Sustained strenuous exercise increases intestinal permeability in racing Alaskan sled dogs

We assessed gastric and intestinal permeability and performed gastroscopy to evaluate the effects of sustained strenuous exercise on the gastrointestinal tract in racing sled dogs. Three teams of racing Alaskan sled dogs were examined approximately 1 week before and 24 hours after the 2003 Iditarod sled dog race (1,100 miles in 10 days). Each examination consisted of the administration of a solution of sucrose, lactulose, and rhamnose to evaluate gastric and intestinal permeability, as well as gastroscopy to visually inspect the gastric mucosa. Of the 54 dogs examined before the race, 16 completed the course and contributed data to the analysis. Sustained strenuous exercise was associated with an increased frequency of gastric erosions or ulcerations seen endoscopically (0% prerace versus 61% postrace). A significant postrace increase occurred in the median lactulose to rhamnose ratio in both serum and urine (0.11 versus 0.165, P = .0363; 0.11 versus 0.165, P = .0090, respectively). No significant differences were found in median serum or urinary sucrose concentrations when pre- and postrace values were compared. No correlation was found between visible gastric lesions and the concentration of sucrose in serum or urine samples obtained 4-5 hours after administration of the sugar solutions. We conclude that sustained strenuous exercise is associated with increased intestinal permeability, but the sucrose permeability test as we performed it did not correlate with visible gastric lesions.     

Efficacy of omeprazole for the prevention of exercise-induced gastritis in racing Alaskan sled dogs

Exercise-induced gastritis and gastric ulcers are common in humans and horses, and recently have been described in racing sled dogs. The cause of exercise-induced gastric disease is not completely understood in any species, but pharmacologic suppression of acid secretion is an effective treatment in humans and horses. Thus, we tested the hypothesis that omeprazole, a proton-pump inhibitor shown to reduce gastric acid secretion in dogs, would reduce the severity of exercise-induced gastric disease. Three teams of 16 dogs each competing in the 2002 Iditarod Sled Dog Race were recruited for participation. Within each team, dogs were randomly assigned to either treatment (20 mg omeprazole PO q24h) or placebo. Treatments were administered until either completion of the race or withdrawal of an individual dog from competition. Gastric endoscopy was performed in all dogs 24 hours after completion or withdrawal, and the gastric mucosa was scored by using a subjective severity score (0 = normal, 3 = numerous bleeding ulcers). Treatment with omeprazole significantly reduced mean gastricseverity score compared to placebo (omeprazole: 0.65 +/- 0.17, placebo: 1.09 +/- 0.18; P = .028), but also was associated with increased frequency of diarrhea during the race (omeprazole 54%, placebo 21%; P = .017). Examination of our data suggests that omeprazole may be an effective treatment for exercise-induced gastric disease in racing sled dogs. However, further investigation regarding the cause and clinical relevance of diarrhea associated with omeprazole treatment must be conducted before omeprazole can be recommended for routine prophylactic treatment in these athletes.     

Efficacy of famotidine for the prevention of exercise-induced gastritis in racing Alaskan sled dogs

BACKGROUND: Omeprazole reduces the severity of exercise-induced gastritis but not the prevalence of gastric lesions in sled dogs. The frequent feeding of sled dogs during competition likely results in decreased absorption of omeprazole and, thereby, decreased efficacy. HYPOTHESIS: Famotidine, a histamine-2 blocker with good bioavailability in the presence of food, would reduce the incidence and severity of exercise-induced gastric disease in sled dogs. ANIMALS: Sixteen fit Alaskan sled dogs (4 female, 12 male, all intact, age 2-6 years). METHODS: Dogs were randomly assigned to treatment (22 mg famotidine PO q24h) or control groups (n = 8 per group). Famotidine was administered with a meal to the treatment group once daily for 7 days before a challenge and once during exercise. Control dogs were fed an identical diet as the principal group. The 16 dog team completed a 100-mile exercise challenge in 18 hours. A gastroscopy was performed 24 hours after the challenge. The appearance of the mucosa was scored by an individual by using a scoring system. RESULTS: Treatment with famotidine significantly reduced the severity score compared with control (P = .0004). No adverse effects of treatment were reported. CONCLUSIONS AND CLINICAL RELEVANCE: Famotidine is effective in reducing the severity of exercise-induced gastric disease in racing Alaskan sled dogs, with minimal to no adverse effects, and may be recommended for prophylactic use in short distance races.     

