Comparing Soybean Meal Products for Dairy

The ruminal degradability and lysine bioavailability of four soybean meals were determined in three studies conducted at Kansas State University. The four soybean meal products were: 1) solvent SBM, 2) solvent SBM treated with 0.05% baker's yeast and toasted at 100°C, 3) expeller SBM, and 4) lignosulfonate-treated SBM. Dietary treatments were formulated by substituting all of the solvent SBM and part of the ground corn with the other three SBM s to yield isonitrogenous diets. The diets were formulated to provide adequate ruminally degradable protein, but deficient ruminal undigestible protein and metabolizable protein supplies. No differences among dietary treatments were observed for dry matter intake, body weight gain, milk and component yields, or efficiency of milk production. The research group concluded that the lack of response to changes in SBM source was likely due to an adequate RUP and metabolizable protein supply by all the diets. The in situ ruminal degradations of yeast/toasted SBM and lignosulfonate-treated SBM were slower than those of solvent or expeller-processed SBM were; thus, ruminal undigestible protein contents of these meals were greater than those of the solvent or expeller-processed SBM. All SBM products had similar small intestinal digestibility. Available lysine contents, estimated chemically or by using a chick growth assay, were less for yeast/toasted and lignosulfonate-treaded SBM than for solvent or expeller-processed SBM, suggesting at the toasting and lignosulfonate treatment reduced lysine availability.

Awawdeh, M.S. and co-workers. 2007. Ruminal degradability and lysine bioavailability of soybean meals and effects on performance of dairy cows. J. Dairy Sci. 90: (4740-4753).