Corn: a valuable fall-grazing resource

Summer months provide the warm, sunny conditions needed for a great growing season, but without adequate moisture from either precipitation or irrigation, crops can quickly become drought stressed. In some cases, crops can be salvaged as standing forage. Two University of Missouri (MU) Extension specialists recently explained how to utilize corn residue for grazing.

Livestock Specialist Eldon Cole consulted with a row crop farmer about a drought-stressed field of corn expected to yield 4.5 bushels per acre. Instead of harvesting the corn, Cole and the farmer worked out a plan to use the corn for forage.

The following steps allowed 80 cow-calf pairs and 20 more pregnant cows to thrive on a crop that would have otherwise been considered a loss.

• Assess plant population. In this case, the plant population was 25,000 plants per acre.

• Establish fencing. A 6-foot mower cleared a path for the new fence rows, and a single strand of wire powered by a solar charger established boundaries for the cattle.

• Move cattle daily to new paddocks. Creating a routine helps the cattle adjust to their new living environment and grazing conditions. Also, giving them only what they need for one day reduces waste.

• Test the forage. Cole suggested testing the forage crop for nitrates before turning livestock out to graze, especially if the forage crop was drought stressed. Nitrate toxicity symptoms can range from reduced appetite to death if not monitored and managed.

Cornstalks are valuable, too

MU Extension beef nutritionist Eric Bailey explained that even if a grain crop is harvested, the remaining cornstalks provide an economical source of forage that will help extend the grazing season.

“Cows are selective grazers, choosing the highest protein and most digestible parts first,” said Bailey. “First, they will eat the corn grain, leaves, and husks, and then finally the stalks.”

Consider the needs of your livestock. Cows may need little or no additional supplements for the first 30 days of cornstalk grazing. After a month of grazing, protein could become limited to meet 0.5 pounds of crude protein per cow per day, and cows may require additional supplements. “Consider the livestock type using grazing the cornstalks, as the needs of lactating and fall-calving cows or stocker calves may be greater,” Bailey said.

To figure stocking density, Bailey uses a simple rule of thumb for quick estimates: Bushels per acre divided by 3.5 equals grazing days per acre for a 1,200-pound cow. For example, if the field produced 150 bushels per acre, then it would provide enough residue for 42 grazing days (150 divided by 3.5).

The beef specialist said a more exact approach can also be used, noting that 16 pounds of leaves and husks will be produced for every bushel of grain. “For a 150-bushel-per-acre crop, there will be 2,400 pounds of dry feed per acre,” Bailey explained. “Assume 1 acre per cow per month and try to leave cows on the field less than two months. This estimate is more conservative than the previous one, but it will keep cows from consuming the lowest-quality stalks and cobs. Some dry matter is lost to trampling or weathering, so assume 50% harvest efficiency,” he added.

Advancements in equipment and technology have made it easier than ever to take the cows to feed instead of bringing the feed to them, which saves farmers time and money. According to Bailey, “Another side benefit is that cows will return nutrients to the land in the form of manure, and they will eat corn grain that has fallen on the ground, which may reduce the amount of volunteer corn in a field the following year.”

Bailey said grazing cornstalks can also save producers money by avoiding shredding and baling costs.

C.J. Weddle

C.J. Weddle served as the 2020 Hay & Forage Grower editorial intern. She currently attends Mississippi State University, majoring in agricultural education, leadership, and communications. She grew up on a farm in Vardaman, Miss., where her family raises sweet potatoes and soybeans.