Immature Soybeans for Feed

The following is from a 1996 Fact Sheet prepared by the Cooperative Extension Service of the University of Illinois at Urbana-Champaign and was submitted by Dr. Herb Buckholtz, Animal Science, Michigan State University.

An alternative for soybeans that will not produce seed due to late planting, frost damage, weedy conditions or poor yield is to use the crop as an alternative forage crop. The crop can be grazed, green chopped, or harvested as silage or hay. The nutrient profile will be similar to legume forages (alfalfa, clover or peas). Stage of maturity will affect yield and quality (Table 1).

Table 1. Yield and quality of soybean forage as influenced by maturity
(Source: University of Wisconsin, 1987 and 1989).

Based on the data, delay harvest as long as possible. But once the lower leaves begin to turn yellow and drop, harvest must begin to avoid leaf loss (high in protein and dry matter content). The stems will be difficult to dry because of hairs (pubescence) on the stems and leaves. The hay will be dusty. Silage should be wilted to dry matter levels optimal for your storage unit (30% for bunkers or bags, 40% to 50% for conventional upright silos, and 50% to 60% for oxygen-limited units). Soybean forage can be mixed with corn silage before ensiling (typically one part soybean forage to two parts corn silage on a dry matter basis).

Check the Herbicide Label For Restrictions If Soybeans Have Been Treated. Many soybean herbicides do not allow grazing or feeding of the crop.

Livestock will readily consume soybean forage if it is properly harvested and stored. Calcium (1.2% to 1.6%) and phosphorus (.20% to .25%) levels will be similar to other legume forages. Adjust your mineral program accordingly. A wet chemistry forage analysis should be conducted to measure nutrient content.

Another alternative is to harvest the soybeans as green seed.

Green soybeans are acceptable sources of protein and energy. Fat (19%) and protein (37%) levels in green seed can be slightly lower than mature beans, but can be an excellent buy if immature soybean seed is discounted at grain terminals.

Be sure moisture levels are low enough for safe storage. The beans may be shrivelled and hard, which may require processing prior to feeding. If the beans are green, they can be heat treated, but higher temperatures and steeping times may be needed to reach optimal undegraded intake protein (UIP or by-pass) values.