In the wake of the New York Racing Association's announcement it would require starters in the June 7 Belmont Stakes to be in a "stakes barn" about 24 hours before the race, officials at two major dual-breed racetracks said detention, or retention, has achieved its goals but continues to be assessed on a regular basis.Woodbine Entertainment Group, which operates Woodbine and Mohawk Raceway in Ontario, Canada, has used a retention barn for Standardbred racing for about 1 1/2 years. Meadowlands in New Jersey has used a retention barn for an even longer period.Hugh Mitchell, vice president of racing for WEG, said horses in two or three races per night are secured in a separate barn 24 hours before a race. Under Ontario Racing Commission rules, other starters on each program must be on the grounds 1 1/2 hours prior to post.Mitchell said the retention policy is effective for Standardbred racing because about 80% of the starters ship from farms and training centers, whereas for Thoroughbred racing at Woodbine, 95% of the starters are stabled on the backstretch."Some trainers are supportive of (retention), and some are not," Mitchell said. "We've been doing it for 1 1/2 years, and to be honest with you, we're still a ways from making any solid conclusions. The people who will decide whether it's successful or not are the bettors. Also, we're trying to create level playing field so the capital providers--the owners--feel like they're getting a fair shake."For harness racing, trainers with recent medication positives must keep all of their starters in the retention barn for a certain period.Thoroughbred racing has its own challenges, Mitchell said. He said the very nature of the animals--temperament, for example--makes it more difficult to move them about from stall to stall or change their environment.In addition, because all but 5% of the starters at Woodbine are on the grounds, Mitchell said the stable area itself serves as a retention facility. Woodbine does pick random races in which starters are under heavy surveillance five hours before post time. Security personnel document all access and treatments."It's a work in progress," Mitchell said. "There is no end point to it, and there may not be any solid conclusions. To not do anything, though, would be the wrong step. Over time, we'll amend and hopefully improve these programs."At Meadowlands, which has exchanged notes with WEG on the retention process, the policy qualifies as a success for harness racing, said Bruce Garland, senior vice president of the racing for the New Jersey Sports and Exposition Authority. Like at Woodbine, detention-barn races are noted in the program and past-performance lines."We've gotten good response from bettors, particularly the big players who say they bet those races much more," Garland said. "It has had a positive impact in terms of perception. We've also have a significant block of owners who support detention, and a minority who do not. With the trainers, a majority supports it, but not as big a majority as the owners. There is a significant group (of trainers) that doesn't support it."Of the three Triple Crown tracks, only Pimlico Race Course, which hosts the Preakness Stakes, has used a stakes barn for some time. A few trainers, however, have opted to keep Preakness starters in other barns on the backstretch.