A jockey was injured and two thoroughbreds destroyed after breaking down in separate races at Laurel Race Course yesterday.

Jesse Davidson was taken to Greater Laurel-Beltsville Hospital after his third-race mount, Shatasha, broke her right foreleg rounding the far turn. Shatasha was destroyed on the track. X-rays of Davidson's left elbow and right leg were negative.

In the seventh race, National Renown broke down at the wire, throwing apprentice jockey Whyatt Johnson. Johnson walked off the track. National Renown, a 4-year-old colt, was removed by a track ambulance and later destroyed.

"I don't think the {track} condition had anything to with {the breakdowns}," said jockey Kent Desormeaux. "The track is deep; those were just a bunch of sore horses who finally went."

Said jockey Donald Miller Jr.: "There's about a four- or five-inch cushion on the track. It might be frozen underneath, but, considering the weather, it's in great shape."

Shatasha was making an outside bid for third place when she went down and bumped Lima Bean, who unseated jockey Mario Pino. Pino reportedly was unhurt but canceled his final two mounts as a precaution.

Shatasha, a 4-year-old filly trained by Nate Heyman for Lee Dyer, was winless in 13 career starts, earning $2,935. National Renown, trained by Clifford Gray Jr. for Carl Jenkins, won four of 25 races, earning $44,480 . . .

Jockey Michael Hunter, who incurred a bruised thigh in a spill at Laurel Tuesday, is expected to resume riding Saturday . . .

Laurel will feature 11-race programs, beginning at noon, every Saturday and Sunday for the remainder of the meeting. That schedule also will apply Jan. 18 and Feb. 15 . . .

Three horses sent out by all-time leading trainer Jack Van Berg and ridden by 1987's national jockey leader, Desormeaux, were soundly beaten in their Maryland debuts Tuesday. Tara's Tammy (5 to 1) finished last in an $8,500 claiming race for nonwinners; Pasducere (2-to-1 favorite) was ninth of 12 in a $6,500 claiming race for nonwinners, and Proud Buck (3 to 1) was fifth among six allowance runners.

These are the first horses Van Berg has run in Maryland since moving a division of his stable to Laurel . . .

Maryland racegoers eager to see the 3-year-old debut of undefeated Sham Say may not have to wait long. Trainer Bernie Bond nominated the gray filly to Sunday's one-mile, $50,000-added Dancealot Stakes.

Trainer Marvin Moncrief, meanwhile, is pointing speedy 3-year-old Clever Power for Laurel's 6 1/2-furlong Marshua Stakes scheduled for Jan. 30. "I don't think {Sham Say or Thirty Eight Go Go} can beat her short," Moncrief said. "But, then again, we can't beat them going any longer." . . .

Trainer Leo Azpurua hasn't raced a horse at Laurel since he was married in Florida last month, but still has the best shot at a spring bonus. Azpurua, scheduled to send out Mafayury K. in today's first race, has won six of 20 starts at Laurel to lead trainers with a 30 percent success rate. The trainer and jockey with the highest percentage when Laurel's meeting ends March 3 will receive $1,000.

Desormeaux, 107 for 482, heads the jockeys at 22 percent . . .

Monday's $885,642 mutuel handle was Laurel's lowest since the meeting began Oct. 18. The drop followed an unprecedented two-day span at Laurel in which the track's handle exceeded $2 million each day . . .

The West Virginia Racing Commission has approved a 251-day race schedule at Charles Town for 1988. Tuesdays and Thursdays will remain dark at the track, which will operate through Dec. 18.