Old-crop corn prices declined sharply in the first half of March as it appeared high prices had sufficiently slowed the rate of consumption.

However, a continued high rate of ethanol production, a resurgence of export sales and larger livestock inventories provided evidence that consumption had not slowed, said a University of Illinois agricultural economist.

"The March 1 Grain Stocks report provided an estimate of smaller-than-expected inventories of corn, and prices rallied to a new high on April 11. That rally was followed by a 40-cent decline last week on renewed talk of slowing consumption," said Darrel Good.

Livestock prices appear to be peaking, and high gasoline prices may point to reduced fuel, including ethanol, consumption. Feed demand for corn is also expected to be reduced by increased wheat feeding, although most of that reduction is expected to occur in the summer months after the harvest of the 2011 wheat crop. Increased wheat feeding is also expected to occur in other parts of the world, potentially reducing the demand for U.S. corn.

"Although markets tend to be forward looking, there is a lag in the reporting of corn consumption estimates, particularly for feed use. As a result, evidence of a slowdown in consumption, if it is occurring, will be revealed slowly and erratically," Good said.

In the case of corn exports, weekly inspections need to average 42.5 million bushels per week through August in order to reach the USDA projection of 1.95 billion bushels for the year. That calculation is made based on cumulative inspections through April 14 adjusted by Census Bureau export estimates through February.

For the four weeks ended April 14, inspections averaged 39 million bushels per week, 6 million above the average weekly rate through March 17. Unshipped export sales as of April 7 totaled 520 million bushels, 138 million larger than unshipped sales of a year earlier.

"Weekly sales are occurring at about twice the rate needed to sell 1.95 billion bushels by the end of August," he said.

To reach the USDA's projection of 5 billion bushels of corn used for ethanol and by-product production this year, ethanol production from March through August needs to exceed that of a year ago by about 4 percent. Ethanol production for the five weeks ended April 8 exceeded that of a year ago by 7 percent.