Can someone explain what George W means here. How many rodeos has he had?

"This isn't, this isn't my first rodeo. In other words, I haven't, this is not the first time I've been in a campaign where people have expressed themselves and in different kinds of ways."

http://www.hostelbookers.com/info/news/17930115

He's saying his horse just died.

I swear I read somewhere he fears cattle...
Can't find anything authoritative, but there's plenty of anecdotal stuff on the internets...
http://perljam.net/google-satellite-maps/id/1448/United_States/Texas/Crawford/George_W_Bushs_Prairie_Chapel_Ranch