The FEI is clamping down on unauthorised treatment of horses at vetgates as the crisis grows about doping in endurance.

Next month (4-7 November), the FEI general assembly will vote on limiting crew sizes, amid criticisms some horses have been concealed behind a “human wall”.

FEI judge Juliette Mallison said that in Dubai in February, her veterinary team saw “a horse surrounded by numerous grooms, the neck covered with a towel, and a further groom inserted the catheter into the [jugular] vein for the infusion disguised in his jacket sleeve”.

The horse was disqualified.

The new rule would limit crews to five people per horse.

In April, the FEI told the Swiss federation, lobbying about doping since March, that the UAE had agreed to cap crews from its winter season this month.

The FEI declined to comment if it hoped teams would follow the rule before it becomes effective on 1 January.