Serum Electrolyte and Plasma Protein Alterations in Horses Used in Endurance Rides

Abstract

SUMMARY Serum electrolyte concentrations were determined in 19 horses before, during, and after a 100-mile endurance trail ride. Packed cell volume ( pcv ) and total plasma protein ( tpp ) concentrations were used as indexes of hydration. The concentrations of chloride (Cl), calcium (Ca), and magnesium (Mg) were significantly decreased at the midride sampling, despite apparent dehydration. Water losses appeared to have been replenished at the postride sampling. At this time there were significant decreases in the concentrations of sodium (Na), potassium (K), Cl, and Ca. Phosphorus (P) concentrations were increased at both the mid- and postride sampling.