Let Your Silage Ferment!
Aug 25, 2020

Tara Jo Bina
Countryside Feed Nutrition
From corn and small grain silages to alfalfa and grass haylages, silages have become an important part of feeding livestock. Increased protein and energy availability, reduced field losses, and improved ration conditioning are just a few benefits that fermented stored forages bring to the table.
New crop silages (silages that are not fully fermented) are often a major contributor to the “fall slump” on many dairies. Early feed out of corn silage provides less energy and less available starch to animals. Without ration adjustments or increased ration costs from ration adjustments, decreased milk production and increased components are typically observed.
Silages of any kind rely on fermentation of sugars to organic acids to preserve nutrients for feeding at a later date. This is a very important process that requires proper harvest, storage, and time to complete. Moisture levels of forages, chop length, packing, and bacterial populations are all key to producing quality silages, click here to read more about silage harvest tips. Commonly, 3 to 4 months of fermentation is recommended for corn silage to allow full fermentation and produce the best feed. Here are a few reasons why:
*Ralph Ward. “Let your corn silage cook a while.”
*Penn State Extension. “From Harvest to Feed: Understanding Silage Management”
Countryside Feed Nutrition
From corn and small grain silages to alfalfa and grass haylages, silages have become an important part of feeding livestock. Increased protein and energy availability, reduced field losses, and improved ration conditioning are just a few benefits that fermented stored forages bring to the table.
New crop silages (silages that are not fully fermented) are often a major contributor to the “fall slump” on many dairies. Early feed out of corn silage provides less energy and less available starch to animals. Without ration adjustments or increased ration costs from ration adjustments, decreased milk production and increased components are typically observed.
Silages of any kind rely on fermentation of sugars to organic acids to preserve nutrients for feeding at a later date. This is a very important process that requires proper harvest, storage, and time to complete. Moisture levels of forages, chop length, packing, and bacterial populations are all key to producing quality silages, click here to read more about silage harvest tips. Commonly, 3 to 4 months of fermentation is recommended for corn silage to allow full fermentation and produce the best feed. Here are a few reasons why:
- Improved Digestibility: The fermentation process is made up of 4 phases that take roughly 21 days to achieve stability. Many people think that fermentation is complete after this 21-day process and that silage is ready to feed. In reality, the stable state of the forage allows for continued fermentation and will continue to convert sugars to organic acids for months after ensiling. This continual improvement in feeding value over time is why nutritionists recommend 3-4 months instead of 21 days of fermentation.
- Reduced Risk of Butyric Acid: Breaking into a pile or bag of silage before it has reached a stable point of fermentation introduces oxygen to the feed. When fermentation is disrupted by many factors, including oxygen exposure, can lead to a 5th phase of fermentation that produces butyric acid. This leaves silage with a very distinct smell that is not pleasant. Cattle will generally go off feed when this acid is present in the feed.
- Reduced Risk of Toxins: Even the best face management still leaves several feet back in the silage exposed to enough oxygen to allow yeasts, molds, and bacteria to grow and produce toxins in the feed that can be harmful or at minimum reduce feed intake.
- Reduce Dry Matter Loss: One of the biggest contributors to dry matter loss and spoilage in silages is a process called aerobic respiration which is required for the growth of these microorganisms. This is why so many of the tips for silage harvest and feed out revolve around reducing oxygen exposure. The less exposure to oxygen the better, especially during fermentation!
- Rumen Health Factors: New crop silages will have a pH that is much higher than fermented silages. When changing to these feeds too early, the pH balance of the rumen is disrupted. Allowing silage to reach at least a pH of 4 or lower helps maintain a consistent rumen pH.
*Ralph Ward. “Let your corn silage cook a while.”
*Penn State Extension. “From Harvest to Feed: Understanding Silage Management”