SOME CHANGES IN THE URINE OF SHEEP FED A HAY HIGH IN SILICA

Abstract

Sheep were fed grass hay (mainly Festuca scabrella) obtained from a ranch in Western Canada where considerable losses had occurred from obstructive urolithiasis in beef cattle. This hay contained much more silica than second-cut red clover from Eastern Canada but less sodium, potassium, calcium and magnesium. The sheep fed the western hay excreted significantly less urine, which had an extremely low pH (ca. 5.5). These and other observations (e.g., specific gravity, water consumption) indicated that a hay low in alkali and relatively high in silica may be important in the etiology of silica urolithiasis. The urine changes caused by the feeding of the western hay were overcome by adding an appropriate salt mixture to the diet.