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Q and A about grazing cornstalksQ and A about grazing cornstalks

An expert answers questions about whether grazing reduces yields, trims organic matter and more.

August 4, 2016

3 Min Read

Residue grazing is a good way to integrate crop and livestock enterprises, says Warren Rusche, South Dakota State University Extension cow-calf field specialist.

"Residue grazing results in a win-win. It represents an opportunity to cut feed costs for ranchers, or serve as a source of supplemental income for crop farmers, without hurting yields next year."

Related:6 steps to prevent cattle from getting sick when grazing cornstalks

The added acres of corn in the Dakotas have produced more residue than available for feed. Because the land cost is charged to the crop enterprise, crop residues are much less costly than either summer pasture or harvested feeds, he says.


Rusche answered the following questions about grazing cornstalks:

Which animals can graze cornstalks?
Crop residue grazing works extremely well for beef cows in midgestation. Because cows will select the higher-quality husks, leaves and any whole ears left in the field, they should not require additional energy or protein supplementation as long as they are not forced to consume poor-quality portions of the plant, such as the stalk. Even cattle with greater nutrient requirements, such as growing calves or replacement heifers, will perform well grazing stalks when provided supplemental protein.

Will grazing cornstalks reduce crop yields next year?
The University of Nebraska recently published the results of a 10-year study on the effects of grazing cornstalks in the fall on soybean yields the following year in a no-till system. In those studies, soybeans planted after cornstalks, which were grazed in the fall, yielded about 3 bushels more compared to ungrazed cornstalks. The same pattern was shown in a one-year comparison at the SDSU Southeast Research Farm, although those differences were not statistically significant.

Will cows remove too much residue that it reduces soil organic matter?
The long-term yield results from Nebraska would suggest that this has not been a significant problem in that system, but it is possible to estimate the quantity removed compared to the amount of residue produced. For every bushel of corn, there is approximately 45 pounds of residue. The husks and leaves represent about 16 pounds of that total. If a 1,400-pound cow consumes 2.5% of bodyweight per day, in 30 days she would eat about 1,050 pounds of husks and leaves. However, not all of that organic matter leaves the field. From 40% to 50% of the husks and leaves are indigestible, meaning that of the 1,050 pounds consumed, about 400 pounds return to the field as manure for a net removal of 650 pounds. A field that yields 150 bushels per acre will produce 6,750 pounds of total residue. In that case, the 650 pounds removed represents only about 10% of the total. Keep in mind that if the field is not grazed or tilled, the husks and leaves can be to be blown into the ditch or fence line.”

Source: SDSU

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