03/23/2005 1:00AM

Etc. . . .


Earth Summit, winner of the 1998 Grand National Steeplechase and the only horse ever to win Britain's National Chasing Triple, was euthanized Wednesday at age 17 after he was found to have cancer of the liver and spleen. Earth Summit won the Scottish National Chase in 1994, the Welsh National Chase in 1997, and then the Grand National. . . . Tampa Bay Downs has raised the purse of the Chris Thomas Turf Classic (formerly the Columbia Stakes) from $60,000 to $75,000 for this year's running on May 7. The track has also added a new stakes to the May 7 card, the $75,000 Lightning City Stakes at five furlongs on turf for fillies and mares.