Objective—To evaluate cartilage and bone biomarkers and body composition in growing large-breed dogs consuming a diet designed for growth.
Animals—43 large-breed 2 month-old-puppies.
Procedures—Dogs were randomly assigned to receive 1 of 2 foods until 18 months of age. Dogs were evaluated at 2, 5, 12, and 18 months of age via dual energy x-ray absorptiometry (DEXA), CBC, serum biochemical profile, and concentrations or activities of taurine, vitamin E, fatty acids, glutathione peroxidase, C-propeptide of type II collagen (CPII), cartilage oligomeric matrix protein (COMP), carboxy-terminal cross-linked fragment of type II collagen (CTXII), bone specific alkaline phosphatase (BAP), osteocalcin, ghrelin, and growth hormone.
Results—Blood components largely reflected the composition of the foods. Dogs fed the food with a higher concentration of protein, calcium, n-3 fatty acids, and antioxidants had a lower percentage of body fat and greater percentage of lean body mass at 5, 12, and 18 months of age, and higher CPII:CTXII ratio and lower COMP at 18 months of age. The BAP activity, osteocalcin concentration, and CTXII concentration declined with age, whereas COMP concentration and CPII concentration were similar at all time points for both foods.
Conclusions and Clinical Relevance—The BAP activity, osteocalcin concentration, and CTXII concentration were greater during growth than at 18 months of age. The food that was proportionately higher in protein, calcium, n-3 fatty acids, and antioxidants increased lean body mass and may have positively affected cartilage turnover as maturity was attained. Whether the rate of cartilage turnover during growth affects development of orthopedic disease or arthritis in adulthood has yet to be determined.
Objective—To determine the effects of 3 rations (low
grain, fat, high grain) on plasma creatine kinase (CK)
activity and lactate concentration in Thoroughbred
horses with recurrent exertional rhabdomyolysis
Animals—5 Thoroughbreds with RER and 3 healthy
Thoroughbreds (control horses).
Procedures—Rations were formulated to meet (lowgrain
and fat rations) or exceed (high-grain ration) daily
energy requirements. Each ration was fed to horses
in a crossover design for 3 weeks. Horses were exercised
on a treadmill Monday through Friday; maximum
speed on Monday and Friday was 11 m/s (6%
slope), on Tuesday and Thursday was 9 m/s, and on
Wednesday was 4.5 m/s. Plasma CK activity and lactate
concentration were determined before and after
Results—Horses with RER fed the high-grain ration
had significantly greater CK activity and change in CK
activity 4 hours after exercise, compared with those
fed the low-grain ration. Horses with RER exercised at
the trot or canter had significantly greater increases in
CK activity, compared with those exercised at the gallop.
Plasma lactate concentrations after exercise
were similar in control and affected horses. Lactate
concentration and CK activity were not correlated in
horses with RER.
Conclusions and Clinical Relevance—Rations high
in grain and formulated to exceed daily energy
requirements may increase episodes of rhabdomyolysis
in Thoroughbred horses susceptible to RER. (Am J
Vet Res 2000;61:1390–1395)
Objective—To determine daily variation in urinary
clearance and fractional excretion (FE) of electrolytes
and minerals within and between horses and to compare
volumetric and single-sample urine collection for
determining FE values of diets with a range of dietary
cation-anion balance (DCAB).
Animals—5 Thoroughbred and 6 mixed-breed mares.
Procedure—3 isocaloric diets with low, medium, and
high DCAB values (85, 190, and 380 mEq/kg of dry
matter, respectively) were each fed for 14 days. Daily
blood samples, single urine samples collected by
using a urinary catheter (5 mares), and volumetric
urine collections (6 mares) were obtained during the
last 72 hours of each diet.
Results—Urine and plasma pH values, plasma concentrations,
and FE values of sodium, chloride, potassium,
magnesium, phosphorus, and calcium were
altered by varying the DCAB. Noticeable variation in
clearance and FE values was detected within horses
from day-to-day on the same diet as well as between
horses. Fractional excretion values were not significantly
different between single-sample and volumetric
methods, except for magnesium in the high DCAB
diet. Volumetric and single-sample collections
revealed similar patterns of change in urinary FE values
with varying DCAB, except for calcium and magnesium.
Conclusions and Clinical Relevance—Substantial
variation in clearance and FE of electrolytes and minerals
are evident within horses between 24-hour periods
as well as between horses fed a specific diet.
Three daily urine samples provide similar information
regarding dietary-induced changes in clearance and
FE values (excluding calcium and magnesium) as that
obtained by volumetric urine collection. (Am J Vet Res 2003;64:284–291)
Objective—To determine whether plasma, urine,
and fecal electrolyte and mineral concentrations differ
between clinically normal horses and
Thoroughbreds with recurrent exertional rhabdomyolysis
(RER) after consumption of diets varying in
Animals—5 Thoroughbred mares with RER and 6
clinically normal mixed-breed mares.
Procedure—Each of 3 isocaloric diets designated as
low, medium, and high on the basis of dietary cationanion
balance (DCAB) values of 85, 190, and 380,
respectively, were fed to horses for 14 days. During
the last 72 hours, 3 horses with RER and 3 control
horses had daily urine and fecal samples obtained by
total 24-hour collection. Remaining horses had urine
samples collected daily by single catheterization.
Results—For each diet, no differences existed
between horses with RER and control horses in plasma
pH, electrolyte concentrations, and creatine
kinase activity or in urine pH and renal fractional
excretion (FE) values. Plasma pH, strong ion difference,
bicarbonate and total carbon dioxide concentrations,
and base excess decreased and plasma chloride
and ionized calcium concentrations increased
with decreasing DCAB. Urine pH decreased with
decreasing DCAB. The FE of chloride and phosphorus
were greatest for horses fed the low diet. The FE values
for all electrolytes exept magnesium did not differ
between urine samples obtained by single catheterization
and total 24-hour collection. Daily balance of
calcium, phosphorus, sodium, chloride, and potassium
did not differ significantly among horses fed the
Conclusions—In clinically normal horses and in horses
with RER, the DCAB strongly affects plasma and
urine pH and the FE of sodium, potassium, chloride,
and phosphorus. (Am J Vet Res 2002;63:1053–1060)