Free nutrition tool

Horse protein calculator

Is your horse’s forage supplying enough protein? Enter bodyweight, workload and what you feed, and see in seconds how it compares with your horse’s daily requirement.

Use the calculator →Test your forage

NRC requirementsUK forage averagesAdjusted for dry matter

Forageplus data insight

85%

of the UK forage samples we test fall below 8% crude protein on an as-fed basis.

Forageplus analysis data · 12,500+ UK samples

Protein from forage

Results update as you type

Start hereEnter your horse’s weight and workload, then how much of each forage you feed a day. Leave anything you don’t feed at zero.

Bodyweightkg

Age and workload

Haykg/day

Protein 7.3% · Dry matter 81%

Haylagekg/day

Protein 8.2% · Dry matter 70%

Grasskg/day

Protein 7.0% · Dry matter 26.1%

Strawkg/day

Protein 2.9% · Dry matter 88%

Hay crude protein %

UK average 7.3% (dry matter basis)

Haylage crude protein %

UK average 8.2% (dry matter basis)

Grass crude protein %

UK average 7.0% (dry matter basis)

Straw crude protein %

UK average 2.9% (dry matter basis)

Hay dry matter %

UK average 81%

Haylage dry matter %

UK average 70%

Grass dry matter %

UK average 26.1%

Straw dry matter %

Typically about 88%

Lab results report crude protein on a dry matter basis. Enter the figures exactly as they appear on your report and the calculator adjusts for moisture.

Calculating

0 g

Your forage0 g

0 g

Crude protein supplied per day

0 g

Below the minimum for basic health

0 g

Below the optimum for muscle and topline

Next step

Ask our nutritionists Test your forage

Want these figures in your inbox?

Free full breakdown

See exactly where the gap is

Unlock the full breakdown: your forage against the minimum and optimum, gram by gram. We’ll email you a copy with your figures, plus practical feeding guidance from our nutritionists.

Methodology. Minimum crude protein from NRC (2007) requirements, scaled to bodyweight from a 500 kg reference. Optimum target = 130% of the minimum. Protein supplied = as-fed weight × dry matter % × crude protein %. Forage only: bucket feeds and supplements are not included. This approach is also consistent with guidance published in the MSD Veterinary Manual.

Why it matters

Why forage so often falls short on protein

Forage is the foundation of every horse’s diet, and for most horses it is also the main source of protein. The trouble is that UK forage is frequently lower in protein than owners expect.

Most UK hay is low in protein

Lab results are reported on a dry matter basis, so a hay that reads 8% on paper delivers less in every mouthful once moisture is accounted for. On an as-fed basis, 85% of the samples we test come in below 8%.

Quantity is only half the picture

Crude protein measures the amount of protein, not its quality. Two forages with the same figure can differ widely in lysine and the other essential amino acids that determine how much of that protein the horse can actually use.

Less forage means less protein

Cutting back hay or swapping some of it for straw to manage weight reduces protein intake as well as calories. Use the straw protein calculator to see the effect.

How it works

How the calculator works

The calculation

Each forage is converted from the weight you feed to the protein it actually delivers:

kg fed × dry matter % × crude protein % = grams of protein

The total is compared with the NRC minimum for your horse’s bodyweight and category, and with an optimum target set at 130% of that minimum. This approach is consistent with guidance published in the MSD Veterinary Manual.

What it doesn’t include

Bucket feeds, chaffs and supplements: it looks at forage only.
Protein quality: lysine and other essential amino acids are not measured by crude protein.
Your actual forage: the defaults are UK averages, and real hay varies widely.

Laboratory analysis services

Your hay isn’t average.

This calculator runs on UK averages. A nutritional analysis of your own hay or haylage shows exactly how much protein it contains, so the diet can be balanced around the forage your horse actually eats.

Test your forage →Read: protein and amino acids

Questions

Frequently asked questions

How much protein does a horse need a day?

Using NRC (2007) figures, a 500 kg mature horse at maintenance needs a minimum of around 630 g of crude protein a day. Work, late pregnancy, lactation and growth all raise the requirement. The calculator scales these figures to your horse’s bodyweight.

Why does the calculator adjust for dry matter?

Laboratories report crude protein on a 100% dry matter basis. Hay is typically around 81% dry matter and haylage around 70%, so the protein in every kilo you feed is lower than the figure on the report. Adjusting for moisture shows what your horse actually receives.

Why is the optimum set at 130% of the minimum?

The NRC minimum is the level needed to sustain basic health, not a target. Forageplus uses 130% of that minimum as a practical feeding target to support muscle maintenance, topline, growth, ageing and recovery.

Is feeding above the optimum harmful?

Surplus protein is not stored. It is broken down and the nitrogen excreted, which increases water intake, urine output and stable ammonia. For a healthy horse, modest amounts above requirement are not the hazard they are often feared to be. On UK forage, too little protein is a far more common problem.

Does this include my horse’s bucket feed?

No. The calculator looks at forage only. If you feed chaff, beet pulp, pellets or a protein supplement, those add to the total. Our nutritionists can take the whole diet into account.

Can I use my own forage analysis?

Yes. Open “Have a forage analysis? Enter your own figures” and type in the crude protein and dry matter figures from your report. This gives a far more accurate result than UK averages.

More free tools

Browse