Document Detail

Comparative ventilation and gas exchange in the horse and the cow.
MedLine Citation:
PMID:  2740627     Owner:  NLM     Status:  MEDLINE    
Ventilation and gas exchange were studied in healthy, adult horses and cows, two large species with different lung structures and different breathing patterns. The oxygen uptake (VO2), carbon dioxide output (VCO2), respiratory rate (fR), minute ventilation (VE), alveolar ventilation (VA), alveolar oxygen pressure (PAO2), and VE/VO2 ratio were higher in the cows, while the tidal volume (VT) and physiological dead space (VD) were larger in the horses. The arterial blood gases, alveolar-arterial oxygen pressure difference (PAO2-PaO2) and VD/VT ratio did not differ between the two species. The higher VO2 in the cows was most likely due to the energy cost of standing, and possibly to a higher cost of digestion. The higher VE, VA, VE/VO2 and PAO2 were most likely secondary to the increased VO2 and the slightly higher respiratory exchange ratio (R) in the cows. In contrast to hypotheses based on allometric equations, the PAO2 of horses and cows did not appear to differ from that of smaller mammals. The VD was larger than that predicted from allometric equations, and even though the VD/VT ratio (0.50) was lower than the previously reported values for horses and cows, it was significantly larger than the predicted weight-independent value of 0.36. Re-examination of the data used to derive the equation for VD raised questions as to the validity of this equation, and it is suggested that caution be exercised in the use of allometric equations for prediction.
G J Gallivan; W N McDonell; J B Forrest
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Research in veterinary science     Volume:  46     ISSN:  0034-5288     ISO Abbreviation:  Res. Vet. Sci.     Publication Date:  1989 May 
Date Detail:
Created Date:  1989-08-09     Completed Date:  1989-08-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0401300     Medline TA:  Res Vet Sci     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  331-6     Citation Subset:  IM    
Department of Anaesthesia, McMaster University Medical Center, Hamilton, Ontario, Canada.
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MeSH Terms
Blood Gas Analysis / veterinary
Cattle / physiology*
Horses / physiology*
Pulmonary Gas Exchange*
Respiratory Dead Space
Species Specificity
Tidal Volume

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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