ARCADIA, Calif. - In an effort to boost field sizes, Santa Anita racing secretary Chris Merz is planning to make minor changes next month to the frequency in which claiming races are offered, conditions for some maiden races, and the duration of condition books detailing proposed races. The changes will go into effect beginning with the March 11 program. Maiden races will be offered for 3-year-olds and up instead of the current structure that restricts some maiden races to 4-year-olds and up. Some claiming races will be offered every three weeks instead of the current cycle of every 25 to 29 days. In addition, condition books will be published in two-week increments instead of the current three-week plan. “Entries have been slow and it’s a reflection of the racing secretary,” Merz said in a Sunday afternoon interview. “I need to write a better book. “I’m not providing the right opportunities for the owners and trainers and the racing office to be successful and I need to change that.” :: Win big at Santa Anita: Get DRF Past Performances, Picks, Clocker Reports and Betting Strategies.  On Friday, Santa Anita will run seven races instead of the normal eight- or nine-race programs that have been common on Fridays since the current winter-spring meeting began Dec. 26. Field sizes have been a concern this winter. Through Saturday, fields have averaged 6.89 runners per race, with 7.71 runners per turf race but 6.17 runners per dirt race. During a comparable period at the start of the 2020-2021 winter-spring meeting, fields averaged 7.96 runners per race, with 8.7 runners per turf race and 7.26 runners per dirt race. Merz said more frequent claiming races could lead to larger fields. “If some of the claimers come back a little quicker, it could generate more interest,” he said. “The claimers are our backbone.” A two-week condition book will offer fewer choices of races and could lead some owners and trainers to be more proactive. “It could force someone to run,” Merz said. The changes will begin with the fifth condition book of the season, which covers six racing days from March 11-20. :: Access morning workout reports straight from the tracks and get an edge with DRF Clocker Reports There are approximately 2,180 horses in training in Southern California among Santa Anita, Los Alamitos, and the San Luis Rey Downs training center, a figure comparable to this time last year, Merz said. With the popularity of turf racing, the track plans to launch two four-race starter series in March for horses that have started for a claiming price of $25,000 or less since the beginning of 2020. A sprint series will include races at five, 5 1/2, six, and 6 1/2 furlongs, while a distance series will include races at a mile, 1 1/8, 1 1/4, and 1 1/2 miles. The final races in the series will be run later in the spring. A starter series of two-turn races for fillies and mares on turf is underway. The race at 1 1/8 miles was run on Sunday and drew a field of nine.