The NCAA allows two and the game as "live contact". The Big 12 is now one and the game or on bye weeks a scrimmage.
http://www.big12sports.com/ViewArticle.dbml?DB_LANG=C&ATCLID=210220054&DB_OEM_ID=10410
http://www.big12sports.com/ViewArticle.dbml?DB_LANG=C&ATCLID=210220054&DB_OEM_ID=10410