Based on research done in the last ten years, that the only time it is necessary to feed a low protein diet is when your dog is uremic, which generally means BUN is over 80 mg/dL (equivalent to 28.6 mmol/L), creatinine is over 4.0 mg/dL (equivalent to 354 µmol/L), and the dog is showing symptoms such as vomiting, nausea,inappetence, ulcers and lethargy, which are caused by the build-up of nitrogen in the blood. Even then, feeding low protein will not extend life, but it will help the dog feel better. Subcutaneous fluids can also help at this time (and before).
If your dog has significant amounts of protein in the urine (urine protein:creatinine ratio above 1.0), then you may need to reduce protein moderately, enough to control the proteinuria, but a really low-protein diet is not considered beneficial, as it can lead to hypoalbuminemia (low albumin levels).
If your dog is not uremic, then the consensus seems to be to feed a moderate amount of very high quality protein. Eggs have the highest quality protein (although egg yolks are high in phosphorus), followed by meat (raw or cooked). The lowest quality protein comes from grains.
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When developing a diet for your dog with kidney failure, the goal is to reduce phosphorus by feeding moderate to high fat, moderate amounts of high quality protein,and low phosphorus carbohydrates to provide calories.
Dogs with kidney problems often do better when fed several small meals throughout the day rather than just one or two large meals.