Complex sentence: American Thoroughbred races are run at a wide variety of distances, most commonly from; with this in mind, breeders of Thoroughbred race horses attempt to breed horses that excel at a particular distance (see Dosage Index).
Split into simpler sentences: American Thoroughbred races are run at a wide variety of distances, most commonly from. With this in mind, breeders of Thoroughbred race horses attempt to breed horses that excel at a particular distance (see Dosage Index).