Table 4.
Animal’s risk factors related to shedding of Listeria monocytogenes in feces on the level of three dairy cattle farms
| Risk factor | Farm I | Farm II | Farm III | |||
|---|---|---|---|---|---|---|
| Total no. of samples | Positive no. (%) | Total no. of samples | Positive no. (%) | Total no. of samples | Positive no. (%) | |
| Age (years) | ||||||
| 3–5 | 136 | 0 | 62 | 2 (3.2) | 110 | 4 (3.6) |
| 6–8 | 89 | 0 | 34 | 5 (14.7) | 77 | 6 (7.8) |
| > 8 | 75 | 9 (12) | 54 | 15 (27.8) | 23 | 4 (17.4) |
| P value | 0.000 | 0.001 | 0.05 | |||
| Parity (no.) | ||||||
| Up to 2 | 18 | 0 | 49 | 2 (4) | 69 | 2 (2.9) |
| 2–4 | 180 | 2 (1.1) | 60 | 8 (13.3) | 120 | 5 (4.2) |
| > 4 | 102 | 7 (6.9) | 41 | 12 (29.3) | 21 | 7 (33.3) |
| P value | 0.01 | 0.003 | 0.000 | |||
| Milk yield (kg/day) | ||||||
| Low (< 12) | 0 | 0 | 50 | 2 (4) | 8 | 0 |
| Medium (12–18) | 80 | 0 | 70 | 8 (11.4) | 114 | 0 |
| High (over 18) | 220 | 9 (4) | 30 | 12 (40) | 98 | 14 (14.3) |
| P value | 0.000 | 0.000 | 0.000 | |||
Factors statistically significant at p ≤ 0.05