Target creature gets +2/+2 and gains horsemanship. (It can't be blocked except by creatures with horsemanship. This effect lasts indefinitely.)
10/1/2009 The spell’s effect has no duration. The targeted creature gets +2/+2 until the game ends or it leaves the battlefield. It has horsemanship until the game ends, it leaves the battlefield, or some other effect causes it to lose horsemanship.