INVESTIGATIONS ON CRISTALLURIA IN SOWS

In 12 breeding sows the influence of high feed levels of calcium (Ca 1 6.0 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 an d renal excretion of minerals (Ca,P, Mg), electrolytes (Na, K) as well as development of urine concrements (crystalluria) was investigated i n 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 crystallur ia was tested. Studies showed that especially high levels of phosphoru s in the feed are responsible for excretion of urinary crystals. Sedim ent consisted of Ca phosphates mainly, which could be detected as amor phous crystals microscopically. Alkaline pH values in urine and an ins ufficient water supply supported development of crystalluria, but form ation of crystals differed greatly between individuals. Cystoscopic in vestigations demonstrated inflammatory alterations of the bladder muco sa in sows with crystalluria. Therefore crystalluria in sows has to be considered as a risk factor for urinary tract infections.