Effects of High Protein Diets with Normal and Low Energy Intake on Wound Healing, Hair Growth, Hair and Serum Zinc, and Serum Alkaline Phosphatase in Dairy Heifers

Abstract

Effects of level of protein and energy intake on several measures were studied in 24 female Holstein calves. The four dietary treatments which provided varying amounts of protein and energy in relation to National Research Council (NRC) requirements were: a) control (100% protein, 100% energy); b) medium high protein (150% protein, 100% energy); c) high protein (200% protein, 100% energy); and d) high protein, restricted intake (same diet as high protein fed at a level to provide 60% of energy needs). Healing was more rapid in animals fed the high protein diet at 100% of energy requirement. Those given the high protein, restricted intake treatment healed at a rate comparable to that of controls, thus indicating that total protein intake had more influence on rate of healing than level of energy intake. Average daily gains were increased, and feed efficiency and hair growth rate slightly increased in those given the high protein treatments. Hair and serum zinc content, serum alkaline phosphatase, packed cell volume (PCV), and hemoglobin values were not materially affected by higher than normal dietary protein intakes. Restricting intake of the high protein feed reduced weight gains, feed efficiency, hair growth, and serum alkaline phosphatase, but did not affect hair and serum zinc, PCV, and hemoglobin values.