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  • Author or Editor: Kenneth W. Hinchcliff x
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Abstract

Objective—To determine serum antibody titers against canine distemper virus (CDV), canine adenovirus type II (CAV-2), and canine parvovirus (CPV) in trained sled dogs prior to and after completion of a long-distance race.

Design—Prospective cohort study.

Animals—195 Alaskan sled dogs (from 18 kennels) that participated in the 2006 Iditarod Trail Race.

Procedures—All 1,323 dogs participating in the race had been vaccinated against the 3 viruses at 19 to 286 days prior to initial blood sample collection (obtained within the month preceding the race). Within 12 hours of race completion, blood samples were collected from 195 dogs (convenience sample) and matched with each dog's prerace sample. Serum antibody titers (90% confidence intervals [CIs]) were determined via serum neutralization assays.

Results—After racing, geometric mean titers against CDV and CPV were significantly higher (2,495 [90% CI, 321 to 16,384] and 6,323 [90% CI, 512 to 32,768], respectively) than prerace values (82 [90% CI, 11 to 362] and 166 [90% CI, 32 to 1,024], respectively). Sixty-one of 194 (31.4%) dogs had t 4-fold increases in anti-CPV antibody titers after racing. Prerace serum antibody titers against CDV, CPV, and CAV-2 varied significantly by sled team but were not associated with time since vaccination.

Conclusions and Clinical Relevance—Postrace increases in serum anti-CDV and anti-CPV antibody titer might reflect exposure of dogs to these agents immediately before or during racing. Dogs had no clinical signs of CDV-, CAV-2-, or CPV-associated disease; therefore, the clinical importance of these titer changes is uncertain.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the efficacy of furosemide for prevention of exercise-induced pulmonary hemorrhage (EIPH) in Thoroughbred racehorses under typical racing conditions.

Design—Randomized, placebo-controlled, blinded, crossover field trial.

Animals—167 Thoroughbred racehorses.

Procedures—Horses were allocated to race fields of 9 to 16 horses each and raced twice, 1 week apart, with each of the 2 races consisting of the same race field and distance. Each horse received furosemide (500 mg, IV) before one race and a placebo (saline solution) before the other, with the order of treatments randomly determined. Severity of EIPH was scored on a scale from 0 to 4 after each race by means of tracheobronchoscopy. Data were analyzed by means of various methods of multivariable logistic regression.

Results—Horses were substantially more likely to develop EIPH (severity score ≥ 1; odds ratio, 3.3 to 4.4) or moderate to severe EIPH (severity score ≥ 2; odds ratio, 6.9 to 11.0) following administration of saline solution than following administration of furosemide. In addition, 81 of the 120 (67.5%) horses that had EIPH after administration of saline solution had a reduction in EIPH severity score of at least 1 when treated with furosemide.

Conclusions and Clinical Relevance—Results indicated that prerace administration of furosemide decreased the incidence and severity of EIPH in Thoroughbreds racing under typical conditions in South Africa.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical and clinicopathologic abnormalities in horses administered a blood transfusion and evaluate effects of blood transfusion on these variables.

Design—Retrospective case series.

Animals—31 adult horses that received ≥ 1 blood transfusion.

Procedures—Medical records of horses receiving a blood transfusion were reviewed to obtain clinical findings, laboratory test results before and after transfusion, adjunctive treatments, transfusion type and volume, response to transfusion, results of donor-recipient compatibility testing, adverse reactions, and outcome.

Results—31 horses received 44 transfusions for hemorrhagic anemia (HG; n = 18 horses), hemolytic anemia (HL; 8), or anemia attributable to erythropoietic failure (EF; 5). Tachycardia and tachypnea were detected in 31 of 31 (100%) and 22 of 31 (71%) horses, respectively, before transfusion. The PCV and hemoglobin concentration were less than the reference range in 11 of 18 horses with HG, 8 of 8 horses with HL, and 5 of 5 horses with EF. Hyperlactatemia was detected in 16 of 17 recorded values before transfusion. Heart rate, respiratory rate, and PCV improved after transfusion, with differences among the types of anemia. Seventeen (54%) horses were discharged, 9 (29%) were euthanized, and 5 (16%) died of natural causes. Adverse reactions were evident during 7 of 44 (16%) transfusions, varying from urticarial reactions to anaphylactic shock.

Conclusions and Clinical Relevance—Abnormalities in clinical and clinicopathologic variables differed depending on the type of anemia. Colic, cold extremities, signs of depression, lethargy, tachycardia, tachypnea, low PCV, low hemoglobin concentration, and hyperlactatemia were commonly detected before transfusion and resolved after transfusion.

Full access
in Journal of the American Veterinary Medical Association

Objective

To determine the relationship of serum biochemical values and change in body weight with finishing status (retired from or finished the race), finishing order of a team, and distance traveled for dogs participating in a long-distance sled dog race.

Animals

262 of 848 dogs that participated in the 1995 Iditarod Trail sled dog race.

Design

Prospective study.

Procedure

Body weight was recorded for 261 dogs before the race and again when these dogs retired from or completed the race. Using a nonrandom convenience sample of participating dogs, blood samples were obtained from 151 dogs that retired from the race and 111 dogs that completed the race.

