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
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.
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
Making Better Feed
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.
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.
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
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
“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.