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Working with less-than-optimum feed

Carla Kuehn Published on 22 March 2010

If you were lucky, the 2009 harvest caused little or no problems. But for many of you, luck just wasn’t part of the program. Hail damage or lack of moisture struck some areas during the summer. In the fall, other areas experienced harvest delays or frost hitting the corn silage. Whatever the case was, you are currently feeding your inventory of high-moisture corn or corn silage.

Silage quality has been variable this year: Molds or mycotoxins have been present, and the feedout of silage is very unstable. No matter what challenges you’ve confronted so far, it’s likely that their effects won’t go away until you’re feeding next year’s crop.



Working with less-than-great silage and corn raises three major questions: What can you do now, what are the alternatives, and how can you better manage next year? Here are some suggestions, and things to watch:

What can I do about feeding this crop?

Know your inventory.

Monitor the feed inventory and quality of the silages and corn that are currently on hand. You’ve already been dealing with these challenges, and many of you have adapted your feeding program to accommodate these feeds. Knowing the inventory of usable feeds will determine any additional adjustments to rations until the new crop is in.

Test for nutrients.

Testing the ensiled feeds is extremely important this year. Nutritional analysis will determine what the feeds contribute to the diet. You and your nutritionist can determine what group of animals the feeds are best suited for. Corn silage can be variable depending on field conditions or harvest timing. As the year continues, the starch of corn silage or high-moisture corn will become more available due to the breakdown of the protein matrix that surrounds the starch, and ration adjustments can be made if necessary. Feeds that contain molds or yeast may have some nutrient limitations and may not work in diets as planned. Shifts in feed quality or pockets of deteriorated feeds that cattle don’t consume can cause ration issues and cattle can become prone to going off of feed or having metabolic problems.


Test for molds and mycotoxins

Molds utilize the nutrients of feeds to grow and lower the nutritional value of feed, so you should continue analyzing the forages for molds or mycotoxins. Whether the molds were present on the feeds when they were harvested, or they grew because of adverse storage conditions, they can cause problems in cattle. The presence of molds can decrease intake because of palatability issues.

Molds in feeds likely indicate the presence of mycotoxins. Without a laboratory test, you cannot know what mycotoxins exist, and, if they are present, at what level they are at. Low feed intakes, digestive upsets, diarrhea, intestinal irritation, low fertility and suppressed immune systems are some of the problems caused by mycotoxins.

Dairyland Labs, Inc. in Arcadia, Wisconsin ( has published a list of the most prevalent molds and mycotoxins they’ve found this year. In samples of corn and corn silages tested for molds, about 70 percent have contained fusarium, mucor or cladosporium. Fusarium molds are associated with deoxynivalenol (DON or vomitoxin), zearalenone, and T-2 toxins. Identification and quantification are important. Never assume that feeding mycotoxin-infested feed is safe.

Test for feed stability

Management techniques in making silage and managing the feedout have been crucial this year. Having an anaerobic and acidic environment are key to preventing adverse microbial growth that can affect silage stability. Presence of oxygen from insufficient packing or too long of a chop length can cause unstable feed. Proper face management is imperative as the oxygen that enters at the face can result in yeast growth up to two feet into the silage.


Fermentation analysis of silages can tell you how well your silage has fermented and how well it is maintaining preservation. A pH of 3.8 to 4.2 for corn silage and 4.0 to 4.5 for high-moisture corn or haylage is the first indicator your silage should be well preserved. In addition, the lactic acid-to-acetic acid ratio should be about 3-to-1 for corn silage and corn and about 2- or 2.5-to-1 for haylage. In all silages you want less than 0.10 percent of the silage dry matter to be butyric acid.

