Effect of various chlorides and calcium carbonate on calcium, phosphorus, sodium, potassium and chloride balance and their relationship to urinary calculi in lambs.

V ARIOUS salts have been used in ruminant rations in attempts to reduce the incidence of urinary calculi. Bushman et al. (1967) have recently reported on the relative effectiveness of ammonium chloride, calcium chloride, sodium chloride and calcium carbonate. Also, a protective effect against phosphatic urolithiasis has been assigned to dietary potassium by Robbins et al. (1965). Crookshank (1966) has presented data indicating a greater protective effect for various potassium salts compared with corresponding sodium salts. In addition, Udall and Chow (1963) have postulated an ion-competition effect for the chloride ion. Elevated urinary phosphorus levels, often accompanied by concomitant decreases in urinary levels of calcium or magnesium or both, have been associated with phosphatic urolithiasis by an increasing number of workers, among them Elam et al. (1956), Emerick et al. (1959), Packett and Hauschild (1964), Bushman et al. (1965a, b) and Robbins et al. (1965). Whereas the characteristics of urine from sheep fed calculogenic rations have received considerable attention, similar data concerning sheep fed various dietary salts for protection against urinary calculi are limited. The studies reported herein were conducted to further determine the degree of protection afforded sheep against urolithiasis by the feeding of various salts, and to determine their effect on excretion and retention of various ions.