Mechanics of breathing during strenuous exercise in thoroughbred horses
1990; Elsevier BV; Volume: 82; Issue: 3 Linguagem: Inglês
10.1016/0034-5687(90)90098-j
ISSN1872-7611
AutoresTatiana Art, Lisa Anderson, A. J. Woakes, Claudia Roberts, P. J. Butler, David Snow, P. LekeuxL,
Tópico(s)Meat and Animal Product Quality
ResumoThe changes induced by exercise on the mechanics of breathing, as well as the simultaneous changes occuring in arterial blood gas tensions and in respiratory gas exchange were investigated in 6 healthy thoroughbred, performing a treadmill exercise of increasing intensity. Respiratory airflow and tidal volume (Vt) were measured with ultrasonic flowmeters. Pleural pressure changes were measured by an oesophageal balloon catheter. Gas concentration of the expired air was analysed with a mass spectrometer; the oxygen consumption (V̇O2) and the carbon dioxide output (V̇CO2) were computed breath-by-breath. Arterial blood gas values were obtained by sampling from the carotid artery. Between rest and fast gallop Vt, respiratory frequency, expired minute ventilation (V̇e),V̇O2,V̇CO2, total pulmonary resistance (Rl), mechanical work of breathing (Ẇrm) and PaCo2 increased significantly while PaO2 decreased significantly. TheW˙rm·V˙O2−1 ratio in galloping horses increased exponentially withV̇e. This is together with the relationship between the changes in PaO2 and in PaCO2 and the increase in the ventilatory mechanics parameters, suggests that the mechanics of breathing may be one of the factors constraining further increase in ventilation in exercising healthy horses.
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