HONG KONG, Aug. 21 (Xinhua) -- Sport horses tested positive for banned substances are "serious blow" to the equestrian competition, a senior official of the International Equestrian Federation (FEI) said here Thursday.

    "It is a serious blow to the sport. We are very well aware of the implications to Jumping and Equestrian sport in general," Alexander Mclin, FEI Chairman of Jumping, said at a press conference.

    "One reason is that the four cases tested positive for the same substance. We are not sure if we can call that a trend but it adds to the seriousness," he added.

    The FEI announced that four positive horses have been banned from competing in Thursday's Olympic Games jumping competition for doping or positive medication cases.

    The four rider-horse combinations are Bernardo Alves of Brazil (Chupa Chup), Christian Ahlmann of Germany (Coster), Denis Lynch of Ireland (Latinus) and Tony Andre Hansen of Norway (Camiro).

    Capsaicin is used as a painkiller. It is used as a topical lotion or paste treatment of the skin. When used on the front legs of horse, it has to be considered a forbidden product.

    On why doping appears to affect jumping more than the other disciplines, Mclin said "it is not only jumping that is affected. But this is by far our biggest discipline with the largest number of participants. Outside the Olympics it is also the sport with the most prize money."

    It is not clear whether the medal order of the team jumping competition will be changed. The United States won the gold and Canada the silver, and Norway the bronze.