Effects of medium protein diets in dogs with chronic renal failure

To study dietary management of chronic renal failure (CRF), 1600 dogs older than 5 y were screened for serum urea and serum creatinine concentration. Three hundred fifty-eight dogs (22.4%) showed values above normal (6.67 mmol/L of serum urea, 88.4 mul/L of serum creatinine). Sixty of these dogs with slight or moderate clinical signs of CRF, at least polyuria, were selected for the study. Thirty-two dogs were fed a commercial canned medium protein diet (MPD) [27% protein, 0.36% phosphorus in dry matter (DM)] and 28 dogs were fed a homemade diet (HMD; 21.5% protein, 0.38% phosphorus in DM). Dogs were reevaluated for clinical status, blood chemistry profile (urea, creatinine, total protein, calcium and phosphorus) and urinalysis at 9 intervals over 28 wk. In general, palatability of both diets was high and dogs maintained their body weight. Nevertheless eight dogs of the MPD and six dogs of the HMD group died or had to be killed during the study. In surviving dogs, serum urea, creatinine, phosphorus and [P x Ca] were significantly reduced nearly to the normal range after 4 wk. A slight increase at the end of the study occurred because clients did not adhere strictly to dietary instruction after recovery of the dogs. These results suggest that elderly dogs frequently show a mild or moderate CRF, and dietary treatment with medium protein and low phosphorus diets is effective in improving blood chemistry data as well as physical condition of those dogs.