ARCADIA, Calif. – There were 2,422 racehorses on the backstretches at Santa Anita and Hollywood Park earlier this month, Santa Anita director of racing Mike Harlow said Wednesday, a drop of about 400 horses from a census taken by racing officials in early September. The reduction in inventory, caused by reasons such as injuries, retirement, and the relocation of horses to other circuits, struck Santa Anita on Sunday when the track did not draw entries as scheduled for Friday’s eight-race program. Friday’s entries were taken Wednesday; the program features 57 entrants. “We probably could have drawn Friday on Sunday, but it wasn’t the product that we wanted to put out,” Harlow said. “We were lacking maybe a half-dozen horses that would have shored up the card.” Saturday’s card, also drawn Wednesday, features 80 entrants in nine races. The struggle with entries has been reflected in average field sizes. Through Sunday, the 11th day of the meeting, the track averaged 7.79 starters per race, compared with 8.11 through a similar period of the 2009-10 meeting. The entire 2009-10 meeting averaged 7.81 starters, a drop from 8.23 starters at the 2008-09 meeting. Getting close to the 2009-10 figures at the current meeting would be satisfactory, Harlow said. “If we can achieve eight or higher, we’d be happy,” he said. Santa Anita is not the only Southern California track that has suffered a decline in average starters per race. The Hollywood Park fall meeting that ended last month had an average of 7.29 starters per race compared to 7.53 starters at the 2009 meeting. In September, Hollywood Park racing secretary Martin Panza estimated that approximately 2,850 horses were housed on backstretches at Southern California tracks but said that approximately 800 of those were not active. Harlow said the drop in average runners per race at Santa Anita has been hampered by a two-week period of near-constant rain in late December. The weather has since improved, with no rain since Jan. 3. “I’m sure it’s a factor of the weather and the horse population that continues to decline,” he said. Harlow said the Santa Anita barn area is at capacity but has yielded 100 stalls of space to the HBO production of the television series “Luck,” which is currently being filmed at Santa Anita. Despite the lower inventory of available horses, he said track officials have no plans to alter the current racing calendar, which features mostly four-day racing weeks through the end of February and five-day weeks in March and April until the conclusion of the meeting on April 17. “I think it’s too early to tell,” he said. “We’ll evaluate it as we go along.”