Depressed cattle prices have prompted the government to purchase $30 million in beef and renew an investigation into whether four dominant processing companies exert unfair influence on the market, U.S. Agriculture Secretary Dan Glickman said. Prices paid to cattle producers are in the doldrums because supplies are huge, American consumers are not eating enough beef to keep pace and exports are down largely due to the Asian financial crisis. The National Cattlemen's Beef Assn. welcomed the beef purchase, even though it said the move isn't enough to have a dramatic impact on prices. Many ranchers contend that the commanding position held by four beef packers is also partly to blame for the low prices. Today, 82% of beef is processed by the four companies, compared with 36% 18 years ago. Glickman said the department wants Congress to approve another $3.8 million for its antitrust enforcement investigations into whether the beef industry is unfairly manipulating the market.