Objective—To examine acid-base and hormonal abnormalities in dogs with diabetes mellitus.
Animals—48 dogs with diabetes mellitus and 17 healthy dogs.
Procedures—Blood was collected and serum ketone, glucose, lactate, electrolytes, insulin, glucagon, cortisol, epinephrine, norepinephrine, nonesterified fatty acid, and triglyceride concentrations were measured. Indicators of acid-base status were calculated and compared between groups.
Results—Serum ketone and glucose concentrations were significantly higher in diabetic than in healthy dogs, but there was no difference in venous blood pH or base excess between groups. Anion gap and strong ion difference were significantly higher and strong ion gap and serum bicarbonate concentration were significantly lower in the diabetic dogs. There were significant linear relationships between measures of acid-base status and serum ketone concentration, but not between measures of acid-base status and serum lactate concentration. Serum insulin concentration did not differ significantly between groups, but diabetic dogs had a wider range of values. All diabetic dogs with a serum ketone concentration > 1,000 μmol/L had a serum insulin concentration < 5 μU/mL. There were strong relationships between serum ketone concentration and serum glucagon-insulin ratio, serum cortisol concentration, and plasma norepinephrine concentration. Serum β-hydroxybutyrate concentration, expressed as a percentage of serum ketone concentration, decreased as serum ketone concentration increased.
Conclusions and Clinical Relevance—Results suggested that ketosis in diabetic dogs was related to the glucagon-insulin ratio with only low concentrations of insulin required to prevent ketosis. Acidosis in ketotic dogs was attributable largely to high serum ketone concentrations.
Objective—To determine whether there is evidence of myocardial injury in horses with acute abdominal disease.
Design—Prospective case series.
Animals—18 healthy horses and 69 horses with acute abdominal disease.
Procedures—18 healthy horses had been admitted to the hospital for investigation and were assigned to group 1. Horses examined for acute abdominal disease were assigned to 3 groups: strangulating obstruction, nonstrangulating obstruction, or inflammatory disease (groups 2, 3, and 4, respectively). Heart rate, Hct, and blood lactate and cardiac troponin I (cTnI) concentrations were measured at initial examination. Myocardial function was assessed by echocardiographic measurement of fractional shortening and left ventricular ejection time (LVET). Heart rhythm was evaluated via ECG.
Results—The proportion of horses with high (> 0.03 ng/mL) cTnI concentration was significantly greater among horses with strangulating (9/25 [36%]) or inflammatory (9/19 [47%]) lesions, compared with healthy horses (0/18). The proportion of horses with high cTnI concentration was significantly greater among nonsurvivors (12/24 [50%]) than among survivors (10/45 [22%]). Serum cTnI concentration was positively correlated with Hct, heart rate, and blood lactate concentration and negatively correlated with LVET.
Conclusions and Clinical Relevance—Evidence of myocardial injury was observed in horses with acute abdominal disease, and this injury was associated with severity of illness. Recognition of myocardial injury could improve treatment of acute abdominal disease in horses.
Objective—To determine the effects of racing and
nontraining on plasma thyroxine (T4), free thyroxine
(fT4), thyroid-stimulating hormone (TSH), and thyroglobulin
autoantibody (TgAA) concentrations in sled
dogs and compare results with reference ranges
established for dogs of other breeds.
Animals—122 sled dogs.
Procedure—Plasma thyroid hormone concentrations
were measured before dogs began and after they finished
or were removed from the Iditarod Trail Sled
Dog Race in Alaska and approximately 3 months after
Results—Concentrations of T4 and fT4 before the race
were less than the reference range for nonsled dogs in
26% and 18% of sled dogs, respectively. Immediately
after racing, 92% of sled dogs had plasma T4 concentrations
less than the reference range. Three months after
the race, 25% of sled dogs had plasma T4 concentrations
less than the reference range. For T4, fT4, TSH, and
TgAA, significant differences were not detected in samples
collected before the race versus 3 months later.
Conclusions and Clinical Relevance—Plasma T4, fT4,
and TSH concentrations decreased in dogs that complete
a long distance sled dog race. Many clinically normal
sled dogs have plasma T4 and fT4 values that are
lower than the reference range for nonsled dogs. We
suggest that the reference ranges for sled dogs are 5.3
to 40.3 nmol/L and 3.0 to 24.0 pmol/L for plasma T4 and
fT4 concentrations, respectively, and 8.0 to 37.0 mU/L
for TSH. (J Am Vet Med Assoc 2004;224:226–231)
Objective—To investigate risk factors for development
of equine protozoal myeloencephalitis (EPM) in
Animals—251 horses admitted to The Ohio State
University Veterinary Teaching Hospital from 1992 to
Procedure—On the basis of clinical signs of neurologic
disease and detection of antibody to Sarcocystis
neurona or S neurona DNA in cerebrospinal fluid, a
diagnosis of EPM was made for 251 horses. Two contemporaneous
series of control horses were selected
from horses admitted to the hospital. One control
series (n = 225) consisted of horses with diseases of
the neurologic system other than EPM (neurologic
control horses), and the other consisted of 251 horses
admitted for reasons other than nervous system
diseases (nonneurologic control horses). Data were
obtained from hospital records and telephone conversations.
