Two randomized 3×3 complete block design experiments were conducted simultaneously to investigate the effects of acute depletion of Ca, PO4 and Sr by hemodialysis from 90-kg, 100-day-old calves. In one experiment the calves were intravenously dosed with 3 mc each of Ca45, P32O4, and Sr89 at 48-, 96- or 144-hr predialysis. In the other experiment, the calves were each intravenously dosed with 0.25 mc of Sr85 at 4-, 14-, or 24-hr predialysis. Total Ca depletion of 0.16 g/hr resulted in a 4.8-fold turnover of plasma calcium after 12 hr of dialysis, while only decreasing the plasma Ca concentration by 26%. Plasma P concentration was decreased only 25% by 12-hr dialyses. Plasma concentrations of all isotopes declined (P<0.01) during dialysis. The radioactivity removed by dialysis decreased as the time after dosing increased. By the observed ratio technique, depleted Sr89 to Ca45 averaged 1.3–1.4, which confirms the data that Ca is bound to the plasma proteins more than Sr. Rib epiphyseal Ca45 showed a significant decrease (P<0.05) after dialysis. Each isotope followed this trend in a proportional manner. Sr85 activity in the epiphyseal rib increased during dialyses, begun 4 hr post-dosing. Ability of the young calf to mobilize reserve calcium, strontium, and phosphate was demonstrated in this study.