Distillers’ grains have become a common supplement to add more protein to beef cattle diets, but the valuable fat content has become more variable.
In recent years, many ethanol plants have been reducing the fat levels in the product. Nutrient levels can vary greatly, depending on where you get the distillers’ grains. The first such change came in 2012 with advent of the oil-removal process, says Galen Erickson, cattle industry professor of animal science and beef feedlot Extension specialist for the University of Nebraska–Lincoln.
“We’ve looked at this in six different diet experiments comparing regular distillers’ grains with de-oiled distillers’ grains,” Erickson says. “In those studies they turned off the oil-removal system at the plant, so we were comparing products from the same plant, and in many cases different batches from the same day at that plant. The feed was the same except for the oil content.”
Erickson says when people first started feeding distillers’ grains they were 12% fat. When the plants started removing the oil, the level went down to 8.5-9% fat.
“More recently they’ve been able to take out a little more oil; some of our last studies showed it was down to 7% or 8% fat, instead of 12%,” he says.
Erickson says they also looked at various components of distillers’ grains, such as protein value, energy, fiber, and at the solubles in liquid distillers’ products. Now some plants are putting in even newer processes, making a high-protein distillers’ dry product that can compete with soybean meal. It’s 38 to 40% protein instead of 30 to 32% protein, he says.
Even more protein
The extra protein is an important component that at first was not fully appreciated. “About 65% of that protein is utilized as bypass protein,” Erickson says. “If distillers’ grain is 30% protein and two-thirds of it is bypassing the rumen, it becomes energetically favorable. Excess protein that gets to the small intestine (that didn’t go through fermentation breakdown) doesn’t have any gas losses and has a lot of value for growing animals. Even in finishing cattle that don’t need the protein, it has value because the excess is burned for energy.”
Erickson thinks much of the high-protein distillers’ grains will be going to swine and poultry operations rather than beef cattle.
“The other product that’s left over, containing more fiber and solubles will probably be a good feed for the beef industry, and comparable to distillers’ grains,” Erickson says.
Most plants are now performing the oil-removal processes and this has an impact on its value for beef cattle, especially cattle on finishing diets. Erickson predicts the next phase will be looking at the value of protein and fiber in that evolving byproduct.
“We are currently researching those, and producers should think about protein not just from the standpoint of meeting the protein needs of cattle but also the excess—burning it for energy,” Erickson explains.
He adds that this may have more value for the finishing animal than for the beef cow wintering on low-quality forages.
However, the decrease in fat content may cause some reduction in performance among feedlot animals, says Ken Olson, Extension beef specialist, South Dakota State University.
“Fats and oils are energy-dense, and this was the original ‘magic’ for feedlot cattle when using distillers’ grains in a finishing diet because it contained both the protein and the oils,” Olson says.
Erickson agrees, saying the diets in his six studies that compared regular distillers’ grains with the de-oiled distillers’ averaged 2.3% poorer in feed efficiency with the de-oiled products.
“If we fed straight distillers’ we’d see a 7% decrease in the conversion, but most people only feed it as 30% of the total diet, so you’d see a 7% decrease in that 30% of the ration,” he explains.
Cow-calf feeds less affected
Some producers use distiller’s grains as protein supplement in winter for the cow herd, when cows are on dormant winter pastures or are being fed low-quality hay.
Ken Olson of South Dakota State University says when ethanol plants started taking the fat out, someone suggested that he do a research trial on the reduced fat in distillers’ grains as a protein supplement for wintering cows.
“I called a nutritionist who works for POET (a biofuel company headquartered in Sioux Falls, South Dakota) and he told me they were reducing the fat levels because this refines the ethanol process,” says Olson. “They are now milling off the seed coat and germ of the corn grain so that what they end up with is closer to pure starch to utilize in the ethanol fermentation process. All they want in the vat is starch, because that’s what’s converted to ethanol.”
“The milled-off seed coat and the corn germ product, which contains most of the corn oil and quite a bit of protein, is a product that can be used in chicken feed. What’s left after the starch is converted to ethanol still has some protein and a little corn oil, but it’s mostly the fiber part of the corn kernel.”
Removing the fat increases the protein content of what’s left. The protein is a higher proportion of the total volume, perhaps 40 to 50%, so it can be a good supplement.
“The study I did was simple, Olson says. “I used cows in mid-gestation. Half of them got the de-oiled distillers’ grain product as protein cake and the other half got soybean meal. Soybean meal has been the standard for a perfect protein supplement because it is easily digestible. Yet we seldom use it anymore as a protein cake because it is very expensive.”
He says both groups of cows had similar protein content in their diet, and both groups readily accepted the supplements. They maintained body condition on both groups through winter, and both types of supplement seemed to work equally well.
“As a protein supplement for cows on low-quality forages it works great,” Olson says. “If it’s meant to be an energy feed, as more commonly required in the feedlot, it has lost some value.”
“Energy from fat is great for improving growth but not a great source of heat. Fiber in the diet is more important for generating body heat (via heat of digestion in the rumen). Since what is left in the distillers’ grain after processing is mostly highly digestible fiber and protein, the fiber is probably a better way to heat the cow in the winter than fat. The fat is more important in a finishing diet,” Olson says.
Test for nutrient inconsistencies
Some ethanol plants remove the fat and some do not, so the end product for cattle supplement can vary quite a bit in fat levels.
As a rule, byproduct feeds are variable in nutrient levels anyway, Ken Olson, a nutritionist and beef specialist for South Dakota State University. “It doesn’t matter whether its distillers’ grains, corn gluten, soybean hulls or any other byproduct feed; they are highly variable from one batch to the next.”
His recommendation is to regularly send samples to feed-testing labs and not make assumptions. He notes that even in the days before the new milling process in distillers’ grains, nutrient levels were highly variable.
“Even producers who are getting their distillers’ grains from plants that are still using that old process should be testing every batch,” he adds. Tests should not only assess energy and protein content but also look at sulfur and phosphorus; those are the two minerals that are highly variable, and sulfur can be highly toxic in high levels,” Olson says.
The oils have been milled off, which means concentration of fiber and protein goes up, and another thing that goes up is phosphorus. Since beef cattle diets, especially in grass-based cow diets in wintertime, are often deficient in phosphorus, this can be a plus,
Since many cattle producers use a mineral supplement containing phosphorus, this can raise a red flag. If cattle are being fed a distillers’ grains protein supplement be careful about having phosphorus in the mineral supplement, Olson warns.
If there is a lot of phosphorus in the mineral, and a lot in the distillers’ grain, cattle may get too much phosphorus. Cows may go from being phosphorus-deficient to overdose, which also creates imbalance in the calcium-phosphorus ratio.
“The milling process varies from plant to plant,” Olson says. “Even within a plant, any adjustments (even with normal maintenance) to the roller mill that’s used to mill off the seed coat and corn germ will create differences, so you expect some variations.”
If everything in the milling is the same from batch to batch, there will still be some differences in the end product because no two corn crops are exactly the same in growing conditions and in what was planted. Olson suspects there may be huge differences between corn hybrids, for instance.
“Even the byproducts that have been with us for decades still have variations, so it’s wise to do regular feed testing,” Olson adds.
Thomas writes from Salmon, Idaho.