GASTRIC-EMPTYING OF ORAL REHYDRATION SOLUTIONS AT REST AND AFTER EXERCISE IN HORSES

We examined the gastric emptying (GE) of oral rehydration solutions (O RS) at rest and after exercise in four Standardbred horses. In one stu dy isotonic, cold isotonic (5 degrees C), isotonic containing glucose and hypertonic fluid were tested at rest. In another study, isotonic f luid was given following a bout of treadmill exercise at 70 per cent ( V)over dot O-2 max until exhaustion or at rest. In both studies, a sin gle dose of 8 litres was given via nasogastric tube. GE and electrolyt e concentrations (Na+, K+ and Cl-) of the stomach content were measure d at 15 minutes intervals for one hour. In both studies, 90 per cent o f the fluid was emptied within 15 minutes of administration. There was no treatment effect on electrolyte concentrations in either study but significant changes did occur over time. The data showed that GE is u nlikely to significantly affect rehydration.