ANGUS BEEF BULLETIN EXTRA

January 6, 2020 | Vol. 12 : No. 12

management

Feed Supplements: Changes in Distillers’ Grains

Changes in distillers’ grains still good for maintaining cows through the winter.

Distillers’ grains are a byproduct of the ethanol industry and have become a common supplement for beef cattle to add protein in the diet. The fat content is also beneficial. In recent years, however, many ethanol plants have been reducing fat levels in the residue that ends up as cattle feed. Cattle producers need to be aware that nutrient levels can vary greatly, depending on where you purchase the distillers’ grains.

Without the oil, energy value of this feed is reduced, says Ken Olson, extension beef specialist at South Dakota State University.

“As a protein supplement for cows on low-quality forages, the de-oiled distillers’ grain works great; but if it’s meant to be an energy feed in the feedlot, it has lost some value.”

“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,” he says.

Some cow-calf producers use distillers' grains to augment protein levels in the diet when cows are on dormant winter pastures or fed low-quality hay. About 12 years ago, however, some ethanol plants started removing the fat to refine the ethanol process.

“They are milling off the seed coat and the germ of the corn grain, ending up with something that’s closer to pure starch in the fermentation process, because that’s what is converted to ethanol,” says Olson.

The seed coat and the corn germ product, which contains most of the corn oil and quite a bit of protein, are generally used in things like chicken feed. What’s left after the starch is converted to ethanol still has some protein and a little oil, but it’s mostly the fiber part of the corn kernel, he explains. Removing the fat increases the protein content of what’s left, because the protein is a higher proportion of the total volume.

The protein in this residue may be as high as 40% to 50%, says Olson. He did a two-year study using cows in mid-gestation; half of them received de-oiled distillers’ grain product as protein cake and the other half got soybean meal.

“Soybean meal has been considered the perfect protein supplement because it’s easily digestible, yet we seldom use it anymore because it is very expensive,” he says.

Both groups of cows in his study received similar protein content, readily accepted the supplements, and maintained body condition through winter.

“As a protein supplement for cows on low-quality forages, the de-oiled distillers’ grain works great; but if it’s meant to be an energy feed in the feedlot, it has lost some value,” he explains.

For mature cows on winter pasture, however, the reduction in fat doesn’t matter.

“Energy from fat can improve growth rates, but is not a good source of heat. Fiber in the diet is more important for generating body heat (via digestion in the rumen). Since what is left in the distillers’ grain after processing is mostly highly digestible fiber and protein, this is a better way to heat the cow in winter than fat,” Olson says.

There is some fiber in the supplement, and the protein enables cows to more adequately digest low-quality forages.

Since some ethanol plants are removing the fat during processing and some are not, the end product for cattle supplement can vary in fat levels.

Producers need to remember that all byproduct feeds are variable in nutrient levels — whether distillers’ grains, corn gluten, soybean hulls or any other byproduct. They are highly variable from one batch to the next, Olson warns. As a nutritionist, he advises producers to regularly send samples to feed-testing labs and not just assume they contain a certain level of a specific nutrient.

Tests should not only assess energy and protein content but also sulfur and phosphorus levels, because these can be quite variable. Sulfur can be toxic at high levels.

Grass-based cow diets in winter are sometimes deficient in phosphorus, and many producers use a mineral supplement containing phosphorus.

If cattle are fed distillers’ grains, which may contain high levels of phosphorus, you don’t need phosphorus in the mineral supplement, says Olson. If the calcium-phosphorus (Ca:P) ratio is too far out of balance, it can be detrimental to the cow and to the growth of her fetus.

Editor’s note: Heather Smith Thomas is a cattlewoman and freelance writer from Salmon, Idaho.