Abstract
Lactic acid was administered to sheep fed the roughage diet, either into the rumen at 0.05% level of the body weight or intravenously 100ml of 0.5M solution, to determine the effects of lactic acid on the blood acid-base status, urine volume and urinary excretion of calcium, phosphorus and magnesium. The intraruminal injection of lactic acid increased the level of serum lactic acid, and gave little effects on the blood acid-base status represented by the blood pH, Pco2 and HCO-3 content, and on the serum levels of minerals. Urine volume tended to decreased after the injection of lactic acid. The urinary concentration and excretion of calcium and magnesium were increased but those of phosphorus were not affected by the intraruminal injection of lactic acid. The intravenous infusion of lactic acid did not affect the blood acid-base status and mineral concent ration though the serum concentration of lactic acid was increased to about 2.5 times the pre-infusion level immediately after the infusion. The urine pH was de- creased for a period and the urinary concentration and excretion of calcium and phosphorus were increased by the intravenous infusion of lactic acid. The results suggest that when the production of lactic acid in the rumen of sheep fed the concentrate diet increases, the urinary excretion of minerals may be changed by the blood level of lactic acid.
