Active Dry (Live) Yeast

Active Dry (also known as “Live”) Yeast is defined as viable yeast which has been dried in such a manner as to preserve a large portion of its fermenting power. It must contain no added cereal or filler and much contain not less than 15 billion live yeast cells per gram.

Key Points:

• Active dry (live) yeast is chosen from a specific strain and separated from its culture medium at the end of production
• Offers improved quality and consistency
• Specific strains are metabolically active in the rumen and can have three main modes of action:
  • Competes with other microorganisms for food, thus reducing lactic acid production
  • Provides nutrients, which stimulate growth of other microorganisms that will help digestion and supply the animal with its metabolizable protein needs
  • Scavenges oxygen, to help the growth of beneficial anaerobic bacteria, which remove lactic acid from the rumen and help improve fiber digestibility
    
• Vital that the yeast remains active in the rumen, as there is a clearly defined mode of action; if the yeast is dead, the benefits are limited
• A natural turnover of live yeast in the rumen occurs over time, due to environmental conditions and predatory organisms, such as Protozoa
• Population is maintained through a combination of reproduction and introduction of the yeast daily, or over time, yeast numbers would diminish dramatically

Selected Active Dry (Live) Yeast

Yeast Taxonomy

Active vs. Cultured Yeasts

Yeast Microencapsulation (PDF)