High Uric Acid Excretion

The majority of dogs excrete small amounts of uric acid in the urine. However, the Dalmatian is exceptional in that these excrete large amounts. This disorder in Dalmatian dogs is due to impaired conversion in the liver of uric acid to allantoin by the enzyme uricase leading to excess excretion of uric acid in the urine. Dalmatians do not suffer more from kidney or bladder stones than other dog breeds, although if they develop such stones, their composition is different and they are called urate uroliths. In the urine, high uric acid levels can promote "crystals" which in turn can form into larger stones. The result can be complete blockage of the urinary tract which is an emergency situation with life-threatening potential. Although male and female Dalmatians can develop stones, males are most likely to do so.

Breeds at Risk

English Bulldogs and Yorkshire Terriers are susceptible to the formation of urate uroliths and familial predisposition is suspected. The cause of urate urolithiasis in these breeds is not known.

Urate uroliths (stones) occur mainly in Dalmatians and in dogs with portosystemic shunts when hepatic conversion or uric acid (a product or purine metabolism) to allantoin is impaired. Although all Dalmatians have the primary defect, only a some dogs develops clinical disease. The high heritability of the disease makes it possible for breeders to effectively select against the disease.

Prevention

Uric acid stones can be effectively prevented by limiting the amount of purine (a type of protein) in the diet. Most vegetables (except beans, peas, asparagus, spinach, and cauliflower) and fruits are low in purines, also eggs, cheese and milk, while meats, fish, and organ meats are high in purines. Processed breads and cereals are low in purines, but whole grain varieties are not. Feeding Dalmatians a low-purine diet and increased water intake is the best way to prevent urate stones in this breed. Drugs such as allopurinol may be needed in some cases but it can result in complications (xanthine stones) in some dogs.

References

1. Roy Robinson. Genetics for Dog Breeders.
2. KM James. Renal Tubular Disorders.
3. D. R. Lane, B. Cooper. Veterinary Nursing
4. Bannasch DL, Ling GV, Bea J, Famula TR. Inheritance of urinary calculi in the Dalmatian
5. Lowell Ackerman. Dr.Ackerman's Book of Dalmatians