When Randy Shaver fields questions from dairy producers about ensiled cornstalks, he often refers them to the Koepke family.
“There's a real interest in stalklage in the industry right now,” points out Shaver, University of Wisconsin extension dairy nutritionist. “The Koepkes are the best resource I know of in terms of guiding other producers to do it the right way.”
They've been making stalklage on their Oconomowoc, WI, farm since the late 1970s. John Koepke manages the herd's nutrition program and handles most inquiries.
“I get more calls in years that producers are short of feed,” says Koepke, who farms with his wife, Kim; dad, Jim; and uncles, Alan and David.
They grow all of the corn, alfalfa and soybeans they need on 800 acres for their 320-cow herd, which has a rolling herd average of over 32,500 lbs of milk.
“Stalklage makes a good, low-cost feed for our heifers and dry cows,” says Koepke. “Up to 45% of the ration fed to our dry cows is stalklage. It's low in potassium and other minerals and has a lot of effective fiber, which helps prevent the build-up of body condition.”
Koepke knows grass hay could replace the stalklage in their heifer and dry cow rations, but says they don't have the acreage available to grow it.
“We live in a rapidly urbanizing part of the state, so land is at a premium,” he explains. “The stalks function very nicely as a second harvest coming off of our corn acres, and they're very plentiful.”
This fall, Koepke anticipates harvesting stalks from about 150 acres. They'll be ensiled in silage bags. Yields vary from ¾ to 2 tons/acre on a dry matter basis.
“Yields are dependent on a number of factors,” he says. “The first one is obviously the size of the corn crop, and the second one is the health of the plant at harvest. If disease is present and the plants are falling apart, a lot of material ends up on the ground.”
Experience has shown that later-maturity hybrids are likely to yield more than earlier maturities because they're typically taller and have more leaves. Bt hybrids also tend to yield more forage vs. conventional ones.
“Bt corn yields more because it has better late-season plant health. There's usually less insect damage.”
The family harvests stalks using an older chopper with a flail head. “We're usually picking up stalks within half an hour after the grain or high-moisture corn is harvested.”
Koepke recommends harvesting as close behind the combine as possible to preserve plant moisture and maximize yields. “The longer it sits, the better chance it has of settling to the ground, where it's not as likely to get picked up.”
He likes to chop stalks as short as possible, using a 3/16” theoretical length of cut.
“Length of cut will vary with harvest conditions. If it's foggy and cloudy, it chops a lot tougher and we get bigger pieces. If it's sunny, we get smaller pieces.”
Moisture levels can vary from 30% to 70%, but that's manageable, he says. “It's better wetter, but it doesn't have to be wet to be good. We've learned that, if we use forage inoculant and get bags sealed tightly, we'll be successful whether the stalks are on the drier or wetter end.”
Silage bags work better than tower silos for ensiling and storage, he says.
“We've put the stalks in a tower silo, but the upper portion can be a little questionable in quality. However, it can ferment fairly well in the tower silo if you have a heavier crop, like late-harvested hay, to pack it down.”
Heifers start getting stalklage in limited amounts at eight to nine months of age. As they get older and bigger, the diet gets proportionately higher in stalks. When they're close to calving, about 30% of their diets are stalklage. Other ration components vary, but might include hay, malt sprouts and brewer's grain.
In addition to stalklage, dry cows get soy hulls and small amounts of alfalfa haylage and corn silage.
“The stalklage makes our dry cow rations very easy to balance,” says the dairyman.
If you need to bulk up your heifer or dry cow rations, consider cornstalks, says Mike Hutjens, University of Illinois extension dairy nutritionist.
“If the stalks are chopped to a functional length, they can provide decent low-cost fiber,” says Hutjens.
He would be cautious about feeding them to milking cows, but they could be used instead of straw at low levels to bulk up high-energy, low-fiber rations. (See “Rationing Straw,” page 32.)
On a 100% dry matter basis, most stalks are approximately 5-6% crude protein, 11% lignin and 34% crude fiber. ADF, TDN and NDF levels are, respectively, 39%, 50% and 67%, he explains.
His feeding recommendations for cornstalks are similar to those for straw. “For dry cows, I would recommend feeding in that 6- to 10-lb/cow/day range or about 30% of the feed intake.”
Stalks can also be ensiled with distillers' grains at a ratio of ⅔ cornstalks to ⅓ distillers' grain, he says. “That's an awfully nice product for heifers over a year old. At feeding, just add minerals and urea.” (See “Stretching Supplies,” page 47.)
Producers have three options in harvesting stalks, he says.
“They can be sun-cured and harvested as dry stover and stored in bales or stacks, they can be harvested and ensiled immediately after the corn's been combined, or they can be grazed.”
If stalks will be ensiled, he urges producers to harvest them quickly because they'll start to dry out rapidly.
They also need to be at the proper particle length to provide effective fiber and prevent sorting.
“I like to see a coarse cut that's similar to coarse corn silage,” says Hutjens. “A 1-2” length of cut is ideal. If stalks are baled vs. chopped, you have to rely on your vertical or horizontal mixer to chop them up.”
Stalks should also be as dirt- and mold-free as possible. “If they're clean, you'll probably be in pretty good shape.”