Electrolyte and glycerol supplementation improve water intake by horses performing a simulated 60 km endurance ride.

This research study investigates the impact of electrolyte and glycerol supplements on the water intake of horses during endurance rides. The study reveals that these supplements can aid in improving water intake, thus reducing weight loss and helping maintain vital physiological balance in the horses.

Study Design and Methodology

• The research involved six Arabian horses undergoing a simulated 60 km endurance ride.
• To mimic real-world practices where riders supplement their horses with hypertonic oral electrolyte pastes to replace the amped-up electrolyte loss during an endurance competition, the horses were supplemented with water (W); a mix of 0.2 g/kg bwt KCl and 0.4 g/kg bwt NaCl in 2.4 ml/kg bwt of water (E); or the same electrolytes mix in 2.4 ml/kg bwt (3 g/kg bwt) of glycerol (GE) before and during the simulation.

Findings and Results Analysis

• The horses depicted greater weight loss when only water (W) was given, that is a 3.2% loss, as compared to intake of E and GE – 1.0% and 0.9% respectively. This was correlated (r = -0.85, P < 0.0001) with less water intake in case of water-only supplementation (12.2 l) than in case of E or GE (23.5 l and 25.8 l, respectively).
• The plasma osmolality in the horses increased significantly when supplemented with GE compared to E and remained invariant with W intake. In other words, the horses had more concentrated blood when given GE.
• Another notable observation was the decrease in plasma protein concentration with E and GE during the later stages of the simulation with no change when administered W, indicative of plasma volume expansion when horses were given E and GE.
• The administration of E and GE resulted in increased plasma Na+ and Cl- concentrations. Yet, contrary to expectations, the plasma K+ concentration decreased at the end of the rest breaks during the simulation and after 60 minutes of recovery, despite the large amount of potassium included within E and GE.
• Notably, no adverse effects of hypertonic oral electrolyte pastes were observed. Furthermore, decreased plasma protein concentrations within 30 minutes after drinking, regardless of the supplement, hinted that intestinal absorption was well maintained during the simulated endurance ride.

Conclusion

• The findings conclude that electrolyte supplementation in the form of hypertonic oral pastes can significantly enhance water intake during endurance exercise in horses.
• However, the combination with glycerol provided no further benefits as compared to the supplementation with electrolytes alone.