Toby Keith is the big dog to watch at the 38th annual Academy of Country Music Awards. When the nominations were unleashed Tuesday (March 4) in Los Angeles, Keith led the pack with eight ACM mentions, including the coveted entertainer of the year category.

Alan Jackson follows closely with six nominations, but one of the biggest surprises is Trick Pony receiving five nominations to tie with Kenny Chesney. Keith, Jackson and Chesney are competing together in four categories -- entertainer of the year, top male vocalist, album of the year and song of the year.

Jackson and Keith are both listed in the video of the year category -- Jackson for "Drive (For Daddy Gene)" and Keith for "Courtesy of the Red, White and Blue (The Angry American)" and "Who's Your Daddy?" They're also nominated for vocal event -- Keith for "Beer for My Horses" (a collaboration with Willie Nelson) and Jackson for "Designated Drinker" (with George Strait).

Song of the year nominations went to Keith for "Courtesy of the Red, White and Blue (The Angry American)," Jackson for "Drive (For Daddy Gene)," and Chesney for "A Lot of Things Different." Other nominees for song of the year are Rebecca Lynn Howard's "Forgive" and Rascal Flatts' "I'm Movin' On." Jackson and Keith wrote their nominated songs. Howard co-wrote "Forgive" with Trey Bruce. Veteran songwriters Bill Anderson and Dean Dillon co-wrote "A Lot of Things Different." The Rascal Flatts hit was co-written by Phillip Brian White and David Vincent Williams.

Trick Pony are nominated for album of the year (for their second project, On a Mission) and top vocal group. The trio's "Just What I Do" is nominated for video and single record of the year. Trick Pony's work with Willie Nelson on "Whiskey River" resulted in a vocal event of the year nomination.

In addition to Keith, Jackson and Trick Pony, video of the year nominations went to Brad Paisley's "I'm Gonna Miss Her (The Fishin' Song)" and Tim McGraw's "She's My Kind of Rain."

Other multiple nominees include Brooks & Dunn, the Dixie Chicks, Howard, McGraw, Rascal Flatts and Lee Ann Womack. Nelson is nominated three times in the vocal event category. In addition his collaborations with Keith and Trick Pony, Nelson and Lee Ann Womack are nominated for their hit, "Mendocino County Line."

Brooks & Dunn, Lonestar and Wynonna are nominated for the second annual Home Depot Humanitarian Award. Last year's fan-voted award went to Reba McEntire, who will host the ACM Awards show May 21 in Las Vegas. The three-hour awards show will be broadcast live on CBS.

Newcomer Jennifer Hanson (nominated for top new female vocalist) and LeAnn Rimes announced the nominations with TV personalities Dick Clark and Nancy O'Dell during a Tuesday morning (March 4) press conference at Tiffany & Co. in Beverly Hills.