Wisconsin has led the nation in corn silage production for decades, harvesting approximately 800,000 acres annually. While alfalfa has been widely accepted as the “Queen” of the Forages, there should be no doubt about who is the “King”. Corn silage enables us to harvest more Milk Per Acre (MPA) (dry matter (DM) yield X Milk Per Ton (MPT) = MPA), than any other forage crop grown statewide.
Milk Per Acre (MPA) = Dry Matter (DM) Yield * Milk Per Ton (MPT)
One of the most common questions this time of year is, “How much is corn silage worth?” The truth is there is no one sure reply. The one constant is that grain prices drive the process of trying to arrive at a “fair” value. Instead of trying to come to an exact price, the goal is to identify and discuss the factors both parties involved in any transaction need to consider.
UW Resources to Help Price Corn Silage
Local corn grain cash prices are approximately $3.75 per bushel in Wisconsin in early mid-August, which is an improvement from where they were just a few days ago. Whether you use this value or the average price based on a combination of futures bids over several months, a base corn price needs to be agreed upon because of the amount of influence it has in any estimate or calculation used to determine an accurate silage value.
UW-Madison Division of Extension regional livestock educator Ryan Sterry developed an easy-to-use Corn Silage Pricing Decision Spreadsheet. This tool is most accurate when farmers can enter their own individual values for corn grain price, expected yield, the local market price per ton for low-protein forage available to the buyer, values for phosphorus (P) and K (potassium), and harvest costs. The advantage this tool provides is it can evaluate pricing from both the buyer’s perspective and the seller’s perspective, which may help both parties negotiate from that point forward.
Statewide, 81% of the corn crop is rated good (57%) or excellent (24%). Reports from independent professional crop consultants in northeastern and east-central Wisconsin indicate no tar spot development currently. This may differ in your part of the state, and conditions are always subject to change. There is still time for disease development to occur. However, given the general condition of the corn crop this year, there will be those who wish to utilize a simpler method to estimate the value of their corn silage crops. Former UW-Madison Corn Agronomist, Dr. Joe Lauer, developed the following chart that can be used to estimate the corn grain equivalents per ton of silage.
Corn Grain Equivalent (15.5% moisture) per Ton of Silage (65% moisture)
| Grain Yield (bushels per acre) | Forage Yield (tons dry matter per acre) | Starch Content (%) | Grain Equivalents (1972) | Grain Equivalents (Revised 2016) | Grain Equivalents (Starch Method) | Difference |
|---|---|---|---|---|---|---|
| Less than 90 | 3.8 | 20.9 | 5.0 | 5.1 | 4.4 | 0.7 |
| 90-110 | 5.4 | 27.3 | 5.5 | 6.6 | 5.8 | 0.8 |
| 110-130 | 6.0 | 29.0 | 6.0 | 7.1 | 6.1 | 1.0 |
| 130-150 | 6.7 | 30.4 | 6.5 | 7.5 | 6.4 | 1.1 |
| 150-170 | 7.3 | 31.4 | 7.0 | 7.8 | 6.6 | 1.2 |
| 170-190 | 7.9 | 32.2 | 7.0 | 8.1 | 6.8 | 1.3 |
| 190-210 | 8.6 | 32.6 | 7.0 | 8.3 | 6.9 | 1.4 |
| 210-230 | 9.3 | 32.6 | 7.0 | 8.5 | 6.9 | 1.6 |
| 230-250 | 9.9 | 32.4 | 7.0 | 8.6 | 6.8 | 1.8 |
Source: Adjusting Corn Silage Contracts, Joe Lauer, UW–Madison
A greater explanation of different corn grain equivalents in the chart above is available here.
Basic Silage Pricing Calculations in Traditional Formulas
If you have ever priced corn silage in Wisconsin, you are likely aware of the formulas that multiply the number of bushels of corn (see range above in table) in a ton of as-fed silage (65%) by the local cash corn price (or other agreed-upon average price) at harvest. This is the easiest and simplest method to come up with an estimate. The 2024 Wisconsin state average corn yield was 174 bushels/acre. Using the value of 8.1 (170-190 bu./acre) bu./wet ton * $3.75/bu. yields $30.38 per ton. However, consideration needs to be given to the fertilizer value of the nutrients from the stover not returned to the soil.
