title: Metabolizable energy intake and sustained energy expenditure of Alaskan sled dogs during heavy exertion in the cold.
abstract: OBJECTIVE
  To measure energy expenditures of Alaskan sled dogs at rest and during racing under frigid conditions, using the doubly labeled water (DLW) technique.
  
  
  METHODS
  18 fit Alaskan sled dogs.
  
  
  METHODS
  Energy expenditure was measured in 9 dogs during a 490-km sled dog race by use of the DLW technique, whereby dogs were administered water enriched with nonradioactive isotopes of hydrogen and oxygen. Energy intake was determined by dietary analysis. Changes in background abundance of the isotopes 2H and 18O were monitored in 5 dogs that did not receive isotope-enriched water.
  
  
  RESULTS
  Dogs completed the 490-km race at an average speed of 7 km/h at ambient temperature of -35 to -10 C. Total energy expenditure, measured by the DLW technique, was 47,100 +/- 5,900 kJ/d (4,400 +/- 400 kJ.kg-0.75/d), and metabolizable energy intake was 44,600 kJ/d (4,100 kJ.kg-0.75/d) during the 70-hour race.
  
  
  CONCLUSIONS
  The sustained metabolic rate for these sled dogs during racing was extraordinarily high for a large mammal. This study validated use of the DLW technique in dogs with exceptionally high energy expenditure associated with prolonged exercise in the cold.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus 43210-1089, USA.
authors.forename: K W
authors.initials: KW
authors.lastname: Hinchcliff
authors.forename: G A
authors.initials: GA
authors.lastname: Reinhart
authors.forename: J R
authors.initials: JR
authors.lastname: Burr
authors.forename: C J
authors.initials: CJ
authors.lastname: Schreier
authors.forename: R A
authors.initials: RA
authors.lastname: Swenson
mesh_terms: D000818:Animals; D001823:Body Composition / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D003080:Cold Temperature; D003903:Deuterium; D004285:Dogs / Q000378:metabolism / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D008297:Male; D010100:Oxygen / Q000378:metabolism; D010103:Oxygen Isotopes; D010805:Physical Conditioning, Animal / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D012146:Rest / Q000502:physiology; D013696:Temperature; D013997:Time Factors
chemical_list: D010103:Oxygen Isotopes; D002245:Carbon Dioxide; D003903:Deuterium; D010100:Oxygen