Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)


Animal Science


A series of experiments was conducted using lambs and rats to determine the effect of various levels and sources of dietary phosphate on the incidence of phosphatic urinary calculi. Additional experiments were conducted to determine the degree of protection afforded sheep against urolithiasis by feeding various salts, and to determine the effect of these salts on excretion and retention of various ions. The lambs used in the sheep experiments were crossbred lambs weighing approximately 30 to 33 kg. They were fed a fattening ration consisting of ground shelled corn, alfalfa hay or silage (corn or sorghum) and soybean meal (approximately 11% crude protein in the diets). Disodium phosphate, monosodium phosphate and sodium tripolyphosphate, fed at levels to provide 0.06% phosphorus in the total ration, resulted in a high (60 – 70%) incidence of urinary calculi with no difference between compounds. Increasing the level of dietary calcium from 0.31 to 0.58% with the sodium phosphates reduced, but did not completely prevent, the incidence of urinary calculi. Dicalcium phosphate fed at a level providing 0.58% calcium and 0.60% phosphorus in the ration did not result in the production of urinary calculi. Serum and urine phosphorus values were lowest for the control lambs and lambs fed dicalcium phosphate. Extensive study of the various types of calculi, especially those composed mainly of phosphate, citrates, oxalates and silica, has been conducted with laboratory animals. Although the research documented in this thesis is concerned almost entirely with phosphatic urinary calculi in sheep, literature dealing with the other types of calculi is discussed in the light of similarities and differences existing between various types. The experiments reported herein were conducted to determine the causative factor(s) in the formation of phosphatic urolithiasis and to establish methods for its prevention in lambs.

Library of Congress Subject Headings

Animal nutrition
Sheep -- Feeding and feeds




South Dakota State University