These agents are considered secondary or opportunistic pathogens, they are incapable of transplacental infection unless the placenta is damage or the cow is immuno-compromised. They cause sporadic abortion; however, their presence in the tissues of an aborted foetus should not be considered as definitive evidence that they caused the abortion.
| Organism | Count |
|---|---|
| Coliforms | 379 |
| Streptococcus spp | 83 |
| Staph. spp | 18 |
| Bacillus spp | 14 |
| Pseudomonas spp | 11 |
| Yeasts and Fungi | 10 |
| Listeria spp | 4 |
| Histophilus somnus | 1 |
| Pasteurella multocida | 1 |
| Yersinia pseudotuberculosis | 1 |