Feed Value Calculator

Two loads of hay can carry the same price per ton and deliver very different amounts of feed. Animals do not eat tons, they eat energy and protein, so this calculator prices a feed by its nutrients: enter the market prices of corn and soybean meal, add the target feed’s TDN and crude protein, and the Petersen method returns what that feed is worth per ton, set against its asking price.

Quick Answer

How to use the feed value calculator

Four prices and percentages go in, and the two reference feeds do the rest. The work is in getting honest inputs, because the arithmetic will faithfully price whatever numbers it is handed.

1. Enter today’s corn and soybean meal prices in dollars per ton, delivered if you can. Corn stands in for energy, soybean meal for protein, and both trade widely enough that their prices fairly state what those nutrients cost right now.
2. Pick a preset or type the target feed’s analysis. Presets fill in TDN and crude protein from the extension tables listed further down. With a lab analysis for the actual lot, type those figures over the preset: book values are averages, your load is not.
3. Enter the asking price for that feed, per ton. This is the number the verdict is judged against.
4. Click Calculate and read the whole result. The headline is the Petersen value per ton. Below it sit the two unit values, the energy and protein contributions, and the difference against the asking price in dollars and percent, with the verdict badge: underpriced or overpriced when the gap passes 5% either way, fairly priced in between.
5. Copy or share the result from the results box. The copied text restates both reference prices and unit values, so the number can be rechecked when markets move.

The Petersen method, step by step

The method sets up one equation per reference feed, solves them together for the value of a pound of TDN and a pound of protein, then prices the target feed from its own analysis. It is the simultaneous-equation approach the New Mexico State University extension guide on economic evaluation of dairy feeds teaches, with TDN used here as the energy measure.

The reference values come from Table 5 of the New Mexico State University ranch ration balancing guide: corn (whole) at 88% TDN and 9.8% crude protein, soybean meal at 84% TDN and 49.9% crude protein, percentages of dry matter, sourced there to NRC (2000). The flow runs in four steps:

One guard is built into the solve. If the reference prices are out of line with the feeds’ nutrient contents, for example corn priced so high against soybean meal that protein solves to a negative value, the calculator refuses the result and says why. A negative nutrient value usually means a price was typed per bushel or per hundredweight instead of per ton.

Worked example: mid-bloom alfalfa hay at $125 a ton

Corn is $150 per ton and soybean meal is $280 per ton, the example prices in the NMSU guide. A seller offers mid-bloom alfalfa hay, 60% TDN and 17% crude protein on a dry matter basis, at $125 per ton. This is the case pre-filled in the calculator above.

The two equations, in dollars per pound, are 0.88a + 0.098b = 0.075 for corn and 0.84a + 0.499b = 0.14 for soybean meal. The determinant is (0.88 × 0.499) − (0.84 × 0.098) = 0.3568. Solving gives a = [(0.075 × 0.499) − (0.14 × 0.098)] ÷ 0.3568 = $0.0664 per pound of TDN and b = [(0.88 × 0.14) − (0.84 × 0.075)] ÷ 0.3568 = $0.1687 per pound of crude protein. Check against corn: 0.88 × 0.0664 + 0.098 × 0.1687 = $0.075 per pound, the corn price back again, so the solve is consistent.

The value, $137.09 per ton, sits $12.09 above the $125 asking price, a 9.67% gap, so the badge reads Underpriced: the hay delivers its nutrients for less than they would cost as corn and soybean meal. The hay still has to be clean, well cured and palatable, but price is not the obstacle. Had the seller asked $160, the same arithmetic returns Overpriced by $22.91 (14.32%), and the right move is to negotiate toward the value or walk to the next lot.

Contributions are rounded to cents, so the two rows may sum a cent either side of the headline value, which is computed from the unrounded unit values.

Preset feed values, and what they are worth at the example prices

Each preset is a published table value on a dry matter basis, and each stays editable because real lots vary. The value column reruns the worked-example prices (corn $150, soybean meal $280) so the presets can be compared on one footing.

Distillers grains top the table because they carry grain-level energy and nearly 30% protein in one ton, the combination a per-ton price hides. The South Dakota State University Extension guide to evaluating feedstuffs on a nutrient cost basis makes the same point: decide whether an ingredient is bought for energy or protein, then compare it against the feed supplying that nutrient cheapest.

Why pricing feed by the ton misleads

Price per ton compares weight, and weight includes water, fibre and ash that feed nothing. The nutrients an animal can use, digestible energy and protein, vary far more between feeds than their prices suggest.

Take the two ends of the preset table. A ton of dried distillers grains holds about 1,760 lb of TDN and 590 lb of crude protein. A ton of corn silage dry matter holds 1,380 lb of TDN and 172 lb of protein, and a ton of silage as it leaves the silo, at roughly a third dry matter, holds only about a third of that again. Quoting all three “per ton” without the basis is how a cheap-looking load becomes the most expensive nutrients on the farm. Petersen strips the comparison back to the two things being bought, and prices those. It also moves with the market: when soybean meal rallies, protein-rich feeds gain value even if their own asking prices have not moved.

