In This Section |
Feeding Green Soybeans to Pigs
The dry conditions we experienced in Ontario this past summer, aggravated by long periods of extremely hot weather, sapped precious moisture and left many soybean fields without enough water to allow the soybeans to naturally reach maturity. The result was somewhat similar to an early frost, but without the usual problem of high moisture seeds that won't dry down. During harvest, producers saw dry soybeans that either had a green seed coat or were green throughout the entire soybean because of the presence of chlorophyll. Whole soybeans typically contain 16 to 20 percent fat (dry matter basis). In the literature, drought-damaged soybeans, particularly green-colored beans, have been reported to have lower protein (anywhere from 25-38%) and fat (14-18%). Laboratory results to date from this year's crop indicate that protein and fat levels are running at the upper end of these ranges with no difference between green and yellow soybeans. However, due to variability in composition, soybeans should be analyzed for nutrient content before formulating rations. All swine rations are balanced for energy, protein (lysine specifically), as well as minerals and vitamins. Diets containing green soybeans should be balanced on a lysine basis to compensate for the lower lysine levels that may be present in immature soybeans. A study conducted at South Dakota in 1992 determined the feeding value of frost-damaged soybeans for grow-finish pigs. In this study, diets were formulated based on analyzed nutrient content of the soybeans. Essentially, there was no difference in the feeding value of extruded frost-damaged soybeans or mature soybeans. Pigs fed extruded soybeans (either frost-damaged or mature) gained as fast as pigs fed a soybean meal-based diet, and there was no difference in carcass quality. Since nutritional value of frost-damaged soybeans may differ from drought-stressed soybeans, a research trial is currently underway at the University of Guelph to determine the impact of high levels of green soybeans in swine rations on performance and carcass quality. Since there is the potential that the green chlorophyll may be incorporated into body fat, fat quality and colour will be monitored. The results of the experiment should be available in December 2002. General Guidelines for Feeding Full Fat SoybeansSince they contain trypsin inhibitors and other anti-nutritional factors, raw soybeans have little application in swine rations, except gestation diets. However, when raw soybeans are heat-treated (extruded, roasted, or micronized), they have a feeding value similar to that of soybean meal. Properly cooking soybeans with either a roaster (240°F to 250°F for 2.5 to 3.5 minutes) or an extruder (exit temperature of 280°F to 300°F) destroys several of these anti-nutritional factors and produces an acceptable protein source for growing, gestating and lactating pigs. Cooked full-fat soybeans cannot replace soybean meal on a weight-for-weight basis because they contain less protein and lysine than soybean meal, while containing more fat and energy. Because of the high fat content, heat-treated whole soybeans offer an alternative to adding liquid fat to swine diets, especially for on-farm mixing. Full fat soybeans fed at high levels may cause deterioration of carcass and meat quality, especially in hogs fed corn-based rations. As a result, full fat soybeans should be limited in finishing hog diets to 10 per cent of corn based rations. Further Information on Feeding Green Soybeans to Pigs
See the following articles: For more information:
|
This site is maintained
by the Government of Ontario
Queen's
Printer for Ontario
Last Modified:
