Cardiorespiratory parameters in draught horses before and after short term draught work pulling loads.

The research article investigates the physiological response of draft horses to pulling loads in order to understand the relationship between the force exerted and the effects on cardiorespiratory functions.

Study Design and Methods

• The researchers worked with five draught horses and measured a series of parameters before and after the horses undertook a task.
• The parameters included heart rate (HR), respiratory rate (RR), arterial and venous blood gases, pH, hemoglobin concentration, and temperature. These measurements were taken at three intervals: during the horses’ rest periods, immediately following exercise, and 30 minutes post-exercise.
• The horses were tasked to pull a wagon loaded with different weights: 946 kg for the low load, 1,979 kg for the medium load, and 2,994 kg for the high load. The distance covered was consistent at 1,500 meters.
• To track the force exerted by the horses and the distance covered, the wagon was equipped with an odometer and a hydraulic dynamometer.

Results

• The study found a linear relationship between the draught force and the load weight, meaning that as the load weight increased, the force exerted by the horses increased proportionally.
• The physiological response of the horse to low and medium loads included a moderate increase in HR, RR, and temperature. Arterial blood gas levels and pH remained unchanged, suggesting that the horses were not under significant stress with these lower loads.
• In contrast, with high-load exercise, there was an increase in HR, RR, temperature, and venous PO2 (a measure of oxygen level in the blood), but arterial PO2 and blood pH remained unchanged. This suggests a greater cardiorespiratory demand on the horses.
• A slight increase in venous lactic acid concentration suggests that the horses were doing some anaerobic work when performing high-load exercise, but this was not high enough to affect blood pH.
• The increased metabolic demands associated with the different levels of load were mirrored by increases in the arterial hemoglobin concentration and oxygen content of the blood.

Interpretation and Implications

• The results of the study is relevant as it provides insights into the physiological effects on horses when performing load-pulling tasks, indicating potential stress on their cardiorespiratory systems especially under high-load conditions.
• This knowledge can help in understanding how load limitations and work-rest cycles may need to be optimized to ensure the welfare of working draught horses.
• The physiological parameters highlighted in the research could be used as indicators to monitor the health and performance of horses carrying out such tasks.