Screening of anionic salts for palatability, effects on acid-base status, and urinary calcium excretion in dairy cows.

Six anionic salts [MgCl2.6H2O, MgSO4.7H2O, CaCl2.2H2O, CaSO4.2H2O, NH4Cl, and (NH4)2SO4] were evaluated for their effects on dietary DM intake, systemic acid-base balance, and urinary excretion of Ca. Each of the six salts was fed to 12 nonlactating, nonpregnant Holstein cows for 1-wk periods in two replicates of a 6 x 6 Latin square design. All salts were fed at the rate of two equivalents cow-1 d-1. Anionic salt treatments did not decrease DM intake compared with the control diet fed without salts. Blood pH was not affected by any of the salt treatments; however, mild, compensated metabolic acidosis was evidenced by decreased blood bicarbonate concentrations and decreased blood base excess when any of the salts was fed. Urinary pH and urinary base excess also were lowered by all of the salts. Fractional excretion of urinary Ca was increased by all salt treatments. All six anionic salts tested were of similar value in their acidifying effects and in their ability to increase urinary excretion of Ca.