If your horse is sweating and breathing hard, you will want to hose, but make sure you cool him down to the point where he is breathing normally before hosing. If it is warm enough or you have warm water in the wash rack, most horses will appreciate a nice hosing. I always hose mine down in the summer. If there is little to no sweat or it is too cold, just groom him, making sure to spend adequate time on the saddle area. Also, if he is sweaty or wet during colder times, make sure to put a cooler on him to prevent chill. Hope this helps!