Horse Digestion Supplement to Prevent Gas Build-up Equi-Spaz Paste is an excellent digestive supplement for horses used to control gases. This supplement is ideal for both grazing and competition horses. This fast acting equine digestion supplement helps prevent gas build-up in horses, giving your horse quick relieve from digestive problems. Primary Benefits: Prevents the accumulation of gases in the horses' digestive tract Rids discomforts associated with gases This is a great great digestion supplement for horses that will help prevent gas build-up and soothe your horses digestive system. It is the best natural treatment for colic in horses.