Drop in dietary control
The increase in the frequency of feline struvite over calcium oxalate from 2003 to 2010 may be associated with decreased use
of diets designed to dissolve sterile feline struvite uroliths as a consequence of the significant increase in calcium oxalate
uroliths in the 1980s and 1990s.
Mineral composition of cat uroliths
The significance of struvite as the predominant mineral type emphasizes the importance of consideration of struvitolytic diet
to manage cats diagnosed with urolithiasis. Currently, prescription diets are available that promote dissolution of struvite
uroliths in a short period of time (Figures 4 and 5). It's likely that some, if not most, of the 5,631 feline struvite uroliths
submitted to the Minnesota Urolith Center in 2010 could have been readily dissolved in one to four weeks by feeding diets
designed to promote formation of urine that is undersaturated with struvite.
Figure 4: Survey lateral abdominal radiograph of a spayed female 11-year-old domestic shorthair cat.
However, not all uroliths can be dissolved with dietary manipulation. Uroliths that have not dissolved in a reasonable amount
of time should be sent to a reputable laboratory for evaluation of mineral composition.
Figure 5: Survey abdominal radiograph taken three weeks after initiation of therapy with a struvitolytic diet.
Editor's note: This article was co-written by Jody P. Lulich, DVM, PhD, Dipl. ACVIM, the co-director of the Minnesota Urolith Center. The
Center—with the support of an educational gift from Hill's Pet Nutrition as well as contributions from veterinarians and pet
owners—provides quantitative urolith analysis at no charge. Online submission, e-mail notification and electronic retrieval
of results are available. The 670,000-sample database offers veterinarians information on urolith trends, treatment and prevention
suggestions. For details, visit
Dr. Lulich is the co-director of The Minnesota Urolith Center and professor of Veterinary Internal Medicine at the University
Dr. Osborne is professor of medicine at the College of Veterinary Medicine, University of Minnesota.
For a complete list of articles by Dr. Osborne, visit