America's fightback against Australia in the battle for the important Japanese market will be limited by the shortage of beef from young cattle.

US officials in Tokyo have forecast that Japan's beef imports from Australia, whose currency is soaring, will rise only marginally next year to 511,000 tonnes.

"The market is highly sensitive to price, so exchange rates are a significant driver of sales for imported meats," an attaché report said.

However, a 24% surge in American exports to Japan in the first half of the year is reversing thanks to a shortage of US cattle that meet trade criteria.

'Limited supply'

Japan, once America's biggest beef export market, has relaxed only some of its curbs on US imports imposed six years ago after BSE was found in the American herd.

Over the full year, beef exports are expected to grow just 8% "due to the limited supply of cattle that meet the under-20 months' requirement", the report said

At 91,000 tonnes, US beef exports to Japan in 2010 will be about one-fifth of those a decade before.

Herd decline 

The report comes amidst a four-year decline in America's cattle herd, which over the summer reached its lowest  levels since record began in 1973, and which has seen an increasing number of heifers – potential breeding stock – sent to slaughter.

The country has long been expected to recover a big chunk of its market share against Australia.

Market response "indicates that Japanese consumers still prefer the taste of American grain-fed beef", the attaché report said.

However, Australia has held its market share above 75% in part because of the lingering BSE restrictions on US beef, and in part, until recently, because of the weakness of the Australian dollar.