Pearson Square Feed Calculator
Target protein to two-feed parts and batch weights.
What it does
Mixing two feeds to a protein target is diagonal subtraction, not guesswork. The Pearson square crosses target with high and low feeds so parts fall out directly. Any batch size scales from there.
The tool above takes target, high, and low protein percents plus batch size, then prints parts and each feed weight. Imperial mode labels pounds; metric mode labels kilograms with identical math. It enforces high above target above low.
Extension ration guides from Penn State to Georgia teach this square for simple two-feed blends with tag values behind the percents. Soybean meal near the mid-40s and corn near 8 bracket most 16 % targets, which the default example mirrors.
Protein is only one nutrient. Energy, fiber, calcium, phosphorus, and vitamins travel with the grains unmeasured here, so confirm the mix against species guides and watch animals, milk, and manure for the verdict.
How to use
- Enter target protein percent.
- Enter high and low feed percents around it.
- Enter batch size in lb or kg.
- Read parts, high weight, and low weight.
- Weigh and mix thoroughly.
- Check energy and minerals after.
Formula
- target
- Wanted crude protein percent.
- high
- Higher-protein feed percent.
- low
- Lower-protein feed percent.
- batch
- Batch size in lb (kg metric).
Needs low below target below high in crude protein percent. Parts are diagonal differences; batch weights prorate by parts over the total. Minerals, vitamins, and energy need separate checks.
Worked example
Example: 16 % from 44 and 8
16 % ration from 44 % soybean meal and 8 % corn, 1000 lb batch.
- Target 16 % protein from 44 % soy and 8 % corn.
- High parts: 16 - 8 = 8.
- Low parts: 44 - 16 = 28.
- 1,000 lb batch: soy 1000 x 8/36 = 222.2 lb.
- Corn: 1000 - 222.2 = 777.8 lb.
Reference table
| Feed | Protein | Role |
|---|---|---|
| Soybean meal | 44 to 48 % | High protein |
| Cottonseed meal | 36 to 41 % | High protein |
| Corn grain | 8 to 9 % | Low energy base |
| Oats | 11 to 13 % | Mid base |
| Alfalfa hay | 15 to 20 % | Forage protein |
Limits
- Two feeds only. Three-plus needs software.
- Protein only; energy and minerals unchecked.
- Tag values required; guesses print nonsense.
- Mixing quality limits real uniformity.
Common mistakes
- Flipping the diagonals.
- Balancing to volume instead of weight.
- Trusting stale tag values.
- Ignoring energy alongside protein.
- Mixing once and feeding for months.
Try it yourself
Quick checks. Answers sit tucked under each question.
500 lb of 18 % from 48 and 9?
Parts are 18-9 = 9 high and 48-18 = 30 low. High is 500 x 9/39 = 115.4 lb, low 384.6 lb.
1000 kg of 16 % from 44 and 8?
Same parts 8 : 28. High is 1000 x 8/36 = 222.2 kg, low 777.8 kg.
Questions
What is the Pearson square?
A square that balances two feeds to one target protein. Diagonal differences give parts: target minus low for the high feed, high minus target for the low feed. Ratios scale to any batch.
Can it mix three feeds?
Only two feeds at once with protein between them. Three or more needs trial software or algebra beyond the square. Pick the two bulk feeds first, then layer minerals after.
Which protein numbers go in?
Crude protein percent of each feed from tags or lab tests. Soybean meal near 44 to 48, corn near 8 to 9. Wrong inputs print confident wrong rations, so verify tags.
Do scoops work instead of scales?
Yes, by weight. A ton is a ton whether scooped or weighed, but scoops vary by density. Weigh the batch the first time and mark the scoop after.
Does protein balance finish the ration?
No. Energy, fiber, minerals, and amino acids ride along unchecked. Balance protein here, then check energy and minerals with extension guides before feeding new mixes.
How do I feed the mix safely?
Mix thoroughly, store dry, feed fresh, and watch manure and milk for feedback. Rebalance when tags or ingredients change.