Results

Serum biochemical indices of skeletal muscle damage were significantly higher in dogs retiring during the first 500 miles of the race than in dogs retiring in the last 638 miles or finishing the race. Serum sodium concentration was less than the reference range in a significantly greater proportion of dogs that retired from the race than of dogs that completed the race. There was little relationship between finishing order and serum biochemical values. Dogs completing the race lost a mean of 8.9% of body weight, and amount of weight lost was not related to finishing order.

Clinical Implications

Results indicated that exertional rhabdomyolysis develops more often in dogs that retire during the initial 500 miles of a long-distance race, compared with dogs that complete the race. There is no detectable relationship between the speed with which the race is run (finishing order) and body weight loss or serum biochemical values. (J Am Vet Med Assoc 1998;213:639-644)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To investigate the effect of a mask and pneumotachograph on ventilation, respiratory frequency, and tracheal and nasopharyngeal pressures in horses running on a treadmill.

Design

Six horses ran at 50, 75, and 100% of the speed that resulted in maximum oxygen consumption, with and without a mask and pneumotachograph. Tracheal and pharyngeal inspiratory and expiratory pressures, respiratory frequency, and arterial blood gases were measured.

Animals

Six Standardbred horses.

Procedure

Oxygen consumption was measured during an incremental exercise test to determine the speed that resulted in maximal oxygen consumption for each horse. Tracheal and pharyngeal pressures were measured, using transnasal tracheal and pharyngeal side-hole catheters connected to differential pressure transducers. Carotid arterial blood samples were collected and PaO2 , PaCO2 , and pH were measured with a blood gas analyzer.

Results

Peak tracheal and pharyngeal inspiratory pressures were significantly more negative, peak tracheal and pharyngeal expiratory pressures were significantly more positive and respiratory frequency was significantly lower (all P < 0.05) at all speeds when horses wore a mask The PaCO2 , was higher and arterial pH and PaO2 , were lower (P < 0.05) when horses wore a mask.

Conclusions

The mask and pneumotachograph altered upper airway pressures, respiratory frequency, and ventilation in horses running on a treadmill.(Am J Vet Res 1996; 57: 250-253)

Free access
in American Journal of Veterinary Research

Objective

To determine whether selected factors were associated with finishing status in a long-distance sled dog race.

Design

Prospective, observational study.

Animals

248 dogs participating in the 1994 Iditarod Trail sled race that were members of 13 teams that finished the race. Dogs were not selected randomly, but were members of teams that were easily accessible for examination before the race. The proportion of teams that were examined that finished the race (14/17) was similar to the proportion of teams that were not examined that finished the race (36/41).

Procedure

Age, sex, body conformation (weight, length, and thoracic width and circumference), cardiac variables (heart rate, natural logarithm of heart period variance, PR interval, QRS duration, QT index, R wave amplitude in leads II and V3, mean electrical axis, presence of cardiac arrhythmias suggestive of myocardial disease), and athletic ranking as assessed by the musher were compared between dogs that finished the race (n = 128) and dogs that did not finish (n = 120).

Results

The only factor found to differ significantly (P < 0.05) between finishers and nonfinishers was athletic ranking as assessed by the musher. Athletic rank and QRS duration or QRS duration normalized for body weight were identified by means of logistic regression as variables associated (P < 0.15) with finishing status. There was a significant (P < 0.0001), but weak (R 2 = 0.18), linear relationship between race time and mean QRS duration for each team.

Clinical Implications

Athletic ranking as assessed by the musher was the most important of the studied variables in determining finishing status, whereas age, sex, body conformation, and body weight were unimportant. Duration of the QRS was of minor importance in determining finishing status. (J Am Vet Med Assoc 1996; 206:879–882)

Free access
in Journal of the American Veterinary Medical Association

Summary

Six nontrained mares were subjected to steady-state, submaximal treadmill exercise to examine the effect of exercise on the plasma concentration of atrial natriuretic peptide (anp) in arterial, compared with mixed venous, blood. Horses ran on a treadmill up a 6° grade for 20 minutes at a speed calculated to require a power equivalent to 80% of maximal oxygen uptake (Vo 2MAX). Arterial and mixed venous blood samples were collected simultaneously from the carotid and pulmonary arteries of horses at rest and at 10 and 20 minutes of exercise. Plasma was stored at − 80 C and was later thawed; anp was extracted, and its concentration was determined by radioimmunoassay. Exercise caused significant (P < 0.05) increases in arterial and venous plasma anp concentrations. Mean ± sem arterial anp concentration increased from 25.2 ± 4.4 pg/ml at rest to 52.7 ± 5.2 pg/ml at 10 minutes of exercise and 62.5 ± 5.2 pg/ml at 20 minutes of exercise. Mean venous anp concentration increased from 24.8 ± 4.3 pg/ml at rest to 67.2 ± 14.5 pg/ml at 10 minutes of exercise and 65.3 ± 13.5 pg/ml at 20 minutes of exercise. Significant differences were not evident between arterial or mixed venous anp concentration at rest or during exercise, indicating that anp either is not metabolized in the lungs or is released from the left atrium at a rate matching that of pulmonary metabolism.

Free access
in American Journal of Veterinary Research