My two male schnauzers Hammy and Morgy had calcium oxalate stones. Males are more likely to have them, probably because females have larger openings and the stones pass through without growing. At least that is one theory.
Infections may cause some type of stones as bacteria interfer with pH value(which indicates the acidity of the urine). Diet and drugs for other conditions may also play a part in forming stones. It looks as if genes play a possible big part in some stone formation.
Telltale signs of stones are
  • straining
  • blood in urine
  • frequent urination.
    Thank goodness Morgy was spared an operation. Poor Ham. Not only did he have one surgery but he also had an obstruction and had emergency rerouting or bypass with a new larger opening which I am not certain he is aware of. I was traumatized..he wasn't by his new opening and continues to pee lifting his leg as if nothing changed. My vet said this way when he formed new gravellike stones...the little ones which do the obstructing would have an easy passage out rather than possibly block the urether again. He said the older stones are bigger and don't cause the obstructions. They don't fit into that tiny opening. Here are some great recent abstracts on the latest research and some hopefully helpful links. Mini schnauzers rank high among the stone bearers. Hammy's recovery from the rerouting was speedy..he was home that night..there was only a lot of blood in his urine for two days. Yes he seems to urinate more frequently now but that might be a matter also of age. He is 14 years old. He also wets his leg at times but that is to be expected. I try to clip the fur more often. He does clean himself more often. As we all know schnauzers are very catlike in their cleanliness. While his littermate was alive, he also would join in and clean his brother. Hopefully shortly I will add a picture to show what the rerouting looks like..not terribly interesting but just to show how natural it becomes to the traumatized human.
    The telltale signs usually of stones are breed and signs of blood in urine. Usually infection is ruled out first.

    There is a study on gallstones "Methionine, but not taurine, protects against formation of canine pigment gallstones.

    Associations between dietary factors in canned food and formation of calcium oxalate uroliths in dogs.
    Lekcharoensuk C, Osborne CA, Lulich JP, Pusoonthornthum R, Kirk CA, Ulrich LK, Koehler LA, Carpenter KA, Swanson LL. Minnesota Urolith Center,Dept of Small An Clin Sci,College of Vet Med,Univ of Minnesota,St Paul 55108,USA
    Am J Vet Res 2002 Feb;63(2):163-9
    OBJECTIVE: To identify dietary factors in commercially available canned foods associated with the development of calcium oxalate (CaOx) uroliths in dogs. ANIMALS: 117 dogs with CaOx uroliths and 74 dogs without urinary tract disease. PROCEDURE: Case dogs were those that developed CaOx uroliths submitted to the Minnesota Urolith Center for quantitative analysis between 1990 and 1992 while fed a commercially available canned diet.Control dogs were those without urinary tract disease evaluated at the same veterinary hospital just prior to or immediately after each case dog. A content-validated multiple-choice questionnaire was mailed to each owner of case and control dogs with the permission of the primary care veterinarian. Univariate and multivariate logistic regressions for each dietary component were performed to test the hypothesis that a given factor was associated with CaOx urolith formation. RESULTS: Canned foods with the highest amount of protein, fat, calcium, phosphorus, magnesium, sodium, potassium, chloride, or moisture were associated with a decreased risk of CaOx urolith formation, compared with diets with the lowest amounts. In contrast, canned diets with the highest amount of carbohydrate were associated with an increased risk of CaOx urolith formation. CONCLUSIONS AND CLINICAL RELEVANCE: Feeding canned diets formulated to contain high amounts of protein, fat, calcium, phosphorus, magnesium, sodium, potassium, chloride, and moisture and a low amount of carbohydrate may minimize the risk of CaOx urolith formation in dogs
    Epidemiology of canine calcium oxalate uroliths. Identifying risk factors.
    Calcium oxalate uroliths are most commonly encountered in Miniature Schnauzers, Lhaso Apsos, Yorkshire Terriers, Bichons Frises, Shih Tzus, and Miniature Poodles. They are more common in males than females, and more common in older than young dogs. Dogs that form abnormal nephrocalcin are also predisposed to calcium oxalate uroliths. Dietary risk factors for calcium oxalate uroliths include excessive calcium supplementation or excessive calcium restriction, excessive oxalic acid, high protein, high sodium, restricted phosphorus, restricted potassium, and restricted moisture (dry formulations). Dogs with hyperadrenocorticism or hypercalcemia are predisposed to calcium oxalate urolith formation.

    Patient and environmental factors associated with calcium oxalate urolithiasis in dogs.
    Lekcharoensuk C, Lulich JP, Osborne CA, Pusoonthornthum R, Allen TA, Koehler LA, Urlich LK, Carpenter KA,
    Swanson LL

