Dr Clauders Special Diet: RSD Kidney review

All four sit in our Average band, and the reason needs saying plainly rather than being left to look like a verdict on the food. Our scoring reads a bag as a general adult diet, rewarding meat content, protein quality and a modest carbohydrate load. These recipes are built the other way round on purpose. The kidney diet holds protein to 15.5% of dry matter and ash to 4.4%, the liver diet sits at 18.8% protein, and the intestinal diet keeps fat down to 7.7% of dry matter. A general reading marks all of that down, while a vet would recognise it as the design. Against the typical adult dry food in our Good band, these are simply not competing on the same terms.

Ingredients, as declared: Rice, barley, poultry protein, animal fat, protein hydrolysate, potassium chloride, cellulose, calcium carbonate, sodium chloride, chicory powder, mussel meat meal.

Cereals lead every recipe here, and that is a design decision, not a corner cut. Rice, corn and barley are efficient sources of digestible energy that bring very little protein and almost no phosphorus with them. That is exactly what a diet built to hold protein or mineral load down is looking for.

The animal side is written in the general: poultry meat meal, poultry protein, poultry fat and, in the kidney recipe, animal fat with no species at all. Meat meal is the dry rendered powder that has been the backbone of kibble for decades and it is a concentrated protein source, but nothing on these labels tells you which bird it came from.

Each recipe adds something for its own job. Linseed, fish oil and thistle oil run through the skin recipe. Green lipped mussel and yeast beta glucans sit in the intestinal one. The liver diet brings parsley, psyllium and ammonium chloride. The kidney diet swaps in calcium carbonate with the protein held low.

Chicory appears on all four labels as a source of inulin, the prebiotic fibre gut bacteria feed on. Potassium chloride is on all four as a mineral top-up. The pairing is a familiar one on restricted diets.

Two of the recipes use cellulose, the purified plant fibre that is essentially bulk without calories. In a diet meant to fill a dog up while holding something else back that is a defensible choice, though it brings nothing else along with it.

The most restricted label of the four: protein at 14% as fed, ash at 4% and calcium at 0.66% of dry matter. Rice and barley sit under it, with poultry protein third. Mussel meat meal closes the list and cellulose supplies bulk. The fat is declared only as animal fat, the one entry in the range with no species behind it at all. Carbohydrate converts to 66.3% of dry matter, the arithmetic consequence of holding protein that far down.

£7.78 a kilo across the range, sold in 1 kg and 4 kg bags.

As a guide, take a 15kg adult dog in moderate condition needing about 840 kcal a day (110 × bodyweight^0.75, the standard maintenance estimate). That comes to £1.78 a day on the liver recipe, £1.81 on the skin and coat, £1.88 on the kidney and £2.02 on the intestinal. Those calorie figures are our estimates from each analysis, since the pack prints none.