On April 17,  Princess Haya, president of the FEI, released a statement concerning the disqualification of McLain Ward's horse Sapphire from the World Cup Final.

“Early this morning the FEI announced that Sapphire, the horse ridden by McLain Ward from the United States, was eliminated from the second round of the FEI
World Cup Final held late last night and was disqualified from the rest
of the event following a positive hypersensitivity test.

I would like to state very clearly at this point that the FEI has very clear policies and rules and we will always protect our horses where there are
welfare concerns to ensure the protection of our horses and to provide a
level playing field for our athletes.

I would like to emphasize that the rules and the protocols allow for disqualification at any stage on welfare grounds. 

We have a duty to care for our horses.  If it is agreed that if a horse is in pain then it has to be eliminated.

 The protocols have been agreed by the Jumping Committee, the Bureau and the General Assembly and the FEI will always uphold these protocols.

I must absolutely stress that this has absolutely no reflection on this event and that everyone should be confident that every time there is an irregularity the rules and regulations are
providing a guarantee for a result that has integrity and will provide
the sponsors, the public and the organizers of this wonderful event with
top sport.

The decision to eliminate Sapphire has absolutely no effect on the value of the competition, nor the outstanding quality of the organization of this World Cup Final.  This is a guarantee to the
vast majority of our athletes that are competing fairly that our rules
and regulations are there to protect them and their horses and that
those rules are being implemented.

We are committed to protecting the welfare of the horse and the image of the sport."

Link to News of Disqualification