A surprisingly large field of 17 timber steeplechasers have filed for the 21st running of the Casanova Cup at Spring Hill Farm today.

However, racing secretary Bill O'keefe predicted yesterday that the number going to the post in the 2 1/2 mile race will be considerably less.

"We're optimistic," said O'Keefe. "the course has been cleared of snow but it's still hard. The footing is getting better all the time . . . we expect a good early thaw tomorrow."

Casanova is the opening meeting (Fairfax was cancelled last Saturday) in the spring point-to-point season. Since the weather has played havoc with conditioning, the entry list is the big story around here. The maiden hurdle race that opens the eight-race card at 12:30 p.m. has drawn 18 jumpers. The open timber race at three miles has 10 entries while the ladies timber race, at 2 1/2 miles, has nine, including the defending Virginia champion, Patty Cassel, and her Never Delay.

The feature, the opening shot in the spring-long Seven Corners Challenge Trophy battle, will see Randy Rouse and Mike duPont renew last spring's rivalry, when Rouse edged duPont for the title. Cousin Wes is scheduled to carry Rouse while duPont will go with Estremadura.

The course at Spring Hill Farm is located just outside the village of Casanova, nine miles southeast of Warrenton.