Extrusion is a process in which feed is ground, quickly cooked at a high temperature, and processed under high pressure. The feed is then pushed through a die, which makes the feed a unique and uniform shape. The main benefit of extruded feed is improved digestibility.
The difference between pelleted and extruded feed is that pellets are not cooked, and are prepared at a much lower temperature and pressure.
For raw feed ingredients—specifically grains such as corn, oats and barley—both pelleting and extrusion can improve the digestibility. The amount of grains in a formula is also a factor in determining if extrusion is beneficial to the overall digestibility.
While extrusion can be very beneficial, the nutritional value of a feed is more dependent on the formula than the type of processing.