According to the USDA's latest Livestock, Dairy and Poultry report, more than 423 million pounds of U.S. pork products were shipped to foreign destinations in January 2013, almost 16 percent below January 2012.

Lower sales to Japan (-7 percent), Mexico (-5 percent), South Korea (-20 percent), snd China/Hong Kong (-56 percent) largely account for the year-over-year lower January export figure.

In Japan’s case, there is little doubt that the depreciated yen is playing a role in smaller imports of U.S. pork products. The figure below shows 2013 yen-U.S. dollar exchange rates for January and February, compared with monthly rates in 2012 and 2011.

The January 2013 yen rate is fully 15.7 percent above January 2012.

The February yen rate is 18.5 percent higher than the yen cost of one U.S. dollar in February 2012. All this means, assuming constant U.S. prices, that American products cost much more in Japan in 2013; when prices go up, quantity demanded goes down.

A low-valued yen benefits foreign buyers of Japanese goods but penalizes Japanese buyers of imported goods. So as the value of the yen stays low, more Japanese goods may be exported, but Japanese consumers of U.S. pork, in particular, will confront higher prices and more than likely respond by buying lower quantities.