Nutrition
Taurine
An amino acid cats cannot make in useful amounts and must eat — the reason a cat cannot live on dog food.
Dogs synthesise taurine from other amino acids. Cats barely can, so for them it is essential in the dietary sense: it has to arrive in the bowl. It is concentrated in animal tissue, particularly heart and other muscle meat, and it is degraded by heat and by processing.
Cats deprived of it develop retinal degeneration and dilated cardiomyopathy, both of which were common until the link was established in the 1980s and manufacturers began supplementing cat foods routinely. It is also the clearest single answer to why cats are obligate carnivores in a way dogs are not, and why vegetarian cat food is a much harder problem than it looks.
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AAFCOThe US body whose nutrient profiles decide what a pet food may call itself complete — it writes the model rules, it does not test or approve foods.FEDIAFThe European pet food industry federation whose nutritional guidelines play the role AAFCO's profiles play in the United States.Complete and balancedA regulated claim that a food supplies every nutrient a pet needs, in the right proportions, as its only diet — the one label phrase that carries real weight.KibbleDry pet food shaped by extrusion — dough cooked under pressure, forced through a die, cut, dried and sprayed with fat and flavour.By-product mealRendered animal parts other than skeletal muscle — organs, mostly — cooked down and dried into a concentrated protein powder.Guaranteed analysisThe small table of minimum and maximum percentages on a pet food label — crude protein, fat, fibre and moisture — and the most misread panel on the bag.