Stewart S R, Emerick R J, Pritchard R H
Chem. Dept., South Dakota State University, Brookings 57007.
J Anim Sci. 1991 May;69(5):2225-9. doi: 10.2527/1991.6952225x.
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.
向钙含量不同的日粮中添加氯化铵，以评估其在预防绵羊硅质尿石形成方面的潜力。一项2×2析因试验涉及自由采食由50%禾本科干草、50%燕麦粉加补充料组成日粮的去势公羔。基础日粮以干物质计含有3.3%二氧化硅、0.31%钙、0.22%磷、11.6%粗蛋白和26%酸性洗涤纤维。处理组（每组38至39只羔羊）包括对照组（C）、添加石灰石使日粮钙含量增至0.6%的组（L）、添加1%氯化铵的组（A）以及L+A组（LA）。经过118天的试验期后，仅在C组和L组发现硅质肾沉积物，硅占尿石灰分的93%至95%。尿石发病率分别为13%（C组）和18%（L组）。饲喂A组和LA组的羔羊未出现尿石形成（氯化铵效应，P<0.01），且C组尿石发病率有低于L组的趋势（P<0.02），这支持了以下假说：日粮的成酸作用以及日粮钙磷比降低可减少硅质尿石的形成。
