Irish Sport Horse. The traditionally bred Irish Sport Horse or half-bred was a cross between the Thoroughbred stallion and the Registered Irish Draught mare. The half-bred mare when crossed again with a Thoroughbred stallion produced a three-quarter bred. The modern Irish Sport Horse may contain bloodlines from many different breeds including European breeds. The terms Irish Sport Horse, Sport Horse, Irish Hunter, Hunter, Non-thoroughbred are names used to describe the same animal