Risk factors associated with disease status
were analyzed, using multivariable logistic regression.
Results—Horses ranged from 1 day to 30 years old
(mean ± SD, 5.7 ± 5.2 years). Risk factors associated
with an increased risk of developing EPM included
age, season of admission, prior diagnosis of EPM on
the premises, opossums on premises, health events
prior to admission, and racing or showing as a primary
use. Factors associated with a reduced risk of
developing EPM included protection of feed from
wildlife and proximity of a creek or river to the premises
where the horse resided.
Conclusions and Clinical Relevance—Development
of EPM was associated with a number of management-related factors that can be altered to decrease
the risk for the disease. (J Am Vet Med Assoc
Objective—To investigate risk factors for use in predicting
clinical improvement and survival of horses
with equine protozoal myeloencephalitis (EPM).
Design—Longitudinal epidemiologic study.
Animals—251 horses with EPM.
Procedure—Between 1992 and 1995, 251 horses
with EPM were admitted to our facility. A diagnosis of
EPM was made on the basis of neurologic abnormalities
and detection of antibody to Sarcocystis neurona
or S neurona DNA in CSF. Data were obtained from
hospital records and through telephone follow-up
interviews. Factors associated with clinical improvement
and survival were analyzed, using multivariable
Results—The likelihood of clinical improvement after
diagnosis of EPM was lower in horses used for breeding
and pleasure activities. Treatment for EPM
increased the probability that a horse would have clinical
improvement. The likelihood of survival among
horses with EPM was lower among horses with more
severe clinical signs and higher among horses that
improved after EPM was diagnosed.
Conclusions and Clinical Relevance—Treatment of
horses with EPM is indicated in most situations; however,
severity of clinical signs should be taken into
consideration when making treatment decisions.
Response to treatment is an important indicator of
survival. (J Am Vet Med Assoc 2000;217:1181–1185)
Objectives—To determine effects of dietary antioxidant
supplementation on plasma concentrations of
antioxidants, exercise-induced oxidative damage, and
resistance to oxidative damage during exercise in
Alaskan sled dogs.
Animals—62 Alaskan sled dogs.
Procedure—Dogs were matched for age, sex, and ability
and assigned to 1 of 3 groups: sedentary and nonsupplemented
(control [C]; n = 21), exercised and supplemented
(S; 22), and exercised and nonsupplemented
(N; 19). Dogs in group S were given 400 units of α-
tocopherol acetate, 3 mg of β-carotene, and 20 mg of
lutein orally per day for 1 month, then dogs in groups S
and N completed 3 days of exercise. Blood samples
were collected before and after 1 and 3 days of exercise
and after 3 days of rest. Plasma antioxidant concentrations
were determined, and oxidative damage to DNA
(plasma 7,8 dihydro-8-oxo-2'deoxyguanosine [8-oxodG]
concentration) and membrane lipids (plasma hydroperoxide
concentration) and resistance of plasma lipoproteins
to oxidation were assessed.
Results—Supplementation increased plasma concentrations
of α-tocopherol, β-carotene, and lutein.
Plasma concentration of α-tocopherol increased
and concentration of lutein decreased in group S
with exercise. Concentration of 8-oxodG decreased
in group S but increased in group N during and after
exercise. Lag time of in vitro oxidation of lipoprotein
particles increased with exercise in group S only.
Conclusions and Clinical Relevance—Dietary supplementation
with antioxidants resulted in increased plasma
concentrations of antioxidants. Moreover, supplementation
decreased DNA oxidation and increased
resistance of lipoprotein particles to in vitro oxidation.
Antioxidant supplementation of sled dogs may attenuate
exercise-induced oxidative damage. (Am J Vet Res
Objective—To determine whether dietary antioxidants
would attenuate exercise-induced increases in
plasma creatine kinase (CK) activity in sled dogs.
Animals—41 trained adult sled dogs.
Procedure—Dogs, randomly assigned to 2 groups,
received the same base diet throughout the study.
After 8 weeks on that diet, 1 group (21 dogs) received
a daily supplement containing vitamins E (457 U) and
C (706 mg) and β-carotene (5.1 mg), and a control
group (20 dogs) received a supplement containing
minimal amounts of antioxidants. After 3 weeks, both
groups performed identical endurance exercise on
each of 3 days. Blood samples were collected before
and 3 weeks after addition of supplements and after
each day of exercise. Plasma was analyzed for vitamins
E and C, retinol, uric acid, triglyceride, and cholesterol
concentrations, total antioxidant status (TAS),
and CK activity.
