urethral diameter. Low Ca:P intake ratio is conducive to phosphatic (e.g. struvite) urolith formation. Incidence among wether lambs can be minimized by maintaining a dietary Ca:P intake ratio of 2:1. Alkaline (higher) pH favors formation of carbonate and phosphate calculi. For domestic ruminants, dietary cation: anion balance is sometimes adjusted to assure a slightly acidic urine pH, for prevention of calculus formation. Differing generalizations regarding effects of pH on formation of silicate uroliths may be found. In this connection, it may be noted that under some circumstances, calcium carbonate accompanies silica in siliceous uroliths. Pelleted feeds may be conducive to formation of phosphate uroliths, because of increased urinary phosphorus excretion. This is attributable to lower saliva production where pelleted rations containing finely ground constituents are fed. With less blood phosphate partitioned into saliva, more tends to be excreted in urine. (Most saliva phosphate is fecally excreted.) Oxalate uroliths can occur in ruminants, although such problems from oxalate ingestion may be relatively uncommon. Ruminant urolithiasis associated with oxalate ingestion has been reported. However, no renal tubular damage or visible deposition of calcium oxalate crystals in kidneys was found in yearling wether sheep fed diets containing soluble oxalate at 6.5 percent of dietary dry matter for about 100 days. Conditions limiting water intake can result in stone formation. Various surgical interventions, e.g. amputation of the urethral process at its base near the glans penis in male ruminants, perineal urethrostomy, or tube cystostomy may be considered for relief of obstructive urolithiasis. See also Nephrocalcinosis Kidney disease Kidney stone formation in space References Notes External links Information from the European Urological Association Kidney Stone Guide Book – University of Chicago Kidney Stone Program Kidney diseases Urological conditions Acute pain Wikipedia medicine articles ready to translate Wikipedia emergency medicine articles ready to translate