Las Vegas casinos lost the signals to five major winter racetracks on Wednesday because of an ongoing dispute over the amount of money the casinos pay for simulcasts, according to the racing official involved in the negotiations.\nScott Daruty, the chief executive of the simulcast-marketing company TrackNet, said Wednesday that although negotiations between TrackNet and the casinos were ongoing, the two sides had not been able to reach a deal. TrackNet, a partnership of Magna Entertainment Corp. and Churchill Downs Inc., sent a counterproposal to the casinos on Tuesday, Daruty said, but on Wednesday morning the casinos had not responded.\nLate Wednesday afternoon, officials for TrackNet and the casinos were back at the negotiating table, but they were unavailable for comment.\nThe blackout affected Santa Anita, Gulfstream, Golden Gate Fields, and Oaklawn Park. Laurel Park will also be blacked out, but did not race Wednesday because of bad weather. All of those tracks are owned by Magna Entertainment, except for Oaklawn, which uses TrackNet to negotiate its simulcast contracts. Only one of Churchill's four racetracks, Fair Grounds, is running a live race meet right now, but the blackout will not affect that track because of a previous agreement between the casinos and Fair Grounds that has not yet expired.\nTrackNet has denied the casinos both the simulcast signal and the data feeds that provide racing information.\nA previous agreement with the Las Vegas casinos covering most of the tracks controlled by TrackNet expired on Jan. 1. However, an extension to the existing agreement allowed the casinos to continue offering the simulcasts until Sunday.\nTrackNet contends that the Vegas casinos should pay a higher rate for simulcast signals. Vegas casinos pay one of the lowest rates for signals in the U.S., in part because of the amount of handle that flows out of the racebooks. But TrackNet contends that the racebooks' share of parimutuel handle has dwindled to the point where the low fee is not justified anymore.\nNevada law allows casinos to book racing bets, but it was unclear on Wednesday if any of the casinos were accepting booked bets. The practice has a downside for horseplayers because of price limits that most racebooks set on exotic wagers. In addition, racebooks will not book superexotic bets such as the pick six.