Urinary Nitrogen and Vitamin E Status of Calves Fed Heat-Denatured Soluble Milk Proteins

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Abstract
Twenty male Holstein calves were assigned at 3 days of age across 4 dietary treatments. Treatments were whole milk and milk with 25, 50 and 75% denatured soluble protein. All diets were fed at 10% of body weight for 10 wk. Three 5-day N balance trials were conducted during the experiment. Chopped wheat straw was fed ad lib. Several basic nitrogenous compounds and Zn excretion were measured in urine samples. Packed cell volume and in vitro erythrocyte hemolysis were measured on whole blood samples. Vitamin E was measured on samples of plasma. Denatured proteins failed to change body weights, N balance, N retained or N digested. All amounts of denatured protein increased packed cell volumes. Hemolysis of erythrocytes and vitamin E in plasma were not changed. Vitamin E in plasma was low. Denatured protein decreased daily excretion of urinary Zn. Denatured protein did not increase urinary excretion of 3-methylhistidine but it did decrease urinary excretion of 1-methylhistidine and increased an unknown 4. Heat-denatured proteins had an effect on mineral metabolism and on N metabolism through excretion of a specific basic nitrogenous compound.