Fibrous Feed Alternative - Soybean Hulls

Stephen Boyle
Beef Specialist
OSU Extension Service
7/99

Many fibrous feeds also have high energy values. The following are a list of fibrous feeds that offer potential for replacing hay or traditional grain sources. This article includes research that suggests these products may actually perform better than these numbers would indicate.

Crude Protein, Fiber, and Other Values of Selected Feedstuffs

 Feed

CPa
(%)

NDFb
(%)

NEmc
(--Mcal/lb---)

NEd
(--Mcal/lb---)

Corn 9.8 10

1.02

0.70
Beet Pulp 9.7 54 0.79 0.52
Citrus Pulp 6.7 23 0.91 0.61
Corn Gluten Feed 25.6 45 0.92 0.62
Cottonseed, whole 23.0 44 1.09 0.77
Dried Brewers Grains 25.4 46 0.68 0.41
Soybean Hulls 12.1 67 0.65 0.39
Wheat middlings 18.4 37 0.73 0.45
   aCrude Protein
   bNeutral Detergent Fiber
  cNet Energy Maintenance
  dNet Energy Gain

Potential Uses: Two areas of considerable potential for using the high-fiber by-product feeds, such as soybean hulls, corn gluten feed, and wheat midds, are to replace hay during the winter and to enhance performance of backgrounded calves. Considerable research has reported the high nutritive value of these feedstuffs to ruminants.

Supplementation with these feeds results in an increased bacterial protein flow post-rumninally similar to ground corn and increased ruminal fiber digestion. Therefore, supplementing fibrous by-products, such as soybean hulls, should enhance forage utilization by ruminants.

What are soybean hulls or soyhulls: Soybean hulls are a by-product of soybean processing for oil and meal production. Typically, soybean hulls do not require special processing to feed. However, soybean hulls have urease (an enzyme), activity which can be a problem in rations containing urea. Heat treatment destroys the urease activity. Soybean hulls which have been heat treated are referred to as soybean mill run, soybean flakes, or soybran flakes.

The fiber in soybean hulls is rapidly fermented and may contain substantial amounts of pectin. Soybean hulls are 67% NDF (neutral detergent fiber), but because of the their small particle size, the effective NDF is much lower.

Replacing Hay: Various researchers have conducted winter feeding experiments to determine the feasibility of using soybean hull in lieu of hay as a winter feed. In one study, cows were grazed on stockpiled tall fescue and fed hay (tall fescue) ad-libitum when pasture became limiting. Feeding 4 pounds of soybean hulls from December through March saved approximately 625 pounds of hay per cow and resulted in less body weight loss (13 pounds) than feeding hay only (86 pounds). Estimating hay costs at $80 per ton and soybean hull costs (delivered) at $80 per ton, more than $6 per cow was saved by feeding soybean hulls.

 Replacing Corn: Other work has been done using soybean hulls as a replacement for corn in steers maintained on forage-based diets. In one study steers were maintained on tall fescue. One set of steers were fed 4 pounds of soybean hulls and another set was fed 4 pounds of corn while on grass. A third set of steers received no supplement. The steers gained similarly on soybean hulls and corn (2 pounds per day gain), with both being greater than the gain of steers that were not supplemented (1.5 pounds per day gain). Soybean hulls have been found to be equal to corn for rate and efficiency of gain when fed as a creep supplement to steer calves. However, there are limits to soybean hulls being equal to corn. Feedlot steers fed corn or soybean hulls as the primary dietary energy source, had similar intakes and daily gains. But the soybean hull diet had poorer feed conversions than the corn diet. Soybean hulls appear to be more beneficial as a supplement for growing animals that are grazing or fed hay, compared with high energy feedlot diets. Differences in feed costs would determine which is the most economical choice.

Method of feeding: They are fed in whole, ground, or pelleted forms. One disadvantage of whole or ground soyhulls is that they are lightweight and have a tendency to blow in commodity barns or when being loaded in windy conditions.

Soybean Hulls Nutritional Content (100% Dry Mater Basis)

 Dry Matter 91%
Total Digestible Nutrients 78%
Crude Protein 11%
Crude Fat 2.2%
Crude Fiber 39.6%
Acid Detergent Fiber 50%
Calcium 0.49%
Phosphorus 0.18%