All animals have a requirement for energy
which has to be met by dietary intake. The energy requirements of animals during
their life cycle stages have been reasonably well established (NRC 1985; NRC 1986;
Lewis et al.1987) but the energy requirements of animals with renal disease have
yet to be accurately determined.
Assessing the body weight of an animal is important in estimating the calorie requirements
of an individual. A reduction in calorie intake should be considered for animals
that are obese, and calorie intake should be increased for animals that are underweight.
Cats and dogs with renal disease frequently present in a catabolic state and they
need a high calorie intake to maintain body functions and to restore normal body
weight. This may not be easy to achieve, as animals in a debilitated state or with
azotaemia are frequently anorectic.
Uraemic animals may vomit any food that is eaten, and in the presence of concomitant
gastrointestinal or hepatic dysfunction, ingestion may not guarantee adequate utilisation
of the food. The diet for such cases should therefore be high in energy density and
digestibility to minimise the amount of food that the animal has to digest and absorb.
Feeding small volumes of food frequently (3-4 times daily) may improve utilisation.
Hand feeding, warming the food and sometimes the administration of diazepine drugs
(e.g. diazepam at a dose rate of 2-14 mg/kg orally (dogs) or 1-2 mg/cat orally or
0.1-0.5 mg/cat given intravenously; or oxazepam at a dose rate of 2 mg/cat orally)
may encourage eating in anorectic patients (Lewis et al. 1987).
Diets claiming good palatability should be selected carefully to avoid those containing
high levels of nutrients (e.g. salt) that might be contraindicated in the presence
of renal disease.
Studies in man have demonstrated an improvement in ability to mainnitrogen equilibrium
by increasing the calorie intake of uraemic patients on a low-protein, high biological
value protein diet (Hyne et al. 1972).
A high calorie-dense diet reduces the amount of food that has to be eaten to meet
daily energy needs, and this can be helpful in reducing the total intake of specific
nutrients that have to be controlled, e.g. phosintake will be less if less food is
Cats, being obligate carnivores, have a high requirement for energy from dietary
protein. In the presence of inadequate protein-calories a cat
will breakdown its own body protein to produce energy, hence severe dietary protein
restriction is not as feasible in the cat as it is in the dog.