Hereditary encephalomyelopathy and polyneuropathy in an Alaskan husky

An Alaskan husky puppy was examined for a neurologic disease which began at six weeks of age with generalised paresis that progressed resulting in recumbency by 18 weeks. Thoracic limbs primarily exhibited lower motor neuron signs that included distal muscle atrophy and persistent elbow and carpal flexion that resisted manual extension. Pelvic limb signs primarily exhibited upper motor neuron and general proprioceptive deficits, but also included lower motor neuron signs. Abnormal vocalisation suggested a laryngeal paresis. Histopathologic lesions included a diffuse axonopathy and secondary demyelination in the nerves of the limbs and larynx and a similar bilaterally symmetrical degeneration in the spinal cord white matter suggestive of a dying back axonopathy. In addition, a degenerative process was present in nuclei in the brain stem and cerebellum. Recognition of this disease through clinical and pathologic examination in other related Alaskan Huskies suggested an autosomal recessive inherited disorder.     

Temporal relationship between gastrointestinal protein loss, gastric ulceration or erosion, and strenuous exercise in racing Alaskan sled dogs

BACKGROUND: Alterations in the appearance and function of gastrointestinal mucosa are common after strenuous exercise. However, the duration of exercise required to alter the gastrointestinal mucosa has not been reported. HYPOTHESIS: We used 42 sled dogs to test the hypothesis that the magnitude of exercise-induced gastrointestinal mucosal dysfunction is related to exercise duration. ANIMALS: Six dogs served as conditioned controls, and the remaining dogs were randomly chosen for examination after 1-5 consecutive days of running at 100 miles/d. METHODS: Gastroduodenoscopy and measurement of gastric permeability were performed 24 hours after cessation of exercise. Intestinal protein loss (represented by fecal alpha-1 protease inhibitor concentration) was measured within 6 hours of cessation of exercise. Twelve of the 42 dogs were examined again after 5 months of detraining to determine the effect of training on gastrointestinal mucosal function. RESULTS: Exercise increased gastric permeability (P = .04) and endoscopic severity of gastric lesions (P < .0001), but neither variable was significantly affected by distance traveled. Acute exercise had no effect on intestinal protein loss. Untrained dogs had significantly lower fecal alpha-1 protease inhibitor concentrations compared with trained, unexercised dogs. Training had no effect on gastric permeability to sucrose or the endoscopic appearance of the stomach. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that relatively modest exercise is required to increase intestinal protein loss, but more substantial exercise is required to cause alterations in the proximal gastrointestinal tract. However, none of these alterations appear to progress with increasing exercise duration.     

Paraoesophageal hiatal hernia and megaoesophagus in a three-week-old Alaskan malamute

Paraoesophageal hiatal hernia was diagnosed in a three-week-old Alaskan malamute. Reduction of the hernia was followed by an oesophagopexy and a bilateral gastropexy. During the early postoperative period, the puppy continued to have signs that were thought to be related to a concurrent megaoesophagus. At nine months of age the dog had gained weight and was well except for occasional episodes of regurgitation. These episodes responded well to medical therapy, and at the time of writing the dog had not required further treatment.     

Paraesophageal hiatal hernia and pyloric obstruction in a dog

Paraesophageal hiatal herniation and pyloric obstruction were diagnosed in a pup with a history of vomiting. Findings of contrast radiography included esophageal reflux, delayed gastric emptying time, and paraesophageal herniation. Exploratory celiotomy revealed increased firmness of the pylorus and a primary defect in the esophageal hiatus, which allowed gastric herniation. Nissen fundoplication was performed following reconstruction of the esophageal hiatus, and pyloroplasty was performed to relieve the gastric outlet obstruction. Pyloric biopsy findings were consistent with a diagnosis of chronic gastritis. Recovery from surgery was initially unremarkable; however, the dog died suddenly 3 weeks after surgery. Necropsy revealed a large diaphragmatic hernia adjacent to the esophageal hiatus; the hernia had resulted in incarceration of the abdominal organs. The hiatal hernia reconstruction remained intact and was not the cause of the diaphragmatic disruption.     

Laparoscopic inguinal herniorrhaphy with barbed suture in a ram

A 7-month-old Hampshire ram, with no history of trauma or breeding, was referred for treatment of acute, unilateral scrotal swelling. Physical examination revealed a moderately sized, soft, left-sided, non-reducible swelling of the proximal scrotum and mild swelling of the scrotal neck. Ultrasound evaluation of the scrotum revealed morphologically normal testicles and a mild accumulation of free fluid in the left vaginal tunic. Unilateral, laparoscopic inguinal herniorrhaphy under general anesthesia was performed. The herniated omentum was reduced and barbed suture was used to imbricate the internal inguinal ring and the vaginal ring. No recurrence of herniation was reported 5 months after surgery.Key clinical message:Laparoscopic inguinal herniorrhaphy with barbed suture can be a safe and effective means of scrotal hernia resolution in a ram. When performed by a competent surgeon experienced in laparoscopy, this treatment for inguinal and scrotal herniation may minimize post-operative pain, provide a rapid return to function, and preserve normal testicular and scrotal anatomy.     

