Guaranteed analysis

Floors and ceilings, not measurements

Two foods can carry identical guarantees and be materially different, because each is stating a bound rather than a value. This is why a "typical analysis" — the average of actual production batches — is more informative, and why the companies that publish one are worth noticing.

It also means the arithmetic everyone does with these numbers, including ours, inherits the imprecision. A dry-matter conversion of a minimum is a minimum. We compute from what is printed because it is what exists, and we would rather be explicit about the limitation than quietly ignore it.

Crude means crude

"Crude protein" is a laboratory method, not a quality judgement: it measures nitrogen and multiplies. Nitrogen from pea protein concentrate counts exactly the same as nitrogen from chicken. That is the whole reason ingredient source is worth reading alongside the number rather than instead of it.

Crude fibre similarly under-counts soluble fibre, so a food can carry more functional fibre than the guarantee suggests.

What is optional

Beyond the four mandatory guarantees, everything is at the manufacturer’s discretion — ash, calcium, phosphorus, magnesium, omega fatty acids, taurine, glucosamine. That optionality is the single biggest constraint on what any pet-food comparison can honestly claim, and it is why the median food in this corpus discloses about 47% of the fields we look for.