A crop that was initially developed for the human food market is now being served up in heaping portions to the humble dairy cow.
High oleic soybeans were born out of the human nutrition movement away from trans fats and partially hydrogenated oils in the early 2000s. Through plant breeding and genetic modification, soybean varieties with more monounsaturated fat (oleic acid) and less saturated fat were developed.
The result was an oil with healthier fats and a longer shelf life that did not require hydrogenation, and was also more heat stable with a longer “fry life.”
Then, voila! Dairy nutritionists caught onto the fact that those same properties made the fat in those soybeans more rumen-friendly and less prone to biohydrogenation in the rumen. The result: the ability to feed more rumen-available unsaturated fat with less risk for milk fat depression and greater energy efficiency for the cow.
“We’ve been feeding high oleic soybeans since about 2017, but recently there has been an explosion of interest from dairy nutritionists on how to utilize these on-farm,” said Dr. Kevin Harvatine, Professor of Nutritional Physiology at Penn State University. “It’s by far the number-one thing I’ve been getting questions on in the last year and a half or so.”
Harvatine shared his insights on the unique feedstuff on a recent episode of the “Real Science Lecture Series” by Balchem. He described feeding high oleic versus conventional soybeans as a “no-brainer,” thanks to the reduced risk for milk fat depression that they afford.
What sort of production response can be expected from feeding high oleic soybeans? Harvatine said like nearly every question in dairy nutrition, “it depends.” But a study published in the Journal of Dairy Science showed an average increase in milk fat of 65 grams/cow/day at a 5% feeding rate.
Another study estimated an improvement in income over feed cost of 15-20₵/head/day, even factoring in a 50₵/bushel premium on the high oleic soybeans.
From a production standpoint, Harvatine cautioned that growing conditions and seasonality of the crop can cause the fat concentration in the beans to swing from year to year. “We know that higher temperatures during seed filling can increase the oil concentration,” he shared. “Double-crop beans are filling in cooler temperatures, and are expected to have a slightly lower fat concentration.”
But he’s a big fan of the opportunity to produce “home-grown” fats, from both an economic and quality control standpoint. “We can really drive profitability when we have home-grown feeds,” he noted. “Since our fat prices have been up recently, this brings a really neat opportunity to the dairy.”
Now, in addition to growing excellent energy and digestible fiber sources, it is possible to also grow the fat, which also can fit squarely into crop rotations with those other crops like corn. “Here we have a nitrogen-fixing plant that can work well into some crop rotations, depending on the situation,” he said.
Finally, while dietary fat and milk fat production may be the primary objectives for feeding high-oleic soybeans, Harvatine cautioned not to forget about value in protein that they also bring to the table.
“Soybeans have a big impact on your metabolizable protein and amino acid absorption that has a large impact on milk protein yield,” he advised. “When you’re least-costing a ration, be careful to do it based on both the fatty acid and protein/amino acid balancing that they provide.”
Harvatine continued, “If you’re feeding these beans, you can’t be feeding them just for fat and thinking about milk fat. You need to also be thinking about them as an integral part of your protein balancing.”
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