In this article sponsored by U.S. Soy from the November 2025 Feedstuffs edition, Dr. R. Dean Boyd, Dr. Nathan Augspurger, and Cate Rush piece together the results of swine trials to calculate a regression curve that estimates the minimum level of soybean meal needed to maximize swine growth and discuss the applications and limitations of this curve.
Soybean meal (SBM) is a remarkable amino acid source that has been a staple in swine diets for more than 50 years. Until recently, swine nutritionists believed that alternative proteins to SBM could be made equivalent by correcting their amino acid deficits. However, maximum growth and feed conversion efficiency (FCE) cannot be achieved in the commercial environment without a ‘certain’ level of SBM.
The ability to improve growth rate of healthy pigs (without clinical signs of disease) with a specific SBM level is a new finding in animal growth expression. This is important knowledge for the commercial sector when growth rate is at a premium.
Conclusions:
- Maximum growth and FCE in the commercial setting is positively associated with dietary SBM level.
- A minimum SBM level is needed to maximize the expression of genetic capacity for growth in pigs.
- Minimum dietary SBM curve was developed for maximum growth, FCE and carcass lean of high-health pigs at all feeding stages from 24 to 295 lbs.
- Feeding diets with DDGS (e.g., 15%–25%) undermines the ability of SBM to maximize growth. When growth is at a premium then dietary DDGS should be kept to <10%.
Read the full article here. And read the other articles in the U.S. Soy Feedstuffs series here.