O'Brien withdraws his four Arc entrants
Aidan O’Brien’s four entrants in the Prix de l’Arc de Triomphe on Sunday in Paris have been withdrawn from the race for fear they will test positive for a banned substance that mysteriously has appeared in equine feed used overseas.
Traces of zilpaterol, which is used to build bulk in cattle, have been found in some equine feeds produced by the Irish company Gain Equine Nutrition. The substance has been discovered in France, England, and Ireland, and led English trainer Roger Varian to scratch his intended runners Saturday. Gain issued a warning to its customers regarding the substance.
Two O’Brien-trained horses that raced Saturday in France tested negative for zilpaterol, which can have deleterious side-effects in horses, but for fear of positive results, Mogul, Japan, Serpentine, and Sovereign won’t race in the Arc. Three other horses on the Arc undercard, one trained by O’Brien and one each by his sons Joseph and Donnacha also were withdrawn from their races.

