Pioneerof the Nile, sire of Triple Crown winner American Pharoah, has died

LOUISVILLE, Ky. (WDRB) -- Pioneerof the Nile, sire of Triple Crown winner American Pharoah, has died at the age of 13.

That's according to a post on the official website of WinStar Farm.

Farm officials say the horse bred a mare Monday morning and began acting uncomfortably once he was taken back to his stall. He died while being taken to a clinic.

"We are all extremely saddened by the loss of Pioneerof the Nile. He was a superior physical specimen, a Triple Crown Sire, and a unique personality. All of us at WinStar are heartbroken," said Elliott Walden, a spokesperson for WinStar Farm.

In addition to American Pharoah, Pioneerof the Nile is the sire of two 2-year-old male Eclipse Award winners and two Breeders' Cup winners from his first four crops to race.

Pioneerof the Nile was also a leading sire of his generation for the past three years.