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Yeast Interpretation

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Yeast Count

Major crops affected: Corn Silage, High Moisture Corn, and Earlage/Snaplage

Conditions favoring production: Cool growing season resulting in late harvest.  These conditions are unfavorable for bacteria species that are responsible for the fermentation and preservation of ensiled feeds.

Symptoms: Very little research is available on the effects of yeasts on animal performance.  The most common result of high yeast counts is unstable silages that heat rapidly and subsequently grow additional mold.  These unstable silages result in nutrient losses and can potentially reduce dry matter intakes.

Mechanism of Yeast and Aerobic Instability

  1. High endemic yeast population is ensiled

  2. During slow fermentations, moderate growth of yeast occurs until oxygen is expired in the silage.

  3. At feedout, yeasts are re-exposed to oxygen

  4. Yeast growth becomes exponential.

  5. Lactic acid is consumed

  6. Heating occurs.

  7. Silage acids are volatilized.

  8. Silage pH rises.

  9. Molds with low oxygen requirements (Mucor) invade the silage.

  10. Aerobic instability.

Yeast Count Interpretation

CFU/g Aerobic Stability Comments
<10,000 120-140 hours Typical values in a well-preserved feed
1,000,000 ~ 40 hours  
25-50,000,000   Upper range for inadequately fermented feed.
For more information call Dairyland Laboratories, Inc. at 608-323-2123 or contact us here.