Hay supplies are limited in parts of Iowa going into winter, following last summer’s dry weather. Hay for sale is fetching high prices. It’s more important than ever to take advantage of grazing cattle on corn crop residue. Crop residue is often an underused resource that can help reduce the cost of wintering beef cows.
“While we call this ‘cornstalk grazing,’ in reality the cattle eat very little of the stalks,” says Joe Sellers, an Iowa State University Extension beef specialist. “Many acres of cornstalks are also mechanically harvested for bedding and feed. But in that case, nutrients are removed from the field and need to be replaced. Grazing will recycle nutrients.”
Corn crop residue helps meet feed needs
Cattle prefer to eat the grain first, followed by the husk and leaf and finally the cob and stalk. Under normal harvest conditions, there is very little grain left in the field. If cows have husk and leaf to select, they will consume a diet that is 52% to 55% total digestible nutrients (TDN) and about 5.5% to 7% crude protein. University of Nebraska data indicates there will be about 16 pounds dry leaf and husk per bushel of corn yield.
Sellers suggests these best management practices for corn residue grazing:
• Strip grazing. This will improve use of the crop residue. Graze smaller areas for a few days and then move to ungrazed fields.
• Supplemental feeding. Pregnant cows in midgestation can graze recently harvested crop residue with no supplementation other than free-choice mineral. Cows nursing calves and cattle grazing a single field later in the window would require both protein and energy supplementation. Corn coproducts such as distillers grains with solubles or corn gluten feed can be a good option.
• Evaluate each field. Due to high winds in Iowa in October, there may be fields with more lodging and, as a result, extra grain left in some fields. The amount of corn ears and grain needs to be evaluated, cattle need to be adapted to the grain, and grazing should be allocated in small portions to reduce the risk of acidosis.
• Manage soil conditions. Many studies have shown well-managed corn residue grazing does not reduce the subsequent corn or soybean yields. Not grazing when fields are muddy and removing the cattle before spring thaw and rainy weather will ensure success.
• Cover crops work well. Some fields may have a combination of corn crop residue and cover crops, such as cereal rye. This would be an even better quality feed for your herd.
• Plan winter grazing. University of Nebraska-Lincoln has a grazing calculator that may help you plan your winter grazing.
UNL also is managing an exchange to connect landowners with potential graziers on crop residue and cover crop acres. A group from Iowa including Iowa Beef Center staff and Practical Farmers of Iowa are in discussions with UNL to see if Iowa can join that effort.
Source: Iowa State University