Get the most from high-oleic soybeans in dairy rations
Introduction of high-oleic soybean varieties reignites discussion of soybean use in dairy nutrition.
By Lynn Davis
For years, numerous studies have consistently demonstrated the power of roasted soybeans — versus raw soybeans or soybean meal — in boosting milk yield and fat-corrected milk. Despite this, many practicing nutritionists have limited conventional oilseeds like soybeans in dairy rations to avoid a high polyunsaturated fatty acid load that can disrupt ruminal fermentation and, ultimately, valuable milk fat synthesis.
But the story doesn’t end there. The recent introduction of high-oleic soybean varieties — which contain more monounsaturated oleic acid over problematic polyunsaturated fatty acids — has reignited the soybean discussion in dairy nutrition.
A study in the Journal of Dairy Science demonstrated that these varietals, when in the ration up to 24% of dry matter, increase production responses of high-producing dairy cows without affecting body reserves. Furthermore, a recent economic analysis showed that high-oleic soybeans have the potential to boost income over feed costs and positively impact a dairy farm’s financial bottom line. This innovation reduces the risk of milk fat depression and puts processed soybean products back into the mix for dairy nutrition.
There is now growing interest from nutritionists, dairy producers and growers alike, and many in the industry see this trend taking off in the future. Will high-oleic soybeans take the place of other soybeans as growers put them in their pipeline? If so, how can we best process them for dairy rations?
Although we know from a recent Journal of Dairy Science study that roasted soybeans outperform their raw counterparts, our more recent work has focused on taking soybean processing beyond simple roasting.
We’ve delved into optimizing roasting methodology — the precise dance of time and temperature, even the effects of steeping and cooling. Moreover, we’ve explored how additional processing steps such as extrusion and expelling can push rumen undegradable protein levels even further than roasting alone. Interestingly, expelling also offers a pathway to reduce the fat content of the final product when that aligns with nutritional goals and economics.
So, how do you ensure you’re getting the most out of your processed soybeans? That’s where quality control comes in. Tools like the protein dispersibility index (PDI), Ross assay and multi-step in vitro protein evaluation (MSPE) are no longer just lab techniques; they are practical tools that can help nutritionists optimize the end product and ensure delivery of consistent, high-quality nutrition for cows and clients.
I'll be sharing the latest insights and practical applications of these advancements at the upcoming American Dairy Science Association Annual Meeting’s “Putting Science into Practice” Applied Nutrition day. The session on June 23 — with Kevin Harvatine of Penn State and Alycia Bales, Michigan State University — will delve deeper into how fine-tuning soybean processing, especially with high-oleic varieties, can unlock new levels of efficiency and productivity in the dairy herd. We’ll discuss optimal processing strategies, the importance of quality control and how to confidently incorporate these valuable feedstuffs into your or your clients’ rations for maximum benefit.
Lynn Davis is a dairy nutritionist and cofounder of Quality Roasting Inc. and Breeze Dairy Group LLC. He grew up on a small dairy farm in northwestern Wisconsin. After earning his bachelor’s degree in dairy science at the University of Wisconsin-River Falls, Davis went on to Iowa State University, where he received a master’s and PhD in animal nutrition.