As far as full-fat bean feeds go, are roasted beans superior to extruded beans?
Roasted, full-fat soybeans are not superior to extruded beans. In fact, adhering to the guidelines for roasting vs. extrusion is much more difficult with roasting. It is essential to exercise rigid control over the heating and the diet formulation; Maintaining proper temperature, speed through the roaster, etc. makes proper roasting of soybeans a real art. However, it can be done and many people do so. Really, it is a matter of economics more than feed quality.
Roasted soybeans are also used in dairy rations. I am sure there is a significant cost difference between the two methods.
The economic feasibility of feeding extruded soybeans to swine is affected by the differences in nutrient content compared to soybean meal, the need to increase the protein in diets containing whole soybeans, the value of extra fat and the cost of processing. In order to determine if using extruded soybeans is economically feasible, the following equation can be used:
A = .86 Y + .18 Z -(S+C), where
A = Cost advantage of extruding soybeans
Y = Cost of a ton of soybean meal (44%)
Z = Value of a ton of supplemental fat
S = Value of a ton of soybeans
C = Cost of extruding a ton of soybeans
.86 comes from 38 w 44 (38% protein in soybeans and 44% protein in soybean meal); .18 is for 18% extractable fat from soybeans. The cost advantage of extruded beans depends on the realtive value of soybean meal and soybeans (holding supplemental fat constant at 15" per pound and extrusion cost at $40 per ton of soybeans).
It requires 35 bushels of whole full-fat soybeans to make a ton of extruded beans due to the loss of >moisture (5%) during the extrusion process.
"Properly" roasted soybeans can be used in growing-finishing swine diets. But to effectively use roasted (heated) soybeans as a replacement for soybean meal, it is essential to exercise rigid control over the heating and the diet formulation. In using roasted soybeans I would recommend the following:
1. The temperature of the roasted beans should be within 220 to 245 degrees F at the discharge point.
2. When roasted, full-fat soybeans serve as a complete replacement for soybean meal as a source of supplemental amino acids, the dietary protein level should be increased 1 to 1 1/2% to maintain the same dietary calorie:amino acid ratio.
I am not familiar with all of the portable roasters that are advertised, but the key is the ability of the roaster to reach the "proper" temperature and the length of time the bean travels through the roaster.
Roasted soybeans can be used in swine rations. Research has evaluated the nutritional value (metabolizable energy ME, etc) of roasted soybean. In general,soybeans that are properly roasted, that is processed with sufficient heat to inactivate anti-nutritional factors but not destroy the protein, make good source of protein for swine.
The use of roasted soybeans versus Soybean Meal is as much an economic decision as a nutritional decision. Several research studies comparing roasted soybeans to soybean meal have indicated that properly roasted soybeans are nutritionally equal or possibly superior to soybean meal for swine. The key, of course, is "properly" roasted soybeans. When soybeans are roasted, as opposed to extruded, they must be roasted at the correct temperature and the correct length of roasting time. Proper roasted soybeans should not have enough residual trypsin to result in decreased protein utilization. But, again, I emphasize the importance of "proper" roasting procedures.
Please allow me to give you the results of a Nebraska study comparing roasted soybeans to soybean meal.
272 cross bred pigs in three studies were fed diets differing in the manner in which ground roasted soybeans replaced soybean meal in 14% and 16% crude protein corn-soybean meal diets for pigs from 50 to 230 pounds live weight. In general, the treatments used in these studies did not affect average daily gain. A slight improvement in feed conversion was observed when roasted soybeans were substituted for soybean meal in the diet. The researchers concluded that,overall, the replacement of soybean meal with roasted soybeans provided neither beneficial or adverse animal performance. If you can formulate nutritionally adequate diets for growing-finishing pigs and lactating sows using properly roasted soybeans for a lower feed cost, I would encourage you to do so.
This information is provided by:
Gilbert Hollis, Ph.D.
For more information about Dr. Hollis, see the Swine Management and Nutrition Answers page.