The placenta encourages fungal growth, resulting in abortions late in pregnancy. There is usually evidence of fungal plaques on the afterbirth. Farmer's lung is an allergic pneumonia associated with inhaling fungal spores. Bacillus Abortion - this bacteria will only grow in poor quality silage. Contamination results in rare outbreaks of abortion in late pregnancy.
Horses are most susceptible.
In conclusion, there is a slight health risk associated with feeding poorly fermented or badly sealed silage.