Responses to submaximal treadmill exercise and training in the horse: changes in haematology, arterial blood gas and acid base measurements, plasma biochemical values and heart rate.

The study investigates the effects of a seven-week treadmill exercise program on various health parameters in standardbred horses, including hematology, arterial blood gas, plasma biochemistry, and heart rate. The primary findings note changes in exercise lactate and protein levels in the exercising and recovery period, alongside a transient increase in certain red blood cell counts and white blood cells after exercise.

Research Context

• The research was conducted on four standardbred horses whose carotid arteries were subcutaneously relocated. The focus was on determining the impacts of a seven-week training program on a range of physiological and biochemical parameters.

Methodology

• The exercise program involved treadmill exercise with a 19 per cent gradient. The protocol consisted of walking for one minute at a speed of 110 meters per minute, followed by trotting for five minutes at 200 meters per minute, performed twice daily in the first week.
• The trotting exercise duration was progressively lengthened by a minute each week. By the end of the seventh week, the horses were engaging in 12 minutes of trotting twice daily.
• Researchers obtained blood samples for complete blood count and plasma biochemistry before beginning the training regime. Additionally, arterial samples were taken for blood gas, acid base, and lactate measurements at rest, after five and 15 minutes of treadmill exercise, as well as 30 and 60 minutes after completing the exercise.
• Heart rate was tracked using a telemetric electrocardiogram at comparable moments. This process of exercise testing and blood sampling was repeated after the first, third, fifth, and seventh weeks of the training program.

Findings

• The study revealed a significant reduction in exercise lactate with training, indicating that the horses’ bodies were better able to cope with the physical strain as time went on.
• There was an increase in total protein during exercise and recovery, suggesting that the body was breaking down and utilizing protein sources more intensely during physical activity and recovery.
• The research also highlighted a transient haematological response to the treadmill exercise. This included an increase in certain red cell parameters and leucocytosis, caused by a surge in both neutrophil and lymphocyte counts.
• Most of these effects were observed to have largely disappeared 30 minutes after exercise. By one hour after exercise, all monitored values had returned to resting levels. This indicates a strong adaptive response in the physiology of the horses.