Extension and Ag Research News


Make the Most of Corn Residue

Corn residue can help cut winter feeding costs for beef cattle.

Grazing corn residues is one way to reduce the cost of wintering beef cows in the upper Midwest, a North Dakota State University cattle expert says.

Corn residue left behind after harvest includes the stalk, leaf, husk and cob, as well as downed ears. The amount of downed ears varies with the corn variety, but it can be as much as 3 to 5 bushels of corn per acre, according to Greg Lardy, North Dakota State University Extension Service beef cattle specialist.

Generally, approximately 50 pounds of residue is left on the field per bushel of corn harvested. For example, a producer who harvests 120 bushels of corn can expect about 6,000 pounds of residue per acre (120 bushels times 50 pounds of residue per bushel).

Obviously, the cow will not graze or use all of that material. At most, a cow will be able to graze about 50 percent of that material (in this example, about 3,000 pounds per acre), Lardy says. One acre of corn residue should support a 1,000-pound dry cow for 1.5 to two months. Strip grazing the fields (dividing the field and limiting access using electric fencing) will improve utilization and allow producers to increase the stocking rate.

The residue portions with the greatest nutritive value include the husk and leaf. The cob is fairly high in digestibility, but very low in protein. The stalk is low in both protein and digestibility.

Cattle are selective grazers by nature. They choose the most digestible and nutritious plant parts first. As a consequence, the longer the cattle graze a particular corn field, the lower in nutrient content their diet will be. This is due to the cattle selecting the higher-quality material first and the loss of nutrients due to weathering. Longer-term grazing may require protein supplementation to meet the nutrient needs of grazing beef cows.

Corn residue also is low in most minerals and vitamin A. Producers should follow a good-quality vitamin and mineral supplementation program when grazing corn residue, according to Lardy.

Corn residue can be grazed long into the winter feeding period, provided snow cover does not limit the cow’s selectivity and grazing ability. The length of winter grazing time will vary from year to year. Once fields are snow-covered, the cow’s ability to select the higher-quality portions of the corn residue is limited.

Two factors are the biggest limitations to grazing corn residue in this area of the country. First, many corn fields are not fenced and, second, many do not have adequate water for grazing livestock.

“However, the amount of residue available for grazing and its cost effectiveness should cause beef cattle producers to at least consider this option as one means of lowering the cost of winter feeding,” Lardy says.

Grazing corn residue also may have other drawbacks. One is an increased risk of founder or acidosis if fields have greater than normal levels of downed ears. Gradually adapting cattle to grain prior to turnout into the cornfield may be warranted if high levels of downed ears are present, Lardy says.

Soil compaction is another issue. It’s often cited as a reason for not grazing corn stalks. However, data collected in Nebraska and Iowa demonstrate that this generally is not a major problem and grazing corn residues does not affect subsequent yields negatively.

“Producers interested in reducing the cost of production for their cow herds should seriously consider the use of corn residues for fall and winter grazing,” Lardy says. “It will typically be more cost effective than other forage feeding options.”

For more information, contact Lardy at (701) 231-7660 or gregory.lardy@ndsu.edu.

NDSU Agriculture Communication

Source:Greg Lardy, (701) 231-7660, gregory.lardy@ndsu.edu.
Editor:Ellen Crawford, (701) 231-5391, ellen.crawford@ndsu.edu
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