Section VI, No. 12 August 2006
WHAT IS THE VALUE OF STANDING CORN FOR GRAZING?
Dwight Aakre, Greg Lardy and Karl Hoppe Farm Management and Beef Cattle Specialists NDSU Extension Service
Grazing corn is likely the least efficient method of harvesting corn and would be considered a salvage operation. One would not choose to graze off a corn crop if other methods of harvest would yield a greater net return. At the other end of the spectrum, a livestock owner would not likely be willing to pay more for grazing corn than other alternatives for feeding his livestock. Therefore, the market value for grazing standing corn will likely fall somewhere within this range. Alternatives Grazing. The most obvious alternative to grazing corn would be other sources of grazing . The interest in grazing corn at least in part is due to a lack of other grazing sources, particularly in the southwestern part of the state. Typical grazing rates for summer pasture run about $15-$16 per animal unit month or about $0.50 per head per day. Dry Lot Feeding. Another alternative for the livestock producer is dry lot feeding. Full cost of dry lot feeding will generally run at least $1.00 per head per day. If the livestock producer is short on pasture, then anything less than the cost of dry lot feeding would represent a lower cost alternative. In addition to the grazing fee, the additional cost of hauling the cattle to the corn must also be included. Other considerations that impact the total cost of grazing include fencing, water, minerals and daily checking of the cattle. Estimating the Value of Standing Corn Estimating Potential Silage Yield. To estimate the value of standing corn, it is first necessary to determine how much yield is in the field. One method to estimate yield would be to hand cut and weight one-thousandth of an acre. This can be done by measuring out 17.4 feet of row length for corn planted in 30 inch rows or 14.5 feet of row for 36 inch rows. Cut all plants at normal chopping height (8 to 10 inches) and weigh the sample. Multiply this weight by 0.5 to estimate tons per acre. Accounting for Loss and Waste. The biggest unknown in this calculation is the percent of the crop that will actually be consumed by grazing and how much gets wasted. Some wastage is going to occur simply because the cattle will likely refuse to eat the lower part of the stalk. Additional losses will occur from trampling as well as leaf loss due to wind. A suggested estimate of the total production that will be consumed is 50 percent of the dry matter produced will be utilized by the animal. The remaining 50% will be lost to trampling, wind losses, and refusal by the animal. Standing corn that is immature and or frozen prior to maturity would contain approximately 80 percent water. Table 1 gives expected moisture levels for immature corn at various stages of maturity.
Estimating Grazable Forage. To estimate the grazing potential per ton of yield per acre, multiply 2000 pounds by the percent dry matter times the percent consumed and divide by the pounds of dry matter consumption per cow per day. Example Yield - 1 ton @ 20 percent dry matter Dry matter utilized @ 50 percent Dry matter per cow (1200 lbs. X 2.5 %) Carrying capacity per ton per acre 400 200 30 6.66 pounds dry matter pounds dry matter pounds dry matter head per ton per acre
If the estimated forage yield per acre is 10 tons this crop would provide one day of grazing for 66.7 (67) cows. Based on average grazing values, an acre of corn yielding 10 tons would have a value of $33.50 per acre or $3.35 per acre per ton of yield potential. As with any market, if supply exceeds demand, the price is likely to fall, and if demand exceeds supply, upward pressure on prices will occur. Other factors to consider include which party will pay for the cost of fencing, tending to the herd and hauling water if necessary. The livestock owner will incur trucking expenses to move the cattle to the corn as well. In addition, if the corn crop is insured, strips will have to be fenced out for final yield adjustment and will not be available as feed until after they are released by the crop insurance company. Other Considerations. Some situations will involve considerable distance between the livestock operation and the corn for grazing. For these arrangements, it is suggested the livestock owner be responsible for building the necessary fence and the owner of the corn crop be responsible for providing the water and daily checking of the fence. Summary When all costs are considered, the livestock owner will likely be unwilling to pay more than it would cost to feed the cattle herd with purchased feed hauled to the ranch. The corn producer would not likely accept less than the fertility value of the dry matter that is consumed. This value would likely be less than $10 per acre. Table 1. Effect of Stage of Maturity on whole plant moisture and maximal silage yield for immature corn. Percent of Maximal Stage of Maturity Silking Blister Late Milk Early Dent Half Milk Line Whole Plant Moisture (%) 80 to 85 80 to 85 75 to 80 70 to 75 60 to 70 Silage Yield 50 60 70 80 100
Adapted from Cornell University. http://www.cce.cornell.edu/yates/AgCorner9.27.00.htm
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