Effects of Sodium and Phosphorus Supplements for Steers on Native Pastures in the Tropical Highlands.

Abstract

Four groups of 14 steers each were given weekly supplements of either sodium or phosphorus, both or neither for 48 weeks. They grazed together on native pasture. Live-weight was recorded at 4 or 5-week intervals. Saliva samples were collected at 0, 30 and 48 weeks and blood samples at O and 30 weeks. Saliva samples were analyzed for sodium and potassium. For blood sample s, the concentrations of sodium, potassium, phosphorus, copper and urea in the serum were determined. Supplementation had no effect on live-weight gain. Steers not supplemented with sodium showed large decreases in sodium, and increases in potassium, in saliva over the experiment. The levels of these elements in serum were normal and generally unaffected by the treatment. Phosphorus, copper, and urea in sera were normal in all groups. Urea content of serum samples was not different among the groups but was lower than normal.