title: Blood oxygen binding in double-muscled calves and dairy calves with conventional muscle conformation.
abstract: OBJECTIVE
  To assess in vivo blood oxygen binding in double-muscled calves and dairy calves with conventional muscle conformation.
  
  
  METHODS
  58 dairy and 48 double-muscled calves.
  
  
  METHODS
  Calves were classified as neonatal (24 hours old) or older calves (2 to 26 days old). Venous and arterial blood samples were collected, and hemoglobin concentration, pH, PCO2, and PO2 were determined. Blood oxygen equilibrium curves (OEC) under standard conditions were constructed, and the oxygen exchange fraction (OEF) and the amount of oxygen released at the tissue level by 100 ml of blood (OEF Vol%) were calculated.
  
  
  RESULTS
  In each breed, partial pressure of oxygen at 50% saturation of hemoglobin (P50) under standard conditions was significantly higher in older than in neonatal calves, indicating a right shift in OEC with age. Venous P50 was significantly lower in neonatal double-muscled calves than in neonatal dairy calves, but arterial and venous P50 were significantly higher in older double-muscled calves than in older dairy calves. In double-muscled, but not in dairy, calves, OEF was significantly higher in older than in neonatal calves. In neonatal calves, OEF Vol% was not significantly different between breeds, but OEF Vol% was significantly higher in older double-muscled calves than in older dairy calves.
  
  
  CONCLUSIONS
  The lower OEF in neonatal double-muscled calves, compared with dairy calves, could contribute to the higher sensitivity of double-muscled calves to hypoxia. Blood oxygen affinity decreased with age, but OEF and OEF Vol% were unchanged with age in dairy calves, whereas they increased with age in double-muscled calves.
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Liège, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Cambier
authors.forename: T
authors.initials: T
authors.lastname: Clerbaux
authors.forename: B
authors.initials: B
authors.lastname: Detry
authors.forename: D
authors.initials: D
authors.lastname: Beerens
authors.forename: A
authors.initials: A
authors.lastname: Frans
authors.forename: P
authors.initials: P
authors.lastname: Gustin
mesh_terms: D019794:2,3-Diphosphoglycerate / Q000097:blood; D000255:Adenosine Triphosphate / Q000097:blood; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000097:blood / Q000502:physiology*; D001784:Blood Gas Analysis / Q000662:veterinary; D001831:Body Temperature; D002417:Cattle / Q000097:blood / Q000502:physiology*; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010100:Oxygen / Q000097:blood / Q000502:physiology*; D010710:Phosphates / Q000097:blood; D012044:Regression Analysis
chemical_list: D006454:Hemoglobins; D010710:Phosphates; D019794:2,3-Diphosphoglycerate; D000255:Adenosine Triphosphate; D010100:Oxygen