Whole Raw Soybean a Competitive Protein Supplement for Cows and Calves

October 17, 2025

Whole Raw Soybean a Competitive Protein Supplement for Cows and Calves

By Aaron Berger - Beef Extension Educator

A feed truck delivers a mixture of hay and grain into a concrete bunk at a feedlot as black and white cattle eat. Numbered pen markers line the fence in the background under clear skies.

With soybean prices dropping, raw, whole soybean is becoming a cost-effective alternative to traditional protein sources like distillers grains and alfalfa hay. Learn how to safely include soybean in cow and calf diets this fall and winter to boost protein intake without risking digestion or performance issues.

Chabella Guzman | PREEC Communications

Current market conditions for raw, whole soybean are making them price competitive in parts of Nebraska with other protein sources, such as distillers grains and alfalfa hay, to be used as a protein supplement for cows, as well as weaned calves.

The following are some principles to remember when feeding raw, whole soybean to cattle.

Soybean is approximately 40% crude protein and 20% fat and should be introduced gradually into the diet. Because high fat levels in cattle diets can negatively impact fiber digestion, they should not be fed at a level higher than needed to meet protein requirements in the diet. 

In growing calves, limit soybeans to 7% of the diet or less, and 5% or less in finishing diets. 

Raw soybean contains a trypsin-inhibiting enzyme important for protein digestion in non-ruminant and monogastric animals. Because of this enzyme, raw soybean should not be fed to nursing calves and calves less than 300 pounds. 

Raw soybeas also should not be fed to animals receiving a diet containing urea. Soybeans contain the enzyme urease, which breaks down urea into ammonia at a very rapid rate. Toxicity occurs when the rate of ammonia entering the bloodstream overrides the liver’s capacity to filter it out.

The protein in soybean is approximately 70% rumen degradable and 30% rumen undegradable. Growing calves being fed corn silage and other feeds that are low in rumen undegradable protein show improved average daily gain performance when protein sources — such as distillers grains that are high in rumen undegradable protein — are utilized to meet protein needs. Feeding raw whole soybean in place of distiller’s grains to meet protein needs in a diet that is predominantly corn silage would result in decreased animal performance.

Raw, whole soybean has a total digestible nutrient value of 91%. While it is a price-competitive protein source at current commodity prices, there are other sources of energy that are more economical. Therefore, they should be used primarily to meet protein requirements.

For mature cows on forage-based diets, soybeans should not be fed at more than 10% of the diet on a dry matter basis. This would be approximately 2-3 pounds per day. Cows needing 0.4-pound of supplemental crude protein per head per day could be fed two pounds every other day and meet their protein requirement.

Raw, whole soybean can be an excellent protein source when utilized as a supplement. Producers looking for an economical protein source for cows to complement low-quality forage should consider the potential of using raw, whole soybean this fall and winter.

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