Urate Crystals / Stones

urate crystals diagram

Dalmatians are susceptible to forming urinary crystals and stones in stagnant urine. Dalmatians must be allowed to drink freely and urinate often. Dalmatians form crystals and stones in acidic urine (pH below 7). These are known as urate crystals/stones. Most other breeds of dogs form stones in alkaline urine (pH above 7) known as struvite or infection stones. This is not to say that Dalmatians cannot form struvite stones.

Dalmatians as a breed find it hard to break down (metabolise) a set type of protein/amino acid called ‘Purines’. There are three types of purines that cause uric acid stone/s.

  1. Oxypurines (like xanthine, hyproxanthne, uric acid and allantoin)
  2. Aminopurines (like adenine, quanine that make up DNA)
  3. Methylpurines (like caffine and theophylline which are drugs)

The liver converts these purines (set proteins) into ‘Allantoin’. However Dalmatians have difficulty converting these purines into allantoin.

Note allantoin is a byproduct of purine metabolism; it is a waste product when uric acid is oxidised or broken down. DNA analysis has identified a specific single gene that is thought to control the normal canine uric acid metabolism, residing on canine chromosome number 3.

The Dalmatian converts these purines/proteins into uric acid. Hence Dalmatians excrete uric acid into their urine without the last conversion to allantoin. Dalmatians are therefore predisposed to uric acid stone formation in the bladder. Stone forming Dalmatians seem to excrete more uric acid than non stone forming counterparts.

Prevention Methods:

To prevent the formation of urate stone disease in Dalmatians the diet must be low in purines, to lower the concentration of uric acid in the urine. To achieve follow the 4 steps;

  1. Increasing the consumption of water
  2. Feed a diet low in purines
  3. Alkalinise the urine
  4. Control urinary tract infections as these contribute to stone formation.

Purine levels in Food

Foods highest in Purines
Organ meats, red meats, seafoods, and brewer’s yeast.

Foods moderately high in Purines
Asparagus, bacon, whole grain breads & cereals, cauliflower, legumes (kidney beans, navy & lima beans, lentils, peas), white meats, meat soups & broths, mushrooms, oatmeal, peas, spinach.

Foods lowest in Purines
Butter, cheese, eggs, fats, fruits & fruit juices (avoid citrus to minimize abnormally acidic urinary pH), gelatin, milk (including butter, condensed, malted), nuts (including peanut butter), pasta (you will have to evaluate the sauce and other ingredients separately), sugars, syrups, sweets, vegetables (except those above), vegetable & cream soups, (made with acceptable vegetables, but not with beef stock).

Dalmatian Pointer Cross was undertaken in 1973 to eradicate urate crystals in the Dalmatian dog.  The “Dalmatian Backcross Project” was conducted by Dr. Robert Schaible from luadalmatians, in an effort to address the fixed genetic defect in Dalmatians that affects uric acid metabolism and that may lead to increased urinary uric acid, urate crystals,urinary bladder aggregate formation, stones, urinary tract obstruction and even death.

This wonderful breeding program is presently at the 14th generation from the original cross. The progeny have 99.98% AKC registered Dalmatians in their pedigrees and on parentage analysis, their DNA is 99.8% the same as AKC registered Dalmatians. The Dalmatians were therefore accepted to be shown for the first time at Crufts in 2011. Note none of the descendants have exhibited symptoms or signs of urate stone disease.

In summary If you own a Dalmatian, have a urinary test performed every year as part of your Dalmatians routine heath check. It is also wise to periodically check the pH at home. pH test strips are available for purchase at most pharmacies. The normal urine pH for a Dalmatian is 6.5 to 7.2. If your Dalmatians urine pH is below 6.5, you should take a sample into your veterinarian for analysis.

PH test scale

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