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.
(Am J Vet Res 2001;62:1782–1786)
Objective—To assess the effect of dietary potassium
citrate supplementation on the urinary pH, relative
supersaturation of calcium oxalate and struvite
(defined as the activity product/solubility product of the
substance), and concentrations of magnesium, ammonium,
phosphate, citrate, calcium, and oxalate in dogs.
Animals—12 healthy adult dogs.
Procedure—Canned dog food was fed to dogs for 37
days. Dogs were randomly allocated to 3 groups and
fed test diets for a period of 8 days. Study periods
were separated by 6-day intervals. During each study
period the dogs were fed either standard diet solus
(control) or standard diet plus 1 of 2 types of potassium
citrate supplements (150 mg potassium citrate/kg
of body weight/d) twice daily. Urinary pH, volume and
specific gravity, relative supersaturation of calcium
oxalate and struvite, and concentrations of magnesium,
ammonium, phosphate, calcium, oxalate, and
citrate were assessed for each treatment.
Results—Mean urine pH was not significantly affected
by dietary potassium citrate supplementation,
although urine pH did increase by 0.2 pH units with
supplementation. Diets containing potassium citrate
maintained a higher urine pH for a longer part of the
day than control diet. Three Miniature Schnauzers had
a significantly lower urinary relative calcium oxalate
supersaturation when fed a diet supplemented with
potassium citrate, compared with control diet.
Conclusions and Clinical Relevance—Dietary
potassium citrate supplementation has limited
effects on urinary variables in most healthy dogs,
although supplementation results in maintenance of a
higher urine pH later in the day. Consequently, if supplementation
is introduced, dogs should be fed twice
daily and potassium citrate should be given with both
meals or with the evening meal only. (Am J Vet Res 2000;61:430–435)