Raiders, Rulers, and Traders: The Horse and the Rise of Empires by David Chaffetz
From the taming of horses to Russian use of cavalry in World War I.
It's a long history. The development of tack features heavily. Actually breeding lines of horses comes rather late, though very early the horse breeders would geld most of the colts. War in the Middle East. China's desperate and lengthy attempt to keep up a cavalry when its land is unfit for pasture -- not enough selenium -- and farmers encroach at such pasture that exist, plus the steppe people having the advantage of unrelating hunting and herding to keep their horses in peak condition. The massive horse trade. The use of hunting, which was often a prelude to war. Genghis Khan. The difficulties of supply in the regions where the horses grew most naturally. The Mughals in India. The effect of people in marginal land in India adding pony herds; they produced massive horse fairs and changed pilgrimage destinations. Russian cavalry, how Ivan the Terrible claimed descent from Genghis Khan to the Great Game between Britain and Russia.
A lot of history.