Dong-Hao Lu

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)



First Advisor

Royce J. Emerick


Urethral obstruction by silica calculi is a major cause of death of cattle and sheep grazing western ranges of the United States. Similar calculi problems have been found in several other countries including Canada, U.S.S.R. and Australia. Range grasses having silica contents of 4 to 7% (dry basis) appear to be the silica source. In addition, silica urinary calculi have been reported to occur in dogs from silicon of unknown origin, humans consuming large quantities of silicate antacids and rats and guinea pigs experimentally fed tetraethylorthosilicate (TES). Emerick and coworkers have found that supplemental dietary phosphate and acid-forming salts provide rats some protection from silica urolithiasis. This protective effect was beyond those effects attributable to increases in water intake and urine volume. The objectives of my thesis research were (1) to study the calculi protective effect of dietary phosphorus using an animal model consisting of laboratory rats fed diets containing 2% tetraethylort 'hosilicate (TES) [(C2 H 5 o)4 Si], (2) to study in vitro the effect of phosphorus on precipitation of a polysilicic acid-protein complex which is believed to be important to the formation of silica calculi, and (3) to develop a ruminant model for future silica urinary calculi studies.

Library of Congress Subject Headings

Phosphorus in animal nutrition


Urinary organs -- Calculi



Number of Pages



South Dakota State University