Clostridia, or butyric bacteria, contamination in silage is always a source of financial loss either due to dry matter loss or health issues of the cows. A recently published study (Borreani et al., Journal of Applied Microbiol, 2009) shows that, even when the analysis of fresh silage shows low clostridia count, the silage can become heavily contaminated at feedout, due to aerobic instability, a pheno-menon that can easily go unnoticed as long as analysis are performed on fresh silage.
  
Silage expert Professor Giorgio Borreani has looked into aerobic spoilage and clostridia spore for-mation in more detail and demonstrated that even a very clean and easily ensiled silage such as corn or sorghum (high cut and rapid acidification typically prevent contamination), could show clostridia contamination. In his study, corn silage analysis shows only a few hundred clostridia spores per gram of fresh silage. But after air exposure, this count skyrockets, with up to 5 million spores/g after a hundred hours in lab conditions.
 
Research showed that silos treated with an anti-fungal bacteria were stable up to 300 hours after air exposure, and clostridia spores did not develop. Consequently, forage dry matter and nutritional quality were preserved and the risk of clostridia contamination in milk was prevented.

This practice tip was provided by Lallemand Inc.