Gastric dilatation and volvulus in a brachycephalic dog with hiatal hernia

A brachycephalic dog was presented with an acute onset of retching and abdominal discomfort. The dog had a chronic history of stertor and exercise intolerance suggestive of brachycephalic airway obstructive syndrome. Radiographs were consistent with a Type II hiatal hernia. The dog was referred and within hours of admission became acutely painful and developed tympanic abdominal distension. A right lateral abdominal radiograph confirmed gastric dilatation and volvulus with herniation of the pylorus through the hiatus. An emergency exploratory coeliotomy was performed, during which the stomach was derotated, and an incisional gastropexy, herniorrhaphy and splenectomy were performed. A staphylectomy was performed immediately following the exploratory coeliotomy. The dog recovered uneventfully. Gastric dilatation and volvulus is a potentially life‐threatening complication that can occur in dogs with Type II hiatal hernia and should be considered a surgical emergency .     

Plasma thyroid hormone concentrations in dogs competing in a long-distance sled dog race

Plasma thyroxine (T4), 3,5,3'-triiodothyronine (T3), total protein, and albumin concentrations were measured in 15 dogs both before and after completion, and in an additional 16 dogs before and 24 dogs after completion, of a long-distance sled dog race. The plasma T4 concentration (mean +/- SD) decreased significantly from 18.2 +/- 5.4 nmol/L before to 14.3 +/- 3.5 nmol/L after the race in dogs evaluated at both times and decreased significantly from 21.8 +/- 10.5 nmol/L before to 15.8 +/- 4.9 nmol/L after the race in dogs sampled only before or only after the race. The mean plasma T3 concentrations in dogs measured twice decreased significantly from 1.20 +/- 0.48 nmol/L before to 0.74 +/- 0.42 nmol/L after the race, as well as in dogs measured either before (1.28 +/- 0.36 nmol/L) or after (0.69 +/- 0.28 nmol/L) the race, respectively. Plasma total protein and albumin concentrations decreased significantly after completion of the race. No significant change was noted in 4 control dogs that did not compete in the race and were tested during a similar time period. The plasma concentrations of T4 and T3 were lower than the normal reference range established for this laboratory in 23 and 39%, respectively, of Alaskan sled dogs tested before the race. Plasma thyroid hormone concentrations frequently are below normal in conditioned Alaskan sled dogs and are further reduced after prolonged submaximal exercise.     

Treatment with a combined cystopexy-colopexy for dysuria and rectal prolapse after bilateral perineal herniorrhaphy in a dog

A 9-year-old castrated male Yorkshire Terrier was evaluated for dysuria and rectal prolapse 2 weeks after bilateral perineal herniorrhaphy. Dysuria was secondary to caudal displacement of the bladder, rather than retroflexion of the bladder. Dysuria and rectal prolapse were associated with disruption of supporting ligaments of the urinary bladder and colon, which may have been caused by tenesmus. Combined cystopexy and colopexy were used successfully to treat the dysuria and rectal prolapse.     

Laparoscopic colopexy for recurrent rectal prolapse in a Maltese dog

A 2.5-kg castrated male Maltese dog, suspected to be older than 10 y, was presented with a prolapsed mass at the anus. This had occurred on 2 previous occasions within the last 4 mo and had been managed with manual reduction and purse-string sutures. The rectal prolapse had viable tissue and was reducible but resulted in straining and fecal accumulation. Colopexy (with intracorporeal sutures) was performed laparoscopically using 3 ports; the distal colon was retracted cranially and attached to the abdominal wall with 3 simple interrupted sutures in a single row. The dog recovered uneventfully, had good appetite and normal activity, did not strain, and defecated without issues. There were no wound-healing complications and at 12-month post-operative examination, the patient was in good condition without clinical signs. Based on this case report, laparoscopic colopexy is clinically practical for management of rectal prolapse in small-breed dogs.     

Effects of training and strenuous exercise on hematologic values and peripheral blood leukocyte subsets in racing sled dogs

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.     