Another indication of silage preservation is a yeast count. Yeast counts over 1 million cfu/g can indicate that the fermented feeds are aerobically unstable. Unstable silage can grow molds or mycotoxins, lose valuable nutrients, or have a short bunk life. During a normal fermentation of the silages in the fall, yeasts grow slightly until the oxygen is expired in the silage. At feedout, or with improper storage conditions, yeasts are re-exposed to oxygen and begin to grow again. The yeasts consume the lactic acid and heating occurs. Silage acids are then consumed as energy, increasing the pH of the silage, causing further growth of molds or mycotoxins in the silage. Secondary fermentations can result in clostridial-infested silage and the presence of butyric acid, which can throw animals off feed.

To handle any of these silage quality situations, know what you have, what you are dealing with, and to what group the feeds are going. Make any ration changes or management changes as you continue to use these feeds.

What are the alternatives to feeding this?

Dry corn for high moisture

If the corn or corn silage is not suitable to feed, if inventory is running low, or if you need to dilute out the feeds, there are some suitable alternatives to add to the diet. Dry corn offers a good source of highly fermentable carbohydrate in the form of starch to the diet. Fermentable carbohydrates are necessary in the rumen to provide energy to the rumen microbes. The price of corn has made it economical to use in dairy diets. If the high- moisture corn has mold or stability issues, adding a dry source of corn is a reasonable alternative and it offers another source of starch that is available to the rumen.

Added sugars

Adding sugar can be a replacement to some corn in the diet. Sugar will ferment more rapidly in the rumen than starch. Adequate nitrogen sources need to be available for its effectiveness in microbial protein synthesis. If sugar is added to the diet, the dietary level can be between 4 to 6 percent of the diet dry matter. Sugar can be added in its straight form, or as a part of a liquid feed source. Liquid feeds have added advantages of minimizing sorting to provide a more consistent diet to the animal.


Distillers grains, corn gluten feed or wheat middlings are feeds that are readily available and can be cost-effective in rations. The feeds will provide protein and energy to the animal. However, because they are byproducts of the milling industry, the starch has been removed and they are not substitutes for starch or sugar sources. Feeds such as beet pulp or soy hulls work nicely in rations because they offer soluble fiber to the diet. Soluble fibers are carbohydrates that can be fermented in the rumen and they yield the volatile fatty acid, acetic acid, which is a weaker acid and will not dramatically lower rumen pH.

What should I do different next year?


Inventory planning is imperative. There are several resources available that will help you plan the allocation of forages to different groups of cattle. Consider the animal numbers and groups that you feed, carryover from this year’s silage, shrink and your storage options. Planning now to store forages for the next harvest can help you plan for adequate packing and feedout rates – which results in better-quality silage.

Strive for quality

If silage quality was a concern this year, think about what changes can be made. We can’t control the weather or other harvest delays or breakdowns. However, we can learn from this and make changes as harvest starts. Make sure you the have the equipment necessary to harvest or shorten the filling time. If delays occur in harvest, consider multiple bags or piles to control the inventory and quality. Plan for bacterial inoculants that can help jumpstart the fermentation process. Look for leaks or cracks in the structures and fix as necessary. Fine-tune the bunk-packing methods of the farm. Keep the face of the silage under control and use enough silage each day to stay ahead of the deterioration.

Select the hybrids

Determining the type of corn silage you plant begins with a planning process that should not be taken lightly. Corn silage hybrids should be selected for their yield and digestible nutrients. The University of Wisconsin offers a downloadable spreadsheet that accounts for the corn silage laboratory analysis of nutrients, digestible energy content, and harvest yield ( This data can generate an index which ranks silages on pounds of milk per ton silage dry matter or as pounds of milk per acre basis as a means to compare different hybrids. This tool can help you to choose corn silage hybrids that are suitable for your area.

Life always seems to send a curve ball. There are many things that are not in your control that contribute to difficult years. During these times it is important to remember the tools that are available to help in making our feeding choices and dealing with such conditions. PD

Dr. Carla Kuehn is a nutritionist at the Form-A-Feed and TechMix companies, headquartered in Stewart, Minnesota. For more information, send an e-mail to or call Kuehn at (800) 422-3649 .

Carla Kuehn
  • Carla Kuehn

  • Nutritionist
  • Form-A-Feed and TechMix
  • Email Carla Kuehn