In this image provided by Purina Pro Plan, Purina hosts the Purina Pro Plan Incredible Dog Challenge at the Rio Hotel and Casino in Las Vegas on Saturday, March 2, 2013. (Photo by Isaac ... more 
In this image provided by Purina Pro Plan, Purina hosts the Purina Pro Plan Incredible Dog Challenge at the Rio Hotel and Casino in Las Vegas on Saturday, March 2, 2013. (Photo by Isaac Brekken/Invision for Purina/AP Images) less 
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Associated Press
Mon, Mar 4, 2013 12:06 PM EST