* US beef from older cattle heads to Japan * First such post mad cow disease shipments * Japan eased rules on beef imports last week By Theopolis Waters TAMPA, Feb 7 (Reuters) - U.S. beef from older cattle are being shipped to Japan for the first time in 10 years following Tokyo's move to ease rules put in place after the outbreak of mad cow disease in 2003, the leader of an export-based industry group on Thursday. "All the rule making and procedures needed to comply are done and (the) USDA is signing export certificates for the product," said the head of the U.S. Meat Export Federation, Philip Seng. "The impact is immediate, it's just a question of how fast it can ramp up," he told Reuters in an interview at an industry gathering here. Japan, the world's third largest economy, said last week it would allow U.S., Canadian and French beef imports from cattle up to 30 months old beginning on Feb 1. Japan's decision, which has been under consideration since 2011, addresses a long-time irritant in U.S.-Japan trade relations ahead of new Prime Minister Shinzo Abe's expected visit to Washington. It also clears a major obstacle to Japan's potential participation in a U.S.-led, regional, free-trade pact called the Trans-Pacific Partnership. Japan initially banned all U.S. beef imports when the first case of mad cow disease was found in the United States in 2003, shutting down the U.S. industry's largest export market and handing Australian producers a prized new opportunity. Under rules imposed in 2005, U.S. beef imports were only allowed from cattle up to 20 months old. Raising the age limit allows leading U.S. beef processors such as Cargill Inc and JBS USA Holdings Inc to recapture lost market share in the world's No. 2 beef importer. Seng said he expects U.S. beef exports to Japan to rise gradually. "There is always this arm wrestling that goes on between the exporter and the Japanese and that's going on right now in a fervent fashion," he said. Japan buys about 65 percent of the beef produced by tonnage in the United States, according to Seng. The Japanese will help offset the potential loss in Russian exports if Moscow goes through with a threat to ban U.S. beef imports because of the feed additive ractopamine. Russia accounts for about $550 million in beef and pork exports from the United States, Seng said. Beef consumption in Japan peaked in 2000, the year before it had the first case of bovine bovine spongiform encephalopathy (BSE) in 2001, said Seng. They were good years for the U.S., Australia and Japanese producers, he said. "Japan still has a relatively high duty on beef imports...but what we found out is that the Japanese are willing to pay more for our product than maybe some of our domestic consumers, so there is still a lot of opportunities in Japan," said Seng.