Using corn for livestock grazing

Typically corn is grown and harvested by livestock producers for either grain or silage. As livestock producers try to reduce their cost of production, many look at ways to reduce their feed cost.

Feed cost has been identified as the biggest single cost of producing an animal making up 50 percent to 70 percent of the cost of production. To reduce feed cost, producers are exploring options to extend the grazing season.

Grazing option. The grazing of standing corn can be a viable alternative forage in some operations. Corn provides several options to livestock producers. As an annual, it is extremely flexible as to when it can be grazed. It has been successfully used during the summer, fall and even winter. Using livestock to graze corn reduces the need for investment in harvest and feeding equipment.

With the potential to produce more than 10 tons of dry forage per acre, few annual crops can compare to corn in terms of dry matter (DM) yield per acre and cost per rate of gain.

Any hybrid of corn can be grazed. Although if the field is only intended for grazing, then the selection should be narrowed to hybrids bred for silage or grazing. There have been several corn varieties bred for high forage yields, high digestibility, low fiber levels and high stover digestibility. Hybrid selection should start with identifying a group of hybrids that are adapted to the area in terms of maturity, disease and insect resistance and drought tolerance and tonnage.

Production changes. Corn intended for grazing can be planted the same as if it was intended for grain or silage. Most corn in Ohio is planted early May to early June. Early planting will produce more dry matter per acre than later planted corn.

When planting no-till or into a sod field, a planter box seed treatment should be used to control wire worms, seed corn maggots, and other corn insects. Care should be given to the type and amounts of herbicide used when planting grazing corn. Since this corn is to be grazed, post emergent herbicides probably are unnecessary. Early season weed control can be achieved with pre-emergence or pre-plant incorporations of herbicides. Late season weed control may not be an issue since this can be accomplished by the grazing animal.

The current edition of the Weed Control Guide for Ohio Field Crops, Bulletin 789, contains a listing of grazing restrictions for different corn herbicides. Check current labels for grazing, harvest and replanting restrictions prior to herbicide use.

Livestock nutrition. Grazing corn can be utilized by many categories of livestock. Stocker cattle, beef heifers and cows have excellent weight gains grazing corn. Dairy farmers have utilized grazing corn to feed dairy cows and dairy heifers for breeding. Sheep, goats, and swine have all been used to graze corn successfully.

From the animals’ nutritional standpoint, grazing immature corn is similar to grazing other summer annuals. The big difference comes when the plant reaches maturity. As the corn matures and dries, the loss in the feed value of the forage, leaves and stalk, is compensated by the gain in value from the grain produced. The main decision for the grazer is deciding when additional forage is needed in their systems.

Corn, being a warm season annual grass, can be planted as it would be for grain or delayed planting as producers would for corn silage. Consequently, harvest by grazing may take place from 30 to 100 or more days following planting.

Traditionally, producers have planted grazing corn as they would for corn silage, planting corn in late May or early June and grazing it 70 to 90 days following planting. This late summer and early fall grazing allows them to rest and stockpile their perennial pastures for late fall and early winter grazing.

Mid-summer slump. Most of our pasture grasses are cool season grasses that go dormant during the hot summer months of late June, July, August and early September. Corn can be grazed for that mid-summer slump that occurs when the temperatures are hot and the moisture is short.

If forages are short during a dry period in early June, some producers have had success grazing sheep on corn when the plants are 18 inches tall. They rotated the animals quickly as to protect the growing point (3-4 inches above the ground).

Corn may also be grazed in late summer or extremely late in the season, even after it is fully mature, providing needed energy and shelter during the winter months. Typically, the corn plant loses some leaves and stalks begin to break down as the winter progresses. This causes a loss in highly digestible plant matter and protein. However, the remaining stalks, leaves, and grain are still excellent supplemental feed for over wintering beef cows, stockers, and growing animals.

Depending on the type of livestock used, producers may need to supplement to compensate for lower protein levels. In an upcoming issue, we’ll discuss how to actually graze the corn.

(Jim Hoorman is an extension agent specializing in water quality in Hardin County. Clif Little and Jeff McCutcheon are agricultural and natural resources agents.)