Table of Contents
Introduction
The expansion of soybean production is an interesting story, records show it was used in China since the 11th Century BCE, introduced to North America possibly during the American Revolutionary era, it was researched in the Southern USA for its forage production capabilities during the 1800’s, but acreage committed to the crop remained low.
Between World War I and II trade disruptions encouraged the domestic production of vegetable oil and soybean was discovered to be a good fit. It wasn’t until after World War II that it moved significantly to the Midwest and since the 1980’s that acreage advanced considerably in Wisconsin1.
Today we know it as the world’s number one oilseed and protein meal crop and production in South America often exceeds that of the US. Farmers in Europe are unable to import it as it is associated with the recent destruction of tropical rainforests2. Also since most North American Soybean is GMO, there are barriers with many countries for both the oil and soybean meal3.
Economic Advantage of Growing Soybeans
Soybean and alfalfa are some of the most productive legumes. Alfalfa will produce more protein per acre but you can’t combine it and crush the seed for oil and protein, in that area soybean is the best in the world. Soybean increased its acreage during the same time that nitrogen fertilizer became widely available. For a crop to compete for protein production during an era of cheap and abundant nitrogen availability is testament to the yield capacity of soybeans.
Logically it follows that growing your own soybean should be economical, cutting out the all the transportation, processing and distribution, the “middle man.”
Optimizing Soybean Processing
The feed industry has long separated the oil from the meal and the oil had more value outside of feeding to livestock. As dairy cows have become more productive, more fats and oils have been utilized to sustain production and bodyweight. However, there are enzymes that disrupt digestion, oils that depress intake and upset de novo fatty acid synthesis in the mammary gland, and highly soluble protein fractions that don’t fit in the diet as well as more rumen undegradable proteins. For about fifty years there has been commercial heat processing of soybeans, (roasting, extrusion) that solve the enzyme and protein fraction problems. Some careful use of particle size has also allowed utilization of soybean oil, but it has remained a problem. Also to keep the beans on the farm has meant itinerant soybean roasters moving from farm to farm to roast the beans. Standardization has been a problem, some beans were burnt, some remained raw, some were a mix of both. Some beans were left entirely whole and found in the manure, while others were reduced to a meal providing too much free oil. We have made huge success in improving fat test in cows today and excess free oil of the wrong type can tank fat test quickly.
High Oleic Soybeans
Plant breeders have entered into the equation. There are now “high oleic” soybeans. The fatty acid of these beans is actually beneficial for butterfat test, rather than depressing milkfat percent. As a new introduction there are challenges on the production end of high oleic soybeans. The maturities available are often longer season than what works well in Wisconsin, the further north you go the less adaptable the high oleic varieties are. Also the herbicide tolerance packages that are widely available are not the preferred ones for fighting invasive Palmer Amaranth and Water hemp. If grown, likely you will want to keep these beans on the farm, as they are not to be intermingled with non-high-oleic beans. There are outlets that will take them, possibly for a premium, but there are many fewer of them available so extra transportation and inventory management can be significant costs. Considering the high cost of some protected, or rumen unavailable, fats but also their effectiveness, growing your own comparable fat could be a home run, but there is a lot of management to cover.
Testing Heat-Treated Soybeans
Most commercial feed testing labs offer a test to measure the adequacy of the heat treatment and processing of your own or your heat treated soybeans. It is a test that is well worth the money. These tests indicate Protein Dispersibility Index (PDI), the desired range is 9-12%, a rough proxy for Rumen Undegradable Protein (RUP); Urease Activity (UA) the desired range is 0.05- 0.10 if urea is in the ration, UI is correlated with destruction of trypsin inhibitors, an anti-digestibility factor in raw soybean. Also Prost Ruminal Available Lysine (PRAL), is the best indicator of potential over-roasting, PRAL > 9 indicates good availability of lysine, an especially sensitive amino acid to heat damage. Roasting procedures requires a combination of temperature and holding time (steep.) Hsu and Sattler (1995) suggest heating soybeans to 295oF. and holding them for 30 minutes.
2025 Soybean Feeding Tips
Some guidelines for 2025 and whole soybean feeding:
- For high producing cows, don’t feed ANY raw soybeans (of any type).
- If well heat treated (must test to document) you may feed up to 5 pounds of soybeans but you may have butterfat test depression.
- If you feed heat treated, high-oleic soybeans, you may support very high production very economically, and you can feed beyond the five pound limit suggested for conventional soybeans.
- Beware of the agronomics- long season length, difficulty with managing invasive weeds, and many fewer options if you decide to market rather than feed the beans.
Some of the challenges with high-oleic soybeans are likely to be solved relatively soon, also if this trait could alter the nature of corn oil (further off) it probably would become widely adopted by dairy farmers.
References
NC Soybean Producers Association https://ncsoy.org/media-resources/history-of-soybeans/#:~:text=1100%20BC,Mr.
Everstream Analytics https://www.everstream.ai/risk-centers/eu-bans-imports-linked-to-deforestation/#:~:text=On%20April%2019%2C%202023%2C%20the,agriculture%20commodities%20and%20derived%20products.
National Library of Medicine National Center of Biotechnology Information https://pmc.ncbi.nlm.nih.gov/articles/PMC10038016/#:~:text=Despite%20their%20benefits%2C%20GMOs%20are,partially%20or%20fully%20banned%20GMOs.&text=Another%2060%20countries%20have%20significant%20restrictions%20on%20GMOs.
Reviewers
Luiz Ferraretto
Ruminant Nutrition Extension Specialist
University of Wisconsin-Madison, Division of Extension
Jackie McCarville
Regional Dairy Educator
University of Wisconsin-Madison, Division of Extension
Manuel Pena
Regional Dairy
University of Wisconsin-Madison, Division of Extension
Author
Matthew Lippert
Regional Dairy Educator – Matt’s focus is on dairy production, dairy cattle nutrition, dairy genetics and farm management. He works closely with grower organizations developing educational programs and newsletters.
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