Assessment of necropsy findings in sled dogs that died during Iditarod Trail sled dog races: 23 cases (1994-2006)

Objective-To describe the character and frequency of causes of death and associated lesions in long-distance racing sled dogs. Design-Retrospective case series. Animals-23 dogs. Procedures-Medical records of dogs that died during or soon after competition in the Iditarod Trail sled dog races (1994 through 2006) were examined for findings of gross necropsy and histologic evaluation of tissue samples. From the data, descriptive and comparative statistics were obtained. Results-Recognized causes of death included aspiration of gastric contents (n = 4), aspiration pneumonia (4), acute blood loss secondary to gastric ulceration (3), and sled dog myopathy (2). A cause of death was not established for 7 dogs. Prevalent lesions among the study population included rhabdomyolysis (n = 15), enteritis (10), gastritis (10), aspiration pneumonia (8), and gastric ulceration (8). All dogs with aspiration pneumonia had concurrent gastric mucosal lesions. Subjective biventricular cardiac hypertrophy was evident in most dogs; other lesions detected frequently included centrilobular hepatic fibrosis, gastric dilatation, and mild cardiac myodegeneration and necrosis. Conclusions and Clinical Relevance-Unexpected death is a rare event among conditioned sled dogs during competition in endurance races. Potentially life-threatening conditions of dogs that are associated with periods of long-distance physical exertion include aspiration pneumonia, gastric mucosal lesions, and severe rhabdomyolysis. Dogs that develop clinical signs suggestive of these conditions should be excluded from strenuous activities. Epiclemiologic investigations are required to clarify the risk for death associated with these lesions in dogs competing in endurance races.