The Minnesota Urolith Center at the University of Minnesota processes more urinary stones than any veterinary center worldwide, analyzing roughly 93,000 cases annually. That scale allows researchers to identify emerging trends that can directly influence how veterinarians prevent and treat stone formation. In this case, what began as just two unusual samples—identified using infrared spectroscopy—eventually revealed a growing pattern. These stones were found to contain choline and tartrate, forming a newly recognized type known as calcium tartrate tetrahydrate (CTT) uroliths.
As additional cases appeared, researchers traced a likely connection to diet. Many affected dogs were consuming fresh or minimally processed foods, or supplements containing choline bitartrate—an ingredient commonly used to balance homemade or fresh diets. After analyzing 33 cases, the team found a consistent association between certain diet formulations and the development of CTT stones, particularly in smaller breeds and male dogs. The findings suggest that the recent rise in fresh dog food adoption may have unintended health implications for some animals.
While the exact formulations responsible are still unclear, the discovery is significant because it identifies both a new type of urinary stone and a probable cause. With further validation, this insight could lead to straightforward prevention strategies, including reformulation by pet food manufacturers. Researchers are optimistic that, with increased awareness and industry response, CTT uroliths could become largely preventable.