Drought in the heartland having consequences

Did you know the U.S. cattle herd is at its lowest level since 1952? Jeffro at The Poor Farm links to this story in the Star Tribune:

Increased feed costs due to the prolonged drought, combined with herd liquidations by cattle ranchers, are severely and adversely contributing to the challenging business conditions we face as an industry.

The U.S. cattle herd has been in a long-term decline for years, particularly since about 2007. Since then, grain prices have shot up due to structural changes in grain markets, thus precipitously boosting the price of cattle feed.

The 2012 drought, the nation's worst in decades, sent corn to over $8 a bushel. The heart of cattle country experienced its second straight year of very arid conditions, toasting pasture land.

What "structural changes in grain markets" is he referring to?

Read more here: http://crazedpw.blogspot.com/2013/02/droughts-have-consequences.html