Rosecroft Raceway tonight opens a 63-night fall harness-racing meet that will feature the $650,000 Breeders Crown championship for 2-year-old pacers in November, the richest horse race in Maryland history.

Tonight also marks the return of the medication Lasix to harness racing in Maryland. Initial use of the diuretic, which helps a horse that bleeds continue to race, apparently will be limited. Only one trotter, Kardiac Arnie in tonight's third race, will be using Lasix on the opening card, and only three pacers are scheduled to use it Thursday. Horses must be certified as bleeders by the state veterinarian before they are allowed to use Lasix. Use of the drug is expected to increase as the meet progresses.

Rosecroft will race five nights a week, Wednesdays through Sundays, until December, when Wednesdays also will be dark. The track will be open three Mondays (Oct. 14, Nov. 11 and Dec. 30, closing night). Post time is 7:30, except Sundays and holidays, when racing starts at 6:30.

The highlight of the meet will be the Breeders Crown division for 2-year-old pacing colts on Nov. 8. Rosecroft will simulcast the other Breeders Crown divisions throughout the meet.

A preview to the Crown will be the $190,000 Presidential Pace final, also for 2-year-old colts, on Oct. 19. Two-year-old pacing fillies will be featured in the $118,000 First Lady final on Oct. 26.

Both the Presidential and the First Lady will have elimination races one week before the final.

The first Saturday of the meet will include the final of the North American Series. Part of a 14-race nationwide series that began in March, the North American final is valued at $100,000.

Rosecroft also will have its usual early closing events, including the popular Medley series, which features races at distances other than the standard mile.

Rosecroft remodeled the betting windows on the first floor, spruced up the finish-line bar and knocked out two large stairwells on the outside of the clubhouse. The result is a more open area, designed to better handle the large crowds that gather in the clubhouse. Rosecroft does nearly 80 percent of its business from its clubhouse.