Probios VETS Plus Feed Granule for Horses, 5-Pound Packaging may vary Contains a source of live (viable), naturally occurring microorganisms to help maintain normal digestive function Can be blended with feed rations or top dressed. Feed 5 gm per head per day for horses and foals Contains a source of live (viable), naturally occurring microorganisms to help maintain normal digestive function Can be blended with feed rations or top dressed Feed 5 gm per head per day for horses and foals