New research shows that changing to a higher-fat soybean meal could improve dry matter intake and milk production without sacrificing milk fat.
In the study, extruded soybean meal containing 10 percent fat was substituted for solvent-extracted soybean meal containing 1.8 percent fat in lactating dairy cow diets, explains Alex Hristov, professor of dairy nutrition at Penn State University. Dry matter intake increased by 2.65 lbs/cow/day and milk production climbed 7.5 lbs/cow/day for cows fed the high-temp extruded soybean meal with 10.9 percent fat. (Total fat in the diet was 4.3 percent on a dry matter basis.) Milk fat, milk protein, and feed efficiency did not change.
While increased fat in the diet is part of the response, it alone did not drive the results. "I think palatability is the key here," says Hristov. "The combination of increased palatability due to higher fat content; increased energy density in the diet due to additional fat, and increased rumen undegraded protein supply from the heat treatment during processing led to these results." Improved palatability led cows to eat more. It's that increase in DMI that drove the increase in milk production.
Some producers and nutritionists are hesitant to formulate a diet with more than 3 or 4 percent total fat. However, lactating cows can benefit from up to an additional 2 to 3 percent total fat in the ration, he says. The product used in the research was a 10 percent fat extruded soybean meal. But there are other heat-treated soybean meal products with up to 6.6 percent fat, such as SoyPlus, that could still deliver an increase in DMI and milk production.
It really depends on the product you select, but producers may feed a lower fat heat-treated soybean meal and still get the benefit of increased intake and milk production, says Hristov. The role of RUP should not be underestimated. "The 6.6 percent fat product is an excellent by-pass protein soybean meal product. I would expect improved cow performance when using it to replace solvent-extracted soybean meal in the diet."
In the Penn State study, the key was the palatability of the product and the increased dry matter intake. If it is not highly palatable it will not drive increased dry matter intake to see positive results.
To read the full paper "Extruded Soybean Meal Increased Feed Intake and Milk Production in Dairy Cows," in the Journal of Dairy Science, please go to: http://dx.doi.org/10.3168/jds.2015-9786