The purpose of this project was to determine if feeding high soybean meal (SBM) diets with adjusted branch chain amino acids would optimize sow lactation performance. In this study, three hundred and fifty-two sows were fed one of four dietary treatments in lactation: low SBM, high SBM, LSBM with adjusted branch chain amino acid ratios, or HSBM with adjusted branch chain amino acid ratios. Increasing SBM inclusion by 14% reduced sow feed intake by approximately 9%, but did not alter sow bodyweight or backfat loss or piglet growth rate. While adjusting the amino acid ratios in the low soybean meal diet slightly reduced sow feed intake, the observed reduction in feed intake was greater in sows fed the high soybean meal diet with adjusted amino acid ratios, suggesting the quantitative branch chain amino acid level in diets containing elevated SBM levels may contribute more to reducing sow feed intake than the relative balance between the branch chain amino acids. Furthermore, the reduction in feed intake did not impact sow reproductive performance or piglet litter growth rates.

This work further adds to the body of knowledge around the allowable inclusion levels of soybean meal in sow diets. Previous research suggested that high levels of soybean meal in lactation could reduce feed intake. This study documents that feeding higher levels of soybean meal can reduce feed intake and while branch chain amino acids may be a factor in the response, it is not a significant driver in the response. In addition, in this work, the reduction in feed intake did not result in negative responses and; therefore, feeding higher levels of soybean meal may not always be a concern. Additional work needs to be conducted to determine what other factors in soybean meal could be driving this response. This work is important as pork producers could utilize more soybean meal in rations when soybean meal prices into the diet as long as factors that could reduce feed intake are addressed.