A total of 2,153 finishing pigs (PIC 337 × 1050; initially 28.8 ± 0.47 kg) were used in a 112-d growth study to determine the productive energy of soybean meal (SBM) relative to corn and feed-grade amino acids. Pens of pigs were blocked by initial BW and allotted to 1 of 4 dietary treatments in a randomized complete block design. There were 26 or 27 pigs per pen and 20 pens per treatment across two barns. Soybean meal NE value used in diet formulation was 2,087 kcal/kg (78% NE of corn). The four treatments consisted of a diet containing a low level of SBM (Low SBM) and three diets with 3.37 (Med-Low SBM), 6.69 (Med-High SBM), or 10% (High SBM) increase in SBM compared to the Low SBM diet. Feed-grade amino acid inclusion decreased as SBM increased with the High SBM diet not containing any feed-grade L-lysine. Treatment diets were fed in four phases. Pigs were weighed and feed disappearance was measured every 14 d to determine ADG, ADFI, G:F, and caloric efficiency (CE). Overall (d 0 to 112), there was a decrease (linear, P < 0.05) in ADG and ADFI as SBM level increased, but there was no effect on G:F. Caloric efficiency improved (linear, P < 0.05) as SBM increased suggesting a greater NE concentration than initially estimated. Increasing SBM decreased (linear, P < 0.05) carcass ADG and carcass G:F, but there was no effect on carcass CE. Increasing SBM decreased (linear, P < 0.05) HCW and carcass yield. Backfat depth and percentage lean were lowest and greatest, respectively, (quadratic, P < 0.05) for pigs fed the intermediate levels of SBM. There was an increase (linear, P < 0.05) in pig removals with increasing SBM but no treatment effect on mortality. However, when combined, removals and mortality were increased (linear, P < 0.05) as SBM increased. The results of this study suggest that when using caloric efficiency, the productive energy of SBM is estimated at 93.5% on a liveweight basis and 83.9% on a carcass weight basis of the energy of corn.

Kim, T., E. Stas, H. Cordoba, M. Tokach, R. Goodband, J. DeRouchey, J. Woodworth, K. Gaffield, J. Gebhardt and K. Haydon. 2025. Determining the productive energy of soybean meal relative to corn and feed-grade amino acids. 2025 American Society of Animal Science Midwest Section meeting, Abstract 179.