[Crystalluria in sows].
In 12 breeding sows the influence of high feed levels of calcium (Ca 16.0 mg/kg, P 5.9 mg/kg, Ca/P ratio 2.71:1), of a mineral feed mixture (Ca 13.8 mg/kg, P 8.3 mg/kg, Ca/P ratio 1,66:1) and of phosphorus (Ca 7.0 mg/kg, P 11.0 mg/kg, Ca/P ratio 0.64:1) on blood concentrations and renal excretion of minerals (Ca, P, Mg), electrolytes (Na, K) as well as development of urine concrements (crystalluria) was investigated in comparison to a control feed (Ca 7.3 mg/kg, P 6.0 mg/kg, Ca/P ratio 1.23:1). Besides the effect of water supply on formation of crystalluria was tested. Studies showed that especially high levels of phosphorus in the feed are responsible for excretion of urinary crystals. Sediment consisted of Ca phosphates mainly, which could be detected as amorphous crystals microscopically. Alkaline pH values in urine and an insufficient water supply supported development of crystalluria, but formation of crystals differed greatly between individuals. Cystoscopic investigations demonstrated inflammatory alterations of the bladder mucosa in sows with crystalluria. Therefore crystalluria in sows has to be considered as a risk factor for urinary tract infections.