Can raw soybeans be used in swine diets?

Since the 1930s, pork producers have known raw soybeans contain anti-growth factors. Use of raw soybeans in swine diets has been discouraged because of decreased pig performance. Anti-growth factors in raw soybeans are destroyed when beans are heated at the proper temperature. The result is an excellent source of supplemental protein.

Soybean meal, a by-product of the soybean oil industry, has been effectively used by the swine industry as a source of supplemental protein. Soybean meal is produced from raw soybeans by processes requiring energy to remove the oil from the beans. Roasting and extruding raw soybeans also requires energy expenditure, adding extra cost to diets using these products.

Previous research has indicated that raw soybeans can replace soybean meal as the supplemental source of protein in gestating sow diets. Also, research has shown that gestation diets supplemented with fat improved pig survival. Raw soybeans contain about 18.5 percent crude fat and average 36 percent protein. The use of raw soybeans in gestating sow diets could be beneficial to the swine producer. Possible advantages include:

• fat content of the diet could be increased without using a liquid fat source.
• mechanical energy could be conserved from the processing of raw beans.
• cost of the diet could be reduced.

Because raw soybeans contain a high level of crude fat, the soybeans should not be stored for any length of time in the ground form without the addition of an antioxidant. It is recommended that only the amount of beans needed in the complete diet be ground, mixed and fed to the gestating sows. Diets containing raw soybeans (without antioxidants) should be mixed frequently in the summer months.

The replacement of soybean meal in a gestation diet with raw soybeans will require more pounds of the raw soybeans than soybean meal to equal the same protein level. Therefore, when evaluating the economics of feeding raw soybeans (RSB) compared to feeding soybean meal (SBM) in gestating sow diets consider the difference in the levels of ingredients (Table 1). Also, one must consider the cost of including a fat source to the soybean meal diet if increasing dietary energy is a desired goal.

Most of the time, replacement of soybean meal with raw soybeans will not be cost effective based upon current ingredient costs. In the event a greater than normal price spread in raw soybeans and soybean meal occurs, the addition of raw soybeans to a gestation diet may become cost effective. This situation may develop when soybeans are damaged or discounted at market. Other considerations in comparing the value of raw soybeans include the addition of fat to the diet and any increase in survival rate of the pigs. If feeding raw soybeans produces an increase in pig survival rate, using raw soybeans will become more cost effective.

Conclusion

At this time, the use of raw soybeans in swine diets other than gestating sow diets is not recommended. The use of raw soybeans in grower/finisher diets will greatly reduce daily gain and increase cost of production. It appears the only diet raw soybeans can be fed without decreasing production is in the gestation diet of sows from breeding to farrowing.

Note: The diets listed above are intended to illustrate cost comparisons and should not be used for mixing feed.