Moisture and dry matter: keep every number on the same basis

All nutrient percentages in this calculator are on a dry matter basis, and the value it returns is per ton of dry matter. Mixing bases is the most common way feed valuation goes wrong, ahead of any arithmetic slip.

Lab reports list nutrients both ways, and the gap is not small. The South Dakota State University Extension guide to understanding feed analysis reports notes that corn silage typically runs 30 to 40% dry matter while grass hay runs 80 to 90%. To move a nutrient figure from as-fed to dry matter, divide by the dry matter fraction: haylage testing 10% crude protein as fed at 50% dry matter is 20% on a dry matter basis, the worked conversion in the University of Nebraska-Lincoln extension guide to feed dry matter conversions. Run it the other way for money: corn silage valued at $120.70 per ton of dry matter is worth about $39.83 per as-fed ton at 33% dry matter, the figure to set against a silage quote. The tonnage and shrink side of a silage deal is covered by the corn silage value calculator.

Using the verdict when buying hay, grain and byproducts

The badge sorts a deal into three actions. Underpriced: the nutrients cost less here than as corn and soybean meal, so buy if quality checks pass. Fairly priced, within 5% either way: decide on quality, distance and reliability of supply. Overpriced: the same nutrients cost less assembled from the reference feeds, so negotiate or substitute.

For hay, run the seller’s analysis, not the preset, whenever a test exists, because hay varies by cutting and weather more than any other feed here: a two-point protein swing moves value by about $6.75 a ton at the worked-example unit prices, and a five-point TDN swing by $6.64. For grains, the verdict mostly arbitrages local pricing: barley worth $154.94 against corn at $150 is a buy only where asking price and freight keep it under that line. For byproducts, re-run the tool whenever corn or soybean meal move, because byproduct quotes lag the reference markets and the lag is where bargains appear. A $12 a ton edge compounds across a winter’s tonnage into the margins tracked by the beef profit calculator and the dairy farm profit calculator, and it is spent long before the animals it feeds are sold through the values in the cattle value calculator.

What competing calculators miss

Under the exact phrase “feed value calculator” there is, at the time of checking, no rival tool at all, and the pages that do exist leave the central question unanswered:

• The previous version of this page: it multiplied weight by price by an “efficiency” percentage the user had to guess. A guessed discount is not a valuation; nothing connected the answer to what the feed contains or what nutrients cost.
• Extension guides, including the NMSU guide this method comes from: sound teaching and real examples, but the simultaneous equations stay on paper or in a downloadable spreadsheet, leaving a producer at a hay auction to do two-equation algebra by hand.
• The UK levy board AHDB’s relative feed value calculator: a genuine nutrient-based tool, but it values feeds against barley and rapeseed meal for a UK market in relative terms, not as a dollar verdict against a US asking price.
• Cost-per-unit articles: good writing that prices a pound of protein or a unit of energy one feed at a time. That ranks single-nutrient sources; it cannot value a feed supplying both, which is most feeds worth buying.
• The gap this page fills: the full Petersen solve as a working tool, unit values shown so the method can be checked, editable extension-table presets, a dry matter warning in the result, and a verdict tied to the actual asking price.

Feed value is not relative feed value (RFV)

Relative feed value is a different number that answers a different question, and the two should never be substituted. RFV is a unitless forage quality score built from fibre: digestible dry matter is estimated from acid detergent fibre, dry matter intake from neutral detergent fibre, and the score is scaled so full-bloom alfalfa sits at 100, as the NC State Extension guide to forage quality indices sets out.

RFV ranks one hay against another for quality. It says nothing about dollars, protein or the corn market, and a high-RFV hay can still be overpriced while a modest one is a bargain. This calculator does the opposite job: it returns a dollar value from energy and protein. Use RFV, or its successor RFQ, to grade hay; use Petersen to price it.

Limits of the Petersen method

Petersen prices two nutrients and ignores everything else in the feed. Used with that in mind, it is a sharp first filter; used as the whole decision, it will mislead.

It says nothing about fibre quality or digestibility beyond what TDN captures, and TDN is usually predicted from fibre rather than measured, so two feeds with equal TDN can perform differently. It treats all crude protein as equal, when amino acid profile matters for pigs and poultry and rumen degradability matters for cattle: protein in soybean meal and protein in a heat-damaged byproduct are priced the same here and are not the same feed. Minerals, fat, palatability, spoilage, mycotoxin risk and freight sit outside the solve, as the NMSU guide itself warns. The method is only as current as its inputs, and extra protein has no value to an animal whose requirement is already met, so a protein-rich feed can be worth less on a particular farm than the tool states. Price with Petersen, then check quality, ration fit and delivered cost before buying.

Frequently asked questions

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