Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Animal Science

First Advisor

Royce J. Emerick


Urinary calculi composed primarily of silica have been identified in range animals by several researchers. Silica calculi have also been found in dogs, humans, rats and guinea pigs. Forman et al conducted a detailed analysis of calculi. They found.that ashing at temperatures of 1500 C decreased calculi weight by 20%. Silica and calcium were shown to make up most of the remaining mineral content. Calculi from grazing ruminants in western Australia contained Si02, but further analysis showed that they were a mixture of substances. Mcintosh found that of the calculi analyzed 47% contained weddelite (Calcium oxalate.H20) and opaline silica, 13% contained calcite or aragonite (CaC03) and silica, 9% contained silica, 13% contained calcite or aragonite, 6% contained weddelite and calcite, 1% contained apatite (calcium phosphate) and 11% were organic calculi consisting of 4'-0-methyl equol crystals. Organic calculi of this type were associated with ruminants grazing clover pastures. Calcite calculi were found most often in ruminants consuming legume hays or grazing legume pastures. In the United states silica has been reported to be in all calculi removed from ruminants grazing native pastures. In some studies, up to 50% or more of the animals grazing western pastures have been found to have calculi. Bailey and Whiting et al found up to 90% of the animals in certain trials fed grass hay to have silica calculi and Whiting et al said that urinary calculi in range animals was a usual condition. Losses due to obstruction of the urinary tract were much lower with estimates varying from 4 to 10 percent of some ruminant flocks and herds. Silica urolithiasis has caused an estimated 0.5 to 1.0 million dollar loss to Canadian livestock producers annually, and in the western United States silica urolithiasis ranked fifth among all nutritional disorders of cattle.

Library of Congress Subject Headings

Ruminants -- Diseases -- Prevention Urinary organs -- Calculi -- Prevention



Number of Pages



South Dakota State University


No Copyright - United State