    Minnesota Urolith Center, St Paul 55108, USA.
    J Am Vet Med Assoc 2000 Aug 15;217(4):515-9
    "OBJECTIVE: To test the hypothesis that breed, age, sex, body condition, and environment are risk factors for development of calcium oxalate uroliths in dogs. DESIGN: Case-control study. ANIMALS: 1,074 dogs that formed calcium oxalate uroliths and 1,724 control dogs that did not have uroliths. PROCEDURE: A validated multiple-choice questionnaire was designed to collect information from veterinarians and owners within 1 year of the date of urolith detection concerning signalment and environment of the dogs. Univariate and multivariate analyses were performed to calculate odds ratios to assess whether breed, age, sex, body condition, and environment were risk factors for calcium oxalate urolith formation. RESULTS: Middle-aged (8- to12-year-old) castrated male dogs had increased risk for formation of calcium oxalate uroliths. Urolith formation was also associated with increasing age. Dogs of certain breeds, including Miniature and Standard Schnauzer, Lhasa Apso, Yorkshire Terrier, Bichon Frise, Shih Tzu, and Miniature and Toy Poodle, had increased risk for developing calcium oxalate uroliths. Overweight dogs also had increased risk.
    CONCLUSIONS AND CLINICAL RELEVANCE: Knowledge of patient and environmental risk factors for development of calcium oxalate uroliths may facilitate development of surveillance strategies that result in earlier detection of this disease. Modification of environmental factors and body weight may minimize calcium oxalate urolith formation and recurrence. "
    (I wish they gave statistics of how many of those breeds are usually castrated and versus not castrated)

    Comparison of urine composition of healthy Labrador retrievers and miniature schnauzers.
    Stevenson AE, Markwell PJ.
    Waltham Center for Pet Nutrition, Waltham on the Wolds, Melton Mowbray, Leics, UK.
    Am J Vet Res 2001 Nov;62(11):1782-6
    OBJECTIVE: To compare urine composition in Labrador Retrievers (LR) and Miniature Schnauzers (MS) fed the same dog food.
    ANIMALS: 8 healthy LR (mean [+/- SD] age, 3.1+/-1.7 years) and 8 healthy MS (mean age, 3.7+/-1.3 years).
    PROCEDURE: A nutritionally complete dry dog food was fed to the dogs for 24 days. Urinary pH, volume, specific gravity, frequency of urination, and urinary concentrations of 12 analytes were measured for each dog; urinary relative supersaturation (RSS) with calcium oxalate and brushite (calcium hydrogen phosphate dihydrate) were calculated from these values.
    RESULTS: MS urinated significantly less often and had a lower urine volume (ml/kg of body weight per d) and a significantly higher urine pH, compared with LR. Urinary calcium concentration and brushite RSS were significantly higher in the urine of MS. As a result of a high calorie requirement, primarily as a result of high surface area to volume ratio, MS had significantly higher intake (per kg body weight) of dietary minerals, compared with LR.
    CONCLUSIONS AND CLINICAL RELEVANCE: Differences in urine composition exist between breeds fed the same diet, some of which, including lower urine volume, higher calcium concentration, and higher brushite RSS, may contribute to the high prevalence of calcium oxalate uroliths observed in MS. Differences between breeds should be considered when evaluating strategies for controlling calcium oxalate stone formation.

    Calcium oxalate urolithiasis in cats
    CAT Buffington, DJ Chew
    Ohio State Univ,Vet Hosp,601 Vernon L Tharp St,Columbus,OH 43210 USA
    Journal of Endourology, 1999, Vol 13, Iss 9, pp 659-663
    Urolithiasis has long been recognized as a cause of irritative voiding in cats, Before the late 1980s, sterile struvite was the most common urolith; today, however, 40% of feline uroliths are of calcium oxalate. This change may be partly attributable to the change to urine-acidifying, magnesium-restricted diets that were introduced to reduce the formation of struvite, However, it is possible that the diet modifications made by cat food manufacturers simply exposed a population of cats predisposed to calcium oxalate stone formation. Urolithiasis in cats appears to be diet sensitive rather than diet induced. As in humans, water is crucial in the prevention and treatment of feline stones.

    genetic?"Calcium oxalate stones in feline littermates
    K M Byrne, K Bynum, L Robinette, L Brownlee
    Journal of Feline Medicine & Surgery , Volume 2, Number 2 , June 2000,p 111-114
    Two feline littermates were diagnosed with calcium oxalate uroliths. Both had been maintained on a commercially available dry diet with reduced magnesium and urine acidifying properties. One female littermate was diagnosed by visualising the stones by radiographs while the second littermate, also female, became blocked when one of the uroliths lodged in the urethra. Two other, unrelated cats in the household, of similar age and rai"

    Associations between dry dietary factors and canine calcium oxalate uroliths.
    " Results suggest that dry diets formulated to contain high concentrations of protein, calcium, phosphorus, magnesium, sodium, potassium, and chloride may minimize formation of CaOx uroliths. In addition, comparison of risk and protective factors of various diet ingredients fed to dogs with CaOx uroliths suggests that although similar findings were observed in canned and dry formulations, in general, greater risk is associated with dry formulations. However, before these hypotheses about dietary modifications are adopted by food manufacturers, they must be investigated by use of appropriately designed clinical studies of dogs with CaOx urolithiasis."
  • Associations between dietary factors in canned food and formation of calcium oxalate uroliths in dogs.
    Feeding canned diets formulated to contain high amounts of protein, fat, calcium, phosphorus, magnesium, sodium, potassium, chloride, and moisture and a low amount of carbohydrate may minimize the risk of CaOx urolith formation in dogs.
  • http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11697365&dopt=Abstract
    Results suggest that diets formulated to contain higher protein, sodium, potassium, moisture, calcium, phosphorus, and magnesium contents and with decreased urine acidifying potential may minimize formation of CaOx uroliths in cats. Diets formulated to contain higher fat content and lower protein and potassium contents and with increased urine acidifying potential may minimize formation of MAP uroliths.
  • supplements for
    kidney stones
    CALCIUM OXALATE calcium oxalate
    and baking soda
    Canine and Feline
    Nephrology and
    Urology Page
    bladder stones
    stone diet
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