Feeding unfermented corn silage

Corn silage should ferment for at least 2-3 weeks before feeding it. If unfermented corn silage must be fed, limit it to 15% of the ration, watch out for acidosis, make sure dietary soluble protein levels are adequate, and feed it fresh.

Unfermented corn silage (correctly termed “corn forage”) is not desirable to feed to cows. It is best if corn can ferment for 2-3 weeks, better yet 6-8 weeks, before feeding it. But, that is not always possible.

Some suggestions for dealing with unfermented corn silage:

1. If possible, don’t let unfermented corn silage make up more than 15% of the ration dry matter.

2. Watch out for acidosis. The silage microorganisms use the readily available sugars in corn forage for energy. In unfermented corn silage, those sugars are still there in higher amounts than they would be in fermented corn silage.

  • Added buffers in the ration need to be adequate (1-1.5% of the ration dry matter). Offer buffers free-choice and watch intake. If free-choice intake dramatically increases, reduce rapidly available starches and sugars in the ration and/or increase effective fiber in the ration.
  • Other rapidly digestible starches and sugars (such as, molasses, high-moisture corn, flour, or bakery product) in the ration may need to be reduced.
  • Adequate effective fiber must be present in the diet. This might be a good time to consider adding 2-3 pounds of hay to the TMR.

 3. Make sure that soluble protein levels in the diet are adequate (30-32% of the CP for a high-producing cow). The silage fermentation increases soluble protein levels in corn silage. So, the amount of soluble protein present in unfermented corn silage will be less than it is in fermented corn silage.

4. If you have to feed unfermented corn silage, feed it fresh. Don’t let it sit in the wagon overnight as it comes out hot, steamy, and unpalatable


Mary Beth de Ondarza

Mary Beth de Ondarza
45 articles

Nutritional consultant for the dairy feed industry at Paradox Nutrition, LLC.

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Dr. de Ondarza received her Ph. D. from Michigan State University and her Masters Degree from Cornell University, both in the field of Dairy Nutrition.

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Paradox Nutrition

Paradox Nutrition

Paradox Nutrition, LLC is a nutritional consultation business for the dairy feed industry. Mary Beth de Ondarza, Ph.D. is the sole proprietor.

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