DUBAI, United Arab Emirates — Companies building the centerpiece of a prominent Dubai race course said last week the original $1.25 billion contract has been canceled, raising questions about the future site of the Middle East’s premier horse race.

The project’s developer, Meydan LLC, blamed a work delay for the decision but vowed to inaugurate the project as planned in time for the 2010 Dubai World Cup. The race promises to top its own record of horse racing’s richest race with a purse of $10 million.