New research and on-farm trials are showing that corn silage can be effectively replaced with corn stover – the plant’s stalks, cobs and leaves – when these harvest residues are treated with a common food ingredient known as hydrated lime.
“Stover is a challenge and an opportunity,” says Steve Peterson, a Monsanto employee who spoke to about 100 farmers and farm professionals at a Sept. 5 meeting in Fond du Lac co-sponsored by Didion Ethanol, Monsanto and the Wisconsin Corn Growers Association. “Growers are starting to spend time managing stover.”
Peterson says there are a number of beef producers in Nebraska, Iowa and Illinois who have been feeding corn stover treated with hydrated lime to their cattle. Wisconsin dairy and beef producers are just starting to learn about feeding corn crop residue to their cattle.
The alternative feeding strategy, which could improve feeders’ financial returns by lowering input costs without impacting the animals’ physical development, has been proven through studies at Iowa State University and the University of Nebraska.
In cattle-feeding trials, adding hydrated lime to corn stover rendered the plant material sufficiently digestible to constitute up to 25% of cattle rations after the treated stover was combined with wet distillers grains. The protein-rich feed ingredient is a bi-product of corn ethanol production.
Hydrated lime, or calcium hydroxide is used in a variety of food applications, from pickling and preserving fruits and vegetables to adding calcium to fruit juices and baby formulas. It is formed by mixing water with calcium oxide derived from limestone.
“You have to treat the stover to get good results,” Peterson explained.
The treatment process involves combining ground or chopped stover with the hydrated lime solution, then storing the treated stover in an oxygen-free container—typically a plastic “ag bag” or a bunker—for at least a week. A 1,200-pound bale of corn stalks can be treated with approximately 50 pounds of calcium hydroxide. The solution loosens the chemical bonds between the stover’s less-digestible lignins and its more digestible components. The relaxing of these bonds enables natural enzymes in a cow’s rumen to digest the stover. The same treatment process can make wheat straw digestible to ruminants as well.
During a six-month Iowa State University trial involving 210 steers, the treatment enabled scientists to cut the percentage of grain in animals’ rations by half –from 70% to 35% -- without impacting the animals’ growth or development. Use of the treated-stover rations resulted in a higher profit per steer than for grain-fed animals.
A similarly structured, University of Nebraska study involving 330 steers showed equal success. Similar trials supported are underway at University of Wisconsin-Madison, University of Illinois and Purdue University. The UW-Madison study involves feeding treated corn stover to dairy heifers and dry cows.
Peterson notes that there are advantages to feeding treated corn stover and distillers grains to dairy or beef cattle:
*Beef cattle fed treated corn stover and distillers grains performed as well as cattle fed a high-grain diet.
*On-farm stover processing can be done using existing equipment such as a TMR mixer and large baler.
*Feeding treated corn stover adds value to crop residues.
“In a year like this one, dairy producers who need to extend their feed supply can use either corn stover or wheat straw and save as much as $27 to $55 per head per year,” Peterson said. “It can really lower ration costs for dry cows and heifers.”
Brian Barlass, who milks 400 registered Jersey cows near Janesville with his parents Bill and Marion, says this is the second year they have been feeding treated corn stover to their heifers.
“Next year, we’re thinking about feeding it to dry cows, too and maybe even or milking cows,” Barlass says. “It all depends on how the feed analysis comes out.”
Barlass believes treated corn stover has the potential to save dairy and beef producers a lot of money.
“This will free up some corn silage so instead of harvesting so much corn for silage we can harvest some grain and sell that,” Barlass says.