title: Effects of dietary ammonium chloride and variations in calcium to phosphorus ratio on silica urolithiasis in sheep.
abstract: Ammonium chloride was added to diets varying in Ca content to evaluate its potential in preventing silica urolith formation in sheep. A 2 x 2 factorial experiment involved wether lambs with ad libitum access to a diet of 50% grass hay and 50% ground oats plus supplement. The basal diet contained on a DM basis 3.3% SiO2, .31% Ca, .22% P, 11.6% CP, and 26% ADF. Treatments (38 to 39 lambs/treatment) consisted of a control (C), limestone to increase dietary calcium to .6% (L), 1% ammonium chloride (A), and L + A (LA). After a 118-d experimental period, siliceous kidney deposits were found only in C and L, with silica making up 93% to 95% of the urolithic ash. Urolith incidences were 13% (C) and 18% (L), respectively. The lack of urolith development in lambs fed A and LA (ammonium chloride effect, P less than .01) and a trend toward a lower urolith incidence in C vs L (P less than .02) support the hypothesis that acid-forming effects of the diet and a reduction in the dietary Ca to P ratio reduce silica urolith formation.
authors.affiliation: Chem. Dept., South Dakota State University, Brookings 57007.
authors.forename: S R
authors.initials: SR
authors.lastname: Stewart
authors.forename: R J
authors.initials: RJ
authors.lastname: Emerick
authors.forename: R H
authors.initials: RH
authors.lastname: Pritchard
mesh_terms: D000643:Ammonium Chloride / Q000627:therapeutic use*; D000821:Animal Feed; D000818:Animals; D002136:Calcium, Dietary / Q000627:therapeutic use*; D008297:Male; D010758:Phosphorus / Q000627:therapeutic use*; D011897:Random Allocation; D012756:Sheep; D012757:Sheep Diseases / Q000517:prevention & control*; D012822:Silicon Dioxide; D014545:Urinary Calculi / Q000517:prevention & control / Q000662:veterinary*
chemical_list: D002136:Calcium, Dietary; D000643:Ammonium Chloride; D010758:Phosphorus; D012822:Silicon Dioxide