Milk replacers containing high levels of protein, at least a portion being non-milk protein, is fed at high feeding rates such as at least 0.73 kg (1.6 pounds) per head per day. Non-milk proteins include hydrolyzed soy protein modified, soy protein concentrate, soy protein isolate, wheat protein, potato protein, egg protein, blood plasma, red blood cells and/or egg, and serve as complementary proteins when used in combination with milk proteins. Complementary proteins within a daily ration for young animals, such as calves, may include non-milk protein from about 1 to about 65 percent by weight of the protein by dry weight. Due to the enhanced feeding rate of the milk replacer, any lack of enzyme development in the young animal's digestive system that is normally required to utilize non-milk proteins may be circumvented, and animal performance may be optimized during the first weeks of ingesting milk replacer.