Estimated P2O5 & K2O Removal of 174-Bushel Grain or 23.7-Ton (65% Moisture) Silage
| P2O5 | K2O | |
|---|---|---|
| Price per lb. | 0.95 | 0.45 |
| Grain | Silage | |
| Yield (bushel or ton per acre) | 174.00 | 23.70 |
| P2O5 (lb per bushel or ton) | 0.38 | 3.60 |
| K2O (lb per bushel or ton) | 0.29 | 8.30 |
| P2O5 ($ per acre) | 62.81 | 81.05 |
| K2O ($ per acre) | 22.71 | 88.52 |
| Nutrient Cost ($ per acre) | 85.52 | 169.57 |
| $ Difference per Acre Silage vs. Grain | $84.05 |
Source: Nutrient application guidelines for field, vegetable, and fruit crops in Wisconsin (A2809), UW–Madison
A 174 bushel/acre corn crop would produce approximately 23.7 tons of as fed (65% moisture) corn silage. The value of P2O5 and K2O per acre ($84.05) divided by the wet tons harvested (23.7) would require that we add $3.55/per wet ton to the initial value of $30.38. So, $30.38 + 3.55 = $33.93/ton as fed 65% moisture.
The next question is what about the other nutrients? Corn stover is estimated to contain 12-15 lbs. of nitrogen per ton of DM as well as sulfur and other micronutrients. Additionally, there is the loss of organic matter the stover would have added to the soil structure as well. It’s advised to add $3-$5 or $4-$6 (when fertilizer prices go higher) per wet ton to the value you came up with after multiplying the agreed upon bushels of corn per ton of wet silage by the agreed upon local corn price. These calculations confirm that those values have been reasonable estimates.
Considerations for BMR (brown midrib) and Highly Digestible Hybrids
Evaluating the top nine or ten World Forage Analysis Superbowl (WFAS) winning entries for both the conventional corn silage and BMR corn silage categories in 2023 and 2024 revealed the following:
The BMR’s produced 2.91% more Milk Per Ton (4,122 lbs.) compared to the conventional hybrids (4,002 lbs.) in 2023. This trend continued in 2024 with a 3.11% increase in MPT (3,374 lbs.) compared to the conventional hybrids (3,269 lbs.). It should be noted Milk 2006 was used to evaluate samples in 2023 vs. Milk 2024 being used last year which accounts for the differences in total estimated lbs. of milk/ton.
BMR’s also edged out the conventional hybrids in NDFD (neutral detergent fiber digestibility) 30-hour results by 7.97% – 70.80% NDFD30 BMR vs. 65.16% NDFD30 in 2024. However, conventional hybrids demonstrated a 3.53% advantage in starch values (37.10) over BMR (35.79) in 2024. Farmers grow and manage both hybrids successfully to produce high quality corn silage for their dairy and livestock enterprises.
Should you negotiate a higher value for BMR silage? Lab analysis suggests these hybrids, when managed correctly, can outperform conventional hybrids in some forage quality metrics. However, if both parties wish to negotiate this aspect, It’s suggested fields be evaluated before harvest and after harvest for any environmental influences that may have limited the upside potential of these hybrids. There is still a lot of time between now and when these crops will be harvested. Forage quality analysis after ensiling and fermentation will provide a more accurate assessment of any quality gains from BMR hybrids. Whatever decision is arrived at, make sure it is clear and written out, not verbal.
Conclusions
Calculating the value of a ton of corn silage is always going to rely on using the best information and estimates available to arrive at a price that is satisfactory to both the buyer and the seller. Once that transaction does occur, the responsibility is on the buyer to do everything they can to maximize both the quantity and quality of that silage crop. Grain yield in the corn silage is affected by the harvest timing as an additional 5-12% increase can still occur when the plant is at 50% kernel milk. More information about timing harvest correctly and maximizing corn silage yield and quality is available.