Spendthrift Farm’s Taiba , Gun Runner ‘s only three-time grade 1-winning son to date, sired his first reported foal this week when a colt was born Jan. 6 at Castleton Lyons near Lexington. Bred by Castleton Lyons and Kilboy Estate, the chestnut colt is out of the Exaggerator mare Wecallherqueenmary…