The development of uroliths (urinary stones) and urinary sludge is a common health problem seen in guinea pigs and rabbits.
These conditions often develop when there is a collection of excess calcium which builds up in the urinary tract.
Sludge (dense calcium crystals) has a toothpaste-like consistency and is often difficult to remove entirely with normal urination. The sludge generally settles at the bottom of the bladder with normal urine on top, and it is usually only in the last part of urination that this gritty grey paste is passed.
Uroliths (small stones or grit) are hard ‘stone like’ build ups that can occur anywhere from the kidneys to the urethra. These can cause localised pain and inflammation, as well as lead to a urinary blockage in some cases.