ANSC Feeds Practice Exam

During the ensiling process, which acid is produced first?

1. Lactic acid

2. Propionic acid

3. Acetic acid

4. Butyric acid

The correct answer is: Acetic acid

During the ensiling process, the initial fermentation is primarily characterized by the production of acetic acid. This is a crucial step because it sets the stage for the subsequent fermentation processes. The presence of acetic acid helps to lower the pH of the silage, creating an acidic environment that is conducive to the growth of lactic acid bacteria while inhibiting the growth of undesirable bacteria and mold. Acetic acid is produced first by the fermentation of sugars available in the plant material, which is facilitated by the natural microbial population present in the forage. Once the acidity increases due to the presence of acetic acid, it encourages lactic acid bacteria to thrive, leading to the production of lactic acid as the fermentation progresses. This transition is essential for producing high-quality silage that is stable and can maintain its quality over time. While lactic acid, propionic acid, and butyric acid are also produced during the ensiling process, they emerge later as the fermentation continues and the conditions evolve.