Performance failure in Alaskan sled dogs: biochemical correlates.

Many dogs competing in long distance sled dog races do not complete the race. In this study the plasma biochemical variables of dogs that completed a long distance sled race were compared with those of dogs that did not complete the race. Blood samples were collected from dogs completing the race and from retired dogs, within six hours of their finishing or retiring. The plasma concentrations of magnesium, phosphate and triglyceride and the plasma activities of alkaline phosphatase and alanine aminotransferase were significantly (P < 0.003) greater in the dogs that retired than in the dogs that completed the race. Dogs that finished had significantly higher (P < 0.003) plasma urea nitrogen and uric acid concentrations and gamma-glutamyl transpeptidase activity than dogs that retired. These differences were judged not to be clinically significant. The dogs that retired showed no evidence of dehydration, significant plasma electrolyte abnormalities, or myopathy.