Assessment of alterations in triglyceride and glycogen concentrations in muscle tissue of Alaskan sled dogs during repetitive prolonged exercise

OBJECTIVE: To assess changes in muscle glycogen (MG) and triglyceride (MT) concentrations in aerobically conditioned sled dogs during prolonged exercise. ANIMALS: 54 Alaskan sled dogs fed a high-fat diet. PROCEDURES: 48 dogs ran 140-km distances on 4 consecutive days (cumulative distance, up to 560 km); 6 dogs remained as nonexercising control animals. Muscle biopsies were performed immediately after running 140, 420, or 560 km (6 dogs each) and subsequently after feeding and 7 hours of rest. Single muscle biopsies were performed during recovery at 28 hours in 7 dogs that completed 560 km and at 50 and 98 hours in 7 and 6 dogs that completed 510 km, respectively. Tissue samples were analyzed for MG and MT concentrations. RESULTS: In control dogs, mean +/- SD MG and MT concentrations were 375 +/- 37 mmol/kg of dry weight (kgDW) and 25.9 +/- 10.3 mmol/kgDW, respectively. Compared with control values, MG concentration was lower after dogs completed 140 and 420 km (137 +/- 36 mmol/kgDW and 203 +/- 30 mmol/kgDW, respectively); MT concentration was lower after dogs completed 140, 420, and 560 km (7.4 +/- 5.4 mmol/kgDW; 9.6 +/- 6.9 mmol/kgDW, and 6.3 +/- 4.9 mmol/kgDW, respectively). Depletion rates during the first run exceeded rates during the final run. Replenishment rates during recovery periods were not different, regardless of distance; only MG concentration at 50 hours was significantly greater than the control value. CONCLUSIONS AND CLINICAL RELEVANCE: Concentration of MG progressively increased in sled dogs undergoing prolonged exercise as a result of attenuated depletion.     

Assessment of serum antibody titers against canine distemper virus, canine adenovirus type II, and canine parvovirus in Alaskan sled dogs before and after a long-distance race

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 > or = 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.     

Pre-operative fibrous osteodystrophy and severe,refractory, post-operative hypocalcemia following parathyroidectomy in a dog

A 13-year-old dog exhibited dramatic, radiographic osteopenia consistent with fibrous osteodystrophy secondary to primary hyperparathyroidism. Following parathyroidectomy, the dog developed severe, prolonged hypocalcemia, but was successfully treated and discharged 32 d after surgery. A variety of factors may have contributed to this dog’s hypocalcemia including hypoparathyroidism and hungry bone syndrome.     

The use of porcine small intestinal submucosa as a biomaterial for perineal herniorrhaphy in the dog

OBJECTIVES: To develop an in vivo perineal hernia model, to develop a technique for using small intestinal submucosa (SIS) in perineal hernia repair, to further elucidate the biological behavior of SIS, and to compare SIS herniorrhaphy with the internal obturator muscle transposition (IOT) technique. STUDY DESIGN: Prospective evaluation comparing SIS herniorrhaphy with IOT. ANIMALS: Twelve adult castrated male, large-breed dogs. METHODS: All dogs had bilateral pelvic diaphragm defects created by complete excision of the levator ani muscle. Each dog had one side repaired using SIS and the other by IOT. Pain and inflammation were subjectively scored. Dogs were killed 2 weeks (n = 4), 12 weeks (n = 4), or 16 weeks (n = 4) after surgery. Each pelvic diaphragm was biomechanically tested to failure. The pelvic diaphragms from 2 normal dogs (n = 4 sides) were also biomechanically tested. Failure site, maximum pressure, displacement at failure, and initial linear stiffness values were determined. Histologic assessment was performed. Statistical analysis was performed with significance set at P <.05 RESULTS: No significant postoperative complications were noted. There were no significant differences in maximum pressure to failure, displacement, or stiffness when comparing normal, SIS, and IOT at any time point. The SIS group had significantly less displacement (P =.004) at 2 weeks than at weeks 12 or 16. For all herniorrhaphy techniques, the failure site was central (n = 22) or at the suture line (n = 2). At 2 weeks, histologic evaluation of tissues from the IOT group showed inflammation, mineralization, and necrosis, which were not present in tissues from the SIS group. Histologic examination at 12 and 16 weeks showed no microscopic differences in cell population or tissue characteristics between the IOT and SIS groups. CONCLUSIONS: SIS herniorrhaphy was successfully performed in this in vivo model of perineal hernia in the dog. CLINICAL RELEVANCE: This study suggests that SIS can be used as a primary means of repair, as augmentation when the internal obturator muscle is thin and friable, or as a salvage procedure in cases of recurrence in dogs with perineal hernia.