Del Mar intends to race five days a week this summer, according to track chief executive officer Joe Harper. This year, Santa Anita and Hollywood Park are primarily running four days a week because of a shortage of available horses in Southern California. Harper is optimistic that Del Mar can run the same 37-day calendar as in 2010. This year’s meeting runs July 20 to Sept. 7. “We’re hanging in there and hoping for the best,” Harper said. “When we get closer to the meeting, we’ll have a better idea of what we can do.” Santa Anita officials have tentatively planned to reduce their racing schedule in March by eliminating racing on the first four Wednesdays and running three five-day weeks through the end of the meeting, beginning March 30. Hollywood Park officials indicated earlier this month that they will run four-day weeks this spring and summer, with five-day weeks in conjunction with the Memorial Day and Fourth of July holidays.