Ventilatory alterations in normal horses in response to changes in inspired oxygen and carbon dioxide.

This research studied how changes in the concentration of Oxygen (O2) and Carbon dioxide (CO2) in turned inspired air affect breathing rate, volume of air breathed in a minute and the volume of air breathed in per breath in healthy horses. The experiment indicated that as CO2 concentration increase, so does the breathing rate and volume per breath while the volume of air per minute increased with decreases in O2 concentration.

Objective

The objective of this study was to explore the impact of different concentrations of carbon dioxide (CO2) and oxygen (O2) in the ambient air on the parameters of ventilation in horses.

Methodology

• The horses tested were neither sedated nor anesthetized in order to represent normal physiological conditions.
• The scientists measured the minute volume (V) referred to as the volume of air expired by the horse in a minute, the tidal volume (VT) which is the volume of air displaced between normal inhalation and exhalation, and the respiratory rate (breaths per minute [BPM]).
• Changes in concentration of O2 and CO2 in the inspired air were manipulated, and the impact on the above parameters was observed and recorded.

Findings

• The VT and BPM were found to have a linear increase in response to increases in the concentration of inspired CO2. This means that the horses breathed faster and with greater volume per breath when the CO2 concentration in the inhaled air was higher.
• The VT and BPM showed a curvilinear relationship with decreases in the concentration of inspired O2. This implies that the effects of decreased levels of O2 on horses’ respiration are not linear and may have varying impact at different concentrations.
• The minute volume (V) showed a curvilinear increase with both increases in inspired CO2 and decreases in inspired O2. This suggests that the horses were exhaling more air per minute in situations of increased CO2 or decreased O2 in the inhaled air.

Implications

The outcomes of this research could have important implications for understanding the ventilatory response of horses in variations of air concentrations. The findings could also be relevant in veterinary medicine and horse care, to improve the breathability of the air for horses in different settings.