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Use Caution When Feeding Soybeans to Cattle

With drought impacting feed availability, and tariffs reducing soybean exports, some of us may be looking at ways to use what we have a lot of to make up for a lack of grazeable forage. While soybeans can be fed to cattle we need to be careful with how much we feed and we need to understand potential, harmful interactions with other supplements. To help with that I’ve included information from a two of sources that represent what I found elsewhere: a fact sheet from Mississippi State Extension and a Press Release from the North Dakota State Agriculture Commission.

Beware of Fat

Soy beans

According to Daniel Rivera and Jane Parish, Mississippi State Extension Specialists, raw whole soybeans contain 40% crude protein and 20% fat on a dry matter basis. That high fat content means that you need to limit soybeans in the diet so that it never exceeds 6% for mature cattle of 4% for growing cattle. They say that “High fat levels can lead to reduced digestibility of forages and other feedstuffs; interfere with calcium, magnesium, and vitamin A absorption; cause fluctuations in feed intake; and result in scours (diarrhea).” When the oil content of the ration exceeds 7%, it can be toxic to the microbes in the cattle’s rumen and decrease digestibility. Too much oil in cattle rations can even lead to cessation of rumen fermentation and, eventually, death.

Because of this, do not feed whole soybeans free-choice or at levels that exceed total dietary fat recommendations. Rivera and Parish add that “Grazing soybean stubble containing whole beans can result in over-consumption and is not recommended.”

Soybeans Aren’t Good for Swine, Horses or Nursing Calves

Raw soybeans have enzymes that can inhibit digestion and reduce the use of nutrients or food intake, which affects livestock’s growth. The beans need to be heat-treated, which inactivates these substances. Monogastrics, like swine and horses are especially affected by this, as are nursing calves or calves under 300 pounds. Because calves may eat soybeans offered to their mothers, feeding these cows soybeans is not recommended.

Do NOT Feed Raw Soybeans With Other Supplements Containing Urea

Check the ingredients on your protein tubs to make sure you’re not going to cause problems.

Rivera and Parish warn that “Many commercially available protein tubs and blocks contain urea, which can potentially be fatal to cattle when fed in conjunction with raw soybeans. Range cubes may also contain urea.”

The reason? Raw soybeans contain urease which breaks urea down into ammonia. This rapid breakdown of urea into ammonia in the rumen can potentially led to ammonia toxicity and cattle death.

Mold Cautions

Damaged soybeans may have mold that may not even be visible so in addition to a feed nutrient analysis, you should add an aflatoxin screening before feeding raw soybeans. Calves are especially susceptible to “aflatoxicosis” which can cause death, but is usually seen as unthriftiness, weakness, anorexia, reduced growth and feed efficiency, and occasional sudden deaths.

How to Feed Soybeans

“Because of these limitations, the recommended upper limit of feeding would be about 20 percent of the ration,” says Karl Hoppe, Extension livestock systems specialist at North Dakota State University’s Carrington Research Extension Center. “Practical feeding levels are probably more like 2 to 3 pounds per head per day. At this low rate of supplementation, soybeans provide an excellent source of protein and energy.”

Spring Valley Family Farms cattle graze on pasture for the first 10 to 12 months of life, and then for three to four months their diet is supplemented with hand-feeding of a mix of corn, soybean meal and cottonseed. Photo courtesy of Delta FarmPress

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Kathy Voth
Kathy Voth
I am the founder, editor and publisher of On Pasture, now retired. My career spanned 40 years of finding creative solutions to problems, and sharing ideas with people that encouraged them to work together and try new things. From figuring out how to teach livestock to eat weeds, to teaching range management to high schoolers, outdoor ed graduation camping trips with fifty 6th graders at a time, building firebreaks with a 130-goat herd, developing the signs and interpretation for the Storm King Fourteen Memorial trail, receiving the Conservation Service Award for my work building the 150-mile mountain bike trail from Grand Junction, Colorado to Moab, Utah...well, the list is long so I'll stop with, I've had a great time and I'm very grateful.


  1. I just returned from a trip to Wisconsin (eastern). What was once a dairy region is now almost all cash crops: corn, winter wheat, soy, alfalfa. I saw no grazing by dairy cows, although I didn’t make a great survey. Lots of the soy had quite the weed load, almost certainly due to poor spraying practices and/or resistant weeds. For the good of that fine farmland, maybe backgrounding some beef and grazing might be a good idea instead of soybeans for export.

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