ANSC Feeds Practice Exam

During ensiling, which type of bacteria grow and multiply?

1. Aerobic bacteria

2. Facultative anaerobic bacteria

3. Anaerobic bacteria

4. Pathogenic bacteria

The correct answer is: Anaerobic bacteria

During ensiling, anaerobic bacteria are the primary organisms involved in the fermentation process. Ensiling is a method of preserving fodder under anaerobic conditions, which means that the material must be stored in a low-oxygen environment. This promotes the activity of anaerobic bacteria, which thrive in these conditions. The fermentation process initiated by these bacteria is crucial as it helps in preserving the nutrients in the silage while inhibiting the growth of undesirable microorganisms. These anaerobic bacteria convert sugars in the plant material into lactic acid, which lowers the pH and creates an environment that is less favorable for spoilage organisms. This not only helps in maintaining the quality of the silage but also enhances its digestibility for livestock. Facultative anaerobic bacteria also can survive in various conditions, including both aerobic and anaerobic environments, but they are not the predominant players in the ensiling process, as their role diminishes when oxygen is limited. Aerobic bacteria require oxygen for their growth and would be inhibited in the low-oxygen environment of a silo. The presence of pathogenic bacteria is also not desirable during the ensiling process, as they can negatively affect the quality and safety of the silage. Ensiling aims to create conditions that avoid the growth