Many of you with horses may have seen the terms extruded feed and pelleted feed and may even be feeding one of them to your horses and not know the difference.  Karen Biggs indicates in The Horse magazine that extrusion is a process of cooking ground grains with pressure and moist heat, then exposing them to cooler air so they pop like a kernel of corn. This method has been used for decades in the pet food industry, and also is the method of manufacturing breakfast foods and corn chips for people.  However, it has only been used for the last 30-40 years for equine foods and today is common in horse feed manufacturing. 

Pelleted feeds are warmed with dry heat for a brief period and are pushed through a die to make the pellets, while extruded feeds are cooked at a temperature of 260°F.  The heat softens the mixture and breaks the cross-links in the crystalline structure of starches, which makes the energy in the starches more available for absorption in the small intestine.  Basically, the cooking process predigests the starch, so the horse’s intestine does less work.  The cooking process takes about 10 minutes and the starches become more soluble in water with extrusion and the protein molecules are ruptured to aid in absorption.  Usually extruded feeds do not have preservatives since the moisture content is so low. However, if one is used, it is usually natural Vitamin C or Vitamin E to prevent the fat from becoming rancid.  Cooking grains has a downside as some of the natural vitamin content is destroyed but most companies add extra vitamins to balance the ration.  However, Dr. Al Kennedy said cooking does not destroy minerals, so consider giving extruded feeds to your horse as there are some advantages over pellets.