Some Biochemical Constituents in Urine of Vitamin A-Deficient Holstein Calves

Summary To study possible effects of hypovitaminosis-A on urine composition, 30 male Holstein calves, average age 53 days and live weight 158lb, and partially depleted of their vitamin A reserves, were fed a vitamin A depletion ration supplemented with artificially dehydrated alfalfa leaf meal to provide a deficient or adequate carotene intake, 15 or 150 μ g per pound of live weight daily. Cerebrospinal fluid pressures were higher in the deficient group accompanied by lower vitamin A concentrations in the plasma and liver. Specific gravity, osmolality, and total solids of urine were significantly lower in the calves receiving a 15 μ g intake. Concentrations and total daily outputs of urea nitrogen and creatinine were slightly less in the urine of the deficient calves. To further study urine composition, repeat collections were made with five pairs of calves. In the deficient calves, average osmolality was again less, as well as concentrations and total daily outputs of sodium and chloride. Potassium was unaffected, but concentrations and total daily outputs of phosphorus were greater. The latter element was the only criterion which was significantly different. Kidney calcium concentrations were slightly higher.