DUBUQUE, Iowa — The best way for cattle to consume cornstalks is by grazing them in the field.

“Cattle pick out the best stuff,” said Galen Erickson, animal science professor at the University of Nebraska-Lincoln.

“Cattle will eat the grain, which there isn’t much of anymore, the husks, the leaves, and leave the other stuff, which is lower in digestibility,” he said during a presentation at the Driftless Region Beef Conference, sponsored by University of Illinois Extension, Iowa State University Extension and Outreach, University of Minnesota Extension and University of Wisconsin Extension.

“We’re on a mission in Nebraska to use residues better because we think this is a resource we’re not utilizing fully,” Erickson said.

“In Nebraska, if we graze all the cattle we have, which is just under 2 million cows, we harvest all the residue we need to feed 1 million back grounding calves and all the roughage needs for 4.5 million head of cattle, we use 10 of our irrigated corn acres,” he noted.

However, the professor said, cattlemen can’t just feed more baled cornstalks and expect great performance by their cattle.

“Baled stalks can be variable. You have to watch soil contamination. We’re really interested in the leaves and husk, not the stems, but you get those with it, and moisture and weathering can be a problem,” he said.

“Historically, alfalfa hay and corn silage were the gold standards for roughage because they gave us better performance than if we fed cornstalks, wheat straw or residues,” he added. “But with distillers’ grains, feeding cornstalks is equivalent to feeding alfalfa hay.”

Making Better Feed

University researchers are looking at how to make cornstalks a better feed for cattle.

“The concept was to use an alkaline treatment, which is not a new concept, because in the ‘70s there was a lot of work done to ammoniate residues,” Erickson noted. “We chose to use calcium oxide to alkaline treat the residue to increase the fiber digestibility.”

For the process, the researchers ground the stalks with a three-inch screen.

“We weighed it into our truck, added 5 percent calcium oxide and 50 percent water,” the professor said. “This must sit for five to seven days.”

The researchers stored the treated cornstalks anaerobically in bags, although Erickson said that’s not necessary in commercial situations.

During his presentation, he discussed several research trials.

“Since corn was getting expensive and residue was inexpensive and abundant, our goal was to determine if we could improve the residue and get similar performance,” he said.

“Ensiling stalks will make them more palatable, but it is debatable how much it improves energy,” he noted.

In one study the researchers ground the cornstalks to a one-inch size.

“I think it’s better to try some things you may think are crazy because periodically those things work,” the professor said. “The one-inch grind improved gain and conversion. But I don’t think many producers are going to grind to one inch.”

A lot of studies completed in Nebraska that included feeding 20 percent treated stalks in place of 15 percent corn have worked well, Erickson said, as long as the ration included 35 percent to 40 percent distillers’ grains.

“Feeding treated stalks works, but you may not get identical performance,” he noted. “But feeding treated stalks is always better than just feeding 20 percent stalks.”

“However, for this to be economical, grain has to be expensive, residue has to be cheap and distillers’ grains have to be a good buy relative to corn,” he said.

A lot of research was completed 40 years ago that focused on feeding silage to cattle.

“In 1974, corn was $3.50 a bushel, which at that time was more expensive than corn today, at $7 or $8 per bushel,” Erickson said. “Since grain is getting more expensive, we want to revisit this area, and it is different today because we have a lot of distillers’ grains.”

Price Matters

Pricing corn silage is an important aspect of evaluating corn silage in a ration.

“We estimate the corn silage price is 7.65 times the price of corn, and you still have to harvest and add the cost of storage,” Erickson said.

“You put up corn silage at 35 percent dry matter, which is not at maximum grain yield,” he said. “So we’re going to do research on putting up drier corn silage.”

In addition, the professor stressed the importance for cattlemen to account for the shrinkage of corn silage.

“If I put up 10,000 tons of silage to feed for the year and there is 15 percent shrink, I need to divide by 0.85 or I’ll run out of silage,” he said.

In a study, the researchers fed cattle a ration of 40 percent distillers’ grains with either 15 percent, 30 percent, 45 percent or 55 percent silage on a dry batter basis.

“We only swapped out corn for the corn silage,” Erickson said. “The gains go down. The conversions got worse if you increase silage in the diet in place of corn, but the question is if the ration is economical.”

The researchers fed yearling cattle either 20 percent or 40 percent distillers’ grains with either 15 percent or 45 percent silage.

“If you feed 15 percent silage versus 45 percent silage with 20 percent distillers’ grains, we saw a 5 percent increase in conversion,” Erickson said. “If you fed 15 percent or 45 percent silage with 40 percent distillers’ grains, we saw a 5.6 percent hurt in conversion.”

With a 10 percent shrink in corn silage and $3.50 corn, the professor said, we think it is economical to feed corn silage.

“If corn goes up to $5, it becomes more economical,” he said.