Protein in the Nutrition of the Growing Dog

Abstract

The protein requirement for growth of young dogs was investigated by adding increments of casein to a basal diet which contained 10.6% of protein (N × 6.25), and was adequate in other nutrients. The other 4 diets contained 12.8, 15.0, 17.2 and 19.4% of crude protein respectively. The basal diet sustained health and a retarded rate of growth in the young dogs. There was a correlation between the comparative gains in body weight and the comparative protein contents of the diets from 12.8 to 17.2% of protein, beyond which point there was no further increase in growth rate caused by additional protein. Since the diet containing 17.2% of protein was adequate for the growth of the pups, their requirements for the 10 essential amino acids apparently do not exceed the amounts that it contained. The utilization of the basal diet was substantially improved by the addition of 2.5% of casein (2.2% “protein”), but more casein caused very little further improvement in this respect. A 5½-month-old pup which had been very retarded in growth for 4 months by a protein deficiency was still able to grow at a normal rate when his dietary protein was raised to 17.2%.