Fertility scare over Tamarisk; Coolmore newcomer fails to impregnate first 12 mares.
Two veterinary experts have been called in to examine the horse, who, it is understood, has failed to impregnate the first 12 mares he covered.
Insurers have been alerted to the difficulties, which are not uncommon in new sires but which, if they were to continue, could lead to an insurance claim on the grounds of infertility.
Coolmore Stud declined to comment yesterday, but one breeder who had booked mares to the son of Green Desert said: "I understand Coolmore are waiting for veterinary reports at this stage. I hope for the horse's sake that he comes through his troubles."
Tamarisk attracted an outstanding book of mares after his exploits on the racecourse, which included victory from Bolshoi and Tomba in the Group 1 Stanley Leisure Sprint Cup at Haydock last September.
He also won the bonus-laden Tattersalls Houghton Sales Stakes and finished second to Xaar in the Dewhurst Stakes at two, and was runner-up to Elnadim in last year's July Cup.
Tamarisk is still well short of his actual fourth birthday, and it has been known for older first-season sires to be slow to kick into gear in their new role.
Bred in Ireland by Mount Coote Stud, Tamarisk was due to cover a first- season book of at least 125 mares, with breeders patronising him from Britain, Ireland, France, Italy and the US. Among them were the Aga Khan, Khalid Abdullah's Juddmonte Farms and the National Stud.
Mare owners are understood to have been advised of the problems with Tamarisk, who stands at Ir10,000gns and reportedly took well to the physical task of covering.
Coolmore bought into Tamarisk towards the end of his racing career for the Highclere Thoroughbred Racing syndicate. But the colt's career on the racecourse ended under something of a cloud when he was switched from Roger Charlton to D Wayne Lukas in the US, disappointed in his first race on dirt and was then overlooked for a place in the Breeders' Cup Sprint by official handicappers.