Silica uroliths in dogs: cause and prevention
6-year-old intact male German Shepherd that became obstructed by a urethrolith, now removed. The urolith was jackstone-shaped (with radial projections) and quantitative analysis shows 95% silica. It eats a budget dry food with much rice hull and soy, and drinks little.
Which preventive measure is most appropriate?
chevron_right Show answer and explanation
A. A struvite dissolution diet, which also dissolves silica
Silica cannot be dissolved by any diet, and acidification adds nothing for this urolith type.
B. Allopurinol to reduce urinary silica excretion
Allopurinol acts on purine (urate) metabolism and has no effect on silica.
C. Switch to a diet with animal-origin protein and few silicate-rich plant ingredients, and increase water intake
Correct. Silica uroliths are associated with diets high in plant ingredients (rice and soy hulls, corn gluten) and sometimes soil ingestion. Removing the source and diluting the urine are the basis of prevention.
D. None: silica is an incidental finding with no risk of recurrence
If the diet and concentrated urine persist, recurrence is likely; this dog has already obstructed.
lightbulb Key takeaway
A jackstone shape suggests silica, although it can also occur with calcium oxalate: always confirm by quantitative analysis. It mainly affects males of large breeds such as German Shepherds and Old English Sheepdogs.
References: Lulich JP et al. ACVIM Small Animal Consensus Recommendations on the Treatment and Prevention of Uroliths in Dogs and Cats (2016)
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.