Aidan O’Brien must travel to this year’s Breeders’ Cup without the animal he recently described as “the ultimate racehorse”, Magical having been found to have a temperature shortly before she was due to fly on Monday morning. The winner of more than £3m in prize money, she was immediately retired and will be covered by No Nay Never in the spring.

“She’s been an unbelievable mare, something you’d never dream of,” O’Brien said. The end of her career came suddenly, as he described her doing her final bit of work at 9am, half an hour before she was due to leave her Ballydoyle stable on the first leg of a long journey to California. But at 9.15am her temperature was taken and found to have spiked.

“If she did develop anything travelling over, then that would have locked up quarantine,” the trainer added. “We didn’t want to risk her, especially after a long season and on a long journey. Before they travel we always want their temperatures to be 100%.”

Magical could be seen as extremely unlucky to have been around at the same time as Enable. But for that rival, her haul of Group One successes would have been eight rather than four and she twice finished less than a length behind her, in the Breeders’ Cup Turf a year ago and again in this summer’s Eclipse.

But Magical had plenty of her own moments in the spotlight and will be remembered for her exceptional toughness, for all that a possible infection has now ended her career. She fought out the finish to a string of top-class races without ever losing her enthusiasm for a battle and was having her ninth run since April when winning the Champion Stakes at Ascot recently.

Her absence robs the Breeders’ Cup of a much-anticipated clash with her US rival Sistercharlie in the Filly & Mare Turf. Sistercharlie is now odds-on with some firms, though O’Brien is still likely to have a say in the outcome through Fleeting.

It was a big day for retirements, as the 39-year-old jump jockey Wayne Hutchinson called time on his own career, having taken no rides over the last two weeks while he considered his future. “It just seems the right time,” he said, confirming that he was fit and well and is now likely to remain so.

Often mentioned in discussions about underrated jockeys, Hutchinson was with the trainer Alan King for 18 years and could have ended on a high if he had made his decision at the end of last season, when he won the Bet365 Gold Cup on Talkischeap. His other big days included winning the Hennessy on Smad Place and a Scottish National on Godsmejudge.

An improved field seems in prospect for the Vertem Futurity, the Group One race for two-year-olds which was lost to the weather on Saturday, along with the rest of the Doncaster card. It will now become the first race on Newcastle’s Friday evening card at 3.40pm and a total of 17 horses could take part, the entries having been reopened.

O’Brien will still have a strong hand, having said he intends to send the same four horses that were declared to run at Doncaster, headed by the well thought-of Mogul. But there are now eight contenders from other stables, rather than the one that was in the race at this point last week.

Ralph Beckett has put in Kinross, an eight-length winner on his recent debut, while John Gosden could send Verboten and Cherokee Trail. Andrew Balding’s Kameko is still in the race, while Jim Bolger, Emmett Mullins, Brian Meehan and William Haggas also have possible runners.

Elegant Escape and Black Corton have been chalked up as the 4-1 joint-favourites for the Charlie Hall Chase at Wetherby on Saturday, regarded by many as the true starting point for each jumps season. La Bague Au Roi and Definitly Red are also among the 12-strong entry.