Crude Protein, Fibre and Oil: Reading the Rest of Your Feed Label

In the first part of this series we took on crude ash — the line that turns out to be nothing more frightening than the mineral content of a feed. This time we’re working through the rest of the panel: crude protein, crude fibre, and crude oils and fats. They sound more familiar than “ash”, which is exactly why they’re so easy to misread.

Because here’s the theme that ties the whole label together: every one of these figures is a measurement of quantity — how much protein, how much fibre, how much oil, by weight. And quantity, on its own, is only ever half the story. The half that actually decides whether a feed suits your horse — quality — barely shows up in these numbers at all.

First, what the panel is

A quick recap on where these numbers come from. The “analytical constituents” are a short, standardised block that GB feed law — the retained version of Regulation (EC) No 767/2009 — requires on compound feeds and many supplements. Each line is a laboratory result, measured the same way across the industry so that you can, in theory, compare one product with another on a level footing. That’s genuinely useful. The skill is in knowing what each measurement does, and doesn’t, capture.

Crude protein: a nitrogen headline

Of all the lines on the label, this is the one people lean on hardest — and the one that most flatters to deceive. Crude protein isn’t measured by looking at protein at all. The lab measures the nitrogen in a sample and multiplies it by a fixed factor of 6.25 to estimate the protein, because protein is on average about 16% nitrogen. It’s quick, cheap and consistent.

What it can’t see is quality. A crude protein figure tells you nothing about the amino acids that make that protein up, or how well your horse can digest them — and the amino acids are the whole point. A horse doesn’t need “protein” in the abstract; it needs specific building blocks, above all lysine and methionine, to maintain muscle, topline, hoof and coat. Two feeds can each declare 12% crude protein while one is genuinely valuable and the other is largely nitrogen the horse can do little with.

This is where a transparent label earns its place. Oxydane, for example, doesn’t just leave you with a protein figure — it declares the individual amino acids it provides, lysine and methionine among them, so you can see the quality behind the quantity. It’s also worth remembering that a supplement fed by the gram adds very little to your horse’s total protein intake; the forage does the heavy lifting there. What a well-made supplement contributes is the targeted amino acids, not a big headline percentage.

Crude fibre: an old measure that sells fibre short

Fibre is the foundation of the equine diet — the horse is built to ferment it in the hindgut, and it’s where a great deal of their energy and gut health quietly comes from. So you would expect crude fibre to be one of the most important lines on the label. In practice, it’s one of the least reliable.

The crude fibre figure comes from an old laboratory technique, the Weende method, which boils a sample in acid and then alkali and weighs what survives. The trouble is that much of the beneficial fibre — a large part of the hemicellulose and the soluble fibres — dissolves during that process and is never counted. So crude fibre routinely under-states the true fibre content, sometimes considerably. More modern measures, which you may occasionally see quoted as NDF or ADF, give a fuller picture.

For your horse, the practical takeaway is simpler still: the fibre that matters comes from forage — your hay, haylage and chaff — not from a concentrated daily supplement fed in grams. So crude fibre is rarely the number to judge a supplement by. It carries far more weight on a bagged feed or a chaff, and even there it’s only ever part of the fibre story.

Crude oils and fats: the number that hides the source

Crude oils and fats — sometimes called crude fat, or “ether extract” after the solvent used to measure it — is simply the total oil in a product. It matters for energy, since oil is the horse’s most concentrated calorie source, and for coat and skin condition.

But once again, the figure is silent on the thing that counts: what kind of oil it is. A high fat percentage could come from a quality cold-pressed oil rich in omega-3, or from a cheap, heavily refined one skewed towards omega-6 — on the label, the two look identical. Source, freshness and the balance of omega-3 to omega-6 are what separate them.

Our 100% Natural Linseed Oil is a neat illustration. As a pure oil it is almost entirely “crude fat” — the percentage is about as high as a number can go — yet that figure isn’t the selling point. The point is that it’s cold-pressed, single-ingredient, and naturally richer in omega-3 than omega-6, which is what helps maintain the glossy coat and healthy skin people are really shopping for. The label number tells you it’s oil. Only the ingredient behind it tells you it’s good oil.

And a quick word on moisture

You’ll often see moisture, or water, declared as well. It’s worth a glance, because water dilutes everything else: a drier powder means more active ingredients in every scoop, while a high-moisture product is partly paying you in water. It’s a small line, but it belongs to the same quantity-versus-value picture as the rest.

The pattern behind the panel

Put the whole block together and a clear rule emerges. The analytical constituents are a quantity report, not a quality report. They will tell you how much protein, fibre, oil and mineral is in the bag — reliably, and in a form you can compare — but not whether any of it is the right protein, the right fibre or the right oil for the horse in front of you.

Quality lives in two places the numbers can’t reach: the ingredient list, and how much detail the brand is willing to put beside the figures. A named amino acid profile, a full mineral breakdown, a single clearly stated oil source — those are the marks of a company with nothing to hide behind the percentages.

The takeaway

That’s the standard we try to hold ourselves to, line by line. It comes back to the same question behind everything we make: would we feed this to a horse we loved? If the answer is yes, we would far rather show you the detail than ask you to take a percentage on trust.

Missed part one? It’s all about crude ash — and why, at Hi Form, a low figure is a mark of quality, not a shortfall.

Hi Form Equine UK — the science of natural health. No filler, no fluff, no shortcuts.