The protein requirements for geriatric cats and dogs have not been determined. In the absence of clinical or subclinical disease minimum protein requirements are probably the same as for adults. It must be remembered that cats are obligate carnivores with higher protein requirements than dogs.

Protein intake should be maintained near to the minimum requirement in situations in which excessive protein intake is considered to be a risk factor for disease progression (e.g. chronic renal failure); or when excessive protein intake may have a direct clinical effect (e.g. hyperammonaemia in hepatic disease, and uraemia). It is controversial whether or not early dietary restriction of protein may prevent the onset of age-related progression of renal failure, though there is good experimental evidence that avoidance of excessive protein intake delays progression once renal damage is present (see Chapter 5 ).

It should be noted that no authorities recommend reducing protein intake below the minimum requirement, and that in the presence of chronic renal failure protein requirements may actually increase to twice that recommended for normal adult animals. Avoidance of unnecessary excesses is recommended not restriction below actual requirements. The term low protein' and protein restriction' which are in common use are therefore somewhat misleading.

Geriatric patients benefit from the feeding of high quality protein sources which are:
Protein sources with a high biological value include egg, liver and other animal source ingredients. Cereals have a lower biological value, but feeding a ration containing a mixture of plant and animal source materials can increase the overall biological value of the protein in the food by providing a better balance of amino acids.