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Abstract

Objective—To determine the effects of training and sustained submaximal exercise on hematologic values in racing sled dogs.

Design—Cohort study.

Animals—39 Alaskan sled dogs bred for endurance racing.

Procedures—Blood samples were collected prior to initiation of a 7-month training regimen (n = 39), after completion of the training regimen (19), and after completion of an 1,100-mile race (9), and a CBC, differential cell count, and flow cytometry for leukocyte surface antigens were performed.

Results—Both training and exercise caused significant decreases in PCV and hemoglobin concentration and significant increases in total WBC count. In contrast, training and exercise were not found to have significant effects on absolute numbers or fractions of CD4+ or CD8+ lymphocytes, other than a significant increase in the fraction of CD8+ lymphocytes associated with training.

Conclusions and Clinical Relevance—Results suggested that training and exercise induced changes in several hematologic values in racing sled dogs. Extracellular fluid volume expansion was the likely explanation for the training-induced decrease in PCV, and acute blood loss secondary to gastrointestinal tract bleeding was likely responsible for the decrease in PCV associated with acute exercise.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether echocardiographic variables differed between successful (elite) and less successful (nonelite) Arabian endurance horses.

Animals—34 Arabian horses that competed in endurance racing.

Procedures—Horses were assigned to either an elite or nonelite group on the basis of results of a previous competition, and a standardized echocardiographic examination was performed on each horse within 1 to 4 weeks after that competition. Multivariable logistic regression with backward stepwise elimination was used to create a prediction model for the determination of horse status (elite or nonelite) as a function of the measured echocardiographic variables.

Results—The elite and nonelite groups consisted of 23 and 11 horses, respectively. One horse in the nonelite group had a frequent ventricular dysrhythmia that could have negatively affected its performance and rider's safety, whereas none of the horses in the elite group had remarkable cardiac abnormalities. The left ventricular internal diameter during systole and diastole and left ventricular mass and stroke volume were significantly greater for horses in the elite group, compared with those for horses in the nonelite group. The final logistic regression model correctly predicted the horse status for all of the horses in the elite group and 8 of 11 horses in the nonelite group.

Conclusions and Clinical Relevance—Results indicated that heart size was significantly associated with performance for Arabian endurance horses in a manner similar to findings for Thoroughbred and Standardbred racehorses in active competition.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine effects of 2 tiludronate administration protocols on measures of lameness in horses with navicular syndrome (NS).

ANIMALS 12 horses with bilateral forelimb NS.

PROCEDURES Horses were randomly assigned to receive tiludronate (1 mg/kg), diluted in 5 L of isotonic electrolyte solution and delivered through a jugular vein catheter (systemic treatment group; n = 6), or tiludronate (0.1 mg/kg), diluted with saline (0.9% NaCl) solution to a total volume of 35 mL and delivered into the lateral digital vein of each forelimb with an IV regional limb perfusion (IVRLP) technique (IVRLP group; 6). Mean peak vertical ground reaction force (pVGRF) measured with a stationary force plate and subjective lameness scores (SLSs) were recorded before (day −1) and at predetermined time points after tiludronate administration on day 0. Mean pVGRFs (standardized as percentage body weight of force) and mean SLSs for the most lame forelimb and for both forelimbs of horses in each group were compared with day −1 values to determine treatment effect.

RESULTS Mean pVGRF for both forelimbs and for the most lame forelimbs of systemically treated horses were significantly increased on days 120 and 200, compared with day −1 results. No significant difference in mean pVGRF was observed for IVRLP-treated horses. The SLSs were not improved at any time point following systemic treatment and were improved only on day 120 following IVRLP.

CONCLUSIONS AND CLINICAL RELEVANCE Tiludronate (1 mg/kg, IV) as a single systemic treatment appeared to be beneficial for horses with NS, but no horses were judged as sound during the study period. Additional research on IVRLP with tiludronate is needed before this method can be recommended. (Am J Vet Res 2016;77:167–173)

Full access
in American Journal of Veterinary Research

Abstract

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.

Full access
in American Journal of Veterinary Research

Abstract

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.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine whether prophylactic administration of valacyclovir hydrochloride versus initiation of treatment at the onset of fever would differentially protect horses from viral replication and clinical disease attributable to equine herpesvirus type-1 (EHV-1) infection.

ANIMALS 18 aged mares.

