About 80 miles from Churchill Downs, down Interstate 64 and on the fringes of Lexington's blue grass country, there is a horse in a field. His name is Storm Cat. He is the most valuable horse in the world.

About 80 miles from Churchill Downs, down Interstate 64 and on the fringes of Lexington's blue grass country, there is a horse in a field. His name is Storm Cat. He is the most valuable horse in the world.

In the absurd world of bloodstock tariff, Storm Cat provokes the craziest figures. At the age of 17, he has just had his stallion covering fee raised to the point where a single coupling with the great horse now costs $400,000 (£295,000). This year he achieved around 115 matings, which resulted in 89 foals on the ground. A similar figure is planned for the next breeding season. The mathematics are staggering.

"He's like winning the lottery every year," Kevin Stephens, a stallion groom at Storm Cat's Overbrook Farm base, said yesterday. When the stallion first embarked on his reproductive career his fee was just $30,000 and the harem a rather scant 30 mares. Storm Cat had been talented and was well bred, but was by no means uniquely qualified in Kentucky. But then people noticed that his progeny tended to be not only swift, but courageous as well.

The number and quality of his consorts improved and now he gets the best. In Britain, we have enjoyed his sons Aljabr and Giant's Causeway. On Saturday, here at Breeders' Cup XVII, his cachet may be further improved by either the latter, Cat Thief or Raging Fever.

It is off-season for Storm Cat at the moment and yesterday, as usual, he was merely grazing in his three-acre paddock. The trees on the breeding shed side of his territory are almost bare now, but their thick foliage in the springtime will serve a purpose. "Otherwise, he would be able to see the activity down here, the mares arriving" Wes Lanter, Overbrook's stallion manager, said. "And like most stallions, he thinks that everything that comes is for him."

On the opposite edge of the paddock, crudely prominent in the rolling grassland, is a portable home, soon to be replaced by a permanent structure. Inside, a sentry ensures that Storm Cat, on the instruction of the stud's owner, W T Young, is constantly monitored. It is not a fabulously rewarding job, but it is not the worst at Overbrook Farm.

That distinction belongs to Cooperstown and Counter Check, the resident teasers, the flowers and chocolates horses. They get to meet mares, but their desire is a little compromised by the immense blacksmith's apron that is tied around their bellies. "They're perfect for the job with their strong libidos and high frustration thresholds," Lanter says. "We always say that to deserve this they must have been Casanovas in a previous life."

Stormy is also well looked after indoors. "I would say his box is probably the best defended, best protected in the world," Lanter says. "There are infra-red detectors in there and a deluge system which can have a flood six-inches deep on the floor in seconds."

There is no Kama Sutra for Storm Cat in the breeding shed, rather one well-practised technique with a five-strong SWAT team. One handler restrains and holds the mare, while another lifts a foreleg to throw her off balance and minimise the risk of a damaging kick. On the other side, someone else braces the mare for the vigorous coupling to come.

Team member No 4 tries to ensure Storm Cat behaves himself. "You don't want him to take control in the shed," Lanter says, "and I like him to be mannerly when he's mounting a mare." The fifth person helps guide Storm Cat where nature would have led him anyway. "It can be a dangerous situation in there," Lanter says, "and you want to make sure there are no random attempts and that the process is just as quick as you can make it."

In this respect, Storm Cat is a great help. From the time the shed door opens to the point where he starts his meander back down the hill and over a covered bridge to his paddock can take as little as two minutes. Stormy can do his bit in 30 seconds.

"He's not difficult to get out of there [the paddock]," Lanter says. "He just comes walking over and says "take me, I know what's going to happen now."

They expect to get another eight or nine years out of Storm Cat and a substantial addition to his offspring total of over 700. If his appearance yesterday is anything to go by it is not a misplaced assumption.

Storm Cat looked quite glorious at rest. Quite appropriately, his dark bay hide seemed to turn golden as it caught the Kentucky sunrays. It took Old Stormy a while to acknowledge us, but then he padded through the brown leaves to grant an audience. But one look, one sniff later he was off. These were not the visitors to Overbrook Farm he most appreciated.

* Sir Michael Stoute was doing his best yesterday to shrug off doubts over Kalanisi ahead of the Breeders' Cup Turf on Saturday. Worries over the colt's ability to handle the sharp track at Churchill Downs surfaced again. In a work-out yesterday on the course, Kalanisi appeared ill-at-ease on the seven-furlong turf circuit. One observer reported that the colt had briefly lost his footing. Kalanisi, 5-2 favourite for Saturday's test, had tried to run out and dumped his jockey when working over the track on Sunday.