Steers under a pasture and feedlot system receiving 3 different diets (treatments), in a complete randomized desing, were bled every 14 days for 6 months. The following concentrations; urea, 11.11 - 16.11 mg/dl; total protein, 5.92 - 6.32 g/dl; inorganic phosphorus, 6.24 - 7-11 mg/dl; calcium, 11.01 - 12.66 mg/dl in plasma, and hemoglobin, 10.14 - 10.55 g/dl in whole blood, were found in animals gaining weight.