Rascal Flatts cancelled its Wednesday night (March 14) performance at the Houston Livestock Show and Rodeo because of lead vocalist Gary LeVox's "severe bronchitis," according to a press release issued by rodeo organizers. Clay Walker, Jack Ingram and Joe Nichols will substitute for the group. Walker performed at the rodeo on March 3, and Ingram made a guest appearance during Pat Green's Friday (March 9) appearance. Other acts appearing at Reliant Stadium during this year's rodeo include George Strait, Reba McEntire, Alan Jackson and Toby Keith. Dierks Bentley will appear there Friday, followed by Brooks & Dunn's concert Saturday. The rodeo closes Sunday with ZZ Top.