PROCEDURES Horses were randomly assigned to receive an oral placebo (control), treatment at detection of fever, or prophylactic treatment (initiated 1 day prior to viral challenge) and then inoculated intranasally with a neuropathogenic strain of EHV-1. Placebo or valacyclovir was administered orally for 7 or 14 days after EHV-1 inoculation or detection of fever (3 horses/group). Effects of treatment on viral replication and clinical disease were evaluated. Plasma acyclovir concentrations and viremia were assessed to determine inhibitory concentrations of valacyclovir.

RESULTS Valacyclovir administration decreased shedding of virus and viremia, compared with findings for control horses. Rectal temperatures and clinical disease scores in horses that received valacyclovir prophylactically for 2 weeks were lower than those in control horses. The severity of but not the risk for ataxia was decreased by valacyclovir administration. Viremia was decreased when steady-state trough plasma acyclovir concentrations were > 0.8 μg/mL, supporting the time-dependent activity of acyclovir.

CONCLUSIONS AND CLINICAL RELEVANCE Valacyclovir treatment significantly decreased viral replication and signs of disease in EHV-1–infected horses; effects were greatest when treatment was initiated before viral inoculation, but treatment was also effective when initiated as late as 2 days after inoculation. During an outbreak of equine herpesvirus myeloencephalopathy, antiviral treatment may be initiated in horses at various stages of infection, including horses that have not yet developed signs of viral disease.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine whether a stainless steel implant sterilized with a novel cold atmospheric plasma sterilization (CAPS) device adversely affects local tissues in rabbits and whether CAPS was as effective as steam sterilization with an autoclave to inactivate Pasteurella multocida.

ANIMALS

31 healthy New Zealand White rabbits.

PROCEDURES

Steam-autoclaved stainless steel implants inoculated with P multocida underwent a second steam autoclave sterilization (AIA) or CAPS (AICAPS). One AIA implant and 3 AICAPS implants were randomly placed subcutaneously at 4 sites in 21 rabbits (84 implants). These rabbits were monitored daily for 5 days for evidence of systemic illness and local tissue reactions at the implantation sites and then euthanized. Samples were taken from each implant site for bacterial culture and histologic examination.

RESULTS

Cultures of samples obtained from all sites were negative for bacterial growth. No significant difference was observed in mean skin thickness or erythema between AIA and AICAPS implant sites on any observed day. Also, individual histologic grades for the epidermis, dermis, subcutis, and muscle and total histologic grade were not significantly different between AIA and AICAPS implant sites.

CONCLUSIONS AND CLINICAL RELEVANCE

Cold atmospheric plasma sterilization was noninferior to steam sterilization of P multocida–contaminated stainless steel implants in the rabbits in the present study. However, studies of the efficacy of CAPS for inactivation of other important bacteria are needed.

Full access
in American Journal of Veterinary Research

Abstract

Case Description—13 equids (10 horses, 2 donkeys, and 1 pony) were examined for signs of colic (n = 7), weight loss (6), anorexia (3), and diarrhea (2). Ten equids were evaluated in the fall (September to November). Seven equids had a history of persimmon ingestion.

Clinical Findings—A diagnosis of phytobezoar caused by persimmon ingestion was made for all equids. Eight equids had gastric persimmon phytobezoars; 5 had enteric persimmon phytobezoars. Gastroscopy or gastroduodenoscopy revealed evidence of persimmon ingestion in 8 of 10 equids in which these procedures were performed.

Treatment and Outcome—2 of 13 equids were euthanatized prior to treatment. Supportive care was instituted in 11 of 13 equids, including IV administration of fluids (n = 8) and treatment with antimicrobials (5), NSAIDs (5), and gastric acid suppressants (4). Persimmon phytobezoar–specific treatments included dietary modification to a pelleted feed (n = 8); oral or nasogastric administration of cola or diet cola (4), cellulase (2), or mineral oil (2); surgery (4); and intrapersimmon phytobezoar injections with acetylcysteine (1). Medical treatment in 5 of 7 equids resulted in resolution of gastric persimmon phytobezoars. Seven of 8 equids with gastric persimmon phytobezoars and 1 of 5 equids with enteric persimmon phytobezoars survived > 1 year after hospital discharge.

Clinical Relevance—Historical knowledge of persimmon ingestion in equids with gastrointestinal disease warrants gastroduodenoscopy for evaluation of the presence of persimmon phytobezoars. In equids with gastric persimmon phytobezoars, medical management (including administration of cola or diet cola and dietary modification to a pelleted feed) may allow for persimmon phytobezoar dissolution.

Full access
in Journal of the American Veterinary Medical Association