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Redistribution of cardiac output in response to heat exposure in the pony
Author(s) -
McCONAGHY FINOLA F.,
HODGSON D. R.,
ROSE R. J.,
HALES J. R. S.
Publication year - 1996
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1996.tb05030.x
Subject(s) - pony , blood flow , cardiac output , respiratory system , thermoregulation , heat stress , respiratory tract , horse , medicine , cardiology , anesthesia , chemistry , hemodynamics , biology , zoology , paleontology , genetics
Summary Radioactive microspheres were used to measure cardiac output and blood flow to most major tissues in 4 ponies at rest in thermoneutral (16°C/60% RH) and mildly hot (41°C/34% RH) environments. In response to heat stress there were increases in cardiac output (2‐fold), respiratory frequency (5‐fold), blood flow to the skin of the body (3‐fold), and limbs (50%), respiratory muscles (2‐fold) and the upper respiratory tract (3‐fold). Ponies were able to maintain body temperature in the hot environment by increasing blood flow to the tissues involved in heat dissipation, while blood flow to all other tissues remained stable. This was achieved by increasing the cardiac output without need for reduction of blood flow to other tissues.