Results—Feeding supplements containing antioxidants
caused a significant increase in vitamin E concentration
but did not change retinol or vitamin C concentrations
or TAS. Exercise caused significantly higher
CK activity, but did not cause a significant difference
in CK activity between groups. Exercise was
associated with significantly lower vitamin E, retinol,
and cholesterol concentrations and TAS but significantly
higher vitamin C, triglyceride, and uric acid concentrations
in both groups.
Conclusions and Clinical Relevance—Use of supplements
containing the doses of antioxidants used
here failed to attenuate exercise-induced increases in
CK activity. Muscle damage in sled dogs, as measured
by plasma CK activity, may be caused by a
mechanism other than oxidant stress. (Am J Vet Res
Objective—To determine whether prolonged exercise by conditioned sled dogs affects urine concentrations of homovanillic acid (a metabolite of dopamine), vanillylmandelic acid (a metabolite of norepinephrine and epinephrine), and cortisol.
Animals—24 conditioned Alaskan sled dogs (2 to 8.5 years old) that were in training for a multiday endurance race.
Procedures—Voided urine samples were collected from 4 groups of dogs (randomly selected from 54 dogs) after no exercise (control group; n = 6 dogs), completion of a 160km run (group A; 3), completion of a 420-km run (group B; 7), and completion of a 560-km run (group C; 6). Urine cortisol concentrations were determined by use of an immunoassay technique; urine vanillylmandelic acid and homovanillic acid concentrations were measured via high-performance liquid chromatography.
Results—Compared with the control group, urine cortisol concentration in groups A, B, and C was significantly different (5.33 × 10−4 ± 2.62 × 10−4 μg/dL vs 1.04 × 10−4 ± 2.31 × 10−5 μg/dL, 8.88 × 10−4 ± 5.49 × 10−4 μg/dL, and 6.31 × 10−4 ± 5.09 × 10−4 μg/dL, respectively). Urine homovanillic acid concentration did not differ among the 4 groups. Vanillylmandelic acid was not detected in any urine samples.
Conclusions and Clinical Relevance—Results indicated that prolonged exercise by sled dogs did not affect urine homovanillic acid concentration but did increase urinary cortisol secretion, which is indicative of adrenocortical stimulation. The apparent lack of vanillylmandelic acid in voided urine samples requires further investigation.
Objective—To determine the interobserver variability
of assessment of exercise-induced pulmonary hemorrhage
(EIPH) during tracheobronchoscopic examination
Animals—747 Thoroughbred racehorses.
Procedure—850 tracheobronchoscopic examinations
were performed within 2 hours of racing for the
horses. Examinations were recorded on videotape,
and EIPH and its severity were assessed independently
by 3 veterinarians. Concordance was determined
by calculation of the Cohen weighted κ statistic
and tabulation of scores assigned by each observer.
Results—Weighted κ statistics ranged from 0.75 to
0.80. In 99.4% of observations, all observers agreed
or 2 of 3 agreed and the third differed by ≤ 1 grade.
Conclusions and Clinical Relevance—Results indicated
that interobserver reliability of tracheobronchoscopic
assessment of EIPH in Thoroughbred racehorses
is high when the examination is conducted by
experienced veterinarians. Concordance among
investigators is sufficient to justify use of this grading
system for further studies and clinical descriptions of
EIPH. (Am J Vet Res 2005;66:596–598)
Objective—To determine the impact of successive days of endurance exercise on select serum chemistry values in conditioned Alaskan sled dogs.
Design—Prospective cohort study.
Animals—10 conditioned Alaskan sled dogs.
Procedures—All dogs ran 160 km/d for 5 consecutive days. Serum was obtained prior to exercise and immediately after each exercise run; all samples were obtained before dogs were fed. Serum electrolyte, mineral, protein, total bilirubin, urea nitrogen, creatinine, and cardiac troponin-I concentrations and serum alkaline phosphatase, alanine aminotransfer-ase, creatine kinase, and aspartate aminotransferase activities were measured. Data were analyzed by means of analysis of covariance for a randomized complete block design with dog as a blocking variable, time as a covariate, and distance run as the treatment of interest. Least square mean values were compared with values obtained prior to exercise, and linear and quadratic contrasts were examined.
Results—Serum globulin concentration was low prior to exercise (mean ± SD, 2.2 ± 0.3g/dL) and progressively decreased as exercise continued. Exercise was associated with increases in serum chloride, urea nitrogen, and cardiac troponin-I concentrations and serum alanine aminotransferase, creatine kinase, and aspartate aminotransferase activities and with pro-gressive decreases in serum potassium, total protein, and albumin concentrations.
Conclusions and Clinical Relevance—Results suggested that multiple successive days of endurance exercise resulted in mild aberrations in serum chemistry variables in conditioned sled dogs. Changes likely reflected the metabolic stresses of prolonged endurance exercise as well as dietary composition. Hypoglobulinemia in resting, conditioned sled dogs may reflect the immunosuppressive or catabolic effects of intense endurance training.