Reduction of renal function in exercising horses.

The research focuses on the study of how exercise impacts the renal function specifically Glomerular filtration rate (GFR) and extracellular volume (ECFV) in thoroughbred horses.

Introduction to the Study

• The research evaluates how horses’ kidney function, specifically the Glomerular filtration rate (GFR) and extracellular volume (ECFV), are impacted before, during, and after treadmill exercise.
• The study was carried out with 5 trained Thoroughbred horses with an average weight of 483 kg.

Research Method

• The Glomerular Filtration Rate (GFR) and the Extracellular Volume (ECFV) were the two key parameters measured in this study. GFR is the volume of fluid filtered from the renal (kidney) glomerular capillaries into Bowman’s capsule per unit time.
• ECFV is the volume of fluid outside the cells, again an important parameter when studying renal function. Both of these parameters were established by plasma’s ability to eliminate Tc-DTPA, a particular kind of radioactive contrast medium.
• ECFV was independently measured by thiocyanate space, which is another method to know the volume outside the cells. Thiocyanate is a salt or ester of thiocyanic acid, often used for measuring extracellular water.

Results and Findings

• The resting GFR averaged 1.6 l/min (3.3 ml/kg/min) which fell by over 40% during exercise, indicating a significant reduction in kidney function.
• This decrease was observed even during the first walk, before the horses started trotting, suggesting the reduction in GFR starts as soon as the horse starts mild exercise. This could indicate an adaptive response in horses allowing greater blood flow to muscles and skin during exercise, thereby reducing the GFR.
• In comparison to humans, the GFR appears to be more resilient to exercise, but direct comparisons are problematic due to the vastly different physiology and exercise intensity between humans and horses.

Conclusion and Implications of the Findings

• The results suggest that even mild exercise could lead to a considerable reduction in the GFR in horses. This potentially indicates that horses might have an adaptive mechanism that prioritizes perfusion of muscles and skin over the maintenance of a steady GFR when involved in physical activity.
• This research could potentially provide insights for further studies regarding renal function adaptations in horses during exercise, which could have implications on both horse training and health management.