Your skill at riding helps your mount avoid attacks.
Benefit: Once per round when your mount must make a saving throw, you can make a Ride check as an immediate action. Your mount makes its save if your Ride check result is greater than the DC of the opponent’s attack.
Pathfinder Chronicles: Cities of Golarion. Copyright 2009, Paizo Publishing, LLC; Authors: Joshua J. Frost, Tim Hitchcock, Jonathan Keith, Rob McCreary, Jason Nelson, and Jeff Quick.