BMW Caulfield Cup winner Mongolian Khan is out of the Emirates Melbourne Cup after suffering a colic attack.

The Murray Baker-trained four-year-old was assessed by vets at Werribee on Thursday morning, and was ruled out of the $6 million feature just prior to midday.

Mongolian Khan, the winner of the ATC Derby in the autumn, was the $10 third favourite before heavily drifting in the market as news broke of an illness to the son of Holy Roman Emperor.

Taking Mongolian Khan out of the order of entry, Sertorius moves to 23rd, The United States is into the field as it stands at 24th - pending the inclusion of Saturday's Lexus Stakes winner - and Saeed Bin Suroor's Secret Number climbs to 25th.

Also requiring veterinary assessments are raiders Sky Hunter and Quest For More, who are guaranteed of their respective places in the Melbourne Cup field at 17th and 19th in the ballot.

The bin Suroor-trained Sky Hunter was reported to have a bruised heel on his left foreleg, while theRoger Charlton-trained Quest For More cast his left fore plate on Thursday.

The pair will be assessed prior to final declarations on Saturday.