ANSC Feeds Practice Exam

Which statement about microbial fermentation is accurate?

1. Fermentation in the silo yields much higher propionic acid

2. Rumen fermentation yields higher lactic acid concentrations

3. Microbial fermentation processes are identical in both environments

4. Fermentation is less effective in a silo than in the rumen

The correct answer is: Fermentation in the silo yields much higher propionic acid

The accurate statement regarding microbial fermentation is that fermentation in the silo yields much higher propionic acid. During the ensiling process, specific conditions favor the growth of certain bacteria that produce propionic acid. This is particularly significant in the preservation of high-moisture feeds and silage, where the presence of propionic acid helps inhibit spoilage and enhances the preservation of the feed. In contrast, rumen fermentation predominantly produces volatile fatty acids such as acetic, butyric, and some lactic acids, but propionic acid is not the primary product under typical ruminal conditions. This differentiation in fermentation profiles between silos and the rumen underscores the importance of understanding the mechanisms at play in each environment for effective feed management and animal nutrition strategies.