TOKYO -- Why the long face? Simple. A pus-filled horse tooth has ended Victoria Max-Theurer's Olympic dressage dreams.

The Austrian's 11-year-old horse, Abegglen NRW, had been behaving strangely in training and, while the Olympic opening ceremony was under way on Friday night, a health check and x-Ray revealed a tooth infection.

It would have been Max-Theurer's fifth Olympics.

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"This news is a heavy setback for Victoria. We hope that Abegglen will feel better soon and that Victoria will continue on her path," said Peter Mennel, of the Austrian Olympic Committee.

Max-Theurer's team mates Christian Schumach and Florian Bacher will now compete only as individuals.

Dressage riders and horses are competing in qualifiers on Saturday and Sunday for the chance to win team and individual medals on July 27 and 28.

Germany’s Isabell Werth, the most decorated Olympian in her sport, and Britain's dressage world record holder Charlotte Dujardin, are hot medal contenders and will start competing on Sunday.

On Saturday, the Netherlands, Denmark and Britain got off to a strong start, while Germany's Jessica von Bredow-Werndl scored the highest individual score, cementing her country's leading position in equestrian sports. (Reporting by Shadia Nasralla; editing by John Stonestreet)