Dehydration and electrolyte imbalance in horses performing or competing in hot conditions cause serious welfare harm that is largely preventable.
Dehydration in performance horses causes profound welfare harm — reduced organ function, impaired thermoregulation and electrolyte imbalance affecting cardiac and muscular function. Horses that are reluctant to drink during exercise are often already dehydrated. Encouraging drinking through flavoured water, electrolyte supplementation and rest stops with water access is important welfare management during long events. Recovery from exercise should include free water access and appropriate electrolyte replacement before feeding. Competition welfare — particularly in endurance events — must prioritise horse welfare over performance outcomes through mandatory veterinary checks and withdrawal protocols.