28) | 3 (0.82) | 0 (0) | 10 (0.7) | 13 (0.63) | 0.45 | (0.06, 3.46) |
All | 8257/21447 | 78 (0.94) | 74 (1.18) | 60 (0.57) | 132 (2.86) | 266 (1.24) | 0.76 | (0.59, 0.98) |