Electro Lytes contains the four most important body salts that need to be replenished after exertion as the horse has sweated a lot.

NAF Electro Lytes covers the horse's need for electrolytes under normal conditions, in case of strong heat / sun, it may be good to use concentrated Electro Salts (powder) instead.
Always make sure that the horse has free access to water.

No waiting/withdrawal period required.