Cows grazing standing corn: A feed option for this summer, fall, and winter
Pasture and hay are in short supply in much of Nebraska due to drought conditions while the price of corn is currently below the cost of production. These circumstances are prompting the consideration of the opportunity of grazing standing corn with the cow herd as a feed option for the rest of the summer, fall and winter.
Summer Corn Grazing – Drought Stressed Fields
In some regions, drought-stressed corn may be released by crop insurance and would provide an option for grazing. A Nebraska Extension article titled “Forage Options for Drought-stressed Non-irrigated Vegetative Corn and Nitrate Concerns” provides information on utilizing dryland, drought stressed corn as a harvested feed or grazing resource. When considering grazing drought-stressed corn, first check herbicide labels for any grazing restrictions.
Will nitrates be a potential concern? Yes, it could be an issue. Cattle should not be turned out hungry. When grazing starts, cattle should self-adapt by eating any developing ears and the tops of plants first and then will be more acclimated to eating the higher nitrate areas lower in the plant. Make sure plenty of clean, fresh water is available to help reduce nitrate risk. Protein is higher when grazing corn in a vegetative stage than as it matures. Depending upon the state of maturity of the corn, as well as the stage of production and need of the cattle grazing, protein supplementation may be needed to meet nutrient requirements.
Summer Corn Grazing – Green, Growing, Good Conditions
For many, the thought of grazing good, green, standing corn that is tasseling and forming ears is hard to imagine. However, corn is a warm season, annual grass and fields at this stage of maturity can provide a large supply of high energy, quality forage. For cow-calf producers who have access to corn they are growing themselves or know a farmer who would be willing to market a portion of their crop in this way, strip grazing standing corn can provide an alternative to dry lot feeding cows if pasture is short. It can be a competitively priced feed option when compared to buying hay or other feed stuffs and including the cost of equipment and labor needed for feeding.
When grazing standing corn that is progressing to maturity, strip grazing will help efficiently utilize the crop and reduce the risk of acidosis as corn ears continue to form and grain is made. Usually, cattle are given 2-3 days of feed at a time with a target of 60-80% grazing efficiency of the forage. Cattle will typically consume 2.5-3% of their body weight on a dry matter basis a day of this quality forage. When grazing cow-calf pairs, don’t forget to count the calf in calculating the amount of feed that will be needed. Supplemental protein may be required depending on the maturity of the corn and nutrient needs of the cattle grazing.
Logistically, rows of corn will need to be laid down using an ATV or other equipment to build the temporary electric fence and keep cows from knocking standing corn down into an electric fence and shorting it out. Always have a second and even a third grazing area ready with fence built ahead of where the cattle are currently. This helps limit cattle getting into the whole field if an escape happens. Another option for strip grazing standing corn is virtual fence technology. Research at the University of Nebraska has shown this to be an effective tool for strip grazing annual forages with containment rates exceeding 98%.
The Economics of Grazing Green Standing Corn – Does it Work?
When considering the economics of grazing standing corn there are several questions that need to be asked.
- What is the cost of the next alternative feed option of comparable quality into the belly of the cow-calf pair or dry cow if grazing in the late summer, fall or winter?
- What are the benefits of reduced expenses by harvesting the crop with cattle versus combining and hauling the grain? For example, the 2026 Nebraska Agricultural Custom Rates report states harvesting irrigated corn is $0.32 per bushel and hauling is $0.15 per bushel for a total of $0.47 per bushel or $94 per acre for harvesting costs if the crop yields 200 bushels per acre.
- What is the value of grazing and recycling nutrients being consumed from grain and stover back on the field as fertilizer (manure and urine) at today’s prices? Around 0.70 lb of nitrogen, 0.31 lb of phosphate, and 0.27 lb of potassium and 0.6 lbs of sulphur are in one bushel (56 lb) of corn grain.
- What is the value of being able to plant additional forage for grazing later in the fall and next spring if standing corn is utilized this summer, providing the option to plant another crop?
- What is the availability of water access for cattle, convenience and cost of delivery?
Quick math for an irrigated corn crop grazing late summer/early fall with cow-calf pairs.
A 200-bushel corn crop at $4.75 per bushel and corn residue grazing at $30 per acre generates a gross value of $985 per acre.
Gross Value per Acre of Grain Harvest and Grazing Residue $985
Reduced Harvest Expense of not Combining and Hauling Corn ($94)
Estimated Value of Corn Grain Nutrients Retained (30% of N, 80% of P&K) ($125)
Value of Grazing per Acre Needed to Equal the Value of Crop After Credits $766
A corn crop is rapidly accumulating dry matter as it moves from the tassel stage when approximately 35% of total dry matter is present to full maturity, black layer, corn. Total plant dry matter is accumulating rapidly from tasseling to black layer and then begins to decrease as the corn plant dies. As an estimate of dry matter yield, based on historic silage yields with 200-bushel corn, we will assume that there is approximately 25 tons of forage per acre at 65% moisture when the crop is at the optimum silage harvest window for forage/grain available. This would be equal to 8.75 tons per acre on a dry matter basis. If 60% of the standing corn crop at peak production, on a dry matter basis, is consumed by the cow-calf pairs during the grazing period, this equals 5.25 tons consumed per acre. At a cost of $766 per acre divided by 5.25 tons of dry corn forage and grain, this equals $145 per ton on a dry matter basis into the belly of the cow-calf pair. On a hay equivalent, if this was valued as a “hay” at 15% moisture, it would have a value of $125 per ton.
Is harvesting 5.25 tons of dry matter per acre with strip grazing standing corn a realistic target? It will depend on the stage at which grazing is initiated and how efficiently grazing occurs. The cost of fencing, any needed protein and energy supplement, as well as management and care would need to be added to the feed cost of $145 per ton on a dry matter basis to get a total cost per day.
Grazing Mature Standing Corn in the Fall and Winter
When corn matures and is going to be grazed standing, daily limit feed access to efficiently utilize the grain and reduce the risk of overeating and acidosis. The amount of area to be allocated daily will be based on estimated corn yield and cattle nutrient need to meet targeted performance. The amount of corn targeted to be consumed determines the amount of area being allocated. Assuming dry, pregnant cows are being grazed and there are 200 bushels of corn per acre with 85% utilization of corn grain, 100 cows would require 0.15 acres per day to meet a target of 13 pounds of grain being consumed per day. Additional forage may need to be supplied, as the husks, leaves and stalk provided with the corn being consumed may not be adequate to meet fiber needed for rumen health. One way this can be accomplished is by combining a portion of the field and leaving strategic strips of standing corn that could be utilized with remaining crop residue. Daily providing the ionophore Rumensin® with a pound of a supplement that contains needed vitamins and minerals, and any additional required protein will help to balance the cow’s diet, improve efficiency and help ensure nutrient requirements are met.
The grazing of standing corn is rarely utilized in Nebraska as a whole. However, with a shortage of forage for grazing and hay, current market conditions for fertilizer and corn, along with the advent of virtual fence technology, circumstances have come together to make it an option worth considering this year to feed the cow herd where hay is quite valuable and in short supply.
Sources:
ANR-11 Using Corn for Livestock Grazing – The Ohio State University Extension
ID-152 Grazing Corn: An Option for Extending the Grazing Season in Kentucky – University of Kentucky Cooperative Extension Service
Grazing Cattle on Corn – Manitoba Agriculture
2026 Nebraska Crop Budgets – Center for Agricultural Profitability, University of Nebraska-Lincoln
-University of Nebraska-Lincoln
