My ethanol co-product inventory is low. What protein sources can I feed my cattle?

Due to pricing and availability, many producers have become accustomed to buying corn ethanol co-products such as dried distiller’s grains with solubles (DDGS) to use as protein sources in rations. Several ethanol plants have had to shut down or scale back on production due to significant reductions in fuel ethanol demand as a result of the COVID-19 pandemic.  This is causing a supply shortage and an increase in price of distillers grains.  So, the question is what else can I feed in place of distillers grains?

Ethanol Co-Product Alternatives

Fortunately, several alternative protein options are available.  However, for this discussion only dry protein sources will be considered.  The first alternatives would be other plant derived protein sources.  The most common plant derived protein sources available in Wisconsin are soybean meal or corn gluten feed.    Some beef producers may consider utilizing raw soybeans they have grown on their farms.  Information for feeding raw soybeans can be found in this article Considerations for feeding raw soybeans at the Wisconsin Beef Information Website.

Another protein alternative option is non-protein nitrogen sources (NPN), such as urea.  Non protein nitrogen sources have limitations on how they can be used depending on the other feed sources and energy levels of the ration, which will be discussed later in this article.  Protein levels for a variety of feedstuffs are shown in Table 1.

Table 1.  Average crude protein content of various feedstuffs commonly offered to beef cattle.

Feedstuff Crude protein, %1
Alfalfa meal 16
Brewers grains, dried 22
Corn gluten feed, dried 21
Corn gluten meal, dried 57
Cottonseed meal, solvent extracted 42
Dried distiller’s grains w/ solubles 28
Flaxseed/Linseed meal 20
Soybean meal 46
Soybeans, whole, raw 38
Urea (non-protein nitrogen source) 287

1Source: https://animalnutrition.org/feed-composition-database  accessed 3/20/20 excluding urea.  Values are expressed on a 90% dry matter basis.

The various pellets, crumbles, and tubs that many feed companies have available are also a  protein option.  Some of these products are labeled as a “natural” protein supplement.  Natural refers to not having an NPN source.  These natural protein products often range between 24-38% crude protein.  Many protein products from a feed company will include sufficient minerals eliminating the need for additional mineral supplementation.  Natural protein products will be slightly more expensive on a price per pound of crude protein basis.  In addition, feed companies also sell protein products that include a blend of plant derived protein and NPN sources.  Urea is the most common NPN source utilized in dry feeds, but biuret is a slower rumen degrading form of NPN that may also be utilized.  On a price per pound of crude protein basis, urea is usually the cheapest source of protein .

If feeds contain NPN, feedtags will include the amount of NPN protein in the feed.  The statement often reads as “This includes not more than XX.X% equivalent crude protein from non-protein nitrogen.”  As an example, a protein supplement may list a guaranteed minimum crude protein level of 44%.  The feedtag states the product contains not more than 18% equivalent NPN protein.  The product would have approximately 40% of the protein from NPN sources (18% NPN / 44% CP).

Considerations for Feeding NPN

Feeding NPN as a protein source is best utilized when feeding diets containing rapidly fermenting carbohydrates such as starch.  Feedlot diets containing mostly corn and/or other cereal grains are ideal for urea.  Urea should be avoided when feeding feedstuffs high in NPN as excessive ammonia production in the rumen can lead to disorders and potentially death. Alfalfa haylage, drought stressed corn or sorghum silages which have accumulated nitrates are examples of feedstuffs in which supplementing  with urea should be avoided.   If water sources are known to contain elevated NPN sources urea should not be offered.    Additionally, urea should not be fed in combination with raw soybeans due to the urease activity of soybeans and risk of ammonia toxicity.

One rule of thumb is NPN sources should not provide more than 1/3 of the total crude protein in the diet.  For example, if a diet contained 13% crude protein, urea should not provide more than 4.3 crude protein units (13% * 0.33).  Another feeding guideline is that the diet should contain no more than 1.5% of urea on a dry matter basis.  This is simplified by recommending no more than ¼ to a 1/3 of a pound of urea be fed daily to a finishing animal.  Generally, urea is avoided in light weight calves and diets comprised of low-quality forages.  In larger feedyards, urea is often delivered mixed into liquid molasses.  Having the urea mixed into a liquid supplements improves mixing and reduces the risk of sorting.  When adding urea sources to diets, ensure it is evenly mixed with the other feedstuffs.

Cost Considerations

The cost of the protein source needs to be considered as well.  A commercial feed that includes the minerals would eliminate the need to provide additional mineral supplement.  It is important to take into account the value of the minerals and other feed additives that are included in some of the manufactured feeds when comparing different feed options.  In many instances, one may purchase alternative protein supplements in bags instead of bulk.  Bagged feed prices will be higher and discounts will be seen if ordered in bulk.

Determining the price per unit of protein is one approach at determining which protein source may be economically better.  Price alone is not the only decision driver.  Handling, mixing, sorting, risk of feeding disorders and other factors should also be considered.

UW-Division of Extension has a decision tool “Feed Cost Comparison for Protein and Energy” to help determine cost considerations of protein alternatives. This tool is available on the Wisconsin Beef Information Center Decision Tools and Software section. Please note that all information in blue cells in the spreadsheet tool, including prices, are examples and should be updated to fit your situation.

Closing Thoughts

In summary, when a protein source becomes limited in availability there are other alternatives to seek out.  Availability of different protein sources may vary over the next few months and it may be necessary to adapt as needed to what is available. Do your homework to learn protein, energy and other nutrient levels in the feedstuffs that are available.  Consider the price on a nutrient basis.  Work with your nutritionist to develop a new feed ration that will meet the nutrient needs of the animals and avoid feeding disorders.  For more information contact your county Extension office and visit with your nutritionist.

Article originally written by: Jeff Lehmkuhler, Katie VanValin, Darrell Johnson, Kevin Laurent, Darrh Bullock, Les Anderson from the University of Kentucky, and adapted for Wisconsin by: Bill Halfman, Ryan Sterry, Amanda Cauffman, UW Madison Division of Extension Livestock Educators, Dr. Megan Nelson, UW Madison Division of Extension Livestock Program Manager and Bernie O’Rourke UW Madison Division of Extension Livestock Specialist  

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