Quiet, gentle animals make a nice cow herd and do better gaining weight more effciently and are just plain easier to care for.  The wilder, more nervous ones have lowest daily weight gains; the calmest ones have the highest gains.  This fact alone is not the only reason that calm cattle make better beef.  Excitable nervous cattle are often "dark cutters" when butchered - the meat is darker than normal and doesn't keep as well or as long.  Abnormally dark meat is due to low levels of muscle glycogen at the time of slaughter, and stress is the main cause of glycogen depletion in muscles.  Physical stress (strenuous exertion) and psychological stress (adrenalin secretion from excitement) are primay factors.  JMJ's small herd is handled in a calm manner. 

Whether you let yearlings fatten on good pasture or grain depends in part on what age you want them to be at butchering.  Cattle grow well on pasture alone and can become quite fat on good grass.  But they will grow faster and finish (reach butchering condition) more quickly if fed grain.  Some folks prefer "grass-fat" beef;  others prefer "corn-fed.  It's your choice when choosing JMJ beef cattle.