The recent surge in ethanol production across the U.S. has fueled the popularity - and availability - of coproducts for use in cattle feedlot rations. Commonly called distillers grains, coproducts are simply the remnants of corn after the ethanol process is complete. They have gotten the green light from beef nutritionists and cattle feeders because they provide an excellent source of energy, protein and several minerals.

What makes coproducts even more attractive to cattle feeders is the fact that they are a low cost alternative to many of the traditional energy and protein sources.

"Coproducts are one of the least expensive protein sources available," says Kent Tjardes, an Extension beef feedlot specialist at South Dakota State University in Brookings. "The crude protein content of distillers' grains ranges from 25-32%, which can make it an effective substitute for soybean meal when soybean meal would be more costly in the ration," he says.

Research has also shown that coproducts can have energy values equal to or greater than corn, making them an economical alternative when corn prices are high. Other attributes ethanol co-products offer over standard grains include: increased palatability, increased digestibility, a high fat content, and a source of by-pass protein - all of which are beneficial for an animal's growth and performance.

Coproducts Aren't Perfect
Despite the long list of attributes, coproducts do have some shortcomings that require special considerations when including these feedstuffs in cattle rations.

"The primary challenge when utilizing coproducts in feedlot rations is that these feedstuffs are variable in nutrient composition and moisture content," says Evan Vermeer, a beef technical consultant with Quality Liquid Feeds, a leading manufacturer of liquid feed supplements.

"The moisture content can vary greatly among both wet and dry distillers grains," affirms Iowa State University ruminant nutritionist Allen Trenkle. He reports that wet distillers grains can have a 5-10% variation in moisture content. And, when coproducts are dried, the high temperatures can decrease degradation of the proteins in the coproduct and may reduce the overall availability of protein to the animal.

For example, even though a coproduct feed ingredient may analyze at 30% protein, only 25-26% may actually be available to the animal, Trenkle says.

Thus, when balancing rations with coproducts, special emphasis needs to be paid to protein content. "If you are feeding coproducts, make adjustments in the supplemental crude protein being fed in the diet, so you aren't overfeeding protein and creating extra expense," Trenkle says.

But also be aware that supplemental protein may be necessary in some instances. Vermeer explains, "Coproducts are high in undegradable intake protein (UIP), but to promote efficient digestion in feedlot settings, degradable intake proteins (DIP) like urea may need to be included in the ration."

Another consideration when balancing coproduct rations is phosphorus. "Coproducts are high in phosphorus, and practically devoid of calcium. Therefore, supplemental calcium needs to be provided to minimize that effect," says SDSU's Tjardes. A 1:1 ratio is typically recommended.

Higher phosphorus levels in the feed also mean higher levels in the manure, which could affect manure management plans - especially as environmental regulations get more stringent in the future. If feeding coproducts, Trenkle advises eliminating any supplemental phosphorus in the ration.

"When coproducts are included in corn-based rations, all supplemental phosphorus needs to come out. This is a cost savings to the feeder, and it minimizes the phosphorus level in the manure," he says.

As coproducts become more commonplace in the feeding industry, Trenkle says ration balancing supplements are being developed to address the nutrient deficiencies in coproducts.

"These supplements are unique because they are being developed specifically for use with coproducts. They contain nutrients that the coproducts lack such as degradable protein (urea), calcium (limestone), and other essential nutrients (vitamins and trace minerals) as well as other additives beneficial for peak animal performance," says Trenkle.

Are Coproducts For You?
The final hurdle in determining if coproducts will work in your feeding operation will hinge on availability and cost.

"Wet distillers grains are about 70% water. So, if you're not within 50 to 75 miles of an ethanol plant, transportation costs may be a limiting factor," says Vermeer.

Wet coproducts also require some special storage and handling. Tjardes points out, "Because the wet coproducts are so high in moisture, they can mold within 5-7 days in warm weather and can freeze into football size chunks in the winter. Therefore, much of the market for wet distillers' grains is local, and the products need to be used relatively quickly once delivered."

And, because coproducts are high in fat, special tanks may be necessary to heat or recirculate condensed distillers' solubles or syrup. "That can add some additional expense," Tjardes says.

Lastly, Trenkle says if you do plan to use coproducts, make sure you'll have a steady supply to meet daily feeding needs.

Once you've addressed all those concerns, Trenkle advises working closely with a nutritionist and going for it. "For those feeding cattle reasonably close to an ethanol plant, I encourage producers and feeders to look at utilizing coproducts," he says.

Trenkle adds, "Coproducts are a cost effective source of energy and protein, and they are safe feeds because most of the starch has been removed, which eliminates the risk of acidosis. Most feeders will probably feel comfortable including 12-15% coproducts in the ration at first, but we have fed distillers grains as high as 40% in the ration and corn gluten at 90% of dry matter in the ration with success. At those levels, you are overfeeding protein and phosphorus - and that may not be economical - but the cattle can perform well on those high levels of coproducts."

That said, the future combination of fueling cars with ethanol and cattle with coproducts looks to be moving full speed ahead. ©