On January 29, 1998, at 1910 central standard time, a Cessna 500, a twin turbojet airplane, N9AX, sustained substantial damage when it struck several deer during the landing roll at the Horseshoe Bay Resort Airport, Horseshoe Bay, Texas. The airplane was operated and flown by a private individual under Title 14 CFR Part 91. The commercial pilot and the passenger were not injured. Night visual meteorological conditions prevailed for the cross country flight that departed Addison Airport, Dallas, Texas, at 1800 on an IFR flight plan. During personal interviews, conducted by the investigator-in-charge, the owner and the pilot reported that, during the landing roll on the south runway, a herd of deer entered the runway environment from the east. The pilot made an attempt to avoid the animals; however, the airplane struck the deer. As the airplane taxied to the ramp, fuel spilled from the left wing. The pilot examined the airplane and found that the main gear, flaps, air brake, and wing received structural damage. An antler was found imbedded in the left wing and penetrated into the fuel tank. Approximately 150 gallons of fuel had drained onto the runway, taxiway, and ramp area.